1 .. SPDX-License-Identifier: GPL-2.0
2
3 ===================================================================
4 The Definitive KVM (Kernel-based Virtual Machine) API Documentation
5 ===================================================================
6
7 1. General description
8 ======================
9
10 The kvm API is a set of ioctls that are issued to control various aspects
11 of a virtual machine. The ioctls belong to the following classes:
12
13 - System ioctls: These query and set global attributes which affect the
14 whole kvm subsystem. In addition a system ioctl is used to create
15 virtual machines.
16
17 - VM ioctls: These query and set attributes that affect an entire virtual
18 machine, for example memory layout. In addition a VM ioctl is used to
19 create virtual cpus (vcpus) and devices.
20
21 VM ioctls must be issued from the same process (address space) that was
22 used to create the VM.
23
24 - vcpu ioctls: These query and set attributes that control the operation
25 of a single virtual cpu.
26
27 vcpu ioctls should be issued from the same thread that was used to create
28 the vcpu, except for asynchronous vcpu ioctl that are marked as such in
29 the documentation. Otherwise, the first ioctl after switching threads
30 could see a performance impact.
31
32 - device ioctls: These query and set attributes that control the operation
33 of a single device.
34
35 device ioctls must be issued from the same process (address space) that
36 was used to create the VM.
37
38 2. File descriptors
39 ===================
40
41 The kvm API is centered around file descriptors. An initial
42 open("/dev/kvm") obtains a handle to the kvm subsystem; this handle
43 can be used to issue system ioctls. A KVM_CREATE_VM ioctl on this
44 handle will create a VM file descriptor which can be used to issue VM
45 ioctls. A KVM_CREATE_VCPU or KVM_CREATE_DEVICE ioctl on a VM fd will
46 create a virtual cpu or device and return a file descriptor pointing to
47 the new resource. Finally, ioctls on a vcpu or device fd can be used
48 to control the vcpu or device. For vcpus, this includes the important
49 task of actually running guest code.
50
51 In general file descriptors can be migrated among processes by means
52 of fork() and the SCM_RIGHTS facility of unix domain socket. These
53 kinds of tricks are explicitly not supported by kvm. While they will
54 not cause harm to the host, their actual behavior is not guaranteed by
55 the API. See "General description" for details on the ioctl usage
56 model that is supported by KVM.
57
58 It is important to note that although VM ioctls may only be issued from
59 the process that created the VM, a VM's lifecycle is associated with its
60 file descriptor, not its creator (process). In other words, the VM and
61 its resources, *including the associated address space*, are not freed
62 until the last reference to the VM's file descriptor has been released.
63 For example, if fork() is issued after ioctl(KVM_CREATE_VM), the VM will
64 not be freed until both the parent (original) process and its child have
65 put their references to the VM's file descriptor.
66
67 Because a VM's resources are not freed until the last reference to its
68 file descriptor is released, creating additional references to a VM
69 via fork(), dup(), etc... without careful consideration is strongly
70 discouraged and may have unwanted side effects, e.g. memory allocated
71 by and on behalf of the VM's process may not be freed/unaccounted when
72 the VM is shut down.
73
74
75 3. Extensions
76 =============
77
78 As of Linux 2.6.22, the KVM ABI has been stabilized: no backward
79 incompatible change are allowed. However, there is an extension
80 facility that allows backward-compatible extensions to the API to be
81 queried and used.
82
83 The extension mechanism is not based on the Linux version number.
84 Instead, kvm defines extension identifiers and a facility to query
85 whether a particular extension identifier is available. If it is, a
86 set of ioctls is available for application use.
87
88
89 4. API description
90 ==================
91
92 This section describes ioctls that can be used to control kvm guests.
93 For each ioctl, the following information is provided along with a
94 description:
95
96 Capability:
97 which KVM extension provides this ioctl. Can be 'basic',
98 which means that is will be provided by any kernel that supports
99 API version 12 (see section 4.1), a KVM_CAP_xyz constant, which
100 means availability needs to be checked with KVM_CHECK_EXTENSION
101 (see section 4.4), or 'none' which means that while not all kernels
102 support this ioctl, there's no capability bit to check its
103 availability: for kernels that don't support the ioctl,
104 the ioctl returns -ENOTTY.
105
106 Architectures:
107 which instruction set architectures provide this ioctl.
108 x86 includes both i386 and x86_64.
109
110 Type:
111 system, vm, or vcpu.
112
113 Parameters:
114 what parameters are accepted by the ioctl.
115
116 Returns:
117 the return value. General error numbers (EBADF, ENOMEM, EINVAL)
118 are not detailed, but errors with specific meanings are.
119
120
121 4.1 KVM_GET_API_VERSION
122 -----------------------
123
124 :Capability: basic
125 :Architectures: all
126 :Type: system ioctl
127 :Parameters: none
128 :Returns: the constant KVM_API_VERSION (=12)
129
130 This identifies the API version as the stable kvm API. It is not
131 expected that this number will change. However, Linux 2.6.20 and
132 2.6.21 report earlier versions; these are not documented and not
133 supported. Applications should refuse to run if KVM_GET_API_VERSION
134 returns a value other than 12. If this check passes, all ioctls
135 described as 'basic' will be available.
136
137
138 4.2 KVM_CREATE_VM
139 -----------------
140
141 :Capability: basic
142 :Architectures: all
143 :Type: system ioctl
144 :Parameters: machine type identifier (KVM_VM_*)
145 :Returns: a VM fd that can be used to control the new virtual machine.
146
147 The new VM has no virtual cpus and no memory.
148 You probably want to use 0 as machine type.
149
150 X86:
151 ^^^^
152
153 Supported X86 VM types can be queried via KVM_CAP_VM_TYPES.
154
155 S390:
156 ^^^^^
157
158 In order to create user controlled virtual machines on S390, check
159 KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as
160 privileged user (CAP_SYS_ADMIN).
161
162 MIPS:
163 ^^^^^
164
165 To use hardware assisted virtualization on MIPS (VZ ASE) rather than
166 the default trap & emulate implementation (which changes the virtual
167 memory layout to fit in user mode), check KVM_CAP_MIPS_VZ and use the
168 flag KVM_VM_MIPS_VZ.
169
170 ARM64:
171 ^^^^^^
172
173 On arm64, the physical address size for a VM (IPA Size limit) is limited
174 to 40bits by default. The limit can be configured if the host supports the
175 extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use
176 KVM_VM_TYPE_ARM_IPA_SIZE(IPA_Bits) to set the size in the machine type
177 identifier, where IPA_Bits is the maximum width of any physical
178 address used by the VM. The IPA_Bits is encoded in bits[7-0] of the
179 machine type identifier.
180
181 e.g, to configure a guest to use 48bit physical address size::
182
183 vm_fd = ioctl(dev_fd, KVM_CREATE_VM, KVM_VM_TYPE_ARM_IPA_SIZE(48));
184
185 The requested size (IPA_Bits) must be:
186
187 == =========================================================
188 0 Implies default size, 40bits (for backward compatibility)
189 N Implies N bits, where N is a positive integer such that,
190 32 <= N <= Host_IPA_Limit
191 == =========================================================
192
193 Host_IPA_Limit is the maximum possible value for IPA_Bits on the host and
194 is dependent on the CPU capability and the kernel configuration. The limit can
195 be retrieved using KVM_CAP_ARM_VM_IPA_SIZE of the KVM_CHECK_EXTENSION
196 ioctl() at run-time.
197
198 Creation of the VM will fail if the requested IPA size (whether it is
199 implicit or explicit) is unsupported on the host.
200
201 Please note that configuring the IPA size does not affect the capability
202 exposed by the guest CPUs in ID_AA64MMFR0_EL1[PARange]. It only affects
203 size of the address translated by the stage2 level (guest physical to
204 host physical address translations).
205
206
207 4.3 KVM_GET_MSR_INDEX_LIST, KVM_GET_MSR_FEATURE_INDEX_LIST
208 ----------------------------------------------------------
209
210 :Capability: basic, KVM_CAP_GET_MSR_FEATURES for KVM_GET_MSR_FEATURE_INDEX_LIST
211 :Architectures: x86
212 :Type: system ioctl
213 :Parameters: struct kvm_msr_list (in/out)
214 :Returns: 0 on success; -1 on error
215
216 Errors:
217
218 ====== ============================================================
219 EFAULT the msr index list cannot be read from or written to
220 E2BIG the msr index list is too big to fit in the array specified by
221 the user.
222 ====== ============================================================
223
224 ::
225
226 struct kvm_msr_list {
227 __u32 nmsrs; /* number of msrs in entries */
228 __u32 indices[0];
229 };
230
231 The user fills in the size of the indices array in nmsrs, and in return
232 kvm adjusts nmsrs to reflect the actual number of msrs and fills in the
233 indices array with their numbers.
234
235 KVM_GET_MSR_INDEX_LIST returns the guest msrs that are supported. The list
236 varies by kvm version and host processor, but does not change otherwise.
237
238 Note: if kvm indicates supports MCE (KVM_CAP_MCE), then the MCE bank MSRs are
239 not returned in the MSR list, as different vcpus can have a different number
240 of banks, as set via the KVM_X86_SETUP_MCE ioctl.
241
242 KVM_GET_MSR_FEATURE_INDEX_LIST returns the list of MSRs that can be passed
243 to the KVM_GET_MSRS system ioctl. This lets userspace probe host capabilities
244 and processor features that are exposed via MSRs (e.g., VMX capabilities).
245 This list also varies by kvm version and host processor, but does not change
246 otherwise.
247
248
249 4.4 KVM_CHECK_EXTENSION
250 -----------------------
251
252 :Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl
253 :Architectures: all
254 :Type: system ioctl, vm ioctl
255 :Parameters: extension identifier (KVM_CAP_*)
256 :Returns: 0 if unsupported; 1 (or some other positive integer) if supported
257
258 The API allows the application to query about extensions to the core
259 kvm API. Userspace passes an extension identifier (an integer) and
260 receives an integer that describes the extension availability.
261 Generally 0 means no and 1 means yes, but some extensions may report
262 additional information in the integer return value.
263
264 Based on their initialization different VMs may have different capabilities.
265 It is thus encouraged to use the vm ioctl to query for capabilities (available
266 with KVM_CAP_CHECK_EXTENSION_VM on the vm fd)
267
268 4.5 KVM_GET_VCPU_MMAP_SIZE
269 --------------------------
270
271 :Capability: basic
272 :Architectures: all
273 :Type: system ioctl
274 :Parameters: none
275 :Returns: size of vcpu mmap area, in bytes
276
277 The KVM_RUN ioctl (cf.) communicates with userspace via a shared
278 memory region. This ioctl returns the size of that region. See the
279 KVM_RUN documentation for details.
280
281 Besides the size of the KVM_RUN communication region, other areas of
282 the VCPU file descriptor can be mmap-ed, including:
283
284 - if KVM_CAP_COALESCED_MMIO is available, a page at
285 KVM_COALESCED_MMIO_PAGE_OFFSET * PAGE_SIZE; for historical reasons,
286 this page is included in the result of KVM_GET_VCPU_MMAP_SIZE.
287 KVM_CAP_COALESCED_MMIO is not documented yet.
288
289 - if KVM_CAP_DIRTY_LOG_RING is available, a number of pages at
290 KVM_DIRTY_LOG_PAGE_OFFSET * PAGE_SIZE. For more information on
291 KVM_CAP_DIRTY_LOG_RING, see section 8.3.
292
293
294 4.7 KVM_CREATE_VCPU
295 -------------------
296
297 :Capability: basic
298 :Architectures: all
299 :Type: vm ioctl
300 :Parameters: vcpu id (apic id on x86)
301 :Returns: vcpu fd on success, -1 on error
302
303 This API adds a vcpu to a virtual machine. No more than max_vcpus may be added.
304 The vcpu id is an integer in the range [0, max_vcpu_id).
305
306 The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of
307 the KVM_CHECK_EXTENSION ioctl() at run-time.
308 The maximum possible value for max_vcpus can be retrieved using the
309 KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time.
310
311 If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4
312 cpus max.
313 If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is
314 same as the value returned from KVM_CAP_NR_VCPUS.
315
316 The maximum possible value for max_vcpu_id can be retrieved using the
317 KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time.
318
319 If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that max_vcpu_id
320 is the same as the value returned from KVM_CAP_MAX_VCPUS.
321
322 On powerpc using book3s_hv mode, the vcpus are mapped onto virtual
323 threads in one or more virtual CPU cores. (This is because the
324 hardware requires all the hardware threads in a CPU core to be in the
325 same partition.) The KVM_CAP_PPC_SMT capability indicates the number
326 of vcpus per virtual core (vcore). The vcore id is obtained by
327 dividing the vcpu id by the number of vcpus per vcore. The vcpus in a
328 given vcore will always be in the same physical core as each other
329 (though that might be a different physical core from time to time).
330 Userspace can control the threading (SMT) mode of the guest by its
331 allocation of vcpu ids. For example, if userspace wants
332 single-threaded guest vcpus, it should make all vcpu ids be a multiple
333 of the number of vcpus per vcore.
334
335 For virtual cpus that have been created with S390 user controlled virtual
336 machines, the resulting vcpu fd can be memory mapped at page offset
337 KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of the virtual
338 cpu's hardware control block.
339
340
341 4.8 KVM_GET_DIRTY_LOG (vm ioctl)
342 --------------------------------
343
344 :Capability: basic
345 :Architectures: all
346 :Type: vm ioctl
347 :Parameters: struct kvm_dirty_log (in/out)
348 :Returns: 0 on success, -1 on error
349
350 ::
351
352 /* for KVM_GET_DIRTY_LOG */
353 struct kvm_dirty_log {
354 __u32 slot;
355 __u32 padding;
356 union {
357 void __user *dirty_bitmap; /* one bit per page */
358 __u64 padding;
359 };
360 };
361
362 Given a memory slot, return a bitmap containing any pages dirtied
363 since the last call to this ioctl. Bit 0 is the first page in the
364 memory slot. Ensure the entire structure is cleared to avoid padding
365 issues.
366
367 If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies
368 the address space for which you want to return the dirty bitmap. See
369 KVM_SET_USER_MEMORY_REGION for details on the usage of slot field.
370
371 The bits in the dirty bitmap are cleared before the ioctl returns, unless
372 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information,
373 see the description of the capability.
374
375 Note that the Xen shared_info page, if configured, shall always be assumed
376 to be dirty. KVM will not explicitly mark it such.
377
378
379 4.10 KVM_RUN
380 ------------
381
382 :Capability: basic
383 :Architectures: all
384 :Type: vcpu ioctl
385 :Parameters: none
386 :Returns: 0 on success, -1 on error
387
388 Errors:
389
390 ======= ==============================================================
391 EINTR an unmasked signal is pending
392 ENOEXEC the vcpu hasn't been initialized or the guest tried to execute
393 instructions from device memory (arm64)
394 ENOSYS data abort outside memslots with no syndrome info and
395 KVM_CAP_ARM_NISV_TO_USER not enabled (arm64)
396 EPERM SVE feature set but not finalized (arm64)
397 ======= ==============================================================
398
399 This ioctl is used to run a guest virtual cpu. While there are no
400 explicit parameters, there is an implicit parameter block that can be
401 obtained by mmap()ing the vcpu fd at offset 0, with the size given by
402 KVM_GET_VCPU_MMAP_SIZE. The parameter block is formatted as a 'struct
403 kvm_run' (see below).
404
405
406 4.11 KVM_GET_REGS
407 -----------------
408
409 :Capability: basic
410 :Architectures: all except arm64
411 :Type: vcpu ioctl
412 :Parameters: struct kvm_regs (out)
413 :Returns: 0 on success, -1 on error
414
415 Reads the general purpose registers from the vcpu.
416
417 ::
418
419 /* x86 */
420 struct kvm_regs {
421 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
422 __u64 rax, rbx, rcx, rdx;
423 __u64 rsi, rdi, rsp, rbp;
424 __u64 r8, r9, r10, r11;
425 __u64 r12, r13, r14, r15;
426 __u64 rip, rflags;
427 };
428
429 /* mips */
430 struct kvm_regs {
431 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
432 __u64 gpr[32];
433 __u64 hi;
434 __u64 lo;
435 __u64 pc;
436 };
437
438 /* LoongArch */
439 struct kvm_regs {
440 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
441 unsigned long gpr[32];
442 unsigned long pc;
443 };
444
445
446 4.12 KVM_SET_REGS
447 -----------------
448
449 :Capability: basic
450 :Architectures: all except arm64
451 :Type: vcpu ioctl
452 :Parameters: struct kvm_regs (in)
453 :Returns: 0 on success, -1 on error
454
455 Writes the general purpose registers into the vcpu.
456
457 See KVM_GET_REGS for the data structure.
458
459
460 4.13 KVM_GET_SREGS
461 ------------------
462
463 :Capability: basic
464 :Architectures: x86, ppc
465 :Type: vcpu ioctl
466 :Parameters: struct kvm_sregs (out)
467 :Returns: 0 on success, -1 on error
468
469 Reads special registers from the vcpu.
470
471 ::
472
473 /* x86 */
474 struct kvm_sregs {
475 struct kvm_segment cs, ds, es, fs, gs, ss;
476 struct kvm_segment tr, ldt;
477 struct kvm_dtable gdt, idt;
478 __u64 cr0, cr2, cr3, cr4, cr8;
479 __u64 efer;
480 __u64 apic_base;
481 __u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64];
482 };
483
484 /* ppc -- see arch/powerpc/include/uapi/asm/kvm.h */
485
486 interrupt_bitmap is a bitmap of pending external interrupts. At most
487 one bit may be set. This interrupt has been acknowledged by the APIC
488 but not yet injected into the cpu core.
489
490
491 4.14 KVM_SET_SREGS
492 ------------------
493
494 :Capability: basic
495 :Architectures: x86, ppc
496 :Type: vcpu ioctl
497 :Parameters: struct kvm_sregs (in)
498 :Returns: 0 on success, -1 on error
499
500 Writes special registers into the vcpu. See KVM_GET_SREGS for the
501 data structures.
502
503
504 4.15 KVM_TRANSLATE
505 ------------------
506
507 :Capability: basic
508 :Architectures: x86
509 :Type: vcpu ioctl
510 :Parameters: struct kvm_translation (in/out)
511 :Returns: 0 on success, -1 on error
512
513 Translates a virtual address according to the vcpu's current address
514 translation mode.
515
516 ::
517
518 struct kvm_translation {
519 /* in */
520 __u64 linear_address;
521
522 /* out */
523 __u64 physical_address;
524 __u8 valid;
525 __u8 writeable;
526 __u8 usermode;
527 __u8 pad[5];
528 };
529
530
531 4.16 KVM_INTERRUPT
532 ------------------
533
534 :Capability: basic
535 :Architectures: x86, ppc, mips, riscv, loongarch
536 :Type: vcpu ioctl
537 :Parameters: struct kvm_interrupt (in)
538 :Returns: 0 on success, negative on failure.
539
540 Queues a hardware interrupt vector to be injected.
541
542 ::
543
544 /* for KVM_INTERRUPT */
545 struct kvm_interrupt {
546 /* in */
547 __u32 irq;
548 };
549
550 X86:
551 ^^^^
552
553 :Returns:
554
555 ========= ===================================
556 0 on success,
557 -EEXIST if an interrupt is already enqueued
558 -EINVAL the irq number is invalid
559 -ENXIO if the PIC is in the kernel
560 -EFAULT if the pointer is invalid
561 ========= ===================================
562
563 Note 'irq' is an interrupt vector, not an interrupt pin or line. This
564 ioctl is useful if the in-kernel PIC is not used.
565
566 PPC:
567 ^^^^
568
569 Queues an external interrupt to be injected. This ioctl is overloaded
570 with 3 different irq values:
571
572 a) KVM_INTERRUPT_SET
573
574 This injects an edge type external interrupt into the guest once it's ready
575 to receive interrupts. When injected, the interrupt is done.
576
577 b) KVM_INTERRUPT_UNSET
578
579 This unsets any pending interrupt.
580
581 Only available with KVM_CAP_PPC_UNSET_IRQ.
582
583 c) KVM_INTERRUPT_SET_LEVEL
584
585 This injects a level type external interrupt into the guest context. The
586 interrupt stays pending until a specific ioctl with KVM_INTERRUPT_UNSET
587 is triggered.
588
589 Only available with KVM_CAP_PPC_IRQ_LEVEL.
590
591 Note that any value for 'irq' other than the ones stated above is invalid
592 and incurs unexpected behavior.
593
594 This is an asynchronous vcpu ioctl and can be invoked from any thread.
595
596 MIPS:
597 ^^^^^
598
599 Queues an external interrupt to be injected into the virtual CPU. A negative
600 interrupt number dequeues the interrupt.
601
602 This is an asynchronous vcpu ioctl and can be invoked from any thread.
603
604 RISC-V:
605 ^^^^^^^
606
607 Queues an external interrupt to be injected into the virtual CPU. This ioctl
608 is overloaded with 2 different irq values:
609
610 a) KVM_INTERRUPT_SET
611
612 This sets external interrupt for a virtual CPU and it will receive
613 once it is ready.
614
615 b) KVM_INTERRUPT_UNSET
616
617 This clears pending external interrupt for a virtual CPU.
618
619 This is an asynchronous vcpu ioctl and can be invoked from any thread.
620
621 LOONGARCH:
622 ^^^^^^^^^^
623
624 Queues an external interrupt to be injected into the virtual CPU. A negative
625 interrupt number dequeues the interrupt.
626
627 This is an asynchronous vcpu ioctl and can be invoked from any thread.
628
629
630 4.18 KVM_GET_MSRS
631 -----------------
632
633 :Capability: basic (vcpu), KVM_CAP_GET_MSR_FEATURES (system)
634 :Architectures: x86
635 :Type: system ioctl, vcpu ioctl
636 :Parameters: struct kvm_msrs (in/out)
637 :Returns: number of msrs successfully returned;
638 -1 on error
639
640 When used as a system ioctl:
641 Reads the values of MSR-based features that are available for the VM. This
642 is similar to KVM_GET_SUPPORTED_CPUID, but it returns MSR indices and values.
643 The list of msr-based features can be obtained using KVM_GET_MSR_FEATURE_INDEX_LIST
644 in a system ioctl.
645
646 When used as a vcpu ioctl:
647 Reads model-specific registers from the vcpu. Supported msr indices can
648 be obtained using KVM_GET_MSR_INDEX_LIST in a system ioctl.
649
650 ::
651
652 struct kvm_msrs {
653 __u32 nmsrs; /* number of msrs in entries */
654 __u32 pad;
655
656 struct kvm_msr_entry entries[0];
657 };
658
659 struct kvm_msr_entry {
660 __u32 index;
661 __u32 reserved;
662 __u64 data;
663 };
664
665 Application code should set the 'nmsrs' member (which indicates the
666 size of the entries array) and the 'index' member of each array entry.
667 kvm will fill in the 'data' member.
668
669
670 4.19 KVM_SET_MSRS
671 -----------------
672
673 :Capability: basic
674 :Architectures: x86
675 :Type: vcpu ioctl
676 :Parameters: struct kvm_msrs (in)
677 :Returns: number of msrs successfully set (see below), -1 on error
678
679 Writes model-specific registers to the vcpu. See KVM_GET_MSRS for the
680 data structures.
681
682 Application code should set the 'nmsrs' member (which indicates the
683 size of the entries array), and the 'index' and 'data' members of each
684 array entry.
685
686 It tries to set the MSRs in array entries[] one by one. If setting an MSR
687 fails, e.g., due to setting reserved bits, the MSR isn't supported/emulated
688 by KVM, etc..., it stops processing the MSR list and returns the number of
689 MSRs that have been set successfully.
690
691
692 4.20 KVM_SET_CPUID
693 ------------------
694
695 :Capability: basic
696 :Architectures: x86
697 :Type: vcpu ioctl
698 :Parameters: struct kvm_cpuid (in)
699 :Returns: 0 on success, -1 on error
700
701 Defines the vcpu responses to the cpuid instruction. Applications
702 should use the KVM_SET_CPUID2 ioctl if available.
703
704 Caveat emptor:
705 - If this IOCTL fails, KVM gives no guarantees that previous valid CPUID
706 configuration (if there is) is not corrupted. Userspace can get a copy
707 of the resulting CPUID configuration through KVM_GET_CPUID2 in case.
708 - Using KVM_SET_CPUID{,2} after KVM_RUN, i.e. changing the guest vCPU model
709 after running the guest, may cause guest instability.
710 - Using heterogeneous CPUID configurations, modulo APIC IDs, topology, etc...
711 may cause guest instability.
712
713 ::
714
715 struct kvm_cpuid_entry {
716 __u32 function;
717 __u32 eax;
718 __u32 ebx;
719 __u32 ecx;
720 __u32 edx;
721 __u32 padding;
722 };
723
724 /* for KVM_SET_CPUID */
725 struct kvm_cpuid {
726 __u32 nent;
727 __u32 padding;
728 struct kvm_cpuid_entry entries[0];
729 };
730
731
732 4.21 KVM_SET_SIGNAL_MASK
733 ------------------------
734
735 :Capability: basic
736 :Architectures: all
737 :Type: vcpu ioctl
738 :Parameters: struct kvm_signal_mask (in)
739 :Returns: 0 on success, -1 on error
740
741 Defines which signals are blocked during execution of KVM_RUN. This
742 signal mask temporarily overrides the threads signal mask. Any
743 unblocked signal received (except SIGKILL and SIGSTOP, which retain
744 their traditional behaviour) will cause KVM_RUN to return with -EINTR.
745
746 Note the signal will only be delivered if not blocked by the original
747 signal mask.
748
749 ::
750
751 /* for KVM_SET_SIGNAL_MASK */
752 struct kvm_signal_mask {
753 __u32 len;
754 __u8 sigset[0];
755 };
756
757
758 4.22 KVM_GET_FPU
759 ----------------
760
761 :Capability: basic
762 :Architectures: x86, loongarch
763 :Type: vcpu ioctl
764 :Parameters: struct kvm_fpu (out)
765 :Returns: 0 on success, -1 on error
766
767 Reads the floating point state from the vcpu.
768
769 ::
770
771 /* x86: for KVM_GET_FPU and KVM_SET_FPU */
772 struct kvm_fpu {
773 __u8 fpr[8][16];
774 __u16 fcw;
775 __u16 fsw;
776 __u8 ftwx; /* in fxsave format */
777 __u8 pad1;
778 __u16 last_opcode;
779 __u64 last_ip;
780 __u64 last_dp;
781 __u8 xmm[16][16];
782 __u32 mxcsr;
783 __u32 pad2;
784 };
785
786 /* LoongArch: for KVM_GET_FPU and KVM_SET_FPU */
787 struct kvm_fpu {
788 __u32 fcsr;
789 __u64 fcc;
790 struct kvm_fpureg {
791 __u64 val64[4];
792 }fpr[32];
793 };
794
795
796 4.23 KVM_SET_FPU
797 ----------------
798
799 :Capability: basic
800 :Architectures: x86, loongarch
801 :Type: vcpu ioctl
802 :Parameters: struct kvm_fpu (in)
803 :Returns: 0 on success, -1 on error
804
805 Writes the floating point state to the vcpu.
806
807 ::
808
809 /* x86: for KVM_GET_FPU and KVM_SET_FPU */
810 struct kvm_fpu {
811 __u8 fpr[8][16];
812 __u16 fcw;
813 __u16 fsw;
814 __u8 ftwx; /* in fxsave format */
815 __u8 pad1;
816 __u16 last_opcode;
817 __u64 last_ip;
818 __u64 last_dp;
819 __u8 xmm[16][16];
820 __u32 mxcsr;
821 __u32 pad2;
822 };
823
824 /* LoongArch: for KVM_GET_FPU and KVM_SET_FPU */
825 struct kvm_fpu {
826 __u32 fcsr;
827 __u64 fcc;
828 struct kvm_fpureg {
829 __u64 val64[4];
830 }fpr[32];
831 };
832
833
834 4.24 KVM_CREATE_IRQCHIP
835 -----------------------
836
837 :Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390)
838 :Architectures: x86, arm64, s390
839 :Type: vm ioctl
840 :Parameters: none
841 :Returns: 0 on success, -1 on error
842
843 Creates an interrupt controller model in the kernel.
844 On x86, creates a virtual ioapic, a virtual PIC (two PICs, nested), and sets up
845 future vcpus to have a local APIC. IRQ routing for GSIs 0-15 is set to both
846 PIC and IOAPIC; GSI 16-23 only go to the IOAPIC.
847 On arm64, a GICv2 is created. Any other GIC versions require the usage of
848 KVM_CREATE_DEVICE, which also supports creating a GICv2. Using
849 KVM_CREATE_DEVICE is preferred over KVM_CREATE_IRQCHIP for GICv2.
850 On s390, a dummy irq routing table is created.
851
852 Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled
853 before KVM_CREATE_IRQCHIP can be used.
854
855
856 4.25 KVM_IRQ_LINE
857 -----------------
858
859 :Capability: KVM_CAP_IRQCHIP
860 :Architectures: x86, arm64
861 :Type: vm ioctl
862 :Parameters: struct kvm_irq_level
863 :Returns: 0 on success, -1 on error
864
865 Sets the level of a GSI input to the interrupt controller model in the kernel.
866 On some architectures it is required that an interrupt controller model has
867 been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered
868 interrupts require the level to be set to 1 and then back to 0.
869
870 On real hardware, interrupt pins can be active-low or active-high. This
871 does not matter for the level field of struct kvm_irq_level: 1 always
872 means active (asserted), 0 means inactive (deasserted).
873
874 x86 allows the operating system to program the interrupt polarity
875 (active-low/active-high) for level-triggered interrupts, and KVM used
876 to consider the polarity. However, due to bitrot in the handling of
877 active-low interrupts, the above convention is now valid on x86 too.
878 This is signaled by KVM_CAP_X86_IOAPIC_POLARITY_IGNORED. Userspace
879 should not present interrupts to the guest as active-low unless this
880 capability is present (or unless it is not using the in-kernel irqchip,
881 of course).
882
883
884 arm64 can signal an interrupt either at the CPU level, or at the
885 in-kernel irqchip (GIC), and for in-kernel irqchip can tell the GIC to
886 use PPIs designated for specific cpus. The irq field is interpreted
887 like this::
888
889 bits: | 31 ... 28 | 27 ... 24 | 23 ... 16 | 15 ... 0 |
890 field: | vcpu2_index | irq_type | vcpu_index | irq_id |
891
892 The irq_type field has the following values:
893
894 - KVM_ARM_IRQ_TYPE_CPU:
895 out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ
896 - KVM_ARM_IRQ_TYPE_SPI:
897 in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.)
898 (the vcpu_index field is ignored)
899 - KVM_ARM_IRQ_TYPE_PPI:
900 in-kernel GIC: PPI, irq_id between 16 and 31 (incl.)
901
902 (The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs)
903
904 In both cases, level is used to assert/deassert the line.
905
906 When KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 is supported, the target vcpu is
907 identified as (256 * vcpu2_index + vcpu_index). Otherwise, vcpu2_index
908 must be zero.
909
910 Note that on arm64, the KVM_CAP_IRQCHIP capability only conditions
911 injection of interrupts for the in-kernel irqchip. KVM_IRQ_LINE can always
912 be used for a userspace interrupt controller.
913
914 ::
915
916 struct kvm_irq_level {
917 union {
918 __u32 irq; /* GSI */
919 __s32 status; /* not used for KVM_IRQ_LEVEL */
920 };
921 __u32 level; /* 0 or 1 */
922 };
923
924
925 4.26 KVM_GET_IRQCHIP
926 --------------------
927
928 :Capability: KVM_CAP_IRQCHIP
929 :Architectures: x86
930 :Type: vm ioctl
931 :Parameters: struct kvm_irqchip (in/out)
932 :Returns: 0 on success, -1 on error
933
934 Reads the state of a kernel interrupt controller created with
935 KVM_CREATE_IRQCHIP into a buffer provided by the caller.
936
937 ::
938
939 struct kvm_irqchip {
940 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */
941 __u32 pad;
942 union {
943 char dummy[512]; /* reserving space */
944 struct kvm_pic_state pic;
945 struct kvm_ioapic_state ioapic;
946 } chip;
947 };
948
949
950 4.27 KVM_SET_IRQCHIP
951 --------------------
952
953 :Capability: KVM_CAP_IRQCHIP
954 :Architectures: x86
955 :Type: vm ioctl
956 :Parameters: struct kvm_irqchip (in)
957 :Returns: 0 on success, -1 on error
958
959 Sets the state of a kernel interrupt controller created with
960 KVM_CREATE_IRQCHIP from a buffer provided by the caller.
961
962 ::
963
964 struct kvm_irqchip {
965 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */
966 __u32 pad;
967 union {
968 char dummy[512]; /* reserving space */
969 struct kvm_pic_state pic;
970 struct kvm_ioapic_state ioapic;
971 } chip;
972 };
973
974
975 4.28 KVM_XEN_HVM_CONFIG
976 -----------------------
977
978 :Capability: KVM_CAP_XEN_HVM
979 :Architectures: x86
980 :Type: vm ioctl
981 :Parameters: struct kvm_xen_hvm_config (in)
982 :Returns: 0 on success, -1 on error
983
984 Sets the MSR that the Xen HVM guest uses to initialize its hypercall
985 page, and provides the starting address and size of the hypercall
986 blobs in userspace. When the guest writes the MSR, kvm copies one
987 page of a blob (32- or 64-bit, depending on the vcpu mode) to guest
988 memory.
989
990 ::
991
992 struct kvm_xen_hvm_config {
993 __u32 flags;
994 __u32 msr;
995 __u64 blob_addr_32;
996 __u64 blob_addr_64;
997 __u8 blob_size_32;
998 __u8 blob_size_64;
999 __u8 pad2[30];
1000 };
1001
1002 If certain flags are returned from the KVM_CAP_XEN_HVM check, they may
1003 be set in the flags field of this ioctl:
1004
1005 The KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag requests KVM to generate
1006 the contents of the hypercall page automatically; hypercalls will be
1007 intercepted and passed to userspace through KVM_EXIT_XEN. In this
1008 case, all of the blob size and address fields must be zero.
1009
1010 The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates to KVM that userspace
1011 will always use the KVM_XEN_HVM_EVTCHN_SEND ioctl to deliver event
1012 channel interrupts rather than manipulating the guest's shared_info
1013 structures directly. This, in turn, may allow KVM to enable features
1014 such as intercepting the SCHEDOP_poll hypercall to accelerate PV
1015 spinlock operation for the guest. Userspace may still use the ioctl
1016 to deliver events if it was advertised, even if userspace does not
1017 send this indication that it will always do so
1018
1019 No other flags are currently valid in the struct kvm_xen_hvm_config.
1020
1021 4.29 KVM_GET_CLOCK
1022 ------------------
1023
1024 :Capability: KVM_CAP_ADJUST_CLOCK
1025 :Architectures: x86
1026 :Type: vm ioctl
1027 :Parameters: struct kvm_clock_data (out)
1028 :Returns: 0 on success, -1 on error
1029
1030 Gets the current timestamp of kvmclock as seen by the current guest. In
1031 conjunction with KVM_SET_CLOCK, it is used to ensure monotonicity on scenarios
1032 such as migration.
1033
1034 When KVM_CAP_ADJUST_CLOCK is passed to KVM_CHECK_EXTENSION, it returns the
1035 set of bits that KVM can return in struct kvm_clock_data's flag member.
1036
1037 The following flags are defined:
1038
1039 KVM_CLOCK_TSC_STABLE
1040 If set, the returned value is the exact kvmclock
1041 value seen by all VCPUs at the instant when KVM_GET_CLOCK was called.
1042 If clear, the returned value is simply CLOCK_MONOTONIC plus a constant
1043 offset; the offset can be modified with KVM_SET_CLOCK. KVM will try
1044 to make all VCPUs follow this clock, but the exact value read by each
1045 VCPU could differ, because the host TSC is not stable.
1046
1047 KVM_CLOCK_REALTIME
1048 If set, the `realtime` field in the kvm_clock_data
1049 structure is populated with the value of the host's real time
1050 clocksource at the instant when KVM_GET_CLOCK was called. If clear,
1051 the `realtime` field does not contain a value.
1052
1053 KVM_CLOCK_HOST_TSC
1054 If set, the `host_tsc` field in the kvm_clock_data
1055 structure is populated with the value of the host's timestamp counter (TSC)
1056 at the instant when KVM_GET_CLOCK was called. If clear, the `host_tsc` field
1057 does not contain a value.
1058
1059 ::
1060
1061 struct kvm_clock_data {
1062 __u64 clock; /* kvmclock current value */
1063 __u32 flags;
1064 __u32 pad0;
1065 __u64 realtime;
1066 __u64 host_tsc;
1067 __u32 pad[4];
1068 };
1069
1070
1071 4.30 KVM_SET_CLOCK
1072 ------------------
1073
1074 :Capability: KVM_CAP_ADJUST_CLOCK
1075 :Architectures: x86
1076 :Type: vm ioctl
1077 :Parameters: struct kvm_clock_data (in)
1078 :Returns: 0 on success, -1 on error
1079
1080 Sets the current timestamp of kvmclock to the value specified in its parameter.
1081 In conjunction with KVM_GET_CLOCK, it is used to ensure monotonicity on scenarios
1082 such as migration.
1083
1084 The following flags can be passed:
1085
1086 KVM_CLOCK_REALTIME
1087 If set, KVM will compare the value of the `realtime` field
1088 with the value of the host's real time clocksource at the instant when
1089 KVM_SET_CLOCK was called. The difference in elapsed time is added to the final
1090 kvmclock value that will be provided to guests.
1091
1092 Other flags returned by ``KVM_GET_CLOCK`` are accepted but ignored.
1093
1094 ::
1095
1096 struct kvm_clock_data {
1097 __u64 clock; /* kvmclock current value */
1098 __u32 flags;
1099 __u32 pad0;
1100 __u64 realtime;
1101 __u64 host_tsc;
1102 __u32 pad[4];
1103 };
1104
1105
1106 4.31 KVM_GET_VCPU_EVENTS
1107 ------------------------
1108
1109 :Capability: KVM_CAP_VCPU_EVENTS
1110 :Extended by: KVM_CAP_INTR_SHADOW
1111 :Architectures: x86, arm64
1112 :Type: vcpu ioctl
1113 :Parameters: struct kvm_vcpu_events (out)
1114 :Returns: 0 on success, -1 on error
1115
1116 X86:
1117 ^^^^
1118
1119 Gets currently pending exceptions, interrupts, and NMIs as well as related
1120 states of the vcpu.
1121
1122 ::
1123
1124 struct kvm_vcpu_events {
1125 struct {
1126 __u8 injected;
1127 __u8 nr;
1128 __u8 has_error_code;
1129 __u8 pending;
1130 __u32 error_code;
1131 } exception;
1132 struct {
1133 __u8 injected;
1134 __u8 nr;
1135 __u8 soft;
1136 __u8 shadow;
1137 } interrupt;
1138 struct {
1139 __u8 injected;
1140 __u8 pending;
1141 __u8 masked;
1142 __u8 pad;
1143 } nmi;
1144 __u32 sipi_vector;
1145 __u32 flags;
1146 struct {
1147 __u8 smm;
1148 __u8 pending;
1149 __u8 smm_inside_nmi;
1150 __u8 latched_init;
1151 } smi;
1152 __u8 reserved[27];
1153 __u8 exception_has_payload;
1154 __u64 exception_payload;
1155 };
1156
1157 The following bits are defined in the flags field:
1158
1159 - KVM_VCPUEVENT_VALID_SHADOW may be set to signal that
1160 interrupt.shadow contains a valid state.
1161
1162 - KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a
1163 valid state.
1164
1165 - KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the
1166 exception_has_payload, exception_payload, and exception.pending
1167 fields contain a valid state. This bit will be set whenever
1168 KVM_CAP_EXCEPTION_PAYLOAD is enabled.
1169
1170 - KVM_VCPUEVENT_VALID_TRIPLE_FAULT may be set to signal that the
1171 triple_fault_pending field contains a valid state. This bit will
1172 be set whenever KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled.
1173
1174 ARM64:
1175 ^^^^^^
1176
1177 If the guest accesses a device that is being emulated by the host kernel in
1178 such a way that a real device would generate a physical SError, KVM may make
1179 a virtual SError pending for that VCPU. This system error interrupt remains
1180 pending until the guest takes the exception by unmasking PSTATE.A.
1181
1182 Running the VCPU may cause it to take a pending SError, or make an access that
1183 causes an SError to become pending. The event's description is only valid while
1184 the VPCU is not running.
1185
1186 This API provides a way to read and write the pending 'event' state that is not
1187 visible to the guest. To save, restore or migrate a VCPU the struct representing
1188 the state can be read then written using this GET/SET API, along with the other
1189 guest-visible registers. It is not possible to 'cancel' an SError that has been
1190 made pending.
1191
1192 A device being emulated in user-space may also wish to generate an SError. To do
1193 this the events structure can be populated by user-space. The current state
1194 should be read first, to ensure no existing SError is pending. If an existing
1195 SError is pending, the architecture's 'Multiple SError interrupts' rules should
1196 be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and
1197 Serviceability (RAS) Specification").
1198
1199 SError exceptions always have an ESR value. Some CPUs have the ability to
1200 specify what the virtual SError's ESR value should be. These systems will
1201 advertise KVM_CAP_ARM_INJECT_SERROR_ESR. In this case exception.has_esr will
1202 always have a non-zero value when read, and the agent making an SError pending
1203 should specify the ISS field in the lower 24 bits of exception.serror_esr. If
1204 the system supports KVM_CAP_ARM_INJECT_SERROR_ESR, but user-space sets the events
1205 with exception.has_esr as zero, KVM will choose an ESR.
1206
1207 Specifying exception.has_esr on a system that does not support it will return
1208 -EINVAL. Setting anything other than the lower 24bits of exception.serror_esr
1209 will return -EINVAL.
1210
1211 It is not possible to read back a pending external abort (injected via
1212 KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered
1213 directly to the virtual CPU).
1214
1215 ::
1216
1217 struct kvm_vcpu_events {
1218 struct {
1219 __u8 serror_pending;
1220 __u8 serror_has_esr;
1221 __u8 ext_dabt_pending;
1222 /* Align it to 8 bytes */
1223 __u8 pad[5];
1224 __u64 serror_esr;
1225 } exception;
1226 __u32 reserved[12];
1227 };
1228
1229 4.32 KVM_SET_VCPU_EVENTS
1230 ------------------------
1231
1232 :Capability: KVM_CAP_VCPU_EVENTS
1233 :Extended by: KVM_CAP_INTR_SHADOW
1234 :Architectures: x86, arm64
1235 :Type: vcpu ioctl
1236 :Parameters: struct kvm_vcpu_events (in)
1237 :Returns: 0 on success, -1 on error
1238
1239 X86:
1240 ^^^^
1241
1242 Set pending exceptions, interrupts, and NMIs as well as related states of the
1243 vcpu.
1244
1245 See KVM_GET_VCPU_EVENTS for the data structure.
1246
1247 Fields that may be modified asynchronously by running VCPUs can be excluded
1248 from the update. These fields are nmi.pending, sipi_vector, smi.smm,
1249 smi.pending. Keep the corresponding bits in the flags field cleared to
1250 suppress overwriting the current in-kernel state. The bits are:
1251
1252 =============================== ==================================
1253 KVM_VCPUEVENT_VALID_NMI_PENDING transfer nmi.pending to the kernel
1254 KVM_VCPUEVENT_VALID_SIPI_VECTOR transfer sipi_vector
1255 KVM_VCPUEVENT_VALID_SMM transfer the smi sub-struct.
1256 =============================== ==================================
1257
1258 If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in
1259 the flags field to signal that interrupt.shadow contains a valid state and
1260 shall be written into the VCPU.
1261
1262 KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available.
1263
1264 If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD
1265 can be set in the flags field to signal that the
1266 exception_has_payload, exception_payload, and exception.pending fields
1267 contain a valid state and shall be written into the VCPU.
1268
1269 If KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled, KVM_VCPUEVENT_VALID_TRIPLE_FAULT
1270 can be set in flags field to signal that the triple_fault field contains
1271 a valid state and shall be written into the VCPU.
1272
1273 ARM64:
1274 ^^^^^^
1275
1276 User space may need to inject several types of events to the guest.
1277
1278 Set the pending SError exception state for this VCPU. It is not possible to
1279 'cancel' an Serror that has been made pending.
1280
1281 If the guest performed an access to I/O memory which could not be handled by
1282 userspace, for example because of missing instruction syndrome decode
1283 information or because there is no device mapped at the accessed IPA, then
1284 userspace can ask the kernel to inject an external abort using the address
1285 from the exiting fault on the VCPU. It is a programming error to set
1286 ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO or
1287 KVM_EXIT_ARM_NISV. This feature is only available if the system supports
1288 KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which provides commonality in
1289 how userspace reports accesses for the above cases to guests, across different
1290 userspace implementations. Nevertheless, userspace can still emulate all Arm
1291 exceptions by manipulating individual registers using the KVM_SET_ONE_REG API.
1292
1293 See KVM_GET_VCPU_EVENTS for the data structure.
1294
1295
1296 4.33 KVM_GET_DEBUGREGS
1297 ----------------------
1298
1299 :Capability: KVM_CAP_DEBUGREGS
1300 :Architectures: x86
1301 :Type: vm ioctl
1302 :Parameters: struct kvm_debugregs (out)
1303 :Returns: 0 on success, -1 on error
1304
1305 Reads debug registers from the vcpu.
1306
1307 ::
1308
1309 struct kvm_debugregs {
1310 __u64 db[4];
1311 __u64 dr6;
1312 __u64 dr7;
1313 __u64 flags;
1314 __u64 reserved[9];
1315 };
1316
1317
1318 4.34 KVM_SET_DEBUGREGS
1319 ----------------------
1320
1321 :Capability: KVM_CAP_DEBUGREGS
1322 :Architectures: x86
1323 :Type: vm ioctl
1324 :Parameters: struct kvm_debugregs (in)
1325 :Returns: 0 on success, -1 on error
1326
1327 Writes debug registers into the vcpu.
1328
1329 See KVM_GET_DEBUGREGS for the data structure. The flags field is unused
1330 yet and must be cleared on entry.
1331
1332
1333 4.35 KVM_SET_USER_MEMORY_REGION
1334 -------------------------------
1335
1336 :Capability: KVM_CAP_USER_MEMORY
1337 :Architectures: all
1338 :Type: vm ioctl
1339 :Parameters: struct kvm_userspace_memory_region (in)
1340 :Returns: 0 on success, -1 on error
1341
1342 ::
1343
1344 struct kvm_userspace_memory_region {
1345 __u32 slot;
1346 __u32 flags;
1347 __u64 guest_phys_addr;
1348 __u64 memory_size; /* bytes */
1349 __u64 userspace_addr; /* start of the userspace allocated memory */
1350 };
1351
1352 /* for kvm_userspace_memory_region::flags */
1353 #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0)
1354 #define KVM_MEM_READONLY (1UL << 1)
1355
1356 This ioctl allows the user to create, modify or delete a guest physical
1357 memory slot. Bits 0-15 of "slot" specify the slot id and this value
1358 should be less than the maximum number of user memory slots supported per
1359 VM. The maximum allowed slots can be queried using KVM_CAP_NR_MEMSLOTS.
1360 Slots may not overlap in guest physical address space.
1361
1362 If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of "slot"
1363 specifies the address space which is being modified. They must be
1364 less than the value that KVM_CHECK_EXTENSION returns for the
1365 KVM_CAP_MULTI_ADDRESS_SPACE capability. Slots in separate address spaces
1366 are unrelated; the restriction on overlapping slots only applies within
1367 each address space.
1368
1369 Deleting a slot is done by passing zero for memory_size. When changing
1370 an existing slot, it may be moved in the guest physical memory space,
1371 or its flags may be modified, but it may not be resized.
1372
1373 Memory for the region is taken starting at the address denoted by the
1374 field userspace_addr, which must point at user addressable memory for
1375 the entire memory slot size. Any object may back this memory, including
1376 anonymous memory, ordinary files, and hugetlbfs.
1377
1378 On architectures that support a form of address tagging, userspace_addr must
1379 be an untagged address.
1380
1381 It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr
1382 be identical. This allows large pages in the guest to be backed by large
1383 pages in the host.
1384
1385 The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and
1386 KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of
1387 writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to
1388 use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it,
1389 to make a new slot read-only. In this case, writes to this memory will be
1390 posted to userspace as KVM_EXIT_MMIO exits.
1391
1392 When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of
1393 the memory region are automatically reflected into the guest. For example, an
1394 mmap() that affects the region will be made visible immediately. Another
1395 example is madvise(MADV_DROP).
1396
1397 Note: On arm64, a write generated by the page-table walker (to update
1398 the Access and Dirty flags, for example) never results in a
1399 KVM_EXIT_MMIO exit when the slot has the KVM_MEM_READONLY flag. This
1400 is because KVM cannot provide the data that would be written by the
1401 page-table walker, making it impossible to emulate the access.
1402 Instead, an abort (data abort if the cause of the page-table update
1403 was a load or a store, instruction abort if it was an instruction
1404 fetch) is injected in the guest.
1405
1406 S390:
1407 ^^^^^
1408
1409 Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set.
1410 Returns -EINVAL if called on a protected VM.
1411
1412 4.36 KVM_SET_TSS_ADDR
1413 ---------------------
1414
1415 :Capability: KVM_CAP_SET_TSS_ADDR
1416 :Architectures: x86
1417 :Type: vm ioctl
1418 :Parameters: unsigned long tss_address (in)
1419 :Returns: 0 on success, -1 on error
1420
1421 This ioctl defines the physical address of a three-page region in the guest
1422 physical address space. The region must be within the first 4GB of the
1423 guest physical address space and must not conflict with any memory slot
1424 or any mmio address. The guest may malfunction if it accesses this memory
1425 region.
1426
1427 This ioctl is required on Intel-based hosts. This is needed on Intel hardware
1428 because of a quirk in the virtualization implementation (see the internals
1429 documentation when it pops into existence).
1430
1431
1432 4.37 KVM_ENABLE_CAP
1433 -------------------
1434
1435 :Capability: KVM_CAP_ENABLE_CAP
1436 :Architectures: mips, ppc, s390, x86, loongarch
1437 :Type: vcpu ioctl
1438 :Parameters: struct kvm_enable_cap (in)
1439 :Returns: 0 on success; -1 on error
1440
1441 :Capability: KVM_CAP_ENABLE_CAP_VM
1442 :Architectures: all
1443 :Type: vm ioctl
1444 :Parameters: struct kvm_enable_cap (in)
1445 :Returns: 0 on success; -1 on error
1446
1447 .. note::
1448
1449 Not all extensions are enabled by default. Using this ioctl the application
1450 can enable an extension, making it available to the guest.
1451
1452 On systems that do not support this ioctl, it always fails. On systems that
1453 do support it, it only works for extensions that are supported for enablement.
1454
1455 To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should
1456 be used.
1457
1458 ::
1459
1460 struct kvm_enable_cap {
1461 /* in */
1462 __u32 cap;
1463
1464 The capability that is supposed to get enabled.
1465
1466 ::
1467
1468 __u32 flags;
1469
1470 A bitfield indicating future enhancements. Has to be 0 for now.
1471
1472 ::
1473
1474 __u64 args[4];
1475
1476 Arguments for enabling a feature. If a feature needs initial values to
1477 function properly, this is the place to put them.
1478
1479 ::
1480
1481 __u8 pad[64];
1482 };
1483
1484 The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl
1485 for vm-wide capabilities.
1486
1487 4.38 KVM_GET_MP_STATE
1488 ---------------------
1489
1490 :Capability: KVM_CAP_MP_STATE
1491 :Architectures: x86, s390, arm64, riscv, loongarch
1492 :Type: vcpu ioctl
1493 :Parameters: struct kvm_mp_state (out)
1494 :Returns: 0 on success; -1 on error
1495
1496 ::
1497
1498 struct kvm_mp_state {
1499 __u32 mp_state;
1500 };
1501
1502 Returns the vcpu's current "multiprocessing state" (though also valid on
1503 uniprocessor guests).
1504
1505 Possible values are:
1506
1507 ========================== ===============================================
1508 KVM_MP_STATE_RUNNABLE the vcpu is currently running
1509 [x86,arm64,riscv,loongarch]
1510 KVM_MP_STATE_UNINITIALIZED the vcpu is an application processor (AP)
1511 which has not yet received an INIT signal [x86]
1512 KVM_MP_STATE_INIT_RECEIVED the vcpu has received an INIT signal, and is
1513 now ready for a SIPI [x86]
1514 KVM_MP_STATE_HALTED the vcpu has executed a HLT instruction and
1515 is waiting for an interrupt [x86]
1516 KVM_MP_STATE_SIPI_RECEIVED the vcpu has just received a SIPI (vector
1517 accessible via KVM_GET_VCPU_EVENTS) [x86]
1518 KVM_MP_STATE_STOPPED the vcpu is stopped [s390,arm64,riscv]
1519 KVM_MP_STATE_CHECK_STOP the vcpu is in a special error state [s390]
1520 KVM_MP_STATE_OPERATING the vcpu is operating (running or halted)
1521 [s390]
1522 KVM_MP_STATE_LOAD the vcpu is in a special load/startup state
1523 [s390]
1524 KVM_MP_STATE_SUSPENDED the vcpu is in a suspend state and is waiting
1525 for a wakeup event [arm64]
1526 ========================== ===============================================
1527
1528 On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an
1529 in-kernel irqchip, the multiprocessing state must be maintained by userspace on
1530 these architectures.
1531
1532 For arm64:
1533 ^^^^^^^^^^
1534
1535 If a vCPU is in the KVM_MP_STATE_SUSPENDED state, KVM will emulate the
1536 architectural execution of a WFI instruction.
1537
1538 If a wakeup event is recognized, KVM will exit to userspace with a
1539 KVM_SYSTEM_EVENT exit, where the event type is KVM_SYSTEM_EVENT_WAKEUP. If
1540 userspace wants to honor the wakeup, it must set the vCPU's MP state to
1541 KVM_MP_STATE_RUNNABLE. If it does not, KVM will continue to await a wakeup
1542 event in subsequent calls to KVM_RUN.
1543
1544 .. warning::
1545
1546 If userspace intends to keep the vCPU in a SUSPENDED state, it is
1547 strongly recommended that userspace take action to suppress the
1548 wakeup event (such as masking an interrupt). Otherwise, subsequent
1549 calls to KVM_RUN will immediately exit with a KVM_SYSTEM_EVENT_WAKEUP
1550 event and inadvertently waste CPU cycles.
1551
1552 Additionally, if userspace takes action to suppress a wakeup event,
1553 it is strongly recommended that it also restores the vCPU to its
1554 original state when the vCPU is made RUNNABLE again. For example,
1555 if userspace masked a pending interrupt to suppress the wakeup,
1556 the interrupt should be unmasked before returning control to the
1557 guest.
1558
1559 For riscv:
1560 ^^^^^^^^^^
1561
1562 The only states that are valid are KVM_MP_STATE_STOPPED and
1563 KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not.
1564
1565 On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect
1566 whether the vcpu is runnable.
1567
1568 4.39 KVM_SET_MP_STATE
1569 ---------------------
1570
1571 :Capability: KVM_CAP_MP_STATE
1572 :Architectures: x86, s390, arm64, riscv, loongarch
1573 :Type: vcpu ioctl
1574 :Parameters: struct kvm_mp_state (in)
1575 :Returns: 0 on success; -1 on error
1576
1577 Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for
1578 arguments.
1579
1580 On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an
1581 in-kernel irqchip, the multiprocessing state must be maintained by userspace on
1582 these architectures.
1583
1584 For arm64/riscv:
1585 ^^^^^^^^^^^^^^^^
1586
1587 The only states that are valid are KVM_MP_STATE_STOPPED and
1588 KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not.
1589
1590 On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect
1591 whether the vcpu is runnable.
1592
1593 4.40 KVM_SET_IDENTITY_MAP_ADDR
1594 ------------------------------
1595
1596 :Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR
1597 :Architectures: x86
1598 :Type: vm ioctl
1599 :Parameters: unsigned long identity (in)
1600 :Returns: 0 on success, -1 on error
1601
1602 This ioctl defines the physical address of a one-page region in the guest
1603 physical address space. The region must be within the first 4GB of the
1604 guest physical address space and must not conflict with any memory slot
1605 or any mmio address. The guest may malfunction if it accesses this memory
1606 region.
1607
1608 Setting the address to 0 will result in resetting the address to its default
1609 (0xfffbc000).
1610
1611 This ioctl is required on Intel-based hosts. This is needed on Intel hardware
1612 because of a quirk in the virtualization implementation (see the internals
1613 documentation when it pops into existence).
1614
1615 Fails if any VCPU has already been created.
1616
1617 4.41 KVM_SET_BOOT_CPU_ID
1618 ------------------------
1619
1620 :Capability: KVM_CAP_SET_BOOT_CPU_ID
1621 :Architectures: x86
1622 :Type: vm ioctl
1623 :Parameters: unsigned long vcpu_id
1624 :Returns: 0 on success, -1 on error
1625
1626 Define which vcpu is the Bootstrap Processor (BSP). Values are the same
1627 as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default
1628 is vcpu 0. This ioctl has to be called before vcpu creation,
1629 otherwise it will return EBUSY error.
1630
1631
1632 4.42 KVM_GET_XSAVE
1633 ------------------
1634
1635 :Capability: KVM_CAP_XSAVE
1636 :Architectures: x86
1637 :Type: vcpu ioctl
1638 :Parameters: struct kvm_xsave (out)
1639 :Returns: 0 on success, -1 on error
1640
1641
1642 ::
1643
1644 struct kvm_xsave {
1645 __u32 region[1024];
1646 __u32 extra[0];
1647 };
1648
1649 This ioctl would copy current vcpu's xsave struct to the userspace.
1650
1651
1652 4.43 KVM_SET_XSAVE
1653 ------------------
1654
1655 :Capability: KVM_CAP_XSAVE and KVM_CAP_XSAVE2
1656 :Architectures: x86
1657 :Type: vcpu ioctl
1658 :Parameters: struct kvm_xsave (in)
1659 :Returns: 0 on success, -1 on error
1660
1661 ::
1662
1663
1664 struct kvm_xsave {
1665 __u32 region[1024];
1666 __u32 extra[0];
1667 };
1668
1669 This ioctl would copy userspace's xsave struct to the kernel. It copies
1670 as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2),
1671 when invoked on the vm file descriptor. The size value returned by
1672 KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096.
1673 Currently, it is only greater than 4096 if a dynamic feature has been
1674 enabled with ``arch_prctl()``, but this may change in the future.
1675
1676 The offsets of the state save areas in struct kvm_xsave follow the
1677 contents of CPUID leaf 0xD on the host.
1678
1679
1680 4.44 KVM_GET_XCRS
1681 -----------------
1682
1683 :Capability: KVM_CAP_XCRS
1684 :Architectures: x86
1685 :Type: vcpu ioctl
1686 :Parameters: struct kvm_xcrs (out)
1687 :Returns: 0 on success, -1 on error
1688
1689 ::
1690
1691 struct kvm_xcr {
1692 __u32 xcr;
1693 __u32 reserved;
1694 __u64 value;
1695 };
1696
1697 struct kvm_xcrs {
1698 __u32 nr_xcrs;
1699 __u32 flags;
1700 struct kvm_xcr xcrs[KVM_MAX_XCRS];
1701 __u64 padding[16];
1702 };
1703
1704 This ioctl would copy current vcpu's xcrs to the userspace.
1705
1706
1707 4.45 KVM_SET_XCRS
1708 -----------------
1709
1710 :Capability: KVM_CAP_XCRS
1711 :Architectures: x86
1712 :Type: vcpu ioctl
1713 :Parameters: struct kvm_xcrs (in)
1714 :Returns: 0 on success, -1 on error
1715
1716 ::
1717
1718 struct kvm_xcr {
1719 __u32 xcr;
1720 __u32 reserved;
1721 __u64 value;
1722 };
1723
1724 struct kvm_xcrs {
1725 __u32 nr_xcrs;
1726 __u32 flags;
1727 struct kvm_xcr xcrs[KVM_MAX_XCRS];
1728 __u64 padding[16];
1729 };
1730
1731 This ioctl would set vcpu's xcr to the value userspace specified.
1732
1733
1734 4.46 KVM_GET_SUPPORTED_CPUID
1735 ----------------------------
1736
1737 :Capability: KVM_CAP_EXT_CPUID
1738 :Architectures: x86
1739 :Type: system ioctl
1740 :Parameters: struct kvm_cpuid2 (in/out)
1741 :Returns: 0 on success, -1 on error
1742
1743 ::
1744
1745 struct kvm_cpuid2 {
1746 __u32 nent;
1747 __u32 padding;
1748 struct kvm_cpuid_entry2 entries[0];
1749 };
1750
1751 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0)
1752 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */
1753 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */
1754
1755 struct kvm_cpuid_entry2 {
1756 __u32 function;
1757 __u32 index;
1758 __u32 flags;
1759 __u32 eax;
1760 __u32 ebx;
1761 __u32 ecx;
1762 __u32 edx;
1763 __u32 padding[3];
1764 };
1765
1766 This ioctl returns x86 cpuid features which are supported by both the
1767 hardware and kvm in its default configuration. Userspace can use the
1768 information returned by this ioctl to construct cpuid information (for
1769 KVM_SET_CPUID2) that is consistent with hardware, kernel, and
1770 userspace capabilities, and with user requirements (for example, the
1771 user may wish to constrain cpuid to emulate older hardware, or for
1772 feature consistency across a cluster).
1773
1774 Dynamically-enabled feature bits need to be requested with
1775 ``arch_prctl()`` before calling this ioctl. Feature bits that have not
1776 been requested are excluded from the result.
1777
1778 Note that certain capabilities, such as KVM_CAP_X86_DISABLE_EXITS, may
1779 expose cpuid features (e.g. MONITOR) which are not supported by kvm in
1780 its default configuration. If userspace enables such capabilities, it
1781 is responsible for modifying the results of this ioctl appropriately.
1782
1783 Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure
1784 with the 'nent' field indicating the number of entries in the variable-size
1785 array 'entries'. If the number of entries is too low to describe the cpu
1786 capabilities, an error (E2BIG) is returned. If the number is too high,
1787 the 'nent' field is adjusted and an error (ENOMEM) is returned. If the
1788 number is just right, the 'nent' field is adjusted to the number of valid
1789 entries in the 'entries' array, which is then filled.
1790
1791 The entries returned are the host cpuid as returned by the cpuid instruction,
1792 with unknown or unsupported features masked out. Some features (for example,
1793 x2apic), may not be present in the host cpu, but are exposed by kvm if it can
1794 emulate them efficiently. The fields in each entry are defined as follows:
1795
1796 function:
1797 the eax value used to obtain the entry
1798
1799 index:
1800 the ecx value used to obtain the entry (for entries that are
1801 affected by ecx)
1802
1803 flags:
1804 an OR of zero or more of the following:
1805
1806 KVM_CPUID_FLAG_SIGNIFCANT_INDEX:
1807 if the index field is valid
1808
1809 eax, ebx, ecx, edx:
1810 the values returned by the cpuid instruction for
1811 this function/index combination
1812
1813 The TSC deadline timer feature (CPUID leaf 1, ecx[24]) is always returned
1814 as false, since the feature depends on KVM_CREATE_IRQCHIP for local APIC
1815 support. Instead it is reported via::
1816
1817 ioctl(KVM_CHECK_EXTENSION, KVM_CAP_TSC_DEADLINE_TIMER)
1818
1819 if that returns true and you use KVM_CREATE_IRQCHIP, or if you emulate the
1820 feature in userspace, then you can enable the feature for KVM_SET_CPUID2.
1821
1822
1823 4.47 KVM_PPC_GET_PVINFO
1824 -----------------------
1825
1826 :Capability: KVM_CAP_PPC_GET_PVINFO
1827 :Architectures: ppc
1828 :Type: vm ioctl
1829 :Parameters: struct kvm_ppc_pvinfo (out)
1830 :Returns: 0 on success, !0 on error
1831
1832 ::
1833
1834 struct kvm_ppc_pvinfo {
1835 __u32 flags;
1836 __u32 hcall[4];
1837 __u8 pad[108];
1838 };
1839
1840 This ioctl fetches PV specific information that need to be passed to the guest
1841 using the device tree or other means from vm context.
1842
1843 The hcall array defines 4 instructions that make up a hypercall.
1844
1845 If any additional field gets added to this structure later on, a bit for that
1846 additional piece of information will be set in the flags bitmap.
1847
1848 The flags bitmap is defined as::
1849
1850 /* the host supports the ePAPR idle hcall
1851 #define KVM_PPC_PVINFO_FLAGS_EV_IDLE (1<<0)
1852
1853 4.52 KVM_SET_GSI_ROUTING
1854 ------------------------
1855
1856 :Capability: KVM_CAP_IRQ_ROUTING
1857 :Architectures: x86 s390 arm64
1858 :Type: vm ioctl
1859 :Parameters: struct kvm_irq_routing (in)
1860 :Returns: 0 on success, -1 on error
1861
1862 Sets the GSI routing table entries, overwriting any previously set entries.
1863
1864 On arm64, GSI routing has the following limitation:
1865
1866 - GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD.
1867
1868 ::
1869
1870 struct kvm_irq_routing {
1871 __u32 nr;
1872 __u32 flags;
1873 struct kvm_irq_routing_entry entries[0];
1874 };
1875
1876 No flags are specified so far, the corresponding field must be set to zero.
1877
1878 ::
1879
1880 struct kvm_irq_routing_entry {
1881 __u32 gsi;
1882 __u32 type;
1883 __u32 flags;
1884 __u32 pad;
1885 union {
1886 struct kvm_irq_routing_irqchip irqchip;
1887 struct kvm_irq_routing_msi msi;
1888 struct kvm_irq_routing_s390_adapter adapter;
1889 struct kvm_irq_routing_hv_sint hv_sint;
1890 struct kvm_irq_routing_xen_evtchn xen_evtchn;
1891 __u32 pad[8];
1892 } u;
1893 };
1894
1895 /* gsi routing entry types */
1896 #define KVM_IRQ_ROUTING_IRQCHIP 1
1897 #define KVM_IRQ_ROUTING_MSI 2
1898 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
1899 #define KVM_IRQ_ROUTING_HV_SINT 4
1900 #define KVM_IRQ_ROUTING_XEN_EVTCHN 5
1901
1902 flags:
1903
1904 - KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry
1905 type, specifies that the devid field contains a valid value. The per-VM
1906 KVM_CAP_MSI_DEVID capability advertises the requirement to provide
1907 the device ID. If this capability is not available, userspace should
1908 never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail.
1909 - zero otherwise
1910
1911 ::
1912
1913 struct kvm_irq_routing_irqchip {
1914 __u32 irqchip;
1915 __u32 pin;
1916 };
1917
1918 struct kvm_irq_routing_msi {
1919 __u32 address_lo;
1920 __u32 address_hi;
1921 __u32 data;
1922 union {
1923 __u32 pad;
1924 __u32 devid;
1925 };
1926 };
1927
1928 If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier
1929 for the device that wrote the MSI message. For PCI, this is usually a
1930 BDF identifier in the lower 16 bits.
1931
1932 On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS
1933 feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled,
1934 address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of
1935 address_hi must be zero.
1936
1937 ::
1938
1939 struct kvm_irq_routing_s390_adapter {
1940 __u64 ind_addr;
1941 __u64 summary_addr;
1942 __u64 ind_offset;
1943 __u32 summary_offset;
1944 __u32 adapter_id;
1945 };
1946
1947 struct kvm_irq_routing_hv_sint {
1948 __u32 vcpu;
1949 __u32 sint;
1950 };
1951
1952 struct kvm_irq_routing_xen_evtchn {
1953 __u32 port;
1954 __u32 vcpu;
1955 __u32 priority;
1956 };
1957
1958
1959 When KVM_CAP_XEN_HVM includes the KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL bit
1960 in its indication of supported features, routing to Xen event channels
1961 is supported. Although the priority field is present, only the value
1962 KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL is supported, which means delivery by
1963 2 level event channels. FIFO event channel support may be added in
1964 the future.
1965
1966
1967 4.55 KVM_SET_TSC_KHZ
1968 --------------------
1969
1970 :Capability: KVM_CAP_TSC_CONTROL / KVM_CAP_VM_TSC_CONTROL
1971 :Architectures: x86
1972 :Type: vcpu ioctl / vm ioctl
1973 :Parameters: virtual tsc_khz
1974 :Returns: 0 on success, -1 on error
1975
1976 Specifies the tsc frequency for the virtual machine. The unit of the
1977 frequency is KHz.
1978
1979 If the KVM_CAP_VM_TSC_CONTROL capability is advertised, this can also
1980 be used as a vm ioctl to set the initial tsc frequency of subsequently
1981 created vCPUs.
1982
1983 4.56 KVM_GET_TSC_KHZ
1984 --------------------
1985
1986 :Capability: KVM_CAP_GET_TSC_KHZ / KVM_CAP_VM_TSC_CONTROL
1987 :Architectures: x86
1988 :Type: vcpu ioctl / vm ioctl
1989 :Parameters: none
1990 :Returns: virtual tsc-khz on success, negative value on error
1991
1992 Returns the tsc frequency of the guest. The unit of the return value is
1993 KHz. If the host has unstable tsc this ioctl returns -EIO instead as an
1994 error.
1995
1996
1997 4.57 KVM_GET_LAPIC
1998 ------------------
1999
2000 :Capability: KVM_CAP_IRQCHIP
2001 :Architectures: x86
2002 :Type: vcpu ioctl
2003 :Parameters: struct kvm_lapic_state (out)
2004 :Returns: 0 on success, -1 on error
2005
2006 ::
2007
2008 #define KVM_APIC_REG_SIZE 0x400
2009 struct kvm_lapic_state {
2010 char regs[KVM_APIC_REG_SIZE];
2011 };
2012
2013 Reads the Local APIC registers and copies them into the input argument. The
2014 data format and layout are the same as documented in the architecture manual.
2015
2016 If KVM_X2APIC_API_USE_32BIT_IDS feature of KVM_CAP_X2APIC_API is
2017 enabled, then the format of APIC_ID register depends on the APIC mode
2018 (reported by MSR_IA32_APICBASE) of its VCPU. x2APIC stores APIC ID in
2019 the APIC_ID register (bytes 32-35). xAPIC only allows an 8-bit APIC ID
2020 which is stored in bits 31-24 of the APIC register, or equivalently in
2021 byte 35 of struct kvm_lapic_state's regs field. KVM_GET_LAPIC must then
2022 be called after MSR_IA32_APICBASE has been set with KVM_SET_MSR.
2023
2024 If KVM_X2APIC_API_USE_32BIT_IDS feature is disabled, struct kvm_lapic_state
2025 always uses xAPIC format.
2026
2027
2028 4.58 KVM_SET_LAPIC
2029 ------------------
2030
2031 :Capability: KVM_CAP_IRQCHIP
2032 :Architectures: x86
2033 :Type: vcpu ioctl
2034 :Parameters: struct kvm_lapic_state (in)
2035 :Returns: 0 on success, -1 on error
2036
2037 ::
2038
2039 #define KVM_APIC_REG_SIZE 0x400
2040 struct kvm_lapic_state {
2041 char regs[KVM_APIC_REG_SIZE];
2042 };
2043
2044 Copies the input argument into the Local APIC registers. The data format
2045 and layout are the same as documented in the architecture manual.
2046
2047 The format of the APIC ID register (bytes 32-35 of struct kvm_lapic_state's
2048 regs field) depends on the state of the KVM_CAP_X2APIC_API capability.
2049 See the note in KVM_GET_LAPIC.
2050
2051
2052 4.59 KVM_IOEVENTFD
2053 ------------------
2054
2055 :Capability: KVM_CAP_IOEVENTFD
2056 :Architectures: all
2057 :Type: vm ioctl
2058 :Parameters: struct kvm_ioeventfd (in)
2059 :Returns: 0 on success, !0 on error
2060
2061 This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address
2062 within the guest. A guest write in the registered address will signal the
2063 provided event instead of triggering an exit.
2064
2065 ::
2066
2067 struct kvm_ioeventfd {
2068 __u64 datamatch;
2069 __u64 addr; /* legal pio/mmio address */
2070 __u32 len; /* 0, 1, 2, 4, or 8 bytes */
2071 __s32 fd;
2072 __u32 flags;
2073 __u8 pad[36];
2074 };
2075
2076 For the special case of virtio-ccw devices on s390, the ioevent is matched
2077 to a subchannel/virtqueue tuple instead.
2078
2079 The following flags are defined::
2080
2081 #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
2082 #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
2083 #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
2084 #define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \
2085 (1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify)
2086
2087 If datamatch flag is set, the event will be signaled only if the written value
2088 to the registered address is equal to datamatch in struct kvm_ioeventfd.
2089
2090 For virtio-ccw devices, addr contains the subchannel id and datamatch the
2091 virtqueue index.
2092
2093 With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and
2094 the kernel will ignore the length of guest write and may get a faster vmexit.
2095 The speedup may only apply to specific architectures, but the ioeventfd will
2096 work anyway.
2097
2098 4.60 KVM_DIRTY_TLB
2099 ------------------
2100
2101 :Capability: KVM_CAP_SW_TLB
2102 :Architectures: ppc
2103 :Type: vcpu ioctl
2104 :Parameters: struct kvm_dirty_tlb (in)
2105 :Returns: 0 on success, -1 on error
2106
2107 ::
2108
2109 struct kvm_dirty_tlb {
2110 __u64 bitmap;
2111 __u32 num_dirty;
2112 };
2113
2114 This must be called whenever userspace has changed an entry in the shared
2115 TLB, prior to calling KVM_RUN on the associated vcpu.
2116
2117 The "bitmap" field is the userspace address of an array. This array
2118 consists of a number of bits, equal to the total number of TLB entries as
2119 determined by the last successful call to KVM_CONFIG_TLB, rounded up to the
2120 nearest multiple of 64.
2121
2122 Each bit corresponds to one TLB entry, ordered the same as in the shared TLB
2123 array.
2124
2125 The array is little-endian: the bit 0 is the least significant bit of the
2126 first byte, bit 8 is the least significant bit of the second byte, etc.
2127 This avoids any complications with differing word sizes.
2128
2129 The "num_dirty" field is a performance hint for KVM to determine whether it
2130 should skip processing the bitmap and just invalidate everything. It must
2131 be set to the number of set bits in the bitmap.
2132
2133
2134 4.62 KVM_CREATE_SPAPR_TCE
2135 -------------------------
2136
2137 :Capability: KVM_CAP_SPAPR_TCE
2138 :Architectures: powerpc
2139 :Type: vm ioctl
2140 :Parameters: struct kvm_create_spapr_tce (in)
2141 :Returns: file descriptor for manipulating the created TCE table
2142
2143 This creates a virtual TCE (translation control entry) table, which
2144 is an IOMMU for PAPR-style virtual I/O. It is used to translate
2145 logical addresses used in virtual I/O into guest physical addresses,
2146 and provides a scatter/gather capability for PAPR virtual I/O.
2147
2148 ::
2149
2150 /* for KVM_CAP_SPAPR_TCE */
2151 struct kvm_create_spapr_tce {
2152 __u64 liobn;
2153 __u32 window_size;
2154 };
2155
2156 The liobn field gives the logical IO bus number for which to create a
2157 TCE table. The window_size field specifies the size of the DMA window
2158 which this TCE table will translate - the table will contain one 64
2159 bit TCE entry for every 4kiB of the DMA window.
2160
2161 When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE
2162 table has been created using this ioctl(), the kernel will handle it
2163 in real mode, updating the TCE table. H_PUT_TCE calls for other
2164 liobns will cause a vm exit and must be handled by userspace.
2165
2166 The return value is a file descriptor which can be passed to mmap(2)
2167 to map the created TCE table into userspace. This lets userspace read
2168 the entries written by kernel-handled H_PUT_TCE calls, and also lets
2169 userspace update the TCE table directly which is useful in some
2170 circumstances.
2171
2172
2173 4.63 KVM_ALLOCATE_RMA
2174 ---------------------
2175
2176 :Capability: KVM_CAP_PPC_RMA
2177 :Architectures: powerpc
2178 :Type: vm ioctl
2179 :Parameters: struct kvm_allocate_rma (out)
2180 :Returns: file descriptor for mapping the allocated RMA
2181
2182 This allocates a Real Mode Area (RMA) from the pool allocated at boot
2183 time by the kernel. An RMA is a physically-contiguous, aligned region
2184 of memory used on older POWER processors to provide the memory which
2185 will be accessed by real-mode (MMU off) accesses in a KVM guest.
2186 POWER processors support a set of sizes for the RMA that usually
2187 includes 64MB, 128MB, 256MB and some larger powers of two.
2188
2189 ::
2190
2191 /* for KVM_ALLOCATE_RMA */
2192 struct kvm_allocate_rma {
2193 __u64 rma_size;
2194 };
2195
2196 The return value is a file descriptor which can be passed to mmap(2)
2197 to map the allocated RMA into userspace. The mapped area can then be
2198 passed to the KVM_SET_USER_MEMORY_REGION ioctl to establish it as the
2199 RMA for a virtual machine. The size of the RMA in bytes (which is
2200 fixed at host kernel boot time) is returned in the rma_size field of
2201 the argument structure.
2202
2203 The KVM_CAP_PPC_RMA capability is 1 or 2 if the KVM_ALLOCATE_RMA ioctl
2204 is supported; 2 if the processor requires all virtual machines to have
2205 an RMA, or 1 if the processor can use an RMA but doesn't require it,
2206 because it supports the Virtual RMA (VRMA) facility.
2207
2208
2209 4.64 KVM_NMI
2210 ------------
2211
2212 :Capability: KVM_CAP_USER_NMI
2213 :Architectures: x86
2214 :Type: vcpu ioctl
2215 :Parameters: none
2216 :Returns: 0 on success, -1 on error
2217
2218 Queues an NMI on the thread's vcpu. Note this is well defined only
2219 when KVM_CREATE_IRQCHIP has not been called, since this is an interface
2220 between the virtual cpu core and virtual local APIC. After KVM_CREATE_IRQCHIP
2221 has been called, this interface is completely emulated within the kernel.
2222
2223 To use this to emulate the LINT1 input with KVM_CREATE_IRQCHIP, use the
2224 following algorithm:
2225
2226 - pause the vcpu
2227 - read the local APIC's state (KVM_GET_LAPIC)
2228 - check whether changing LINT1 will queue an NMI (see the LVT entry for LINT1)
2229 - if so, issue KVM_NMI
2230 - resume the vcpu
2231
2232 Some guests configure the LINT1 NMI input to cause a panic, aiding in
2233 debugging.
2234
2235
2236 4.65 KVM_S390_UCAS_MAP
2237 ----------------------
2238
2239 :Capability: KVM_CAP_S390_UCONTROL
2240 :Architectures: s390
2241 :Type: vcpu ioctl
2242 :Parameters: struct kvm_s390_ucas_mapping (in)
2243 :Returns: 0 in case of success
2244
2245 The parameter is defined like this::
2246
2247 struct kvm_s390_ucas_mapping {
2248 __u64 user_addr;
2249 __u64 vcpu_addr;
2250 __u64 length;
2251 };
2252
2253 This ioctl maps the memory at "user_addr" with the length "length" to
2254 the vcpu's address space starting at "vcpu_addr". All parameters need to
2255 be aligned by 1 megabyte.
2256
2257
2258 4.66 KVM_S390_UCAS_UNMAP
2259 ------------------------
2260
2261 :Capability: KVM_CAP_S390_UCONTROL
2262 :Architectures: s390
2263 :Type: vcpu ioctl
2264 :Parameters: struct kvm_s390_ucas_mapping (in)
2265 :Returns: 0 in case of success
2266
2267 The parameter is defined like this::
2268
2269 struct kvm_s390_ucas_mapping {
2270 __u64 user_addr;
2271 __u64 vcpu_addr;
2272 __u64 length;
2273 };
2274
2275 This ioctl unmaps the memory in the vcpu's address space starting at
2276 "vcpu_addr" with the length "length". The field "user_addr" is ignored.
2277 All parameters need to be aligned by 1 megabyte.
2278
2279
2280 4.67 KVM_S390_VCPU_FAULT
2281 ------------------------
2282
2283 :Capability: KVM_CAP_S390_UCONTROL
2284 :Architectures: s390
2285 :Type: vcpu ioctl
2286 :Parameters: vcpu absolute address (in)
2287 :Returns: 0 in case of success
2288
2289 This call creates a page table entry on the virtual cpu's address space
2290 (for user controlled virtual machines) or the virtual machine's address
2291 space (for regular virtual machines). This only works for minor faults,
2292 thus it's recommended to access subject memory page via the user page
2293 table upfront. This is useful to handle validity intercepts for user
2294 controlled virtual machines to fault in the virtual cpu's lowcore pages
2295 prior to calling the KVM_RUN ioctl.
2296
2297
2298 4.68 KVM_SET_ONE_REG
2299 --------------------
2300
2301 :Capability: KVM_CAP_ONE_REG
2302 :Architectures: all
2303 :Type: vcpu ioctl
2304 :Parameters: struct kvm_one_reg (in)
2305 :Returns: 0 on success, negative value on failure
2306
2307 Errors:
2308
2309 ====== ============================================================
2310 ENOENT no such register
2311 EINVAL invalid register ID, or no such register or used with VMs in
2312 protected virtualization mode on s390
2313 EPERM (arm64) register access not allowed before vcpu finalization
2314 EBUSY (riscv) changing register value not allowed after the vcpu
2315 has run at least once
2316 ====== ============================================================
2317
2318 (These error codes are indicative only: do not rely on a specific error
2319 code being returned in a specific situation.)
2320
2321 ::
2322
2323 struct kvm_one_reg {
2324 __u64 id;
2325 __u64 addr;
2326 };
2327
2328 Using this ioctl, a single vcpu register can be set to a specific value
2329 defined by user space with the passed in struct kvm_one_reg, where id
2330 refers to the register identifier as described below and addr is a pointer
2331 to a variable with the respective size. There can be architecture agnostic
2332 and architecture specific registers. Each have their own range of operation
2333 and their own constants and width. To keep track of the implemented
2334 registers, find a list below:
2335
2336 ======= =============================== ============
2337 Arch Register Width (bits)
2338 ======= =============================== ============
2339 PPC KVM_REG_PPC_HIOR 64
2340 PPC KVM_REG_PPC_IAC1 64
2341 PPC KVM_REG_PPC_IAC2 64
2342 PPC KVM_REG_PPC_IAC3 64
2343 PPC KVM_REG_PPC_IAC4 64
2344 PPC KVM_REG_PPC_DAC1 64
2345 PPC KVM_REG_PPC_DAC2 64
2346 PPC KVM_REG_PPC_DABR 64
2347 PPC KVM_REG_PPC_DSCR 64
2348 PPC KVM_REG_PPC_PURR 64
2349 PPC KVM_REG_PPC_SPURR 64
2350 PPC KVM_REG_PPC_DAR 64
2351 PPC KVM_REG_PPC_DSISR 32
2352 PPC KVM_REG_PPC_AMR 64
2353 PPC KVM_REG_PPC_UAMOR 64
2354 PPC KVM_REG_PPC_MMCR0 64
2355 PPC KVM_REG_PPC_MMCR1 64
2356 PPC KVM_REG_PPC_MMCRA 64
2357 PPC KVM_REG_PPC_MMCR2 64
2358 PPC KVM_REG_PPC_MMCRS 64
2359 PPC KVM_REG_PPC_MMCR3 64
2360 PPC KVM_REG_PPC_SIAR 64
2361 PPC KVM_REG_PPC_SDAR 64
2362 PPC KVM_REG_PPC_SIER 64
2363 PPC KVM_REG_PPC_SIER2 64
2364 PPC KVM_REG_PPC_SIER3 64
2365 PPC KVM_REG_PPC_PMC1 32
2366 PPC KVM_REG_PPC_PMC2 32
2367 PPC KVM_REG_PPC_PMC3 32
2368 PPC KVM_REG_PPC_PMC4 32
2369 PPC KVM_REG_PPC_PMC5 32
2370 PPC KVM_REG_PPC_PMC6 32
2371 PPC KVM_REG_PPC_PMC7 32
2372 PPC KVM_REG_PPC_PMC8 32
2373 PPC KVM_REG_PPC_FPR0 64
2374 ...
2375 PPC KVM_REG_PPC_FPR31 64
2376 PPC KVM_REG_PPC_VR0 128
2377 ...
2378 PPC KVM_REG_PPC_VR31 128
2379 PPC KVM_REG_PPC_VSR0 128
2380 ...
2381 PPC KVM_REG_PPC_VSR31 128
2382 PPC KVM_REG_PPC_FPSCR 64
2383 PPC KVM_REG_PPC_VSCR 32
2384 PPC KVM_REG_PPC_VPA_ADDR 64
2385 PPC KVM_REG_PPC_VPA_SLB 128
2386 PPC KVM_REG_PPC_VPA_DTL 128
2387 PPC KVM_REG_PPC_EPCR 32
2388 PPC KVM_REG_PPC_EPR 32
2389 PPC KVM_REG_PPC_TCR 32
2390 PPC KVM_REG_PPC_TSR 32
2391 PPC KVM_REG_PPC_OR_TSR 32
2392 PPC KVM_REG_PPC_CLEAR_TSR 32
2393 PPC KVM_REG_PPC_MAS0 32
2394 PPC KVM_REG_PPC_MAS1 32
2395 PPC KVM_REG_PPC_MAS2 64
2396 PPC KVM_REG_PPC_MAS7_3 64
2397 PPC KVM_REG_PPC_MAS4 32
2398 PPC KVM_REG_PPC_MAS6 32
2399 PPC KVM_REG_PPC_MMUCFG 32
2400 PPC KVM_REG_PPC_TLB0CFG 32
2401 PPC KVM_REG_PPC_TLB1CFG 32
2402 PPC KVM_REG_PPC_TLB2CFG 32
2403 PPC KVM_REG_PPC_TLB3CFG 32
2404 PPC KVM_REG_PPC_TLB0PS 32
2405 PPC KVM_REG_PPC_TLB1PS 32
2406 PPC KVM_REG_PPC_TLB2PS 32
2407 PPC KVM_REG_PPC_TLB3PS 32
2408 PPC KVM_REG_PPC_EPTCFG 32
2409 PPC KVM_REG_PPC_ICP_STATE 64
2410 PPC KVM_REG_PPC_VP_STATE 128
2411 PPC KVM_REG_PPC_TB_OFFSET 64
2412 PPC KVM_REG_PPC_SPMC1 32
2413 PPC KVM_REG_PPC_SPMC2 32
2414 PPC KVM_REG_PPC_IAMR 64
2415 PPC KVM_REG_PPC_TFHAR 64
2416 PPC KVM_REG_PPC_TFIAR 64
2417 PPC KVM_REG_PPC_TEXASR 64
2418 PPC KVM_REG_PPC_FSCR 64
2419 PPC KVM_REG_PPC_PSPB 32
2420 PPC KVM_REG_PPC_EBBHR 64
2421 PPC KVM_REG_PPC_EBBRR 64
2422 PPC KVM_REG_PPC_BESCR 64
2423 PPC KVM_REG_PPC_TAR 64
2424 PPC KVM_REG_PPC_DPDES 64
2425 PPC KVM_REG_PPC_DAWR 64
2426 PPC KVM_REG_PPC_DAWRX 64
2427 PPC KVM_REG_PPC_CIABR 64
2428 PPC KVM_REG_PPC_IC 64
2429 PPC KVM_REG_PPC_VTB 64
2430 PPC KVM_REG_PPC_CSIGR 64
2431 PPC KVM_REG_PPC_TACR 64
2432 PPC KVM_REG_PPC_TCSCR 64
2433 PPC KVM_REG_PPC_PID 64
2434 PPC KVM_REG_PPC_ACOP 64
2435 PPC KVM_REG_PPC_VRSAVE 32
2436 PPC KVM_REG_PPC_LPCR 32
2437 PPC KVM_REG_PPC_LPCR_64 64
2438 PPC KVM_REG_PPC_PPR 64
2439 PPC KVM_REG_PPC_ARCH_COMPAT 32
2440 PPC KVM_REG_PPC_DABRX 32
2441 PPC KVM_REG_PPC_WORT 64
2442 PPC KVM_REG_PPC_SPRG9 64
2443 PPC KVM_REG_PPC_DBSR 32
2444 PPC KVM_REG_PPC_TIDR 64
2445 PPC KVM_REG_PPC_PSSCR 64
2446 PPC KVM_REG_PPC_DEC_EXPIRY 64
2447 PPC KVM_REG_PPC_PTCR 64
2448 PPC KVM_REG_PPC_HASHKEYR 64
2449 PPC KVM_REG_PPC_HASHPKEYR 64
2450 PPC KVM_REG_PPC_DAWR1 64
2451 PPC KVM_REG_PPC_DAWRX1 64
2452 PPC KVM_REG_PPC_DEXCR 64
2453 PPC KVM_REG_PPC_TM_GPR0 64
2454 ...
2455 PPC KVM_REG_PPC_TM_GPR31 64
2456 PPC KVM_REG_PPC_TM_VSR0 128
2457 ...
2458 PPC KVM_REG_PPC_TM_VSR63 128
2459 PPC KVM_REG_PPC_TM_CR 64
2460 PPC KVM_REG_PPC_TM_LR 64
2461 PPC KVM_REG_PPC_TM_CTR 64
2462 PPC KVM_REG_PPC_TM_FPSCR 64
2463 PPC KVM_REG_PPC_TM_AMR 64
2464 PPC KVM_REG_PPC_TM_PPR 64
2465 PPC KVM_REG_PPC_TM_VRSAVE 64
2466 PPC KVM_REG_PPC_TM_VSCR 32
2467 PPC KVM_REG_PPC_TM_DSCR 64
2468 PPC KVM_REG_PPC_TM_TAR 64
2469 PPC KVM_REG_PPC_TM_XER 64
2470
2471 MIPS KVM_REG_MIPS_R0 64
2472 ...
2473 MIPS KVM_REG_MIPS_R31 64
2474 MIPS KVM_REG_MIPS_HI 64
2475 MIPS KVM_REG_MIPS_LO 64
2476 MIPS KVM_REG_MIPS_PC 64
2477 MIPS KVM_REG_MIPS_CP0_INDEX 32
2478 MIPS KVM_REG_MIPS_CP0_ENTRYLO0 64
2479 MIPS KVM_REG_MIPS_CP0_ENTRYLO1 64
2480 MIPS KVM_REG_MIPS_CP0_CONTEXT 64
2481 MIPS KVM_REG_MIPS_CP0_CONTEXTCONFIG 32
2482 MIPS KVM_REG_MIPS_CP0_USERLOCAL 64
2483 MIPS KVM_REG_MIPS_CP0_XCONTEXTCONFIG 64
2484 MIPS KVM_REG_MIPS_CP0_PAGEMASK 32
2485 MIPS KVM_REG_MIPS_CP0_PAGEGRAIN 32
2486 MIPS KVM_REG_MIPS_CP0_SEGCTL0 64
2487 MIPS KVM_REG_MIPS_CP0_SEGCTL1 64
2488 MIPS KVM_REG_MIPS_CP0_SEGCTL2 64
2489 MIPS KVM_REG_MIPS_CP0_PWBASE 64
2490 MIPS KVM_REG_MIPS_CP0_PWFIELD 64
2491 MIPS KVM_REG_MIPS_CP0_PWSIZE 64
2492 MIPS KVM_REG_MIPS_CP0_WIRED 32
2493 MIPS KVM_REG_MIPS_CP0_PWCTL 32
2494 MIPS KVM_REG_MIPS_CP0_HWRENA 32
2495 MIPS KVM_REG_MIPS_CP0_BADVADDR 64
2496 MIPS KVM_REG_MIPS_CP0_BADINSTR 32
2497 MIPS KVM_REG_MIPS_CP0_BADINSTRP 32
2498 MIPS KVM_REG_MIPS_CP0_COUNT 32
2499 MIPS KVM_REG_MIPS_CP0_ENTRYHI 64
2500 MIPS KVM_REG_MIPS_CP0_COMPARE 32
2501 MIPS KVM_REG_MIPS_CP0_STATUS 32
2502 MIPS KVM_REG_MIPS_CP0_INTCTL 32
2503 MIPS KVM_REG_MIPS_CP0_CAUSE 32
2504 MIPS KVM_REG_MIPS_CP0_EPC 64
2505 MIPS KVM_REG_MIPS_CP0_PRID 32
2506 MIPS KVM_REG_MIPS_CP0_EBASE 64
2507 MIPS KVM_REG_MIPS_CP0_CONFIG 32
2508 MIPS KVM_REG_MIPS_CP0_CONFIG1 32
2509 MIPS KVM_REG_MIPS_CP0_CONFIG2 32
2510 MIPS KVM_REG_MIPS_CP0_CONFIG3 32
2511 MIPS KVM_REG_MIPS_CP0_CONFIG4 32
2512 MIPS KVM_REG_MIPS_CP0_CONFIG5 32
2513 MIPS KVM_REG_MIPS_CP0_CONFIG7 32
2514 MIPS KVM_REG_MIPS_CP0_XCONTEXT 64
2515 MIPS KVM_REG_MIPS_CP0_ERROREPC 64
2516 MIPS KVM_REG_MIPS_CP0_KSCRATCH1 64
2517 MIPS KVM_REG_MIPS_CP0_KSCRATCH2 64
2518 MIPS KVM_REG_MIPS_CP0_KSCRATCH3 64
2519 MIPS KVM_REG_MIPS_CP0_KSCRATCH4 64
2520 MIPS KVM_REG_MIPS_CP0_KSCRATCH5 64
2521 MIPS KVM_REG_MIPS_CP0_KSCRATCH6 64
2522 MIPS KVM_REG_MIPS_CP0_MAAR(0..63) 64
2523 MIPS KVM_REG_MIPS_COUNT_CTL 64
2524 MIPS KVM_REG_MIPS_COUNT_RESUME 64
2525 MIPS KVM_REG_MIPS_COUNT_HZ 64
2526 MIPS KVM_REG_MIPS_FPR_32(0..31) 32
2527 MIPS KVM_REG_MIPS_FPR_64(0..31) 64
2528 MIPS KVM_REG_MIPS_VEC_128(0..31) 128
2529 MIPS KVM_REG_MIPS_FCR_IR 32
2530 MIPS KVM_REG_MIPS_FCR_CSR 32
2531 MIPS KVM_REG_MIPS_MSA_IR 32
2532 MIPS KVM_REG_MIPS_MSA_CSR 32
2533 ======= =============================== ============
2534
2535 ARM registers are mapped using the lower 32 bits. The upper 16 of that
2536 is the register group type, or coprocessor number:
2537
2538 ARM core registers have the following id bit patterns::
2539
2540 0x4020 0000 0010 <index into the kvm_regs struct:16>
2541
2542 ARM 32-bit CP15 registers have the following id bit patterns::
2543
2544 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3>
2545
2546 ARM 64-bit CP15 registers have the following id bit patterns::
2547
2548 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3>
2549
2550 ARM CCSIDR registers are demultiplexed by CSSELR value::
2551
2552 0x4020 0000 0011 00 <csselr:8>
2553
2554 ARM 32-bit VFP control registers have the following id bit patterns::
2555
2556 0x4020 0000 0012 1 <regno:12>
2557
2558 ARM 64-bit FP registers have the following id bit patterns::
2559
2560 0x4030 0000 0012 0 <regno:12>
2561
2562 ARM firmware pseudo-registers have the following bit pattern::
2563
2564 0x4030 0000 0014 <regno:16>
2565
2566
2567 arm64 registers are mapped using the lower 32 bits. The upper 16 of
2568 that is the register group type, or coprocessor number:
2569
2570 arm64 core/FP-SIMD registers have the following id bit patterns. Note
2571 that the size of the access is variable, as the kvm_regs structure
2572 contains elements ranging from 32 to 128 bits. The index is a 32bit
2573 value in the kvm_regs structure seen as a 32bit array::
2574
2575 0x60x0 0000 0010 <index into the kvm_regs struct:16>
2576
2577 Specifically:
2578
2579 ======================= ========= ===== =======================================
2580 Encoding Register Bits kvm_regs member
2581 ======================= ========= ===== =======================================
2582 0x6030 0000 0010 0000 X0 64 regs.regs[0]
2583 0x6030 0000 0010 0002 X1 64 regs.regs[1]
2584 ...
2585 0x6030 0000 0010 003c X30 64 regs.regs[30]
2586 0x6030 0000 0010 003e SP 64 regs.sp
2587 0x6030 0000 0010 0040 PC 64 regs.pc
2588 0x6030 0000 0010 0042 PSTATE 64 regs.pstate
2589 0x6030 0000 0010 0044 SP_EL1 64 sp_el1
2590 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1
2591 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC)
2592 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT]
2593 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND]
2594 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ]
2595 0x6030 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ]
2596 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] [1]_
2597 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] [1]_
2598 ...
2599 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] [1]_
2600 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr
2601 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr
2602 ======================= ========= ===== =======================================
2603
2604 .. [1] These encodings are not accepted for SVE-enabled vcpus. See
2605 KVM_ARM_VCPU_INIT.
2606
2607 The equivalent register content can be accessed via bits [127:0] of
2608 the corresponding SVE Zn registers instead for vcpus that have SVE
2609 enabled (see below).
2610
2611 arm64 CCSIDR registers are demultiplexed by CSSELR value::
2612
2613 0x6020 0000 0011 00 <csselr:8>
2614
2615 arm64 system registers have the following id bit patterns::
2616
2617 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3>
2618
2619 .. warning::
2620
2621 Two system register IDs do not follow the specified pattern. These
2622 are KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT, which map to
2623 system registers CNTV_CVAL_EL0 and CNTVCT_EL0 respectively. These
2624 two had their values accidentally swapped, which means TIMER_CVAL is
2625 derived from the register encoding for CNTVCT_EL0 and TIMER_CNT is
2626 derived from the register encoding for CNTV_CVAL_EL0. As this is
2627 API, it must remain this way.
2628
2629 arm64 firmware pseudo-registers have the following bit pattern::
2630
2631 0x6030 0000 0014 <regno:16>
2632
2633 arm64 SVE registers have the following bit patterns::
2634
2635 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice]
2636 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice]
2637 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice]
2638 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register
2639
2640 Access to register IDs where 2048 * slice >= 128 * max_vq will fail with
2641 ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit
2642 quadwords: see [2]_ below.
2643
2644 These registers are only accessible on vcpus for which SVE is enabled.
2645 See KVM_ARM_VCPU_INIT for details.
2646
2647 In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not
2648 accessible until the vcpu's SVE configuration has been finalized
2649 using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT
2650 and KVM_ARM_VCPU_FINALIZE for more information about this procedure.
2651
2652 KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector
2653 lengths supported by the vcpu to be discovered and configured by
2654 userspace. When transferred to or from user memory via KVM_GET_ONE_REG
2655 or KVM_SET_ONE_REG, the value of this register is of type
2656 __u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as
2657 follows::
2658
2659 __u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS];
2660
2661 if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX &&
2662 ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >>
2663 ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1))
2664 /* Vector length vq * 16 bytes supported */
2665 else
2666 /* Vector length vq * 16 bytes not supported */
2667
2668 .. [2] The maximum value vq for which the above condition is true is
2669 max_vq. This is the maximum vector length available to the guest on
2670 this vcpu, and determines which register slices are visible through
2671 this ioctl interface.
2672
2673 (See Documentation/arch/arm64/sve.rst for an explanation of the "vq"
2674 nomenclature.)
2675
2676 KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT.
2677 KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that
2678 the host supports.
2679
2680 Userspace may subsequently modify it if desired until the vcpu's SVE
2681 configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE).
2682
2683 Apart from simply removing all vector lengths from the host set that
2684 exceed some value, support for arbitrarily chosen sets of vector lengths
2685 is hardware-dependent and may not be available. Attempting to configure
2686 an invalid set of vector lengths via KVM_SET_ONE_REG will fail with
2687 EINVAL.
2688
2689 After the vcpu's SVE configuration is finalized, further attempts to
2690 write this register will fail with EPERM.
2691
2692 arm64 bitmap feature firmware pseudo-registers have the following bit pattern::
2693
2694 0x6030 0000 0016 <regno:16>
2695
2696 The bitmap feature firmware registers exposes the hypercall services that
2697 are available for userspace to configure. The set bits corresponds to the
2698 services that are available for the guests to access. By default, KVM
2699 sets all the supported bits during VM initialization. The userspace can
2700 discover the available services via KVM_GET_ONE_REG, and write back the
2701 bitmap corresponding to the features that it wishes guests to see via
2702 KVM_SET_ONE_REG.
2703
2704 Note: These registers are immutable once any of the vCPUs of the VM has
2705 run at least once. A KVM_SET_ONE_REG in such a scenario will return
2706 a -EBUSY to userspace.
2707
2708 (See Documentation/virt/kvm/arm/hypercalls.rst for more details.)
2709
2710
2711 MIPS registers are mapped using the lower 32 bits. The upper 16 of that is
2712 the register group type:
2713
2714 MIPS core registers (see above) have the following id bit patterns::
2715
2716 0x7030 0000 0000 <reg:16>
2717
2718 MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit
2719 patterns depending on whether they're 32-bit or 64-bit registers::
2720
2721 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit)
2722 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit)
2723
2724 Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64
2725 versions of the EntryLo registers regardless of the word size of the host
2726 hardware, host kernel, guest, and whether XPA is present in the guest, i.e.
2727 with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and
2728 the PFNX field starting at bit 30.
2729
2730 MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit
2731 patterns::
2732
2733 0x7030 0000 0001 01 <reg:8>
2734
2735 MIPS KVM control registers (see above) have the following id bit patterns::
2736
2737 0x7030 0000 0002 <reg:16>
2738
2739 MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following
2740 id bit patterns depending on the size of the register being accessed. They are
2741 always accessed according to the current guest FPU mode (Status.FR and
2742 Config5.FRE), i.e. as the guest would see them, and they become unpredictable
2743 if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector
2744 registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they
2745 overlap the FPU registers::
2746
2747 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers)
2748 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers)
2749 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers)
2750
2751 MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the
2752 following id bit patterns::
2753
2754 0x7020 0000 0003 01 <0:3> <reg:5>
2755
2756 MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the
2757 following id bit patterns::
2758
2759 0x7020 0000 0003 02 <0:3> <reg:5>
2760
2761 RISC-V registers are mapped using the lower 32 bits. The upper 8 bits of
2762 that is the register group type.
2763
2764 RISC-V config registers are meant for configuring a Guest VCPU and it has
2765 the following id bit patterns::
2766
2767 0x8020 0000 01 <index into the kvm_riscv_config struct:24> (32bit Host)
2768 0x8030 0000 01 <index into the kvm_riscv_config struct:24> (64bit Host)
2769
2770 Following are the RISC-V config registers:
2771
2772 ======================= ========= =============================================
2773 Encoding Register Description
2774 ======================= ========= =============================================
2775 0x80x0 0000 0100 0000 isa ISA feature bitmap of Guest VCPU
2776 ======================= ========= =============================================
2777
2778 The isa config register can be read anytime but can only be written before
2779 a Guest VCPU runs. It will have ISA feature bits matching underlying host
2780 set by default.
2781
2782 RISC-V core registers represent the general execution state of a Guest VCPU
2783 and it has the following id bit patterns::
2784
2785 0x8020 0000 02 <index into the kvm_riscv_core struct:24> (32bit Host)
2786 0x8030 0000 02 <index into the kvm_riscv_core struct:24> (64bit Host)
2787
2788 Following are the RISC-V core registers:
2789
2790 ======================= ========= =============================================
2791 Encoding Register Description
2792 ======================= ========= =============================================
2793 0x80x0 0000 0200 0000 regs.pc Program counter
2794 0x80x0 0000 0200 0001 regs.ra Return address
2795 0x80x0 0000 0200 0002 regs.sp Stack pointer
2796 0x80x0 0000 0200 0003 regs.gp Global pointer
2797 0x80x0 0000 0200 0004 regs.tp Task pointer
2798 0x80x0 0000 0200 0005 regs.t0 Caller saved register 0
2799 0x80x0 0000 0200 0006 regs.t1 Caller saved register 1
2800 0x80x0 0000 0200 0007 regs.t2 Caller saved register 2
2801 0x80x0 0000 0200 0008 regs.s0 Callee saved register 0
2802 0x80x0 0000 0200 0009 regs.s1 Callee saved register 1
2803 0x80x0 0000 0200 000a regs.a0 Function argument (or return value) 0
2804 0x80x0 0000 0200 000b regs.a1 Function argument (or return value) 1
2805 0x80x0 0000 0200 000c regs.a2 Function argument 2
2806 0x80x0 0000 0200 000d regs.a3 Function argument 3
2807 0x80x0 0000 0200 000e regs.a4 Function argument 4
2808 0x80x0 0000 0200 000f regs.a5 Function argument 5
2809 0x80x0 0000 0200 0010 regs.a6 Function argument 6
2810 0x80x0 0000 0200 0011 regs.a7 Function argument 7
2811 0x80x0 0000 0200 0012 regs.s2 Callee saved register 2
2812 0x80x0 0000 0200 0013 regs.s3 Callee saved register 3
2813 0x80x0 0000 0200 0014 regs.s4 Callee saved register 4
2814 0x80x0 0000 0200 0015 regs.s5 Callee saved register 5
2815 0x80x0 0000 0200 0016 regs.s6 Callee saved register 6
2816 0x80x0 0000 0200 0017 regs.s7 Callee saved register 7
2817 0x80x0 0000 0200 0018 regs.s8 Callee saved register 8
2818 0x80x0 0000 0200 0019 regs.s9 Callee saved register 9
2819 0x80x0 0000 0200 001a regs.s10 Callee saved register 10
2820 0x80x0 0000 0200 001b regs.s11 Callee saved register 11
2821 0x80x0 0000 0200 001c regs.t3 Caller saved register 3
2822 0x80x0 0000 0200 001d regs.t4 Caller saved register 4
2823 0x80x0 0000 0200 001e regs.t5 Caller saved register 5
2824 0x80x0 0000 0200 001f regs.t6 Caller saved register 6
2825 0x80x0 0000 0200 0020 mode Privilege mode (1 = S-mode or 0 = U-mode)
2826 ======================= ========= =============================================
2827
2828 RISC-V csr registers represent the supervisor mode control/status registers
2829 of a Guest VCPU and it has the following id bit patterns::
2830
2831 0x8020 0000 03 <index into the kvm_riscv_csr struct:24> (32bit Host)
2832 0x8030 0000 03 <index into the kvm_riscv_csr struct:24> (64bit Host)
2833
2834 Following are the RISC-V csr registers:
2835
2836 ======================= ========= =============================================
2837 Encoding Register Description
2838 ======================= ========= =============================================
2839 0x80x0 0000 0300 0000 sstatus Supervisor status
2840 0x80x0 0000 0300 0001 sie Supervisor interrupt enable
2841 0x80x0 0000 0300 0002 stvec Supervisor trap vector base
2842 0x80x0 0000 0300 0003 sscratch Supervisor scratch register
2843 0x80x0 0000 0300 0004 sepc Supervisor exception program counter
2844 0x80x0 0000 0300 0005 scause Supervisor trap cause
2845 0x80x0 0000 0300 0006 stval Supervisor bad address or instruction
2846 0x80x0 0000 0300 0007 sip Supervisor interrupt pending
2847 0x80x0 0000 0300 0008 satp Supervisor address translation and protection
2848 ======================= ========= =============================================
2849
2850 RISC-V timer registers represent the timer state of a Guest VCPU and it has
2851 the following id bit patterns::
2852
2853 0x8030 0000 04 <index into the kvm_riscv_timer struct:24>
2854
2855 Following are the RISC-V timer registers:
2856
2857 ======================= ========= =============================================
2858 Encoding Register Description
2859 ======================= ========= =============================================
2860 0x8030 0000 0400 0000 frequency Time base frequency (read-only)
2861 0x8030 0000 0400 0001 time Time value visible to Guest
2862 0x8030 0000 0400 0002 compare Time compare programmed by Guest
2863 0x8030 0000 0400 0003 state Time compare state (1 = ON or 0 = OFF)
2864 ======================= ========= =============================================
2865
2866 RISC-V F-extension registers represent the single precision floating point
2867 state of a Guest VCPU and it has the following id bit patterns::
2868
2869 0x8020 0000 05 <index into the __riscv_f_ext_state struct:24>
2870
2871 Following are the RISC-V F-extension registers:
2872
2873 ======================= ========= =============================================
2874 Encoding Register Description
2875 ======================= ========= =============================================
2876 0x8020 0000 0500 0000 f[0] Floating point register 0
2877 ...
2878 0x8020 0000 0500 001f f[31] Floating point register 31
2879 0x8020 0000 0500 0020 fcsr Floating point control and status register
2880 ======================= ========= =============================================
2881
2882 RISC-V D-extension registers represent the double precision floating point
2883 state of a Guest VCPU and it has the following id bit patterns::
2884
2885 0x8020 0000 06 <index into the __riscv_d_ext_state struct:24> (fcsr)
2886 0x8030 0000 06 <index into the __riscv_d_ext_state struct:24> (non-fcsr)
2887
2888 Following are the RISC-V D-extension registers:
2889
2890 ======================= ========= =============================================
2891 Encoding Register Description
2892 ======================= ========= =============================================
2893 0x8030 0000 0600 0000 f[0] Floating point register 0
2894 ...
2895 0x8030 0000 0600 001f f[31] Floating point register 31
2896 0x8020 0000 0600 0020 fcsr Floating point control and status register
2897 ======================= ========= =============================================
2898
2899 LoongArch registers are mapped using the lower 32 bits. The upper 16 bits of
2900 that is the register group type.
2901
2902 LoongArch csr registers are used to control guest cpu or get status of guest
2903 cpu, and they have the following id bit patterns::
2904
2905 0x9030 0000 0001 00 <reg:5> <sel:3> (64-bit)
2906
2907 LoongArch KVM control registers are used to implement some new defined functions
2908 such as set vcpu counter or reset vcpu, and they have the following id bit patterns::
2909
2910 0x9030 0000 0002 <reg:16>
2911
2912
2913 4.69 KVM_GET_ONE_REG
2914 --------------------
2915
2916 :Capability: KVM_CAP_ONE_REG
2917 :Architectures: all
2918 :Type: vcpu ioctl
2919 :Parameters: struct kvm_one_reg (in and out)
2920 :Returns: 0 on success, negative value on failure
2921
2922 Errors include:
2923
2924 ======== ============================================================
2925 ENOENT no such register
2926 EINVAL invalid register ID, or no such register or used with VMs in
2927 protected virtualization mode on s390
2928 EPERM (arm64) register access not allowed before vcpu finalization
2929 ======== ============================================================
2930
2931 (These error codes are indicative only: do not rely on a specific error
2932 code being returned in a specific situation.)
2933
2934 This ioctl allows to receive the value of a single register implemented
2935 in a vcpu. The register to read is indicated by the "id" field of the
2936 kvm_one_reg struct passed in. On success, the register value can be found
2937 at the memory location pointed to by "addr".
2938
2939 The list of registers accessible using this interface is identical to the
2940 list in 4.68.
2941
2942
2943 4.70 KVM_KVMCLOCK_CTRL
2944 ----------------------
2945
2946 :Capability: KVM_CAP_KVMCLOCK_CTRL
2947 :Architectures: Any that implement pvclocks (currently x86 only)
2948 :Type: vcpu ioctl
2949 :Parameters: None
2950 :Returns: 0 on success, -1 on error
2951
2952 This ioctl sets a flag accessible to the guest indicating that the specified
2953 vCPU has been paused by the host userspace.
2954
2955 The host will set a flag in the pvclock structure that is checked from the
2956 soft lockup watchdog. The flag is part of the pvclock structure that is
2957 shared between guest and host, specifically the second bit of the flags
2958 field of the pvclock_vcpu_time_info structure. It will be set exclusively by
2959 the host and read/cleared exclusively by the guest. The guest operation of
2960 checking and clearing the flag must be an atomic operation so
2961 load-link/store-conditional, or equivalent must be used. There are two cases
2962 where the guest will clear the flag: when the soft lockup watchdog timer resets
2963 itself or when a soft lockup is detected. This ioctl can be called any time
2964 after pausing the vcpu, but before it is resumed.
2965
2966
2967 4.71 KVM_SIGNAL_MSI
2968 -------------------
2969
2970 :Capability: KVM_CAP_SIGNAL_MSI
2971 :Architectures: x86 arm64
2972 :Type: vm ioctl
2973 :Parameters: struct kvm_msi (in)
2974 :Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error
2975
2976 Directly inject a MSI message. Only valid with in-kernel irqchip that handles
2977 MSI messages.
2978
2979 ::
2980
2981 struct kvm_msi {
2982 __u32 address_lo;
2983 __u32 address_hi;
2984 __u32 data;
2985 __u32 flags;
2986 __u32 devid;
2987 __u8 pad[12];
2988 };
2989
2990 flags:
2991 KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM
2992 KVM_CAP_MSI_DEVID capability advertises the requirement to provide
2993 the device ID. If this capability is not available, userspace
2994 should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail.
2995
2996 If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier
2997 for the device that wrote the MSI message. For PCI, this is usually a
2998 BDF identifier in the lower 16 bits.
2999
3000 On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS
3001 feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled,
3002 address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of
3003 address_hi must be zero.
3004
3005
3006 4.71 KVM_CREATE_PIT2
3007 --------------------
3008
3009 :Capability: KVM_CAP_PIT2
3010 :Architectures: x86
3011 :Type: vm ioctl
3012 :Parameters: struct kvm_pit_config (in)
3013 :Returns: 0 on success, -1 on error
3014
3015 Creates an in-kernel device model for the i8254 PIT. This call is only valid
3016 after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following
3017 parameters have to be passed::
3018
3019 struct kvm_pit_config {
3020 __u32 flags;
3021 __u32 pad[15];
3022 };
3023
3024 Valid flags are::
3025
3026 #define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */
3027
3028 PIT timer interrupts may use a per-VM kernel thread for injection. If it
3029 exists, this thread will have a name of the following pattern::
3030
3031 kvm-pit/<owner-process-pid>
3032
3033 When running a guest with elevated priorities, the scheduling parameters of
3034 this thread may have to be adjusted accordingly.
3035
3036 This IOCTL replaces the obsolete KVM_CREATE_PIT.
3037
3038
3039 4.72 KVM_GET_PIT2
3040 -----------------
3041
3042 :Capability: KVM_CAP_PIT_STATE2
3043 :Architectures: x86
3044 :Type: vm ioctl
3045 :Parameters: struct kvm_pit_state2 (out)
3046 :Returns: 0 on success, -1 on error
3047
3048 Retrieves the state of the in-kernel PIT model. Only valid after
3049 KVM_CREATE_PIT2. The state is returned in the following structure::
3050
3051 struct kvm_pit_state2 {
3052 struct kvm_pit_channel_state channels[3];
3053 __u32 flags;
3054 __u32 reserved[9];
3055 };
3056
3057 Valid flags are::
3058
3059 /* disable PIT in HPET legacy mode */
3060 #define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001
3061 /* speaker port data bit enabled */
3062 #define KVM_PIT_FLAGS_SPEAKER_DATA_ON 0x00000002
3063
3064 This IOCTL replaces the obsolete KVM_GET_PIT.
3065
3066
3067 4.73 KVM_SET_PIT2
3068 -----------------
3069
3070 :Capability: KVM_CAP_PIT_STATE2
3071 :Architectures: x86
3072 :Type: vm ioctl
3073 :Parameters: struct kvm_pit_state2 (in)
3074 :Returns: 0 on success, -1 on error
3075
3076 Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2.
3077 See KVM_GET_PIT2 for details on struct kvm_pit_state2.
3078
3079 This IOCTL replaces the obsolete KVM_SET_PIT.
3080
3081
3082 4.74 KVM_PPC_GET_SMMU_INFO
3083 --------------------------
3084
3085 :Capability: KVM_CAP_PPC_GET_SMMU_INFO
3086 :Architectures: powerpc
3087 :Type: vm ioctl
3088 :Parameters: None
3089 :Returns: 0 on success, -1 on error
3090
3091 This populates and returns a structure describing the features of
3092 the "Server" class MMU emulation supported by KVM.
3093 This can in turn be used by userspace to generate the appropriate
3094 device-tree properties for the guest operating system.
3095
3096 The structure contains some global information, followed by an
3097 array of supported segment page sizes::
3098
3099 struct kvm_ppc_smmu_info {
3100 __u64 flags;
3101 __u32 slb_size;
3102 __u32 pad;
3103 struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ];
3104 };
3105
3106 The supported flags are:
3107
3108 - KVM_PPC_PAGE_SIZES_REAL:
3109 When that flag is set, guest page sizes must "fit" the backing
3110 store page sizes. When not set, any page size in the list can
3111 be used regardless of how they are backed by userspace.
3112
3113 - KVM_PPC_1T_SEGMENTS
3114 The emulated MMU supports 1T segments in addition to the
3115 standard 256M ones.
3116
3117 - KVM_PPC_NO_HASH
3118 This flag indicates that HPT guests are not supported by KVM,
3119 thus all guests must use radix MMU mode.
3120
3121 The "slb_size" field indicates how many SLB entries are supported
3122
3123 The "sps" array contains 8 entries indicating the supported base
3124 page sizes for a segment in increasing order. Each entry is defined
3125 as follow::
3126
3127 struct kvm_ppc_one_seg_page_size {
3128 __u32 page_shift; /* Base page shift of segment (or 0) */
3129 __u32 slb_enc; /* SLB encoding for BookS */
3130 struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ];
3131 };
3132
3133 An entry with a "page_shift" of 0 is unused. Because the array is
3134 organized in increasing order, a lookup can stop when encountering
3135 such an entry.
3136
3137 The "slb_enc" field provides the encoding to use in the SLB for the
3138 page size. The bits are in positions such as the value can directly
3139 be OR'ed into the "vsid" argument of the slbmte instruction.
3140
3141 The "enc" array is a list which for each of those segment base page
3142 size provides the list of supported actual page sizes (which can be
3143 only larger or equal to the base page size), along with the
3144 corresponding encoding in the hash PTE. Similarly, the array is
3145 8 entries sorted by increasing sizes and an entry with a "0" shift
3146 is an empty entry and a terminator::
3147
3148 struct kvm_ppc_one_page_size {
3149 __u32 page_shift; /* Page shift (or 0) */
3150 __u32 pte_enc; /* Encoding in the HPTE (>>12) */
3151 };
3152
3153 The "pte_enc" field provides a value that can OR'ed into the hash
3154 PTE's RPN field (ie, it needs to be shifted left by 12 to OR it
3155 into the hash PTE second double word).
3156
3157 4.75 KVM_IRQFD
3158 --------------
3159
3160 :Capability: KVM_CAP_IRQFD
3161 :Architectures: x86 s390 arm64
3162 :Type: vm ioctl
3163 :Parameters: struct kvm_irqfd (in)
3164 :Returns: 0 on success, -1 on error
3165
3166 Allows setting an eventfd to directly trigger a guest interrupt.
3167 kvm_irqfd.fd specifies the file descriptor to use as the eventfd and
3168 kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When
3169 an event is triggered on the eventfd, an interrupt is injected into
3170 the guest using the specified gsi pin. The irqfd is removed using
3171 the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd
3172 and kvm_irqfd.gsi.
3173
3174 With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify
3175 mechanism allowing emulation of level-triggered, irqfd-based
3176 interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an
3177 additional eventfd in the kvm_irqfd.resamplefd field. When operating
3178 in resample mode, posting of an interrupt through kvm_irq.fd asserts
3179 the specified gsi in the irqchip. When the irqchip is resampled, such
3180 as from an EOI, the gsi is de-asserted and the user is notified via
3181 kvm_irqfd.resamplefd. It is the user's responsibility to re-queue
3182 the interrupt if the device making use of it still requires service.
3183 Note that closing the resamplefd is not sufficient to disable the
3184 irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
3185 and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
3186
3187 On arm64, gsi routing being supported, the following can happen:
3188
3189 - in case no routing entry is associated to this gsi, injection fails
3190 - in case the gsi is associated to an irqchip routing entry,
3191 irqchip.pin + 32 corresponds to the injected SPI ID.
3192 - in case the gsi is associated to an MSI routing entry, the MSI
3193 message and device ID are translated into an LPI (support restricted
3194 to GICv3 ITS in-kernel emulation).
3195
3196 4.76 KVM_PPC_ALLOCATE_HTAB
3197 --------------------------
3198
3199 :Capability: KVM_CAP_PPC_ALLOC_HTAB
3200 :Architectures: powerpc
3201 :Type: vm ioctl
3202 :Parameters: Pointer to u32 containing hash table order (in/out)
3203 :Returns: 0 on success, -1 on error
3204
3205 This requests the host kernel to allocate an MMU hash table for a
3206 guest using the PAPR paravirtualization interface. This only does
3207 anything if the kernel is configured to use the Book 3S HV style of
3208 virtualization. Otherwise the capability doesn't exist and the ioctl
3209 returns an ENOTTY error. The rest of this description assumes Book 3S
3210 HV.
3211
3212 There must be no vcpus running when this ioctl is called; if there
3213 are, it will do nothing and return an EBUSY error.
3214
3215 The parameter is a pointer to a 32-bit unsigned integer variable
3216 containing the order (log base 2) of the desired size of the hash
3217 table, which must be between 18 and 46. On successful return from the
3218 ioctl, the value will not be changed by the kernel.
3219
3220 If no hash table has been allocated when any vcpu is asked to run
3221 (with the KVM_RUN ioctl), the host kernel will allocate a
3222 default-sized hash table (16 MB).
3223
3224 If this ioctl is called when a hash table has already been allocated,
3225 with a different order from the existing hash table, the existing hash
3226 table will be freed and a new one allocated. If this is ioctl is
3227 called when a hash table has already been allocated of the same order
3228 as specified, the kernel will clear out the existing hash table (zero
3229 all HPTEs). In either case, if the guest is using the virtualized
3230 real-mode area (VRMA) facility, the kernel will re-create the VMRA
3231 HPTEs on the next KVM_RUN of any vcpu.
3232
3233 4.77 KVM_S390_INTERRUPT
3234 -----------------------
3235
3236 :Capability: basic
3237 :Architectures: s390
3238 :Type: vm ioctl, vcpu ioctl
3239 :Parameters: struct kvm_s390_interrupt (in)
3240 :Returns: 0 on success, -1 on error
3241
3242 Allows to inject an interrupt to the guest. Interrupts can be floating
3243 (vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type.
3244
3245 Interrupt parameters are passed via kvm_s390_interrupt::
3246
3247 struct kvm_s390_interrupt {
3248 __u32 type;
3249 __u32 parm;
3250 __u64 parm64;
3251 };
3252
3253 type can be one of the following:
3254
3255 KVM_S390_SIGP_STOP (vcpu)
3256 - sigp stop; optional flags in parm
3257 KVM_S390_PROGRAM_INT (vcpu)
3258 - program check; code in parm
3259 KVM_S390_SIGP_SET_PREFIX (vcpu)
3260 - sigp set prefix; prefix address in parm
3261 KVM_S390_RESTART (vcpu)
3262 - restart
3263 KVM_S390_INT_CLOCK_COMP (vcpu)
3264 - clock comparator interrupt
3265 KVM_S390_INT_CPU_TIMER (vcpu)
3266 - CPU timer interrupt
3267 KVM_S390_INT_VIRTIO (vm)
3268 - virtio external interrupt; external interrupt
3269 parameters in parm and parm64
3270 KVM_S390_INT_SERVICE (vm)
3271 - sclp external interrupt; sclp parameter in parm
3272 KVM_S390_INT_EMERGENCY (vcpu)
3273 - sigp emergency; source cpu in parm
3274 KVM_S390_INT_EXTERNAL_CALL (vcpu)
3275 - sigp external call; source cpu in parm
3276 KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm)
3277 - compound value to indicate an
3278 I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel);
3279 I/O interruption parameters in parm (subchannel) and parm64 (intparm,
3280 interruption subclass)
3281 KVM_S390_MCHK (vm, vcpu)
3282 - machine check interrupt; cr 14 bits in parm, machine check interrupt
3283 code in parm64 (note that machine checks needing further payload are not
3284 supported by this ioctl)
3285
3286 This is an asynchronous vcpu ioctl and can be invoked from any thread.
3287
3288 4.78 KVM_PPC_GET_HTAB_FD
3289 ------------------------
3290
3291 :Capability: KVM_CAP_PPC_HTAB_FD
3292 :Architectures: powerpc
3293 :Type: vm ioctl
3294 :Parameters: Pointer to struct kvm_get_htab_fd (in)
3295 :Returns: file descriptor number (>= 0) on success, -1 on error
3296
3297 This returns a file descriptor that can be used either to read out the
3298 entries in the guest's hashed page table (HPT), or to write entries to
3299 initialize the HPT. The returned fd can only be written to if the
3300 KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and
3301 can only be read if that bit is clear. The argument struct looks like
3302 this::
3303
3304 /* For KVM_PPC_GET_HTAB_FD */
3305 struct kvm_get_htab_fd {
3306 __u64 flags;
3307 __u64 start_index;
3308 __u64 reserved[2];
3309 };
3310
3311 /* Values for kvm_get_htab_fd.flags */
3312 #define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1)
3313 #define KVM_GET_HTAB_WRITE ((__u64)0x2)
3314
3315 The 'start_index' field gives the index in the HPT of the entry at
3316 which to start reading. It is ignored when writing.
3317
3318 Reads on the fd will initially supply information about all
3319 "interesting" HPT entries. Interesting entries are those with the
3320 bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise
3321 all entries. When the end of the HPT is reached, the read() will
3322 return. If read() is called again on the fd, it will start again from
3323 the beginning of the HPT, but will only return HPT entries that have
3324 changed since they were last read.
3325
3326 Data read or written is structured as a header (8 bytes) followed by a
3327 series of valid HPT entries (16 bytes) each. The header indicates how
3328 many valid HPT entries there are and how many invalid entries follow
3329 the valid entries. The invalid entries are not represented explicitly
3330 in the stream. The header format is::
3331
3332 struct kvm_get_htab_header {
3333 __u32 index;
3334 __u16 n_valid;
3335 __u16 n_invalid;
3336 };
3337
3338 Writes to the fd create HPT entries starting at the index given in the
3339 header; first 'n_valid' valid entries with contents from the data
3340 written, then 'n_invalid' invalid entries, invalidating any previously
3341 valid entries found.
3342
3343 4.79 KVM_CREATE_DEVICE
3344 ----------------------
3345
3346 :Capability: KVM_CAP_DEVICE_CTRL
3347 :Architectures: all
3348 :Type: vm ioctl
3349 :Parameters: struct kvm_create_device (in/out)
3350 :Returns: 0 on success, -1 on error
3351
3352 Errors:
3353
3354 ====== =======================================================
3355 ENODEV The device type is unknown or unsupported
3356 EEXIST Device already created, and this type of device may not
3357 be instantiated multiple times
3358 ====== =======================================================
3359
3360 Other error conditions may be defined by individual device types or
3361 have their standard meanings.
3362
3363 Creates an emulated device in the kernel. The file descriptor returned
3364 in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR.
3365
3366 If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the
3367 device type is supported (not necessarily whether it can be created
3368 in the current vm).
3369
3370 Individual devices should not define flags. Attributes should be used
3371 for specifying any behavior that is not implied by the device type
3372 number.
3373
3374 ::
3375
3376 struct kvm_create_device {
3377 __u32 type; /* in: KVM_DEV_TYPE_xxx */
3378 __u32 fd; /* out: device handle */
3379 __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */
3380 };
3381
3382 4.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR
3383 --------------------------------------------
3384
3385 :Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
3386 KVM_CAP_VCPU_ATTRIBUTES for vcpu device
3387 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device (no set)
3388 :Architectures: x86, arm64, s390
3389 :Type: device ioctl, vm ioctl, vcpu ioctl
3390 :Parameters: struct kvm_device_attr
3391 :Returns: 0 on success, -1 on error
3392
3393 Errors:
3394
3395 ===== =============================================================
3396 ENXIO The group or attribute is unknown/unsupported for this device
3397 or hardware support is missing.
3398 EPERM The attribute cannot (currently) be accessed this way
3399 (e.g. read-only attribute, or attribute that only makes
3400 sense when the device is in a different state)
3401 ===== =============================================================
3402
3403 Other error conditions may be defined by individual device types.
3404
3405 Gets/sets a specified piece of device configuration and/or state. The
3406 semantics are device-specific. See individual device documentation in
3407 the "devices" directory. As with ONE_REG, the size of the data
3408 transferred is defined by the particular attribute.
3409
3410 ::
3411
3412 struct kvm_device_attr {
3413 __u32 flags; /* no flags currently defined */
3414 __u32 group; /* device-defined */
3415 __u64 attr; /* group-defined */
3416 __u64 addr; /* userspace address of attr data */
3417 };
3418
3419 4.81 KVM_HAS_DEVICE_ATTR
3420 ------------------------
3421
3422 :Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device,
3423 KVM_CAP_VCPU_ATTRIBUTES for vcpu device
3424 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device
3425 :Type: device ioctl, vm ioctl, vcpu ioctl
3426 :Parameters: struct kvm_device_attr
3427 :Returns: 0 on success, -1 on error
3428
3429 Errors:
3430
3431 ===== =============================================================
3432 ENXIO The group or attribute is unknown/unsupported for this device
3433 or hardware support is missing.
3434 ===== =============================================================
3435
3436 Tests whether a device supports a particular attribute. A successful
3437 return indicates the attribute is implemented. It does not necessarily
3438 indicate that the attribute can be read or written in the device's
3439 current state. "addr" is ignored.
3440
3441 .. _KVM_ARM_VCPU_INIT:
3442
3443 4.82 KVM_ARM_VCPU_INIT
3444 ----------------------
3445
3446 :Capability: basic
3447 :Architectures: arm64
3448 :Type: vcpu ioctl
3449 :Parameters: struct kvm_vcpu_init (in)
3450 :Returns: 0 on success; -1 on error
3451
3452 Errors:
3453
3454 ====== =================================================================
3455 EINVAL the target is unknown, or the combination of features is invalid.
3456 ENOENT a features bit specified is unknown.
3457 ====== =================================================================
3458
3459 This tells KVM what type of CPU to present to the guest, and what
3460 optional features it should have. This will cause a reset of the cpu
3461 registers to their initial values. If this is not called, KVM_RUN will
3462 return ENOEXEC for that vcpu.
3463
3464 The initial values are defined as:
3465 - Processor state:
3466 * AArch64: EL1h, D, A, I and F bits set. All other bits
3467 are cleared.
3468 * AArch32: SVC, A, I and F bits set. All other bits are
3469 cleared.
3470 - General Purpose registers, including PC and SP: set to 0
3471 - FPSIMD/NEON registers: set to 0
3472 - SVE registers: set to 0
3473 - System registers: Reset to their architecturally defined
3474 values as for a warm reset to EL1 (resp. SVC)
3475
3476 Note that because some registers reflect machine topology, all vcpus
3477 should be created before this ioctl is invoked.
3478
3479 Userspace can call this function multiple times for a given vcpu, including
3480 after the vcpu has been run. This will reset the vcpu to its initial
3481 state. All calls to this function after the initial call must use the same
3482 target and same set of feature flags, otherwise EINVAL will be returned.
3483
3484 Possible features:
3485
3486 - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state.
3487 Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on
3488 and execute guest code when KVM_RUN is called.
3489 - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode.
3490 Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only).
3491 - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision
3492 backward compatible with v0.2) for the CPU.
3493 Depends on KVM_CAP_ARM_PSCI_0_2.
3494 - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU.
3495 Depends on KVM_CAP_ARM_PMU_V3.
3496
3497 - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication
3498 for arm64 only.
3499 Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS.
3500 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are
3501 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and
3502 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be
3503 requested.
3504
3505 - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication
3506 for arm64 only.
3507 Depends on KVM_CAP_ARM_PTRAUTH_GENERIC.
3508 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are
3509 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and
3510 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be
3511 requested.
3512
3513 - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only).
3514 Depends on KVM_CAP_ARM_SVE.
3515 Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):
3516
3517 * After KVM_ARM_VCPU_INIT:
3518
3519 - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the
3520 initial value of this pseudo-register indicates the best set of
3521 vector lengths possible for a vcpu on this host.
3522
3523 * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):
3524
3525 - KVM_RUN and KVM_GET_REG_LIST are not available;
3526
3527 - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access
3528 the scalable architectural SVE registers
3529 KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or
3530 KVM_REG_ARM64_SVE_FFR;
3531
3532 - KVM_REG_ARM64_SVE_VLS may optionally be written using
3533 KVM_SET_ONE_REG, to modify the set of vector lengths available
3534 for the vcpu.
3535
3536 * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE):
3537
3538 - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can
3539 no longer be written using KVM_SET_ONE_REG.
3540
3541 4.83 KVM_ARM_PREFERRED_TARGET
3542 -----------------------------
3543
3544 :Capability: basic
3545 :Architectures: arm64
3546 :Type: vm ioctl
3547 :Parameters: struct kvm_vcpu_init (out)
3548 :Returns: 0 on success; -1 on error
3549
3550 Errors:
3551
3552 ====== ==========================================
3553 ENODEV no preferred target available for the host
3554 ====== ==========================================
3555
3556 This queries KVM for preferred CPU target type which can be emulated
3557 by KVM on underlying host.
3558
3559 The ioctl returns struct kvm_vcpu_init instance containing information
3560 about preferred CPU target type and recommended features for it. The
3561 kvm_vcpu_init->features bitmap returned will have feature bits set if
3562 the preferred target recommends setting these features, but this is
3563 not mandatory.
3564
3565 The information returned by this ioctl can be used to prepare an instance
3566 of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in
3567 VCPU matching underlying host.
3568
3569
3570 4.84 KVM_GET_REG_LIST
3571 ---------------------
3572
3573 :Capability: basic
3574 :Architectures: arm64, mips, riscv
3575 :Type: vcpu ioctl
3576 :Parameters: struct kvm_reg_list (in/out)
3577 :Returns: 0 on success; -1 on error
3578
3579 Errors:
3580
3581 ===== ==============================================================
3582 E2BIG the reg index list is too big to fit in the array specified by
3583 the user (the number required will be written into n).
3584 ===== ==============================================================
3585
3586 ::
3587
3588 struct kvm_reg_list {
3589 __u64 n; /* number of registers in reg[] */
3590 __u64 reg[0];
3591 };
3592
3593 This ioctl returns the guest registers that are supported for the
3594 KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.
3595
3596
3597 4.85 KVM_ARM_SET_DEVICE_ADDR (deprecated)
3598 -----------------------------------------
3599
3600 :Capability: KVM_CAP_ARM_SET_DEVICE_ADDR
3601 :Architectures: arm64
3602 :Type: vm ioctl
3603 :Parameters: struct kvm_arm_device_address (in)
3604 :Returns: 0 on success, -1 on error
3605
3606 Errors:
3607
3608 ====== ============================================
3609 ENODEV The device id is unknown
3610 ENXIO Device not supported on current system
3611 EEXIST Address already set
3612 E2BIG Address outside guest physical address space
3613 EBUSY Address overlaps with other device range
3614 ====== ============================================
3615
3616 ::
3617
3618 struct kvm_arm_device_addr {
3619 __u64 id;
3620 __u64 addr;
3621 };
3622
3623 Specify a device address in the guest's physical address space where guests
3624 can access emulated or directly exposed devices, which the host kernel needs
3625 to know about. The id field is an architecture specific identifier for a
3626 specific device.
3627
3628 arm64 divides the id field into two parts, a device id and an
3629 address type id specific to the individual device::
3630
3631 bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 |
3632 field: | 0x00000000 | device id | addr type id |
3633
3634 arm64 currently only require this when using the in-kernel GIC
3635 support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2
3636 as the device id. When setting the base address for the guest's
3637 mapping of the VGIC virtual CPU and distributor interface, the ioctl
3638 must be called after calling KVM_CREATE_IRQCHIP, but before calling
3639 KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the
3640 base addresses will return -EEXIST.
3641
3642 Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API
3643 should be used instead.
3644
3645
3646 4.86 KVM_PPC_RTAS_DEFINE_TOKEN
3647 ------------------------------
3648
3649 :Capability: KVM_CAP_PPC_RTAS
3650 :Architectures: ppc
3651 :Type: vm ioctl
3652 :Parameters: struct kvm_rtas_token_args
3653 :Returns: 0 on success, -1 on error
3654
3655 Defines a token value for a RTAS (Run Time Abstraction Services)
3656 service in order to allow it to be handled in the kernel. The
3657 argument struct gives the name of the service, which must be the name
3658 of a service that has a kernel-side implementation. If the token
3659 value is non-zero, it will be associated with that service, and
3660 subsequent RTAS calls by the guest specifying that token will be
3661 handled by the kernel. If the token value is 0, then any token
3662 associated with the service will be forgotten, and subsequent RTAS
3663 calls by the guest for that service will be passed to userspace to be
3664 handled.
3665
3666 4.87 KVM_SET_GUEST_DEBUG
3667 ------------------------
3668
3669 :Capability: KVM_CAP_SET_GUEST_DEBUG
3670 :Architectures: x86, s390, ppc, arm64
3671 :Type: vcpu ioctl
3672 :Parameters: struct kvm_guest_debug (in)
3673 :Returns: 0 on success; -1 on error
3674
3675 ::
3676
3677 struct kvm_guest_debug {
3678 __u32 control;
3679 __u32 pad;
3680 struct kvm_guest_debug_arch arch;
3681 };
3682
3683 Set up the processor specific debug registers and configure vcpu for
3684 handling guest debug events. There are two parts to the structure, the
3685 first a control bitfield indicates the type of debug events to handle
3686 when running. Common control bits are:
3687
3688 - KVM_GUESTDBG_ENABLE: guest debugging is enabled
3689 - KVM_GUESTDBG_SINGLESTEP: the next run should single-step
3690
3691 The top 16 bits of the control field are architecture specific control
3692 flags which can include the following:
3693
3694 - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64]
3695 - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390]
3696 - KVM_GUESTDBG_USE_HW: using hardware debug events [arm64]
3697 - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86]
3698 - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86]
3699 - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390]
3700 - KVM_GUESTDBG_BLOCKIRQ: avoid injecting interrupts/NMI/SMI [x86]
3701
3702 For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints
3703 are enabled in memory so we need to ensure breakpoint exceptions are
3704 correctly trapped and the KVM run loop exits at the breakpoint and not
3705 running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP
3706 we need to ensure the guest vCPUs architecture specific registers are
3707 updated to the correct (supplied) values.
3708
3709 The second part of the structure is architecture specific and
3710 typically contains a set of debug registers.
3711
3712 For arm64 the number of debug registers is implementation defined and
3713 can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and
3714 KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number
3715 indicating the number of supported registers.
3716
3717 For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether
3718 the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported.
3719
3720 Also when supported, KVM_CAP_SET_GUEST_DEBUG2 capability indicates the
3721 supported KVM_GUESTDBG_* bits in the control field.
3722
3723 When debug events exit the main run loop with the reason
3724 KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run
3725 structure containing architecture specific debug information.
3726
3727 4.88 KVM_GET_EMULATED_CPUID
3728 ---------------------------
3729
3730 :Capability: KVM_CAP_EXT_EMUL_CPUID
3731 :Architectures: x86
3732 :Type: system ioctl
3733 :Parameters: struct kvm_cpuid2 (in/out)
3734 :Returns: 0 on success, -1 on error
3735
3736 ::
3737
3738 struct kvm_cpuid2 {
3739 __u32 nent;
3740 __u32 flags;
3741 struct kvm_cpuid_entry2 entries[0];
3742 };
3743
3744 The member 'flags' is used for passing flags from userspace.
3745
3746 ::
3747
3748 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0)
3749 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */
3750 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */
3751
3752 struct kvm_cpuid_entry2 {
3753 __u32 function;
3754 __u32 index;
3755 __u32 flags;
3756 __u32 eax;
3757 __u32 ebx;
3758 __u32 ecx;
3759 __u32 edx;
3760 __u32 padding[3];
3761 };
3762
3763 This ioctl returns x86 cpuid features which are emulated by
3764 kvm.Userspace can use the information returned by this ioctl to query
3765 which features are emulated by kvm instead of being present natively.
3766
3767 Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2
3768 structure with the 'nent' field indicating the number of entries in
3769 the variable-size array 'entries'. If the number of entries is too low
3770 to describe the cpu capabilities, an error (E2BIG) is returned. If the
3771 number is too high, the 'nent' field is adjusted and an error (ENOMEM)
3772 is returned. If the number is just right, the 'nent' field is adjusted
3773 to the number of valid entries in the 'entries' array, which is then
3774 filled.
3775
3776 The entries returned are the set CPUID bits of the respective features
3777 which kvm emulates, as returned by the CPUID instruction, with unknown
3778 or unsupported feature bits cleared.
3779
3780 Features like x2apic, for example, may not be present in the host cpu
3781 but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be
3782 emulated efficiently and thus not included here.
3783
3784 The fields in each entry are defined as follows:
3785
3786 function:
3787 the eax value used to obtain the entry
3788 index:
3789 the ecx value used to obtain the entry (for entries that are
3790 affected by ecx)
3791 flags:
3792 an OR of zero or more of the following:
3793
3794 KVM_CPUID_FLAG_SIGNIFCANT_INDEX:
3795 if the index field is valid
3796
3797 eax, ebx, ecx, edx:
3798
3799 the values returned by the cpuid instruction for
3800 this function/index combination
3801
3802 4.89 KVM_S390_MEM_OP
3803 --------------------
3804
3805 :Capability: KVM_CAP_S390_MEM_OP, KVM_CAP_S390_PROTECTED, KVM_CAP_S390_MEM_OP_EXTENSION
3806 :Architectures: s390
3807 :Type: vm ioctl, vcpu ioctl
3808 :Parameters: struct kvm_s390_mem_op (in)
3809 :Returns: = 0 on success,
3810 < 0 on generic error (e.g. -EFAULT or -ENOMEM),
3811 16 bit program exception code if the access causes such an exception
3812
3813 Read or write data from/to the VM's memory.
3814 The KVM_CAP_S390_MEM_OP_EXTENSION capability specifies what functionality is
3815 supported.
3816
3817 Parameters are specified via the following structure::
3818
3819 struct kvm_s390_mem_op {
3820 __u64 gaddr; /* the guest address */
3821 __u64 flags; /* flags */
3822 __u32 size; /* amount of bytes */
3823 __u32 op; /* type of operation */
3824 __u64 buf; /* buffer in userspace */
3825 union {
3826 struct {
3827 __u8 ar; /* the access register number */
3828 __u8 key; /* access key, ignored if flag unset */
3829 __u8 pad1[6]; /* ignored */
3830 __u64 old_addr; /* ignored if flag unset */
3831 };
3832 __u32 sida_offset; /* offset into the sida */
3833 __u8 reserved[32]; /* ignored */
3834 };
3835 };
3836
3837 The start address of the memory region has to be specified in the "gaddr"
3838 field, and the length of the region in the "size" field (which must not
3839 be 0). The maximum value for "size" can be obtained by checking the
3840 KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the
3841 userspace application where the read data should be written to for
3842 a read access, or where the data that should be written is stored for
3843 a write access. The "reserved" field is meant for future extensions.
3844 Reserved and unused values are ignored. Future extension that add members must
3845 introduce new flags.
3846
3847 The type of operation is specified in the "op" field. Flags modifying
3848 their behavior can be set in the "flags" field. Undefined flag bits must
3849 be set to 0.
3850
3851 Possible operations are:
3852 * ``KVM_S390_MEMOP_LOGICAL_READ``
3853 * ``KVM_S390_MEMOP_LOGICAL_WRITE``
3854 * ``KVM_S390_MEMOP_ABSOLUTE_READ``
3855 * ``KVM_S390_MEMOP_ABSOLUTE_WRITE``
3856 * ``KVM_S390_MEMOP_SIDA_READ``
3857 * ``KVM_S390_MEMOP_SIDA_WRITE``
3858 * ``KVM_S390_MEMOP_ABSOLUTE_CMPXCHG``
3859
3860 Logical read/write:
3861 ^^^^^^^^^^^^^^^^^^^
3862
3863 Access logical memory, i.e. translate the given guest address to an absolute
3864 address given the state of the VCPU and use the absolute address as target of
3865 the access. "ar" designates the access register number to be used; the valid
3866 range is 0..15.
3867 Logical accesses are permitted for the VCPU ioctl only.
3868 Logical accesses are permitted for non-protected guests only.
3869
3870 Supported flags:
3871 * ``KVM_S390_MEMOP_F_CHECK_ONLY``
3872 * ``KVM_S390_MEMOP_F_INJECT_EXCEPTION``
3873 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION``
3874
3875 The KVM_S390_MEMOP_F_CHECK_ONLY flag can be set to check whether the
3876 corresponding memory access would cause an access exception; however,
3877 no actual access to the data in memory at the destination is performed.
3878 In this case, "buf" is unused and can be NULL.
3879
3880 In case an access exception occurred during the access (or would occur
3881 in case of KVM_S390_MEMOP_F_CHECK_ONLY), the ioctl returns a positive
3882 error number indicating the type of exception. This exception is also
3883 raised directly at the corresponding VCPU if the flag
3884 KVM_S390_MEMOP_F_INJECT_EXCEPTION is set.
3885 On protection exceptions, unless specified otherwise, the injected
3886 translation-exception identifier (TEID) indicates suppression.
3887
3888 If the KVM_S390_MEMOP_F_SKEY_PROTECTION flag is set, storage key
3889 protection is also in effect and may cause exceptions if accesses are
3890 prohibited given the access key designated by "key"; the valid range is 0..15.
3891 KVM_S390_MEMOP_F_SKEY_PROTECTION is available if KVM_CAP_S390_MEM_OP_EXTENSION
3892 is > 0.
3893 Since the accessed memory may span multiple pages and those pages might have
3894 different storage keys, it is possible that a protection exception occurs
3895 after memory has been modified. In this case, if the exception is injected,
3896 the TEID does not indicate suppression.
3897
3898 Absolute read/write:
3899 ^^^^^^^^^^^^^^^^^^^^
3900
3901 Access absolute memory. This operation is intended to be used with the
3902 KVM_S390_MEMOP_F_SKEY_PROTECTION flag, to allow accessing memory and performing
3903 the checks required for storage key protection as one operation (as opposed to
3904 user space getting the storage keys, performing the checks, and accessing
3905 memory thereafter, which could lead to a delay between check and access).
3906 Absolute accesses are permitted for the VM ioctl if KVM_CAP_S390_MEM_OP_EXTENSION
3907 has the KVM_S390_MEMOP_EXTENSION_CAP_BASE bit set.
3908 Currently absolute accesses are not permitted for VCPU ioctls.
3909 Absolute accesses are permitted for non-protected guests only.
3910
3911 Supported flags:
3912 * ``KVM_S390_MEMOP_F_CHECK_ONLY``
3913 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION``
3914
3915 The semantics of the flags common with logical accesses are as for logical
3916 accesses.
3917
3918 Absolute cmpxchg:
3919 ^^^^^^^^^^^^^^^^^
3920
3921 Perform cmpxchg on absolute guest memory. Intended for use with the
3922 KVM_S390_MEMOP_F_SKEY_PROTECTION flag.
3923 Instead of doing an unconditional write, the access occurs only if the target
3924 location contains the value pointed to by "old_addr".
3925 This is performed as an atomic cmpxchg with the length specified by the "size"
3926 parameter. "size" must be a power of two up to and including 16.
3927 If the exchange did not take place because the target value doesn't match the
3928 old value, the value "old_addr" points to is replaced by the target value.
3929 User space can tell if an exchange took place by checking if this replacement
3930 occurred. The cmpxchg op is permitted for the VM ioctl if
3931 KVM_CAP_S390_MEM_OP_EXTENSION has flag KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG set.
3932
3933 Supported flags:
3934 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION``
3935
3936 SIDA read/write:
3937 ^^^^^^^^^^^^^^^^
3938
3939 Access the secure instruction data area which contains memory operands necessary
3940 for instruction emulation for protected guests.
3941 SIDA accesses are available if the KVM_CAP_S390_PROTECTED capability is available.
3942 SIDA accesses are permitted for the VCPU ioctl only.
3943 SIDA accesses are permitted for protected guests only.
3944
3945 No flags are supported.
3946
3947 4.90 KVM_S390_GET_SKEYS
3948 -----------------------
3949
3950 :Capability: KVM_CAP_S390_SKEYS
3951 :Architectures: s390
3952 :Type: vm ioctl
3953 :Parameters: struct kvm_s390_skeys
3954 :Returns: 0 on success, KVM_S390_GET_SKEYS_NONE if guest is not using storage
3955 keys, negative value on error
3956
3957 This ioctl is used to get guest storage key values on the s390
3958 architecture. The ioctl takes parameters via the kvm_s390_skeys struct::
3959
3960 struct kvm_s390_skeys {
3961 __u64 start_gfn;
3962 __u64 count;
3963 __u64 skeydata_addr;
3964 __u32 flags;
3965 __u32 reserved[9];
3966 };
3967
3968 The start_gfn field is the number of the first guest frame whose storage keys
3969 you want to get.
3970
3971 The count field is the number of consecutive frames (starting from start_gfn)
3972 whose storage keys to get. The count field must be at least 1 and the maximum
3973 allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range
3974 will cause the ioctl to return -EINVAL.
3975
3976 The skeydata_addr field is the address to a buffer large enough to hold count
3977 bytes. This buffer will be filled with storage key data by the ioctl.
3978
3979 4.91 KVM_S390_SET_SKEYS
3980 -----------------------
3981
3982 :Capability: KVM_CAP_S390_SKEYS
3983 :Architectures: s390
3984 :Type: vm ioctl
3985 :Parameters: struct kvm_s390_skeys
3986 :Returns: 0 on success, negative value on error
3987
3988 This ioctl is used to set guest storage key values on the s390
3989 architecture. The ioctl takes parameters via the kvm_s390_skeys struct.
3990 See section on KVM_S390_GET_SKEYS for struct definition.
3991
3992 The start_gfn field is the number of the first guest frame whose storage keys
3993 you want to set.
3994
3995 The count field is the number of consecutive frames (starting from start_gfn)
3996 whose storage keys to get. The count field must be at least 1 and the maximum
3997 allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range
3998 will cause the ioctl to return -EINVAL.
3999
4000 The skeydata_addr field is the address to a buffer containing count bytes of
4001 storage keys. Each byte in the buffer will be set as the storage key for a
4002 single frame starting at start_gfn for count frames.
4003
4004 Note: If any architecturally invalid key value is found in the given data then
4005 the ioctl will return -EINVAL.
4006
4007 4.92 KVM_S390_IRQ
4008 -----------------
4009
4010 :Capability: KVM_CAP_S390_INJECT_IRQ
4011 :Architectures: s390
4012 :Type: vcpu ioctl
4013 :Parameters: struct kvm_s390_irq (in)
4014 :Returns: 0 on success, -1 on error
4015
4016 Errors:
4017
4018
4019 ====== =================================================================
4020 EINVAL interrupt type is invalid
4021 type is KVM_S390_SIGP_STOP and flag parameter is invalid value,
4022 type is KVM_S390_INT_EXTERNAL_CALL and code is bigger
4023 than the maximum of VCPUs
4024 EBUSY type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped,
4025 type is KVM_S390_SIGP_STOP and a stop irq is already pending,
4026 type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt
4027 is already pending
4028 ====== =================================================================
4029
4030 Allows to inject an interrupt to the guest.
4031
4032 Using struct kvm_s390_irq as a parameter allows
4033 to inject additional payload which is not
4034 possible via KVM_S390_INTERRUPT.
4035
4036 Interrupt parameters are passed via kvm_s390_irq::
4037
4038 struct kvm_s390_irq {
4039 __u64 type;
4040 union {
4041 struct kvm_s390_io_info io;
4042 struct kvm_s390_ext_info ext;
4043 struct kvm_s390_pgm_info pgm;
4044 struct kvm_s390_emerg_info emerg;
4045 struct kvm_s390_extcall_info extcall;
4046 struct kvm_s390_prefix_info prefix;
4047 struct kvm_s390_stop_info stop;
4048 struct kvm_s390_mchk_info mchk;
4049 char reserved[64];
4050 } u;
4051 };
4052
4053 type can be one of the following:
4054
4055 - KVM_S390_SIGP_STOP - sigp stop; parameter in .stop
4056 - KVM_S390_PROGRAM_INT - program check; parameters in .pgm
4057 - KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix
4058 - KVM_S390_RESTART - restart; no parameters
4059 - KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters
4060 - KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters
4061 - KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg
4062 - KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall
4063 - KVM_S390_MCHK - machine check interrupt; parameters in .mchk
4064
4065 This is an asynchronous vcpu ioctl and can be invoked from any thread.
4066
4067 4.94 KVM_S390_GET_IRQ_STATE
4068 ---------------------------
4069
4070 :Capability: KVM_CAP_S390_IRQ_STATE
4071 :Architectures: s390
4072 :Type: vcpu ioctl
4073 :Parameters: struct kvm_s390_irq_state (out)
4074 :Returns: >= number of bytes copied into buffer,
4075 -EINVAL if buffer size is 0,
4076 -ENOBUFS if buffer size is too small to fit all pending interrupts,
4077 -EFAULT if the buffer address was invalid
4078
4079 This ioctl allows userspace to retrieve the complete state of all currently
4080 pending interrupts in a single buffer. Use cases include migration
4081 and introspection. The parameter structure contains the address of a
4082 userspace buffer and its length::
4083
4084 struct kvm_s390_irq_state {
4085 __u64 buf;
4086 __u32 flags; /* will stay unused for compatibility reasons */
4087 __u32 len;
4088 __u32 reserved[4]; /* will stay unused for compatibility reasons */
4089 };
4090
4091 Userspace passes in the above struct and for each pending interrupt a
4092 struct kvm_s390_irq is copied to the provided buffer.
4093
4094 The structure contains a flags and a reserved field for future extensions. As
4095 the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and
4096 reserved, these fields can not be used in the future without breaking
4097 compatibility.
4098
4099 If -ENOBUFS is returned the buffer provided was too small and userspace
4100 may retry with a bigger buffer.
4101
4102 4.95 KVM_S390_SET_IRQ_STATE
4103 ---------------------------
4104
4105 :Capability: KVM_CAP_S390_IRQ_STATE
4106 :Architectures: s390
4107 :Type: vcpu ioctl
4108 :Parameters: struct kvm_s390_irq_state (in)
4109 :Returns: 0 on success,
4110 -EFAULT if the buffer address was invalid,
4111 -EINVAL for an invalid buffer length (see below),
4112 -EBUSY if there were already interrupts pending,
4113 errors occurring when actually injecting the
4114 interrupt. See KVM_S390_IRQ.
4115
4116 This ioctl allows userspace to set the complete state of all cpu-local
4117 interrupts currently pending for the vcpu. It is intended for restoring
4118 interrupt state after a migration. The input parameter is a userspace buffer
4119 containing a struct kvm_s390_irq_state::
4120
4121 struct kvm_s390_irq_state {
4122 __u64 buf;
4123 __u32 flags; /* will stay unused for compatibility reasons */
4124 __u32 len;
4125 __u32 reserved[4]; /* will stay unused for compatibility reasons */
4126 };
4127
4128 The restrictions for flags and reserved apply as well.
4129 (see KVM_S390_GET_IRQ_STATE)
4130
4131 The userspace memory referenced by buf contains a struct kvm_s390_irq
4132 for each interrupt to be injected into the guest.
4133 If one of the interrupts could not be injected for some reason the
4134 ioctl aborts.
4135
4136 len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0
4137 and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq),
4138 which is the maximum number of possibly pending cpu-local interrupts.
4139
4140 4.96 KVM_SMI
4141 ------------
4142
4143 :Capability: KVM_CAP_X86_SMM
4144 :Architectures: x86
4145 :Type: vcpu ioctl
4146 :Parameters: none
4147 :Returns: 0 on success, -1 on error
4148
4149 Queues an SMI on the thread's vcpu.
4150
4151 4.97 KVM_X86_SET_MSR_FILTER
4152 ----------------------------
4153
4154 :Capability: KVM_CAP_X86_MSR_FILTER
4155 :Architectures: x86
4156 :Type: vm ioctl
4157 :Parameters: struct kvm_msr_filter
4158 :Returns: 0 on success, < 0 on error
4159
4160 ::
4161
4162 struct kvm_msr_filter_range {
4163 #define KVM_MSR_FILTER_READ (1 << 0)
4164 #define KVM_MSR_FILTER_WRITE (1 << 1)
4165 __u32 flags;
4166 __u32 nmsrs; /* number of msrs in bitmap */
4167 __u32 base; /* MSR index the bitmap starts at */
4168 __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */
4169 };
4170
4171 #define KVM_MSR_FILTER_MAX_RANGES 16
4172 struct kvm_msr_filter {
4173 #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0)
4174 #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0)
4175 __u32 flags;
4176 struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES];
4177 };
4178
4179 flags values for ``struct kvm_msr_filter_range``:
4180
4181 ``KVM_MSR_FILTER_READ``
4182
4183 Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap
4184 indicates that read accesses should be denied, while a 1 indicates that
4185 a read for a particular MSR should be allowed regardless of the default
4186 filter action.
4187
4188 ``KVM_MSR_FILTER_WRITE``
4189
4190 Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap
4191 indicates that write accesses should be denied, while a 1 indicates that
4192 a write for a particular MSR should be allowed regardless of the default
4193 filter action.
4194
4195 flags values for ``struct kvm_msr_filter``:
4196
4197 ``KVM_MSR_FILTER_DEFAULT_ALLOW``
4198
4199 If no filter range matches an MSR index that is getting accessed, KVM will
4200 allow accesses to all MSRs by default.
4201
4202 ``KVM_MSR_FILTER_DEFAULT_DENY``
4203
4204 If no filter range matches an MSR index that is getting accessed, KVM will
4205 deny accesses to all MSRs by default.
4206
4207 This ioctl allows userspace to define up to 16 bitmaps of MSR ranges to deny
4208 guest MSR accesses that would normally be allowed by KVM. If an MSR is not
4209 covered by a specific range, the "default" filtering behavior applies. Each
4210 bitmap range covers MSRs from [base .. base+nmsrs).
4211
4212 If an MSR access is denied by userspace, the resulting KVM behavior depends on
4213 whether or not KVM_CAP_X86_USER_SPACE_MSR's KVM_MSR_EXIT_REASON_FILTER is
4214 enabled. If KVM_MSR_EXIT_REASON_FILTER is enabled, KVM will exit to userspace
4215 on denied accesses, i.e. userspace effectively intercepts the MSR access. If
4216 KVM_MSR_EXIT_REASON_FILTER is not enabled, KVM will inject a #GP into the guest
4217 on denied accesses. Note, if an MSR access is denied during emulation of MSR
4218 load/stores during VMX transitions, KVM ignores KVM_MSR_EXIT_REASON_FILTER.
4219 See the below warning for full details.
4220
4221 If an MSR access is allowed by userspace, KVM will emulate and/or virtualize
4222 the access in accordance with the vCPU model. Note, KVM may still ultimately
4223 inject a #GP if an access is allowed by userspace, e.g. if KVM doesn't support
4224 the MSR, or to follow architectural behavior for the MSR.
4225
4226 By default, KVM operates in KVM_MSR_FILTER_DEFAULT_ALLOW mode with no MSR range
4227 filters.
4228
4229 Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR
4230 filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes
4231 an error.
4232
4233 .. warning::
4234 MSR accesses that are side effects of instruction execution (emulated or
4235 native) are not filtered as hardware does not honor MSR bitmaps outside of
4236 RDMSR and WRMSR, and KVM mimics that behavior when emulating instructions
4237 to avoid pointless divergence from hardware. E.g. RDPID reads MSR_TSC_AUX,
4238 SYSENTER reads the SYSENTER MSRs, etc.
4239
4240 MSRs that are loaded/stored via dedicated VMCS fields are not filtered as
4241 part of VM-Enter/VM-Exit emulation.
4242
4243 MSRs that are loaded/store via VMX's load/store lists _are_ filtered as part
4244 of VM-Enter/VM-Exit emulation. If an MSR access is denied on VM-Enter, KVM
4245 synthesizes a consistency check VM-Exit(EXIT_REASON_MSR_LOAD_FAIL). If an
4246 MSR access is denied on VM-Exit, KVM synthesizes a VM-Abort. In short, KVM
4247 extends Intel's architectural list of MSRs that cannot be loaded/saved via
4248 the VM-Enter/VM-Exit MSR list. It is platform owner's responsibility to
4249 to communicate any such restrictions to their end users.
4250
4251 x2APIC MSR accesses cannot be filtered (KVM silently ignores filters that
4252 cover any x2APIC MSRs).
4253
4254 Note, invoking this ioctl while a vCPU is running is inherently racy. However,
4255 KVM does guarantee that vCPUs will see either the previous filter or the new
4256 filter, e.g. MSRs with identical settings in both the old and new filter will
4257 have deterministic behavior.
4258
4259 Similarly, if userspace wishes to intercept on denied accesses,
4260 KVM_MSR_EXIT_REASON_FILTER must be enabled before activating any filters, and
4261 left enabled until after all filters are deactivated. Failure to do so may
4262 result in KVM injecting a #GP instead of exiting to userspace.
4263
4264 4.98 KVM_CREATE_SPAPR_TCE_64
4265 ----------------------------
4266
4267 :Capability: KVM_CAP_SPAPR_TCE_64
4268 :Architectures: powerpc
4269 :Type: vm ioctl
4270 :Parameters: struct kvm_create_spapr_tce_64 (in)
4271 :Returns: file descriptor for manipulating the created TCE table
4272
4273 This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit
4274 windows, described in 4.62 KVM_CREATE_SPAPR_TCE
4275
4276 This capability uses extended struct in ioctl interface::
4277
4278 /* for KVM_CAP_SPAPR_TCE_64 */
4279 struct kvm_create_spapr_tce_64 {
4280 __u64 liobn;
4281 __u32 page_shift;
4282 __u32 flags;
4283 __u64 offset; /* in pages */
4284 __u64 size; /* in pages */
4285 };
4286
4287 The aim of extension is to support an additional bigger DMA window with
4288 a variable page size.
4289 KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and
4290 a bus offset of the corresponding DMA window, @size and @offset are numbers
4291 of IOMMU pages.
4292
4293 @flags are not used at the moment.
4294
4295 The rest of functionality is identical to KVM_CREATE_SPAPR_TCE.
4296
4297 4.99 KVM_REINJECT_CONTROL
4298 -------------------------
4299
4300 :Capability: KVM_CAP_REINJECT_CONTROL
4301 :Architectures: x86
4302 :Type: vm ioctl
4303 :Parameters: struct kvm_reinject_control (in)
4304 :Returns: 0 on success,
4305 -EFAULT if struct kvm_reinject_control cannot be read,
4306 -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier.
4307
4308 i8254 (PIT) has two modes, reinject and !reinject. The default is reinject,
4309 where KVM queues elapsed i8254 ticks and monitors completion of interrupt from
4310 vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its
4311 interrupt whenever there isn't a pending interrupt from i8254.
4312 !reinject mode injects an interrupt as soon as a tick arrives.
4313
4314 ::
4315
4316 struct kvm_reinject_control {
4317 __u8 pit_reinject;
4318 __u8 reserved[31];
4319 };
4320
4321 pit_reinject = 0 (!reinject mode) is recommended, unless running an old
4322 operating system that uses the PIT for timing (e.g. Linux 2.4.x).
4323
4324 4.100 KVM_PPC_CONFIGURE_V3_MMU
4325 ------------------------------
4326
4327 :Capability: KVM_CAP_PPC_MMU_RADIX or KVM_CAP_PPC_MMU_HASH_V3
4328 :Architectures: ppc
4329 :Type: vm ioctl
4330 :Parameters: struct kvm_ppc_mmuv3_cfg (in)
4331 :Returns: 0 on success,
4332 -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read,
4333 -EINVAL if the configuration is invalid
4334
4335 This ioctl controls whether the guest will use radix or HPT (hashed
4336 page table) translation, and sets the pointer to the process table for
4337 the guest.
4338
4339 ::
4340
4341 struct kvm_ppc_mmuv3_cfg {
4342 __u64 flags;
4343 __u64 process_table;
4344 };
4345
4346 There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and
4347 KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest
4348 to use radix tree translation, and if clear, to use HPT translation.
4349 KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest
4350 to be able to use the global TLB and SLB invalidation instructions;
4351 if clear, the guest may not use these instructions.
4352
4353 The process_table field specifies the address and size of the guest
4354 process table, which is in the guest's space. This field is formatted
4355 as the second doubleword of the partition table entry, as defined in
4356 the Power ISA V3.00, Book III section 5.7.6.1.
4357
4358 4.101 KVM_PPC_GET_RMMU_INFO
4359 ---------------------------
4360
4361 :Capability: KVM_CAP_PPC_MMU_RADIX
4362 :Architectures: ppc
4363 :Type: vm ioctl
4364 :Parameters: struct kvm_ppc_rmmu_info (out)
4365 :Returns: 0 on success,
4366 -EFAULT if struct kvm_ppc_rmmu_info cannot be written,
4367 -EINVAL if no useful information can be returned
4368
4369 This ioctl returns a structure containing two things: (a) a list
4370 containing supported radix tree geometries, and (b) a list that maps
4371 page sizes to put in the "AP" (actual page size) field for the tlbie
4372 (TLB invalidate entry) instruction.
4373
4374 ::
4375
4376 struct kvm_ppc_rmmu_info {
4377 struct kvm_ppc_radix_geom {
4378 __u8 page_shift;
4379 __u8 level_bits[4];
4380 __u8 pad[3];
4381 } geometries[8];
4382 __u32 ap_encodings[8];
4383 };
4384
4385 The geometries[] field gives up to 8 supported geometries for the
4386 radix page table, in terms of the log base 2 of the smallest page
4387 size, and the number of bits indexed at each level of the tree, from
4388 the PTE level up to the PGD level in that order. Any unused entries
4389 will have 0 in the page_shift field.
4390
4391 The ap_encodings gives the supported page sizes and their AP field
4392 encodings, encoded with the AP value in the top 3 bits and the log
4393 base 2 of the page size in the bottom 6 bits.
4394
4395 4.102 KVM_PPC_RESIZE_HPT_PREPARE
4396 --------------------------------
4397
4398 :Capability: KVM_CAP_SPAPR_RESIZE_HPT
4399 :Architectures: powerpc
4400 :Type: vm ioctl
4401 :Parameters: struct kvm_ppc_resize_hpt (in)
4402 :Returns: 0 on successful completion,
4403 >0 if a new HPT is being prepared, the value is an estimated
4404 number of milliseconds until preparation is complete,
4405 -EFAULT if struct kvm_reinject_control cannot be read,
4406 -EINVAL if the supplied shift or flags are invalid,
4407 -ENOMEM if unable to allocate the new HPT,
4408
4409 Used to implement the PAPR extension for runtime resizing of a guest's
4410 Hashed Page Table (HPT). Specifically this starts, stops or monitors
4411 the preparation of a new potential HPT for the guest, essentially
4412 implementing the H_RESIZE_HPT_PREPARE hypercall.
4413
4414 ::
4415
4416 struct kvm_ppc_resize_hpt {
4417 __u64 flags;
4418 __u32 shift;
4419 __u32 pad;
4420 };
4421
4422 If called with shift > 0 when there is no pending HPT for the guest,
4423 this begins preparation of a new pending HPT of size 2^(shift) bytes.
4424 It then returns a positive integer with the estimated number of
4425 milliseconds until preparation is complete.
4426
4427 If called when there is a pending HPT whose size does not match that
4428 requested in the parameters, discards the existing pending HPT and
4429 creates a new one as above.
4430
4431 If called when there is a pending HPT of the size requested, will:
4432
4433 * If preparation of the pending HPT is already complete, return 0
4434 * If preparation of the pending HPT has failed, return an error
4435 code, then discard the pending HPT.
4436 * If preparation of the pending HPT is still in progress, return an
4437 estimated number of milliseconds until preparation is complete.
4438
4439 If called with shift == 0, discards any currently pending HPT and
4440 returns 0 (i.e. cancels any in-progress preparation).
4441
4442 flags is reserved for future expansion, currently setting any bits in
4443 flags will result in an -EINVAL.
4444
4445 Normally this will be called repeatedly with the same parameters until
4446 it returns <= 0. The first call will initiate preparation, subsequent
4447 ones will monitor preparation until it completes or fails.
4448
4449 4.103 KVM_PPC_RESIZE_HPT_COMMIT
4450 -------------------------------
4451
4452 :Capability: KVM_CAP_SPAPR_RESIZE_HPT
4453 :Architectures: powerpc
4454 :Type: vm ioctl
4455 :Parameters: struct kvm_ppc_resize_hpt (in)
4456 :Returns: 0 on successful completion,
4457 -EFAULT if struct kvm_reinject_control cannot be read,
4458 -EINVAL if the supplied shift or flags are invalid,
4459 -ENXIO is there is no pending HPT, or the pending HPT doesn't
4460 have the requested size,
4461 -EBUSY if the pending HPT is not fully prepared,
4462 -ENOSPC if there was a hash collision when moving existing
4463 HPT entries to the new HPT,
4464 -EIO on other error conditions
4465
4466 Used to implement the PAPR extension for runtime resizing of a guest's
4467 Hashed Page Table (HPT). Specifically this requests that the guest be
4468 transferred to working with the new HPT, essentially implementing the
4469 H_RESIZE_HPT_COMMIT hypercall.
4470
4471 ::
4472
4473 struct kvm_ppc_resize_hpt {
4474 __u64 flags;
4475 __u32 shift;
4476 __u32 pad;
4477 };
4478
4479 This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has
4480 returned 0 with the same parameters. In other cases
4481 KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or
4482 -EBUSY, though others may be possible if the preparation was started,
4483 but failed).
4484
4485 This will have undefined effects on the guest if it has not already
4486 placed itself in a quiescent state where no vcpu will make MMU enabled
4487 memory accesses.
4488
4489 On successful completion, the pending HPT will become the guest's active
4490 HPT and the previous HPT will be discarded.
4491
4492 On failure, the guest will still be operating on its previous HPT.
4493
4494 4.104 KVM_X86_GET_MCE_CAP_SUPPORTED
4495 -----------------------------------
4496
4497 :Capability: KVM_CAP_MCE
4498 :Architectures: x86
4499 :Type: system ioctl
4500 :Parameters: u64 mce_cap (out)
4501 :Returns: 0 on success, -1 on error
4502
4503 Returns supported MCE capabilities. The u64 mce_cap parameter
4504 has the same format as the MSR_IA32_MCG_CAP register. Supported
4505 capabilities will have the corresponding bits set.
4506
4507 4.105 KVM_X86_SETUP_MCE
4508 -----------------------
4509
4510 :Capability: KVM_CAP_MCE
4511 :Architectures: x86
4512 :Type: vcpu ioctl
4513 :Parameters: u64 mcg_cap (in)
4514 :Returns: 0 on success,
4515 -EFAULT if u64 mcg_cap cannot be read,
4516 -EINVAL if the requested number of banks is invalid,
4517 -EINVAL if requested MCE capability is not supported.
4518
4519 Initializes MCE support for use. The u64 mcg_cap parameter
4520 has the same format as the MSR_IA32_MCG_CAP register and
4521 specifies which capabilities should be enabled. The maximum
4522 supported number of error-reporting banks can be retrieved when
4523 checking for KVM_CAP_MCE. The supported capabilities can be
4524 retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED.
4525
4526 4.106 KVM_X86_SET_MCE
4527 ---------------------
4528
4529 :Capability: KVM_CAP_MCE
4530 :Architectures: x86
4531 :Type: vcpu ioctl
4532 :Parameters: struct kvm_x86_mce (in)
4533 :Returns: 0 on success,
4534 -EFAULT if struct kvm_x86_mce cannot be read,
4535 -EINVAL if the bank number is invalid,
4536 -EINVAL if VAL bit is not set in status field.
4537
4538 Inject a machine check error (MCE) into the guest. The input
4539 parameter is::
4540
4541 struct kvm_x86_mce {
4542 __u64 status;
4543 __u64 addr;
4544 __u64 misc;
4545 __u64 mcg_status;
4546 __u8 bank;
4547 __u8 pad1[7];
4548 __u64 pad2[3];
4549 };
4550
4551 If the MCE being reported is an uncorrected error, KVM will
4552 inject it as an MCE exception into the guest. If the guest
4553 MCG_STATUS register reports that an MCE is in progress, KVM
4554 causes an KVM_EXIT_SHUTDOWN vmexit.
4555
4556 Otherwise, if the MCE is a corrected error, KVM will just
4557 store it in the corresponding bank (provided this bank is
4558 not holding a previously reported uncorrected error).
4559
4560 4.107 KVM_S390_GET_CMMA_BITS
4561 ----------------------------
4562
4563 :Capability: KVM_CAP_S390_CMMA_MIGRATION
4564 :Architectures: s390
4565 :Type: vm ioctl
4566 :Parameters: struct kvm_s390_cmma_log (in, out)
4567 :Returns: 0 on success, a negative value on error
4568
4569 Errors:
4570
4571 ====== =============================================================
4572 ENOMEM not enough memory can be allocated to complete the task
4573 ENXIO if CMMA is not enabled
4574 EINVAL if KVM_S390_CMMA_PEEK is not set but migration mode was not enabled
4575 EINVAL if KVM_S390_CMMA_PEEK is not set but dirty tracking has been
4576 disabled (and thus migration mode was automatically disabled)
4577 EFAULT if the userspace address is invalid or if no page table is
4578 present for the addresses (e.g. when using hugepages).
4579 ====== =============================================================
4580
4581 This ioctl is used to get the values of the CMMA bits on the s390
4582 architecture. It is meant to be used in two scenarios:
4583
4584 - During live migration to save the CMMA values. Live migration needs
4585 to be enabled via the KVM_REQ_START_MIGRATION VM property.
4586 - To non-destructively peek at the CMMA values, with the flag
4587 KVM_S390_CMMA_PEEK set.
4588
4589 The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired
4590 values are written to a buffer whose location is indicated via the "values"
4591 member in the kvm_s390_cmma_log struct. The values in the input struct are
4592 also updated as needed.
4593
4594 Each CMMA value takes up one byte.
4595
4596 ::
4597
4598 struct kvm_s390_cmma_log {
4599 __u64 start_gfn;
4600 __u32 count;
4601 __u32 flags;
4602 union {
4603 __u64 remaining;
4604 __u64 mask;
4605 };
4606 __u64 values;
4607 };
4608
4609 start_gfn is the number of the first guest frame whose CMMA values are
4610 to be retrieved,
4611
4612 count is the length of the buffer in bytes,
4613
4614 values points to the buffer where the result will be written to.
4615
4616 If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be
4617 KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with
4618 other ioctls.
4619
4620 The result is written in the buffer pointed to by the field values, and
4621 the values of the input parameter are updated as follows.
4622
4623 Depending on the flags, different actions are performed. The only
4624 supported flag so far is KVM_S390_CMMA_PEEK.
4625
4626 The default behaviour if KVM_S390_CMMA_PEEK is not set is:
4627 start_gfn will indicate the first page frame whose CMMA bits were dirty.
4628 It is not necessarily the same as the one passed as input, as clean pages
4629 are skipped.
4630
4631 count will indicate the number of bytes actually written in the buffer.
4632 It can (and very often will) be smaller than the input value, since the
4633 buffer is only filled until 16 bytes of clean values are found (which
4634 are then not copied in the buffer). Since a CMMA migration block needs
4635 the base address and the length, for a total of 16 bytes, we will send
4636 back some clean data if there is some dirty data afterwards, as long as
4637 the size of the clean data does not exceed the size of the header. This
4638 allows to minimize the amount of data to be saved or transferred over
4639 the network at the expense of more roundtrips to userspace. The next
4640 invocation of the ioctl will skip over all the clean values, saving
4641 potentially more than just the 16 bytes we found.
4642
4643 If KVM_S390_CMMA_PEEK is set:
4644 the existing storage attributes are read even when not in migration
4645 mode, and no other action is performed;
4646
4647 the output start_gfn will be equal to the input start_gfn,
4648
4649 the output count will be equal to the input count, except if the end of
4650 memory has been reached.
4651
4652 In both cases:
4653 the field "remaining" will indicate the total number of dirty CMMA values
4654 still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is
4655 not enabled.
4656
4657 mask is unused.
4658
4659 values points to the userspace buffer where the result will be stored.
4660
4661 4.108 KVM_S390_SET_CMMA_BITS
4662 ----------------------------
4663
4664 :Capability: KVM_CAP_S390_CMMA_MIGRATION
4665 :Architectures: s390
4666 :Type: vm ioctl
4667 :Parameters: struct kvm_s390_cmma_log (in)
4668 :Returns: 0 on success, a negative value on error
4669
4670 This ioctl is used to set the values of the CMMA bits on the s390
4671 architecture. It is meant to be used during live migration to restore
4672 the CMMA values, but there are no restrictions on its use.
4673 The ioctl takes parameters via the kvm_s390_cmma_values struct.
4674 Each CMMA value takes up one byte.
4675
4676 ::
4677
4678 struct kvm_s390_cmma_log {
4679 __u64 start_gfn;
4680 __u32 count;
4681 __u32 flags;
4682 union {
4683 __u64 remaining;
4684 __u64 mask;
4685 };
4686 __u64 values;
4687 };
4688
4689 start_gfn indicates the starting guest frame number,
4690
4691 count indicates how many values are to be considered in the buffer,
4692
4693 flags is not used and must be 0.
4694
4695 mask indicates which PGSTE bits are to be considered.
4696
4697 remaining is not used.
4698
4699 values points to the buffer in userspace where to store the values.
4700
4701 This ioctl can fail with -ENOMEM if not enough memory can be allocated to
4702 complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if
4703 the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or
4704 if the flags field was not 0, with -EFAULT if the userspace address is
4705 invalid, if invalid pages are written to (e.g. after the end of memory)
4706 or if no page table is present for the addresses (e.g. when using
4707 hugepages).
4708
4709 4.109 KVM_PPC_GET_CPU_CHAR
4710 --------------------------
4711
4712 :Capability: KVM_CAP_PPC_GET_CPU_CHAR
4713 :Architectures: powerpc
4714 :Type: vm ioctl
4715 :Parameters: struct kvm_ppc_cpu_char (out)
4716 :Returns: 0 on successful completion,
4717 -EFAULT if struct kvm_ppc_cpu_char cannot be written
4718
4719 This ioctl gives userspace information about certain characteristics
4720 of the CPU relating to speculative execution of instructions and
4721 possible information leakage resulting from speculative execution (see
4722 CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is
4723 returned in struct kvm_ppc_cpu_char, which looks like this::
4724
4725 struct kvm_ppc_cpu_char {
4726 __u64 character; /* characteristics of the CPU */
4727 __u64 behaviour; /* recommended software behaviour */
4728 __u64 character_mask; /* valid bits in character */
4729 __u64 behaviour_mask; /* valid bits in behaviour */
4730 };
4731
4732 For extensibility, the character_mask and behaviour_mask fields
4733 indicate which bits of character and behaviour have been filled in by
4734 the kernel. If the set of defined bits is extended in future then
4735 userspace will be able to tell whether it is running on a kernel that
4736 knows about the new bits.
4737
4738 The character field describes attributes of the CPU which can help
4739 with preventing inadvertent information disclosure - specifically,
4740 whether there is an instruction to flash-invalidate the L1 data cache
4741 (ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set
4742 to a mode where entries can only be used by the thread that created
4743 them, whether the bcctr[l] instruction prevents speculation, and
4744 whether a speculation barrier instruction (ori 31,31,0) is provided.
4745
4746 The behaviour field describes actions that software should take to
4747 prevent inadvertent information disclosure, and thus describes which
4748 vulnerabilities the hardware is subject to; specifically whether the
4749 L1 data cache should be flushed when returning to user mode from the
4750 kernel, and whether a speculation barrier should be placed between an
4751 array bounds check and the array access.
4752
4753 These fields use the same bit definitions as the new
4754 H_GET_CPU_CHARACTERISTICS hypercall.
4755
4756 4.110 KVM_MEMORY_ENCRYPT_OP
4757 ---------------------------
4758
4759 :Capability: basic
4760 :Architectures: x86
4761 :Type: vm
4762 :Parameters: an opaque platform specific structure (in/out)
4763 :Returns: 0 on success; -1 on error
4764
4765 If the platform supports creating encrypted VMs then this ioctl can be used
4766 for issuing platform-specific memory encryption commands to manage those
4767 encrypted VMs.
4768
4769 Currently, this ioctl is used for issuing Secure Encrypted Virtualization
4770 (SEV) commands on AMD Processors. The SEV commands are defined in
4771 Documentation/virt/kvm/x86/amd-memory-encryption.rst.
4772
4773 4.111 KVM_MEMORY_ENCRYPT_REG_REGION
4774 -----------------------------------
4775
4776 :Capability: basic
4777 :Architectures: x86
4778 :Type: system
4779 :Parameters: struct kvm_enc_region (in)
4780 :Returns: 0 on success; -1 on error
4781
4782 This ioctl can be used to register a guest memory region which may
4783 contain encrypted data (e.g. guest RAM, SMRAM etc).
4784
4785 It is used in the SEV-enabled guest. When encryption is enabled, a guest
4786 memory region may contain encrypted data. The SEV memory encryption
4787 engine uses a tweak such that two identical plaintext pages, each at
4788 different locations will have differing ciphertexts. So swapping or
4789 moving ciphertext of those pages will not result in plaintext being
4790 swapped. So relocating (or migrating) physical backing pages for the SEV
4791 guest will require some additional steps.
4792
4793 Note: The current SEV key management spec does not provide commands to
4794 swap or migrate (move) ciphertext pages. Hence, for now we pin the guest
4795 memory region registered with the ioctl.
4796
4797 4.112 KVM_MEMORY_ENCRYPT_UNREG_REGION
4798 -------------------------------------
4799
4800 :Capability: basic
4801 :Architectures: x86
4802 :Type: system
4803 :Parameters: struct kvm_enc_region (in)
4804 :Returns: 0 on success; -1 on error
4805
4806 This ioctl can be used to unregister the guest memory region registered
4807 with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above.
4808
4809 4.113 KVM_HYPERV_EVENTFD
4810 ------------------------
4811
4812 :Capability: KVM_CAP_HYPERV_EVENTFD
4813 :Architectures: x86
4814 :Type: vm ioctl
4815 :Parameters: struct kvm_hyperv_eventfd (in)
4816
4817 This ioctl (un)registers an eventfd to receive notifications from the guest on
4818 the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without
4819 causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number
4820 (bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit.
4821
4822 ::
4823
4824 struct kvm_hyperv_eventfd {
4825 __u32 conn_id;
4826 __s32 fd;
4827 __u32 flags;
4828 __u32 padding[3];
4829 };
4830
4831 The conn_id field should fit within 24 bits::
4832
4833 #define KVM_HYPERV_CONN_ID_MASK 0x00ffffff
4834
4835 The acceptable values for the flags field are::
4836
4837 #define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0)
4838
4839 :Returns: 0 on success,
4840 -EINVAL if conn_id or flags is outside the allowed range,
4841 -ENOENT on deassign if the conn_id isn't registered,
4842 -EEXIST on assign if the conn_id is already registered
4843
4844 4.114 KVM_GET_NESTED_STATE
4845 --------------------------
4846
4847 :Capability: KVM_CAP_NESTED_STATE
4848 :Architectures: x86
4849 :Type: vcpu ioctl
4850 :Parameters: struct kvm_nested_state (in/out)
4851 :Returns: 0 on success, -1 on error
4852
4853 Errors:
4854
4855 ===== =============================================================
4856 E2BIG the total state size exceeds the value of 'size' specified by
4857 the user; the size required will be written into size.
4858 ===== =============================================================
4859
4860 ::
4861
4862 struct kvm_nested_state {
4863 __u16 flags;
4864 __u16 format;
4865 __u32 size;
4866
4867 union {
4868 struct kvm_vmx_nested_state_hdr vmx;
4869 struct kvm_svm_nested_state_hdr svm;
4870
4871 /* Pad the header to 128 bytes. */
4872 __u8 pad[120];
4873 } hdr;
4874
4875 union {
4876 struct kvm_vmx_nested_state_data vmx[0];
4877 struct kvm_svm_nested_state_data svm[0];
4878 } data;
4879 };
4880
4881 #define KVM_STATE_NESTED_GUEST_MODE 0x00000001
4882 #define KVM_STATE_NESTED_RUN_PENDING 0x00000002
4883 #define KVM_STATE_NESTED_EVMCS 0x00000004
4884
4885 #define KVM_STATE_NESTED_FORMAT_VMX 0
4886 #define KVM_STATE_NESTED_FORMAT_SVM 1
4887
4888 #define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000
4889
4890 #define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001
4891 #define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002
4892
4893 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001
4894
4895 struct kvm_vmx_nested_state_hdr {
4896 __u64 vmxon_pa;
4897 __u64 vmcs12_pa;
4898
4899 struct {
4900 __u16 flags;
4901 } smm;
4902
4903 __u32 flags;
4904 __u64 preemption_timer_deadline;
4905 };
4906
4907 struct kvm_vmx_nested_state_data {
4908 __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
4909 __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
4910 };
4911
4912 This ioctl copies the vcpu's nested virtualization state from the kernel to
4913 userspace.
4914
4915 The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE
4916 to the KVM_CHECK_EXTENSION ioctl().
4917
4918 4.115 KVM_SET_NESTED_STATE
4919 --------------------------
4920
4921 :Capability: KVM_CAP_NESTED_STATE
4922 :Architectures: x86
4923 :Type: vcpu ioctl
4924 :Parameters: struct kvm_nested_state (in)
4925 :Returns: 0 on success, -1 on error
4926
4927 This copies the vcpu's kvm_nested_state struct from userspace to the kernel.
4928 For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE.
4929
4930 4.116 KVM_(UN)REGISTER_COALESCED_MMIO
4931 -------------------------------------
4932
4933 :Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio)
4934 KVM_CAP_COALESCED_PIO (for coalesced pio)
4935 :Architectures: all
4936 :Type: vm ioctl
4937 :Parameters: struct kvm_coalesced_mmio_zone
4938 :Returns: 0 on success, < 0 on error
4939
4940 Coalesced I/O is a performance optimization that defers hardware
4941 register write emulation so that userspace exits are avoided. It is
4942 typically used to reduce the overhead of emulating frequently accessed
4943 hardware registers.
4944
4945 When a hardware register is configured for coalesced I/O, write accesses
4946 do not exit to userspace and their value is recorded in a ring buffer
4947 that is shared between kernel and userspace.
4948
4949 Coalesced I/O is used if one or more write accesses to a hardware
4950 register can be deferred until a read or a write to another hardware
4951 register on the same device. This last access will cause a vmexit and
4952 userspace will process accesses from the ring buffer before emulating
4953 it. That will avoid exiting to userspace on repeated writes.
4954
4955 Coalesced pio is based on coalesced mmio. There is little difference
4956 between coalesced mmio and pio except that coalesced pio records accesses
4957 to I/O ports.
4958
4959 4.117 KVM_CLEAR_DIRTY_LOG (vm ioctl)
4960 ------------------------------------
4961
4962 :Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
4963 :Architectures: x86, arm64, mips
4964 :Type: vm ioctl
4965 :Parameters: struct kvm_clear_dirty_log (in)
4966 :Returns: 0 on success, -1 on error
4967
4968 ::
4969
4970 /* for KVM_CLEAR_DIRTY_LOG */
4971 struct kvm_clear_dirty_log {
4972 __u32 slot;
4973 __u32 num_pages;
4974 __u64 first_page;
4975 union {
4976 void __user *dirty_bitmap; /* one bit per page */
4977 __u64 padding;
4978 };
4979 };
4980
4981 The ioctl clears the dirty status of pages in a memory slot, according to
4982 the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap
4983 field. Bit 0 of the bitmap corresponds to page "first_page" in the
4984 memory slot, and num_pages is the size in bits of the input bitmap.
4985 first_page must be a multiple of 64; num_pages must also be a multiple of
4986 64 unless first_page + num_pages is the size of the memory slot. For each
4987 bit that is set in the input bitmap, the corresponding page is marked "clean"
4988 in KVM's dirty bitmap, and dirty tracking is re-enabled for that page
4989 (for example via write-protection, or by clearing the dirty bit in
4990 a page table entry).
4991
4992 If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies
4993 the address space for which you want to clear the dirty status. See
4994 KVM_SET_USER_MEMORY_REGION for details on the usage of slot field.
4995
4996 This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
4997 is enabled; for more information, see the description of the capability.
4998 However, it can always be used as long as KVM_CHECK_EXTENSION confirms
4999 that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present.
5000
5001 4.118 KVM_GET_SUPPORTED_HV_CPUID
5002 --------------------------------
5003
5004 :Capability: KVM_CAP_HYPERV_CPUID (vcpu), KVM_CAP_SYS_HYPERV_CPUID (system)
5005 :Architectures: x86
5006 :Type: system ioctl, vcpu ioctl
5007 :Parameters: struct kvm_cpuid2 (in/out)
5008 :Returns: 0 on success, -1 on error
5009
5010 ::
5011
5012 struct kvm_cpuid2 {
5013 __u32 nent;
5014 __u32 padding;
5015 struct kvm_cpuid_entry2 entries[0];
5016 };
5017
5018 struct kvm_cpuid_entry2 {
5019 __u32 function;
5020 __u32 index;
5021 __u32 flags;
5022 __u32 eax;
5023 __u32 ebx;
5024 __u32 ecx;
5025 __u32 edx;
5026 __u32 padding[3];
5027 };
5028
5029 This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in
5030 KVM. Userspace can use the information returned by this ioctl to construct
5031 cpuid information presented to guests consuming Hyper-V enlightenments (e.g.
5032 Windows or Hyper-V guests).
5033
5034 CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level
5035 Functional Specification (TLFS). These leaves can't be obtained with
5036 KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature
5037 leaves (0x40000000, 0x40000001).
5038
5039 Currently, the following list of CPUID leaves are returned:
5040
5041 - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS
5042 - HYPERV_CPUID_INTERFACE
5043 - HYPERV_CPUID_VERSION
5044 - HYPERV_CPUID_FEATURES
5045 - HYPERV_CPUID_ENLIGHTMENT_INFO
5046 - HYPERV_CPUID_IMPLEMENT_LIMITS
5047 - HYPERV_CPUID_NESTED_FEATURES
5048 - HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS
5049 - HYPERV_CPUID_SYNDBG_INTERFACE
5050 - HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES
5051
5052 Userspace invokes KVM_GET_SUPPORTED_HV_CPUID by passing a kvm_cpuid2 structure
5053 with the 'nent' field indicating the number of entries in the variable-size
5054 array 'entries'. If the number of entries is too low to describe all Hyper-V
5055 feature leaves, an error (E2BIG) is returned. If the number is more or equal
5056 to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the
5057 number of valid entries in the 'entries' array, which is then filled.
5058
5059 'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved,
5060 userspace should not expect to get any particular value there.
5061
5062 Note, vcpu version of KVM_GET_SUPPORTED_HV_CPUID is currently deprecated. Unlike
5063 system ioctl which exposes all supported feature bits unconditionally, vcpu
5064 version has the following quirks:
5065
5066 - HYPERV_CPUID_NESTED_FEATURES leaf and HV_X64_ENLIGHTENED_VMCS_RECOMMENDED
5067 feature bit are only exposed when Enlightened VMCS was previously enabled
5068 on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS).
5069 - HV_STIMER_DIRECT_MODE_AVAILABLE bit is only exposed with in-kernel LAPIC.
5070 (presumes KVM_CREATE_IRQCHIP has already been called).
5071
5072 4.119 KVM_ARM_VCPU_FINALIZE
5073 ---------------------------
5074
5075 :Architectures: arm64
5076 :Type: vcpu ioctl
5077 :Parameters: int feature (in)
5078 :Returns: 0 on success, -1 on error
5079
5080 Errors:
5081
5082 ====== ==============================================================
5083 EPERM feature not enabled, needs configuration, or already finalized
5084 EINVAL feature unknown or not present
5085 ====== ==============================================================
5086
5087 Recognised values for feature:
5088
5089 ===== ===========================================
5090 arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE)
5091 ===== ===========================================
5092
5093 Finalizes the configuration of the specified vcpu feature.
5094
5095 The vcpu must already have been initialised, enabling the affected feature, by
5096 means of a successful KVM_ARM_VCPU_INIT call with the appropriate flag set in
5097 features[].
5098
5099 For affected vcpu features, this is a mandatory step that must be performed
5100 before the vcpu is fully usable.
5101
5102 Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be
5103 configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration
5104 that should be performed and how to do it are feature-dependent.
5105
5106 Other calls that depend on a particular feature being finalized, such as
5107 KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with
5108 -EPERM unless the feature has already been finalized by means of a
5109 KVM_ARM_VCPU_FINALIZE call.
5110
5111 See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization
5112 using this ioctl.
5113
5114 4.120 KVM_SET_PMU_EVENT_FILTER
5115 ------------------------------
5116
5117 :Capability: KVM_CAP_PMU_EVENT_FILTER
5118 :Architectures: x86
5119 :Type: vm ioctl
5120 :Parameters: struct kvm_pmu_event_filter (in)
5121 :Returns: 0 on success, -1 on error
5122
5123 Errors:
5124
5125 ====== ============================================================
5126 EFAULT args[0] cannot be accessed
5127 EINVAL args[0] contains invalid data in the filter or filter events
5128 E2BIG nevents is too large
5129 EBUSY not enough memory to allocate the filter
5130 ====== ============================================================
5131
5132 ::
5133
5134 struct kvm_pmu_event_filter {
5135 __u32 action;
5136 __u32 nevents;
5137 __u32 fixed_counter_bitmap;
5138 __u32 flags;
5139 __u32 pad[4];
5140 __u64 events[0];
5141 };
5142
5143 This ioctl restricts the set of PMU events the guest can program by limiting
5144 which event select and unit mask combinations are permitted.
5145
5146 The argument holds a list of filter events which will be allowed or denied.
5147
5148 Filter events only control general purpose counters; fixed purpose counters
5149 are controlled by the fixed_counter_bitmap.
5150
5151 Valid values for 'flags'::
5152
5153 ``0``
5154
5155 To use this mode, clear the 'flags' field.
5156
5157 In this mode each event will contain an event select + unit mask.
5158
5159 When the guest attempts to program the PMU the guest's event select +
5160 unit mask is compared against the filter events to determine whether the
5161 guest should have access.
5162
5163 ``KVM_PMU_EVENT_FLAG_MASKED_EVENTS``
5164 :Capability: KVM_CAP_PMU_EVENT_MASKED_EVENTS
5165
5166 In this mode each filter event will contain an event select, mask, match, and
5167 exclude value. To encode a masked event use::
5168
5169 KVM_PMU_ENCODE_MASKED_ENTRY()
5170
5171 An encoded event will follow this layout::
5172
5173 Bits Description
5174 ---- -----------
5175 7:0 event select (low bits)
5176 15:8 umask match
5177 31:16 unused
5178 35:32 event select (high bits)
5179 36:54 unused
5180 55 exclude bit
5181 63:56 umask mask
5182
5183 When the guest attempts to program the PMU, these steps are followed in
5184 determining if the guest should have access:
5185
5186 1. Match the event select from the guest against the filter events.
5187 2. If a match is found, match the guest's unit mask to the mask and match
5188 values of the included filter events.
5189 I.e. (unit mask & mask) == match && !exclude.
5190 3. If a match is found, match the guest's unit mask to the mask and match
5191 values of the excluded filter events.
5192 I.e. (unit mask & mask) == match && exclude.
5193 4.
5194 a. If an included match is found and an excluded match is not found, filter
5195 the event.
5196 b. For everything else, do not filter the event.
5197 5.
5198 a. If the event is filtered and it's an allow list, allow the guest to
5199 program the event.
5200 b. If the event is filtered and it's a deny list, do not allow the guest to
5201 program the event.
5202
5203 When setting a new pmu event filter, -EINVAL will be returned if any of the
5204 unused fields are set or if any of the high bits (35:32) in the event
5205 select are set when called on Intel.
5206
5207 Valid values for 'action'::
5208
5209 #define KVM_PMU_EVENT_ALLOW 0
5210 #define KVM_PMU_EVENT_DENY 1
5211
5212 Via this API, KVM userspace can also control the behavior of the VM's fixed
5213 counters (if any) by configuring the "action" and "fixed_counter_bitmap" fields.
5214
5215 Specifically, KVM follows the following pseudo-code when determining whether to
5216 allow the guest FixCtr[i] to count its pre-defined fixed event::
5217
5218 FixCtr[i]_is_allowed = (action == ALLOW) && (bitmap & BIT(i)) ||
5219 (action == DENY) && !(bitmap & BIT(i));
5220 FixCtr[i]_is_denied = !FixCtr[i]_is_allowed;
5221
5222 KVM always consumes fixed_counter_bitmap, it's userspace's responsibility to
5223 ensure fixed_counter_bitmap is set correctly, e.g. if userspace wants to define
5224 a filter that only affects general purpose counters.
5225
5226 Note, the "events" field also applies to fixed counters' hardcoded event_select
5227 and unit_mask values. "fixed_counter_bitmap" has higher priority than "events"
5228 if there is a contradiction between the two.
5229
5230 4.121 KVM_PPC_SVM_OFF
5231 ---------------------
5232
5233 :Capability: basic
5234 :Architectures: powerpc
5235 :Type: vm ioctl
5236 :Parameters: none
5237 :Returns: 0 on successful completion,
5238
5239 Errors:
5240
5241 ====== ================================================================
5242 EINVAL if ultravisor failed to terminate the secure guest
5243 ENOMEM if hypervisor failed to allocate new radix page tables for guest
5244 ====== ================================================================
5245
5246 This ioctl is used to turn off the secure mode of the guest or transition
5247 the guest from secure mode to normal mode. This is invoked when the guest
5248 is reset. This has no effect if called for a normal guest.
5249
5250 This ioctl issues an ultravisor call to terminate the secure guest,
5251 unpins the VPA pages and releases all the device pages that are used to
5252 track the secure pages by hypervisor.
5253
5254 4.122 KVM_S390_NORMAL_RESET
5255 ---------------------------
5256
5257 :Capability: KVM_CAP_S390_VCPU_RESETS
5258 :Architectures: s390
5259 :Type: vcpu ioctl
5260 :Parameters: none
5261 :Returns: 0
5262
5263 This ioctl resets VCPU registers and control structures according to
5264 the cpu reset definition in the POP (Principles Of Operation).
5265
5266 4.123 KVM_S390_INITIAL_RESET
5267 ----------------------------
5268
5269 :Capability: none
5270 :Architectures: s390
5271 :Type: vcpu ioctl
5272 :Parameters: none
5273 :Returns: 0
5274
5275 This ioctl resets VCPU registers and control structures according to
5276 the initial cpu reset definition in the POP. However, the cpu is not
5277 put into ESA mode. This reset is a superset of the normal reset.
5278
5279 4.124 KVM_S390_CLEAR_RESET
5280 --------------------------
5281
5282 :Capability: KVM_CAP_S390_VCPU_RESETS
5283 :Architectures: s390
5284 :Type: vcpu ioctl
5285 :Parameters: none
5286 :Returns: 0
5287
5288 This ioctl resets VCPU registers and control structures according to
5289 the clear cpu reset definition in the POP. However, the cpu is not put
5290 into ESA mode. This reset is a superset of the initial reset.
5291
5292
5293 4.125 KVM_S390_PV_COMMAND
5294 -------------------------
5295
5296 :Capability: KVM_CAP_S390_PROTECTED
5297 :Architectures: s390
5298 :Type: vm ioctl
5299 :Parameters: struct kvm_pv_cmd
5300 :Returns: 0 on success, < 0 on error
5301
5302 ::
5303
5304 struct kvm_pv_cmd {
5305 __u32 cmd; /* Command to be executed */
5306 __u16 rc; /* Ultravisor return code */
5307 __u16 rrc; /* Ultravisor return reason code */
5308 __u64 data; /* Data or address */
5309 __u32 flags; /* flags for future extensions. Must be 0 for now */
5310 __u32 reserved[3];
5311 };
5312
5313 **Ultravisor return codes**
5314 The Ultravisor return (reason) codes are provided by the kernel if a
5315 Ultravisor call has been executed to achieve the results expected by
5316 the command. Therefore they are independent of the IOCTL return
5317 code. If KVM changes `rc`, its value will always be greater than 0
5318 hence setting it to 0 before issuing a PV command is advised to be
5319 able to detect a change of `rc`.
5320
5321 **cmd values:**
5322
5323 KVM_PV_ENABLE
5324 Allocate memory and register the VM with the Ultravisor, thereby
5325 donating memory to the Ultravisor that will become inaccessible to
5326 KVM. All existing CPUs are converted to protected ones. After this
5327 command has succeeded, any CPU added via hotplug will become
5328 protected during its creation as well.
5329
5330 Errors:
5331
5332 ===== =============================
5333 EINTR an unmasked signal is pending
5334 ===== =============================
5335
5336 KVM_PV_DISABLE
5337 Deregister the VM from the Ultravisor and reclaim the memory that had
5338 been donated to the Ultravisor, making it usable by the kernel again.
5339 All registered VCPUs are converted back to non-protected ones. If a
5340 previous protected VM had been prepared for asynchronous teardown with
5341 KVM_PV_ASYNC_CLEANUP_PREPARE and not subsequently torn down with
5342 KVM_PV_ASYNC_CLEANUP_PERFORM, it will be torn down in this call
5343 together with the current protected VM.
5344
5345 KVM_PV_VM_SET_SEC_PARMS
5346 Pass the image header from VM memory to the Ultravisor in
5347 preparation of image unpacking and verification.
5348
5349 KVM_PV_VM_UNPACK
5350 Unpack (protect and decrypt) a page of the encrypted boot image.
5351
5352 KVM_PV_VM_VERIFY
5353 Verify the integrity of the unpacked image. Only if this succeeds,
5354 KVM is allowed to start protected VCPUs.
5355
5356 KVM_PV_INFO
5357 :Capability: KVM_CAP_S390_PROTECTED_DUMP
5358
5359 Presents an API that provides Ultravisor related data to userspace
5360 via subcommands. len_max is the size of the user space buffer,
5361 len_written is KVM's indication of how much bytes of that buffer
5362 were actually written to. len_written can be used to determine the
5363 valid fields if more response fields are added in the future.
5364
5365 ::
5366
5367 enum pv_cmd_info_id {
5368 KVM_PV_INFO_VM,
5369 KVM_PV_INFO_DUMP,
5370 };
5371
5372 struct kvm_s390_pv_info_header {
5373 __u32 id;
5374 __u32 len_max;
5375 __u32 len_written;
5376 __u32 reserved;
5377 };
5378
5379 struct kvm_s390_pv_info {
5380 struct kvm_s390_pv_info_header header;
5381 struct kvm_s390_pv_info_dump dump;
5382 struct kvm_s390_pv_info_vm vm;
5383 };
5384
5385 **subcommands:**
5386
5387 KVM_PV_INFO_VM
5388 This subcommand provides basic Ultravisor information for PV
5389 hosts. These values are likely also exported as files in the sysfs
5390 firmware UV query interface but they are more easily available to
5391 programs in this API.
5392
5393 The installed calls and feature_indication members provide the
5394 installed UV calls and the UV's other feature indications.
5395
5396 The max_* members provide information about the maximum number of PV
5397 vcpus, PV guests and PV guest memory size.
5398
5399 ::
5400
5401 struct kvm_s390_pv_info_vm {
5402 __u64 inst_calls_list[4];
5403 __u64 max_cpus;
5404 __u64 max_guests;
5405 __u64 max_guest_addr;
5406 __u64 feature_indication;
5407 };
5408
5409
5410 KVM_PV_INFO_DUMP
5411 This subcommand provides information related to dumping PV guests.
5412
5413 ::
5414
5415 struct kvm_s390_pv_info_dump {
5416 __u64 dump_cpu_buffer_len;
5417 __u64 dump_config_mem_buffer_per_1m;
5418 __u64 dump_config_finalize_len;
5419 };
5420
5421 KVM_PV_DUMP
5422 :Capability: KVM_CAP_S390_PROTECTED_DUMP
5423
5424 Presents an API that provides calls which facilitate dumping a
5425 protected VM.
5426
5427 ::
5428
5429 struct kvm_s390_pv_dmp {
5430 __u64 subcmd;
5431 __u64 buff_addr;
5432 __u64 buff_len;
5433 __u64 gaddr; /* For dump storage state */
5434 };
5435
5436 **subcommands:**
5437
5438 KVM_PV_DUMP_INIT
5439 Initializes the dump process of a protected VM. If this call does
5440 not succeed all other subcommands will fail with -EINVAL. This
5441 subcommand will return -EINVAL if a dump process has not yet been
5442 completed.
5443
5444 Not all PV vms can be dumped, the owner needs to set `dump
5445 allowed` PCF bit 34 in the SE header to allow dumping.
5446
5447 KVM_PV_DUMP_CONFIG_STOR_STATE
5448 Stores `buff_len` bytes of tweak component values starting with
5449 the 1MB block specified by the absolute guest address
5450 (`gaddr`). `buff_len` needs to be `conf_dump_storage_state_len`
5451 aligned and at least >= the `conf_dump_storage_state_len` value
5452 provided by the dump uv_info data. buff_user might be written to
5453 even if an error rc is returned. For instance if we encounter a
5454 fault after writing the first page of data.
5455
5456 KVM_PV_DUMP_COMPLETE
5457 If the subcommand succeeds it completes the dump process and lets
5458 KVM_PV_DUMP_INIT be called again.
5459
5460 On success `conf_dump_finalize_len` bytes of completion data will be
5461 stored to the `buff_addr`. The completion data contains a key
5462 derivation seed, IV, tweak nonce and encryption keys as well as an
5463 authentication tag all of which are needed to decrypt the dump at a
5464 later time.
5465
5466 KVM_PV_ASYNC_CLEANUP_PREPARE
5467 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE
5468
5469 Prepare the current protected VM for asynchronous teardown. Most
5470 resources used by the current protected VM will be set aside for a
5471 subsequent asynchronous teardown. The current protected VM will then
5472 resume execution immediately as non-protected. There can be at most
5473 one protected VM prepared for asynchronous teardown at any time. If
5474 a protected VM had already been prepared for teardown without
5475 subsequently calling KVM_PV_ASYNC_CLEANUP_PERFORM, this call will
5476 fail. In that case, the userspace process should issue a normal
5477 KVM_PV_DISABLE. The resources set aside with this call will need to
5478 be cleaned up with a subsequent call to KVM_PV_ASYNC_CLEANUP_PERFORM
5479 or KVM_PV_DISABLE, otherwise they will be cleaned up when KVM
5480 terminates. KVM_PV_ASYNC_CLEANUP_PREPARE can be called again as soon
5481 as cleanup starts, i.e. before KVM_PV_ASYNC_CLEANUP_PERFORM finishes.
5482
5483 KVM_PV_ASYNC_CLEANUP_PERFORM
5484 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE
5485
5486 Tear down the protected VM previously prepared for teardown with
5487 KVM_PV_ASYNC_CLEANUP_PREPARE. The resources that had been set aside
5488 will be freed during the execution of this command. This PV command
5489 should ideally be issued by userspace from a separate thread. If a
5490 fatal signal is received (or the process terminates naturally), the
5491 command will terminate immediately without completing, and the normal
5492 KVM shutdown procedure will take care of cleaning up all remaining
5493 protected VMs, including the ones whose teardown was interrupted by
5494 process termination.
5495
5496 4.126 KVM_XEN_HVM_SET_ATTR
5497 --------------------------
5498
5499 :Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
5500 :Architectures: x86
5501 :Type: vm ioctl
5502 :Parameters: struct kvm_xen_hvm_attr
5503 :Returns: 0 on success, < 0 on error
5504
5505 ::
5506
5507 struct kvm_xen_hvm_attr {
5508 __u16 type;
5509 __u16 pad[3];
5510 union {
5511 __u8 long_mode;
5512 __u8 vector;
5513 __u8 runstate_update_flag;
5514 union {
5515 __u64 gfn;
5516 __u64 hva;
5517 } shared_info;
5518 struct {
5519 __u32 send_port;
5520 __u32 type; /* EVTCHNSTAT_ipi / EVTCHNSTAT_interdomain */
5521 __u32 flags;
5522 union {
5523 struct {
5524 __u32 port;
5525 __u32 vcpu;
5526 __u32 priority;
5527 } port;
5528 struct {
5529 __u32 port; /* Zero for eventfd */
5530 __s32 fd;
5531 } eventfd;
5532 __u32 padding[4];
5533 } deliver;
5534 } evtchn;
5535 __u32 xen_version;
5536 __u64 pad[8];
5537 } u;
5538 };
5539
5540 type values:
5541
5542 KVM_XEN_ATTR_TYPE_LONG_MODE
5543 Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This
5544 determines the layout of the shared_info page exposed to the VM.
5545
5546 KVM_XEN_ATTR_TYPE_SHARED_INFO
5547 Sets the guest physical frame number at which the Xen shared_info
5548 page resides. Note that although Xen places vcpu_info for the first
5549 32 vCPUs in the shared_info page, KVM does not automatically do so
5550 and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO or
5551 KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA be used explicitly even when
5552 the vcpu_info for a given vCPU resides at the "default" location
5553 in the shared_info page. This is because KVM may not be aware of
5554 the Xen CPU id which is used as the index into the vcpu_info[]
5555 array, so may know the correct default location.
5556
5557 Note that the shared_info page may be constantly written to by KVM;
5558 it contains the event channel bitmap used to deliver interrupts to
5559 a Xen guest, amongst other things. It is exempt from dirty tracking
5560 mechanisms — KVM will not explicitly mark the page as dirty each
5561 time an event channel interrupt is delivered to the guest! Thus,
5562 userspace should always assume that the designated GFN is dirty if
5563 any vCPU has been running or any event channel interrupts can be
5564 routed to the guest.
5565
5566 Setting the gfn to KVM_XEN_INVALID_GFN will disable the shared_info
5567 page.
5568
5569 KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA
5570 If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the
5571 Xen capabilities, then this attribute may be used to set the
5572 userspace address at which the shared_info page resides, which
5573 will always be fixed in the VMM regardless of where it is mapped
5574 in guest physical address space. This attribute should be used in
5575 preference to KVM_XEN_ATTR_TYPE_SHARED_INFO as it avoids
5576 unnecessary invalidation of an internal cache when the page is
5577 re-mapped in guest physcial address space.
5578
5579 Setting the hva to zero will disable the shared_info page.
5580
5581 KVM_XEN_ATTR_TYPE_UPCALL_VECTOR
5582 Sets the exception vector used to deliver Xen event channel upcalls.
5583 This is the HVM-wide vector injected directly by the hypervisor
5584 (not through the local APIC), typically configured by a guest via
5585 HVM_PARAM_CALLBACK_IRQ. This can be disabled again (e.g. for guest
5586 SHUTDOWN_soft_reset) by setting it to zero.
5587
5588 KVM_XEN_ATTR_TYPE_EVTCHN
5589 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates
5590 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures
5591 an outbound port number for interception of EVTCHNOP_send requests
5592 from the guest. A given sending port number may be directed back to
5593 a specified vCPU (by APIC ID) / port / priority on the guest, or to
5594 trigger events on an eventfd. The vCPU and priority can be changed
5595 by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but other
5596 fields cannot change for a given sending port. A port mapping is
5597 removed by using KVM_XEN_EVTCHN_DEASSIGN in the flags field. Passing
5598 KVM_XEN_EVTCHN_RESET in the flags field removes all interception of
5599 outbound event channels. The values of the flags field are mutually
5600 exclusive and cannot be combined as a bitmask.
5601
5602 KVM_XEN_ATTR_TYPE_XEN_VERSION
5603 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates
5604 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures
5605 the 32-bit version code returned to the guest when it invokes the
5606 XENVER_version call; typically (XEN_MAJOR << 16 | XEN_MINOR). PV
5607 Xen guests will often use this to as a dummy hypercall to trigger
5608 event channel delivery, so responding within the kernel without
5609 exiting to userspace is beneficial.
5610
5611 KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG
5612 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates
5613 support for KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG. It enables the
5614 XEN_RUNSTATE_UPDATE flag which allows guest vCPUs to safely read
5615 other vCPUs' vcpu_runstate_info. Xen guests enable this feature via
5616 the VMASST_TYPE_runstate_update_flag of the HYPERVISOR_vm_assist
5617 hypercall.
5618
5619 4.127 KVM_XEN_HVM_GET_ATTR
5620 --------------------------
5621
5622 :Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
5623 :Architectures: x86
5624 :Type: vm ioctl
5625 :Parameters: struct kvm_xen_hvm_attr
5626 :Returns: 0 on success, < 0 on error
5627
5628 Allows Xen VM attributes to be read. For the structure and types,
5629 see KVM_XEN_HVM_SET_ATTR above. The KVM_XEN_ATTR_TYPE_EVTCHN
5630 attribute cannot be read.
5631
5632 4.128 KVM_XEN_VCPU_SET_ATTR
5633 ---------------------------
5634
5635 :Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
5636 :Architectures: x86
5637 :Type: vcpu ioctl
5638 :Parameters: struct kvm_xen_vcpu_attr
5639 :Returns: 0 on success, < 0 on error
5640
5641 ::
5642
5643 struct kvm_xen_vcpu_attr {
5644 __u16 type;
5645 __u16 pad[3];
5646 union {
5647 __u64 gpa;
5648 __u64 pad[4];
5649 struct {
5650 __u64 state;
5651 __u64 state_entry_time;
5652 __u64 time_running;
5653 __u64 time_runnable;
5654 __u64 time_blocked;
5655 __u64 time_offline;
5656 } runstate;
5657 __u32 vcpu_id;
5658 struct {
5659 __u32 port;
5660 __u32 priority;
5661 __u64 expires_ns;
5662 } timer;
5663 __u8 vector;
5664 } u;
5665 };
5666
5667 type values:
5668
5669 KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO
5670 Sets the guest physical address of the vcpu_info for a given vCPU.
5671 As with the shared_info page for the VM, the corresponding page may be
5672 dirtied at any time if event channel interrupt delivery is enabled, so
5673 userspace should always assume that the page is dirty without relying
5674 on dirty logging. Setting the gpa to KVM_XEN_INVALID_GPA will disable
5675 the vcpu_info.
5676
5677 KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA
5678 If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the
5679 Xen capabilities, then this attribute may be used to set the
5680 userspace address of the vcpu_info for a given vCPU. It should
5681 only be used when the vcpu_info resides at the "default" location
5682 in the shared_info page. In this case it is safe to assume the
5683 userspace address will not change, because the shared_info page is
5684 an overlay on guest memory and remains at a fixed host address
5685 regardless of where it is mapped in guest physical address space
5686 and hence unnecessary invalidation of an internal cache may be
5687 avoided if the guest memory layout is modified.
5688 If the vcpu_info does not reside at the "default" location then
5689 it is not guaranteed to remain at the same host address and
5690 hence the aforementioned cache invalidation is required.
5691
5692 KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO
5693 Sets the guest physical address of an additional pvclock structure
5694 for a given vCPU. This is typically used for guest vsyscall support.
5695 Setting the gpa to KVM_XEN_INVALID_GPA will disable the structure.
5696
5697 KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR
5698 Sets the guest physical address of the vcpu_runstate_info for a given
5699 vCPU. This is how a Xen guest tracks CPU state such as steal time.
5700 Setting the gpa to KVM_XEN_INVALID_GPA will disable the runstate area.
5701
5702 KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT
5703 Sets the runstate (RUNSTATE_running/_runnable/_blocked/_offline) of
5704 the given vCPU from the .u.runstate.state member of the structure.
5705 KVM automatically accounts running and runnable time but blocked
5706 and offline states are only entered explicitly.
5707
5708 KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA
5709 Sets all fields of the vCPU runstate data from the .u.runstate member
5710 of the structure, including the current runstate. The state_entry_time
5711 must equal the sum of the other four times.
5712
5713 KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST
5714 This *adds* the contents of the .u.runstate members of the structure
5715 to the corresponding members of the given vCPU's runstate data, thus
5716 permitting atomic adjustments to the runstate times. The adjustment
5717 to the state_entry_time must equal the sum of the adjustments to the
5718 other four times. The state field must be set to -1, or to a valid
5719 runstate value (RUNSTATE_running, RUNSTATE_runnable, RUNSTATE_blocked
5720 or RUNSTATE_offline) to set the current accounted state as of the
5721 adjusted state_entry_time.
5722
5723 KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID
5724 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates
5725 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the Xen
5726 vCPU ID of the given vCPU, to allow timer-related VCPU operations to
5727 be intercepted by KVM.
5728
5729 KVM_XEN_VCPU_ATTR_TYPE_TIMER
5730 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates
5731 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the
5732 event channel port/priority for the VIRQ_TIMER of the vCPU, as well
5733 as allowing a pending timer to be saved/restored. Setting the timer
5734 port to zero disables kernel handling of the singleshot timer.
5735
5736 KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR
5737 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates
5738 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the
5739 per-vCPU local APIC upcall vector, configured by a Xen guest with
5740 the HVMOP_set_evtchn_upcall_vector hypercall. This is typically
5741 used by Windows guests, and is distinct from the HVM-wide upcall
5742 vector configured with HVM_PARAM_CALLBACK_IRQ. It is disabled by
5743 setting the vector to zero.
5744
5745
5746 4.129 KVM_XEN_VCPU_GET_ATTR
5747 ---------------------------
5748
5749 :Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
5750 :Architectures: x86
5751 :Type: vcpu ioctl
5752 :Parameters: struct kvm_xen_vcpu_attr
5753 :Returns: 0 on success, < 0 on error
5754
5755 Allows Xen vCPU attributes to be read. For the structure and types,
5756 see KVM_XEN_VCPU_SET_ATTR above.
5757
5758 The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used
5759 with the KVM_XEN_VCPU_GET_ATTR ioctl.
5760
5761 4.130 KVM_ARM_MTE_COPY_TAGS
5762 ---------------------------
5763
5764 :Capability: KVM_CAP_ARM_MTE
5765 :Architectures: arm64
5766 :Type: vm ioctl
5767 :Parameters: struct kvm_arm_copy_mte_tags
5768 :Returns: number of bytes copied, < 0 on error (-EINVAL for incorrect
5769 arguments, -EFAULT if memory cannot be accessed).
5770
5771 ::
5772
5773 struct kvm_arm_copy_mte_tags {
5774 __u64 guest_ipa;
5775 __u64 length;
5776 void __user *addr;
5777 __u64 flags;
5778 __u64 reserved[2];
5779 };
5780
5781 Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The
5782 ``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned.
5783 ``length`` must not be bigger than 2^31 - PAGE_SIZE bytes. The ``addr``
5784 field must point to a buffer which the tags will be copied to or from.
5785
5786 ``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or
5787 ``KVM_ARM_TAGS_FROM_GUEST``.
5788
5789 The size of the buffer to store the tags is ``(length / 16)`` bytes
5790 (granules in MTE are 16 bytes long). Each byte contains a single tag
5791 value. This matches the format of ``PTRACE_PEEKMTETAGS`` and
5792 ``PTRACE_POKEMTETAGS``.
5793
5794 If an error occurs before any data is copied then a negative error code is
5795 returned. If some tags have been copied before an error occurs then the number
5796 of bytes successfully copied is returned. If the call completes successfully
5797 then ``length`` is returned.
5798
5799 4.131 KVM_GET_SREGS2
5800 --------------------
5801
5802 :Capability: KVM_CAP_SREGS2
5803 :Architectures: x86
5804 :Type: vcpu ioctl
5805 :Parameters: struct kvm_sregs2 (out)
5806 :Returns: 0 on success, -1 on error
5807
5808 Reads special registers from the vcpu.
5809 This ioctl (when supported) replaces the KVM_GET_SREGS.
5810
5811 ::
5812
5813 struct kvm_sregs2 {
5814 /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */
5815 struct kvm_segment cs, ds, es, fs, gs, ss;
5816 struct kvm_segment tr, ldt;
5817 struct kvm_dtable gdt, idt;
5818 __u64 cr0, cr2, cr3, cr4, cr8;
5819 __u64 efer;
5820 __u64 apic_base;
5821 __u64 flags;
5822 __u64 pdptrs[4];
5823 };
5824
5825 flags values for ``kvm_sregs2``:
5826
5827 ``KVM_SREGS2_FLAGS_PDPTRS_VALID``
5828
5829 Indicates that the struct contains valid PDPTR values.
5830
5831
5832 4.132 KVM_SET_SREGS2
5833 --------------------
5834
5835 :Capability: KVM_CAP_SREGS2
5836 :Architectures: x86
5837 :Type: vcpu ioctl
5838 :Parameters: struct kvm_sregs2 (in)
5839 :Returns: 0 on success, -1 on error
5840
5841 Writes special registers into the vcpu.
5842 See KVM_GET_SREGS2 for the data structures.
5843 This ioctl (when supported) replaces the KVM_SET_SREGS.
5844
5845 4.133 KVM_GET_STATS_FD
5846 ----------------------
5847
5848 :Capability: KVM_CAP_STATS_BINARY_FD
5849 :Architectures: all
5850 :Type: vm ioctl, vcpu ioctl
5851 :Parameters: none
5852 :Returns: statistics file descriptor on success, < 0 on error
5853
5854 Errors:
5855
5856 ====== ======================================================
5857 ENOMEM if the fd could not be created due to lack of memory
5858 EMFILE if the number of opened files exceeds the limit
5859 ====== ======================================================
5860
5861 The returned file descriptor can be used to read VM/vCPU statistics data in
5862 binary format. The data in the file descriptor consists of four blocks
5863 organized as follows:
5864
5865 +-------------+
5866 | Header |
5867 +-------------+
5868 | id string |
5869 +-------------+
5870 | Descriptors |
5871 +-------------+
5872 | Stats Data |
5873 +-------------+
5874
5875 Apart from the header starting at offset 0, please be aware that it is
5876 not guaranteed that the four blocks are adjacent or in the above order;
5877 the offsets of the id, descriptors and data blocks are found in the
5878 header. However, all four blocks are aligned to 64 bit offsets in the
5879 file and they do not overlap.
5880
5881 All blocks except the data block are immutable. Userspace can read them
5882 only one time after retrieving the file descriptor, and then use ``pread`` or
5883 ``lseek`` to read the statistics repeatedly.
5884
5885 All data is in system endianness.
5886
5887 The format of the header is as follows::
5888
5889 struct kvm_stats_header {
5890 __u32 flags;
5891 __u32 name_size;
5892 __u32 num_desc;
5893 __u32 id_offset;
5894 __u32 desc_offset;
5895 __u32 data_offset;
5896 };
5897
5898 The ``flags`` field is not used at the moment. It is always read as 0.
5899
5900 The ``name_size`` field is the size (in byte) of the statistics name string
5901 (including trailing '\0') which is contained in the "id string" block and
5902 appended at the end of every descriptor.
5903
5904 The ``num_desc`` field is the number of descriptors that are included in the
5905 descriptor block. (The actual number of values in the data block may be
5906 larger, since each descriptor may comprise more than one value).
5907
5908 The ``id_offset`` field is the offset of the id string from the start of the
5909 file indicated by the file descriptor. It is a multiple of 8.
5910
5911 The ``desc_offset`` field is the offset of the Descriptors block from the start
5912 of the file indicated by the file descriptor. It is a multiple of 8.
5913
5914 The ``data_offset`` field is the offset of the Stats Data block from the start
5915 of the file indicated by the file descriptor. It is a multiple of 8.
5916
5917 The id string block contains a string which identifies the file descriptor on
5918 which KVM_GET_STATS_FD was invoked. The size of the block, including the
5919 trailing ``'\0'``, is indicated by the ``name_size`` field in the header.
5920
5921 The descriptors block is only needed to be read once for the lifetime of the
5922 file descriptor contains a sequence of ``struct kvm_stats_desc``, each followed
5923 by a string of size ``name_size``.
5924 ::
5925
5926 #define KVM_STATS_TYPE_SHIFT 0
5927 #define KVM_STATS_TYPE_MASK (0xF << KVM_STATS_TYPE_SHIFT)
5928 #define KVM_STATS_TYPE_CUMULATIVE (0x0 << KVM_STATS_TYPE_SHIFT)
5929 #define KVM_STATS_TYPE_INSTANT (0x1 << KVM_STATS_TYPE_SHIFT)
5930 #define KVM_STATS_TYPE_PEAK (0x2 << KVM_STATS_TYPE_SHIFT)
5931 #define KVM_STATS_TYPE_LINEAR_HIST (0x3 << KVM_STATS_TYPE_SHIFT)
5932 #define KVM_STATS_TYPE_LOG_HIST (0x4 << KVM_STATS_TYPE_SHIFT)
5933 #define KVM_STATS_TYPE_MAX KVM_STATS_TYPE_LOG_HIST
5934
5935 #define KVM_STATS_UNIT_SHIFT 4
5936 #define KVM_STATS_UNIT_MASK (0xF << KVM_STATS_UNIT_SHIFT)
5937 #define KVM_STATS_UNIT_NONE (0x0 << KVM_STATS_UNIT_SHIFT)
5938 #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT)
5939 #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT)
5940 #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT)
5941 #define KVM_STATS_UNIT_BOOLEAN (0x4 << KVM_STATS_UNIT_SHIFT)
5942 #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_BOOLEAN
5943
5944 #define KVM_STATS_BASE_SHIFT 8
5945 #define KVM_STATS_BASE_MASK (0xF << KVM_STATS_BASE_SHIFT)
5946 #define KVM_STATS_BASE_POW10 (0x0 << KVM_STATS_BASE_SHIFT)
5947 #define KVM_STATS_BASE_POW2 (0x1 << KVM_STATS_BASE_SHIFT)
5948 #define KVM_STATS_BASE_MAX KVM_STATS_BASE_POW2
5949
5950 struct kvm_stats_desc {
5951 __u32 flags;
5952 __s16 exponent;
5953 __u16 size;
5954 __u32 offset;
5955 __u32 bucket_size;
5956 char name[];
5957 };
5958
5959 The ``flags`` field contains the type and unit of the statistics data described
5960 by this descriptor. Its endianness is CPU native.
5961 The following flags are supported:
5962
5963 Bits 0-3 of ``flags`` encode the type:
5964
5965 * ``KVM_STATS_TYPE_CUMULATIVE``
5966 The statistics reports a cumulative count. The value of data can only be increased.
5967 Most of the counters used in KVM are of this type.
5968 The corresponding ``size`` field for this type is always 1.
5969 All cumulative statistics data are read/write.
5970 * ``KVM_STATS_TYPE_INSTANT``
5971 The statistics reports an instantaneous value. Its value can be increased or
5972 decreased. This type is usually used as a measurement of some resources,
5973 like the number of dirty pages, the number of large pages, etc.
5974 All instant statistics are read only.
5975 The corresponding ``size`` field for this type is always 1.
5976 * ``KVM_STATS_TYPE_PEAK``
5977 The statistics data reports a peak value, for example the maximum number
5978 of items in a hash table bucket, the longest time waited and so on.
5979 The value of data can only be increased.
5980 The corresponding ``size`` field for this type is always 1.
5981 * ``KVM_STATS_TYPE_LINEAR_HIST``
5982 The statistic is reported as a linear histogram. The number of
5983 buckets is specified by the ``size`` field. The size of buckets is specified
5984 by the ``hist_param`` field. The range of the Nth bucket (1 <= N < ``size``)
5985 is [``hist_param``*(N-1), ``hist_param``*N), while the range of the last
5986 bucket is [``hist_param``*(``size``-1), +INF). (+INF means positive infinity
5987 value.)
5988 * ``KVM_STATS_TYPE_LOG_HIST``
5989 The statistic is reported as a logarithmic histogram. The number of
5990 buckets is specified by the ``size`` field. The range of the first bucket is
5991 [0, 1), while the range of the last bucket is [pow(2, ``size``-2), +INF).
5992 Otherwise, The Nth bucket (1 < N < ``size``) covers
5993 [pow(2, N-2), pow(2, N-1)).
5994
5995 Bits 4-7 of ``flags`` encode the unit:
5996
5997 * ``KVM_STATS_UNIT_NONE``
5998 There is no unit for the value of statistics data. This usually means that
5999 the value is a simple counter of an event.
6000 * ``KVM_STATS_UNIT_BYTES``
6001 It indicates that the statistics data is used to measure memory size, in the
6002 unit of Byte, KiByte, MiByte, GiByte, etc. The unit of the data is
6003 determined by the ``exponent`` field in the descriptor.
6004 * ``KVM_STATS_UNIT_SECONDS``
6005 It indicates that the statistics data is used to measure time or latency.
6006 * ``KVM_STATS_UNIT_CYCLES``
6007 It indicates that the statistics data is used to measure CPU clock cycles.
6008 * ``KVM_STATS_UNIT_BOOLEAN``
6009 It indicates that the statistic will always be either 0 or 1. Boolean
6010 statistics of "peak" type will never go back from 1 to 0. Boolean
6011 statistics can be linear histograms (with two buckets) but not logarithmic
6012 histograms.
6013
6014 Note that, in the case of histograms, the unit applies to the bucket
6015 ranges, while the bucket value indicates how many samples fell in the
6016 bucket's range.
6017
6018 Bits 8-11 of ``flags``, together with ``exponent``, encode the scale of the
6019 unit:
6020
6021 * ``KVM_STATS_BASE_POW10``
6022 The scale is based on power of 10. It is used for measurement of time and
6023 CPU clock cycles. For example, an exponent of -9 can be used with
6024 ``KVM_STATS_UNIT_SECONDS`` to express that the unit is nanoseconds.
6025 * ``KVM_STATS_BASE_POW2``
6026 The scale is based on power of 2. It is used for measurement of memory size.
6027 For example, an exponent of 20 can be used with ``KVM_STATS_UNIT_BYTES`` to
6028 express that the unit is MiB.
6029
6030 The ``size`` field is the number of values of this statistics data. Its
6031 value is usually 1 for most of simple statistics. 1 means it contains an
6032 unsigned 64bit data.
6033
6034 The ``offset`` field is the offset from the start of Data Block to the start of
6035 the corresponding statistics data.
6036
6037 The ``bucket_size`` field is used as a parameter for histogram statistics data.
6038 It is only used by linear histogram statistics data, specifying the size of a
6039 bucket in the unit expressed by bits 4-11 of ``flags`` together with ``exponent``.
6040
6041 The ``name`` field is the name string of the statistics data. The name string
6042 starts at the end of ``struct kvm_stats_desc``. The maximum length including
6043 the trailing ``'\0'``, is indicated by ``name_size`` in the header.
6044
6045 The Stats Data block contains an array of 64-bit values in the same order
6046 as the descriptors in Descriptors block.
6047
6048 4.134 KVM_GET_XSAVE2
6049 --------------------
6050
6051 :Capability: KVM_CAP_XSAVE2
6052 :Architectures: x86
6053 :Type: vcpu ioctl
6054 :Parameters: struct kvm_xsave (out)
6055 :Returns: 0 on success, -1 on error
6056
6057
6058 ::
6059
6060 struct kvm_xsave {
6061 __u32 region[1024];
6062 __u32 extra[0];
6063 };
6064
6065 This ioctl would copy current vcpu's xsave struct to the userspace. It
6066 copies as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2)
6067 when invoked on the vm file descriptor. The size value returned by
6068 KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096.
6069 Currently, it is only greater than 4096 if a dynamic feature has been
6070 enabled with ``arch_prctl()``, but this may change in the future.
6071
6072 The offsets of the state save areas in struct kvm_xsave follow the contents
6073 of CPUID leaf 0xD on the host.
6074
6075 4.135 KVM_XEN_HVM_EVTCHN_SEND
6076 -----------------------------
6077
6078 :Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND
6079 :Architectures: x86
6080 :Type: vm ioctl
6081 :Parameters: struct kvm_irq_routing_xen_evtchn
6082 :Returns: 0 on success, < 0 on error
6083
6084
6085 ::
6086
6087 struct kvm_irq_routing_xen_evtchn {
6088 __u32 port;
6089 __u32 vcpu;
6090 __u32 priority;
6091 };
6092
6093 This ioctl injects an event channel interrupt directly to the guest vCPU.
6094
6095 4.136 KVM_S390_PV_CPU_COMMAND
6096 -----------------------------
6097
6098 :Capability: KVM_CAP_S390_PROTECTED_DUMP
6099 :Architectures: s390
6100 :Type: vcpu ioctl
6101 :Parameters: none
6102 :Returns: 0 on success, < 0 on error
6103
6104 This ioctl closely mirrors `KVM_S390_PV_COMMAND` but handles requests
6105 for vcpus. It re-uses the kvm_s390_pv_dmp struct and hence also shares
6106 the command ids.
6107
6108 **command:**
6109
6110 KVM_PV_DUMP
6111 Presents an API that provides calls which facilitate dumping a vcpu
6112 of a protected VM.
6113
6114 **subcommand:**
6115
6116 KVM_PV_DUMP_CPU
6117 Provides encrypted dump data like register values.
6118 The length of the returned data is provided by uv_info.guest_cpu_stor_len.
6119
6120 4.137 KVM_S390_ZPCI_OP
6121 ----------------------
6122
6123 :Capability: KVM_CAP_S390_ZPCI_OP
6124 :Architectures: s390
6125 :Type: vm ioctl
6126 :Parameters: struct kvm_s390_zpci_op (in)
6127 :Returns: 0 on success, <0 on error
6128
6129 Used to manage hardware-assisted virtualization features for zPCI devices.
6130
6131 Parameters are specified via the following structure::
6132
6133 struct kvm_s390_zpci_op {
6134 /* in */
6135 __u32 fh; /* target device */
6136 __u8 op; /* operation to perform */
6137 __u8 pad[3];
6138 union {
6139 /* for KVM_S390_ZPCIOP_REG_AEN */
6140 struct {
6141 __u64 ibv; /* Guest addr of interrupt bit vector */
6142 __u64 sb; /* Guest addr of summary bit */
6143 __u32 flags;
6144 __u32 noi; /* Number of interrupts */
6145 __u8 isc; /* Guest interrupt subclass */
6146 __u8 sbo; /* Offset of guest summary bit vector */
6147 __u16 pad;
6148 } reg_aen;
6149 __u64 reserved[8];
6150 } u;
6151 };
6152
6153 The type of operation is specified in the "op" field.
6154 KVM_S390_ZPCIOP_REG_AEN is used to register the VM for adapter event
6155 notification interpretation, which will allow firmware delivery of adapter
6156 events directly to the vm, with KVM providing a backup delivery mechanism;
6157 KVM_S390_ZPCIOP_DEREG_AEN is used to subsequently disable interpretation of
6158 adapter event notifications.
6159
6160 The target zPCI function must also be specified via the "fh" field. For the
6161 KVM_S390_ZPCIOP_REG_AEN operation, additional information to establish firmware
6162 delivery must be provided via the "reg_aen" struct.
6163
6164 The "pad" and "reserved" fields may be used for future extensions and should be
6165 set to 0s by userspace.
6166
6167 4.138 KVM_ARM_SET_COUNTER_OFFSET
6168 --------------------------------
6169
6170 :Capability: KVM_CAP_COUNTER_OFFSET
6171 :Architectures: arm64
6172 :Type: vm ioctl
6173 :Parameters: struct kvm_arm_counter_offset (in)
6174 :Returns: 0 on success, < 0 on error
6175
6176 This capability indicates that userspace is able to apply a single VM-wide
6177 offset to both the virtual and physical counters as viewed by the guest
6178 using the KVM_ARM_SET_CNT_OFFSET ioctl and the following data structure:
6179
6180 ::
6181
6182 struct kvm_arm_counter_offset {
6183 __u64 counter_offset;
6184 __u64 reserved;
6185 };
6186
6187 The offset describes a number of counter cycles that are subtracted from
6188 both virtual and physical counter views (similar to the effects of the
6189 CNTVOFF_EL2 and CNTPOFF_EL2 system registers, but only global). The offset
6190 always applies to all vcpus (already created or created after this ioctl)
6191 for this VM.
6192
6193 It is userspace's responsibility to compute the offset based, for example,
6194 on previous values of the guest counters.
6195
6196 Any value other than 0 for the "reserved" field may result in an error
6197 (-EINVAL) being returned. This ioctl can also return -EBUSY if any vcpu
6198 ioctl is issued concurrently.
6199
6200 Note that using this ioctl results in KVM ignoring subsequent userspace
6201 writes to the CNTVCT_EL0 and CNTPCT_EL0 registers using the SET_ONE_REG
6202 interface. No error will be returned, but the resulting offset will not be
6203 applied.
6204
6205 .. _KVM_ARM_GET_REG_WRITABLE_MASKS:
6206
6207 4.139 KVM_ARM_GET_REG_WRITABLE_MASKS
6208 -------------------------------------------
6209
6210 :Capability: KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES
6211 :Architectures: arm64
6212 :Type: vm ioctl
6213 :Parameters: struct reg_mask_range (in/out)
6214 :Returns: 0 on success, < 0 on error
6215
6216
6217 ::
6218
6219 #define KVM_ARM_FEATURE_ID_RANGE 0
6220 #define KVM_ARM_FEATURE_ID_RANGE_SIZE (3 * 8 * 8)
6221
6222 struct reg_mask_range {
6223 __u64 addr; /* Pointer to mask array */
6224 __u32 range; /* Requested range */
6225 __u32 reserved[13];
6226 };
6227
6228 This ioctl copies the writable masks for a selected range of registers to
6229 userspace.
6230
6231 The ``addr`` field is a pointer to the destination array where KVM copies
6232 the writable masks.
6233
6234 The ``range`` field indicates the requested range of registers.
6235 ``KVM_CHECK_EXTENSION`` for the ``KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES``
6236 capability returns the supported ranges, expressed as a set of flags. Each
6237 flag's bit index represents a possible value for the ``range`` field.
6238 All other values are reserved for future use and KVM may return an error.
6239
6240 The ``reserved[13]`` array is reserved for future use and should be 0, or
6241 KVM may return an error.
6242
6243 KVM_ARM_FEATURE_ID_RANGE (0)
6244 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
6245
6246 The Feature ID range is defined as the AArch64 System register space with
6247 op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, op2=={0-7}.
6248
6249 The mask returned array pointed to by ``addr`` is indexed by the macro
6250 ``ARM64_FEATURE_ID_RANGE_IDX(op0, op1, crn, crm, op2)``, allowing userspace
6251 to know what fields can be changed for the system register described by
6252 ``op0, op1, crn, crm, op2``. KVM rejects ID register values that describe a
6253 superset of the features supported by the system.
6254
6255 4.140 KVM_SET_USER_MEMORY_REGION2
6256 ---------------------------------
6257
6258 :Capability: KVM_CAP_USER_MEMORY2
6259 :Architectures: all
6260 :Type: vm ioctl
6261 :Parameters: struct kvm_userspace_memory_region2 (in)
6262 :Returns: 0 on success, -1 on error
6263
6264 KVM_SET_USER_MEMORY_REGION2 is an extension to KVM_SET_USER_MEMORY_REGION that
6265 allows mapping guest_memfd memory into a guest. All fields shared with
6266 KVM_SET_USER_MEMORY_REGION identically. Userspace can set KVM_MEM_GUEST_MEMFD
6267 in flags to have KVM bind the memory region to a given guest_memfd range of
6268 [guest_memfd_offset, guest_memfd_offset + memory_size]. The target guest_memfd
6269 must point at a file created via KVM_CREATE_GUEST_MEMFD on the current VM, and
6270 the target range must not be bound to any other memory region. All standard
6271 bounds checks apply (use common sense).
6272
6273 ::
6274
6275 struct kvm_userspace_memory_region2 {
6276 __u32 slot;
6277 __u32 flags;
6278 __u64 guest_phys_addr;
6279 __u64 memory_size; /* bytes */
6280 __u64 userspace_addr; /* start of the userspace allocated memory */
6281 __u64 guest_memfd_offset;
6282 __u32 guest_memfd;
6283 __u32 pad1;
6284 __u64 pad2[14];
6285 };
6286
6287 A KVM_MEM_GUEST_MEMFD region _must_ have a valid guest_memfd (private memory) and
6288 userspace_addr (shared memory). However, "valid" for userspace_addr simply
6289 means that the address itself must be a legal userspace address. The backing
6290 mapping for userspace_addr is not required to be valid/populated at the time of
6291 KVM_SET_USER_MEMORY_REGION2, e.g. shared memory can be lazily mapped/allocated
6292 on-demand.
6293
6294 When mapping a gfn into the guest, KVM selects shared vs. private, i.e consumes
6295 userspace_addr vs. guest_memfd, based on the gfn's KVM_MEMORY_ATTRIBUTE_PRIVATE
6296 state. At VM creation time, all memory is shared, i.e. the PRIVATE attribute
6297 is '0' for all gfns. Userspace can control whether memory is shared/private by
6298 toggling KVM_MEMORY_ATTRIBUTE_PRIVATE via KVM_SET_MEMORY_ATTRIBUTES as needed.
6299
6300 S390:
6301 ^^^^^
6302
6303 Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set.
6304 Returns -EINVAL if called on a protected VM.
6305
6306 4.141 KVM_SET_MEMORY_ATTRIBUTES
6307 -------------------------------
6308
6309 :Capability: KVM_CAP_MEMORY_ATTRIBUTES
6310 :Architectures: x86
6311 :Type: vm ioctl
6312 :Parameters: struct kvm_memory_attributes (in)
6313 :Returns: 0 on success, <0 on error
6314
6315 KVM_SET_MEMORY_ATTRIBUTES allows userspace to set memory attributes for a range
6316 of guest physical memory.
6317
6318 ::
6319
6320 struct kvm_memory_attributes {
6321 __u64 address;
6322 __u64 size;
6323 __u64 attributes;
6324 __u64 flags;
6325 };
6326
6327 #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3)
6328
6329 The address and size must be page aligned. The supported attributes can be
6330 retrieved via ioctl(KVM_CHECK_EXTENSION) on KVM_CAP_MEMORY_ATTRIBUTES. If
6331 executed on a VM, KVM_CAP_MEMORY_ATTRIBUTES precisely returns the attributes
6332 supported by that VM. If executed at system scope, KVM_CAP_MEMORY_ATTRIBUTES
6333 returns all attributes supported by KVM. The only attribute defined at this
6334 time is KVM_MEMORY_ATTRIBUTE_PRIVATE, which marks the associated gfn as being
6335 guest private memory.
6336
6337 Note, there is no "get" API. Userspace is responsible for explicitly tracking
6338 the state of a gfn/page as needed.
6339
6340 The "flags" field is reserved for future extensions and must be '0'.
6341
6342 4.142 KVM_CREATE_GUEST_MEMFD
6343 ----------------------------
6344
6345 :Capability: KVM_CAP_GUEST_MEMFD
6346 :Architectures: none
6347 :Type: vm ioctl
6348 :Parameters: struct kvm_create_guest_memfd(in)
6349 :Returns: A file descriptor on success, <0 on error
6350
6351 KVM_CREATE_GUEST_MEMFD creates an anonymous file and returns a file descriptor
6352 that refers to it. guest_memfd files are roughly analogous to files created
6353 via memfd_create(), e.g. guest_memfd files live in RAM, have volatile storage,
6354 and are automatically released when the last reference is dropped. Unlike
6355 "regular" memfd_create() files, guest_memfd files are bound to their owning
6356 virtual machine (see below), cannot be mapped, read, or written by userspace,
6357 and cannot be resized (guest_memfd files do however support PUNCH_HOLE).
6358
6359 ::
6360
6361 struct kvm_create_guest_memfd {
6362 __u64 size;
6363 __u64 flags;
6364 __u64 reserved[6];
6365 };
6366
6367 Conceptually, the inode backing a guest_memfd file represents physical memory,
6368 i.e. is coupled to the virtual machine as a thing, not to a "struct kvm". The
6369 file itself, which is bound to a "struct kvm", is that instance's view of the
6370 underlying memory, e.g. effectively provides the translation of guest addresses
6371 to host memory. This allows for use cases where multiple KVM structures are
6372 used to manage a single virtual machine, e.g. when performing intrahost
6373 migration of a virtual machine.
6374
6375 KVM currently only supports mapping guest_memfd via KVM_SET_USER_MEMORY_REGION2,
6376 and more specifically via the guest_memfd and guest_memfd_offset fields in
6377 "struct kvm_userspace_memory_region2", where guest_memfd_offset is the offset
6378 into the guest_memfd instance. For a given guest_memfd file, there can be at
6379 most one mapping per page, i.e. binding multiple memory regions to a single
6380 guest_memfd range is not allowed (any number of memory regions can be bound to
6381 a single guest_memfd file, but the bound ranges must not overlap).
6382
6383 See KVM_SET_USER_MEMORY_REGION2 for additional details.
6384
6385 4.143 KVM_PRE_FAULT_MEMORY
6386 ---------------------------
6387
6388 :Capability: KVM_CAP_PRE_FAULT_MEMORY
6389 :Architectures: none
6390 :Type: vcpu ioctl
6391 :Parameters: struct kvm_pre_fault_memory (in/out)
6392 :Returns: 0 if at least one page is processed, < 0 on error
6393
6394 Errors:
6395
6396 ========== ===============================================================
6397 EINVAL The specified `gpa` and `size` were invalid (e.g. not
6398 page aligned, causes an overflow, or size is zero).
6399 ENOENT The specified `gpa` is outside defined memslots.
6400 EINTR An unmasked signal is pending and no page was processed.
6401 EFAULT The parameter address was invalid.
6402 EOPNOTSUPP Mapping memory for a GPA is unsupported by the
6403 hypervisor, and/or for the current vCPU state/mode.
6404 EIO unexpected error conditions (also causes a WARN)
6405 ========== ===============================================================
6406
6407 ::
6408
6409 struct kvm_pre_fault_memory {
6410 /* in/out */
6411 __u64 gpa;
6412 __u64 size;
6413 /* in */
6414 __u64 flags;
6415 __u64 padding[5];
6416 };
6417
6418 KVM_PRE_FAULT_MEMORY populates KVM's stage-2 page tables used to map memory
6419 for the current vCPU state. KVM maps memory as if the vCPU generated a
6420 stage-2 read page fault, e.g. faults in memory as needed, but doesn't break
6421 CoW. However, KVM does not mark any newly created stage-2 PTE as Accessed.
6422
6423 In the case of confidential VM types where there is an initial set up of
6424 private guest memory before the guest is 'finalized'/measured, this ioctl
6425 should only be issued after completing all the necessary setup to put the
6426 guest into a 'finalized' state so that the above semantics can be reliably
6427 ensured.
6428
6429 In some cases, multiple vCPUs might share the page tables. In this
6430 case, the ioctl can be called in parallel.
6431
6432 When the ioctl returns, the input values are updated to point to the
6433 remaining range. If `size` > 0 on return, the caller can just issue
6434 the ioctl again with the same `struct kvm_map_memory` argument.
6435
6436 Shadow page tables cannot support this ioctl because they
6437 are indexed by virtual address or nested guest physical address.
6438 Calling this ioctl when the guest is using shadow page tables (for
6439 example because it is running a nested guest with nested page tables)
6440 will fail with `EOPNOTSUPP` even if `KVM_CHECK_EXTENSION` reports
6441 the capability to be present.
6442
6443 `flags` must currently be zero.
6444
6445
6446 5. The kvm_run structure
6447 ========================
6448
6449 Application code obtains a pointer to the kvm_run structure by
6450 mmap()ing a vcpu fd. From that point, application code can control
6451 execution by changing fields in kvm_run prior to calling the KVM_RUN
6452 ioctl, and obtain information about the reason KVM_RUN returned by
6453 looking up structure members.
6454
6455 ::
6456
6457 struct kvm_run {
6458 /* in */
6459 __u8 request_interrupt_window;
6460
6461 Request that KVM_RUN return when it becomes possible to inject external
6462 interrupts into the guest. Useful in conjunction with KVM_INTERRUPT.
6463
6464 ::
6465
6466 __u8 immediate_exit;
6467
6468 This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN
6469 exits immediately, returning -EINTR. In the common scenario where a
6470 signal is used to "kick" a VCPU out of KVM_RUN, this field can be used
6471 to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability.
6472 Rather than blocking the signal outside KVM_RUN, userspace can set up
6473 a signal handler that sets run->immediate_exit to a non-zero value.
6474
6475 This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available.
6476
6477 ::
6478
6479 __u8 padding1[6];
6480
6481 /* out */
6482 __u32 exit_reason;
6483
6484 When KVM_RUN has returned successfully (return value 0), this informs
6485 application code why KVM_RUN has returned. Allowable values for this
6486 field are detailed below.
6487
6488 ::
6489
6490 __u8 ready_for_interrupt_injection;
6491
6492 If request_interrupt_window has been specified, this field indicates
6493 an interrupt can be injected now with KVM_INTERRUPT.
6494
6495 ::
6496
6497 __u8 if_flag;
6498
6499 The value of the current interrupt flag. Only valid if in-kernel
6500 local APIC is not used.
6501
6502 ::
6503
6504 __u16 flags;
6505
6506 More architecture-specific flags detailing state of the VCPU that may
6507 affect the device's behavior. Current defined flags::
6508
6509 /* x86, set if the VCPU is in system management mode */
6510 #define KVM_RUN_X86_SMM (1 << 0)
6511 /* x86, set if bus lock detected in VM */
6512 #define KVM_RUN_X86_BUS_LOCK (1 << 1)
6513 /* x86, set if the VCPU is executing a nested (L2) guest */
6514 #define KVM_RUN_X86_GUEST_MODE (1 << 2)
6515
6516 /* arm64, set for KVM_EXIT_DEBUG */
6517 #define KVM_DEBUG_ARCH_HSR_HIGH_VALID (1 << 0)
6518
6519 ::
6520
6521 /* in (pre_kvm_run), out (post_kvm_run) */
6522 __u64 cr8;
6523
6524 The value of the cr8 register. Only valid if in-kernel local APIC is
6525 not used. Both input and output.
6526
6527 ::
6528
6529 __u64 apic_base;
6530
6531 The value of the APIC BASE msr. Only valid if in-kernel local
6532 APIC is not used. Both input and output.
6533
6534 ::
6535
6536 union {
6537 /* KVM_EXIT_UNKNOWN */
6538 struct {
6539 __u64 hardware_exit_reason;
6540 } hw;
6541
6542 If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown
6543 reasons. Further architecture-specific information is available in
6544 hardware_exit_reason.
6545
6546 ::
6547
6548 /* KVM_EXIT_FAIL_ENTRY */
6549 struct {
6550 __u64 hardware_entry_failure_reason;
6551 __u32 cpu; /* if KVM_LAST_CPU */
6552 } fail_entry;
6553
6554 If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due
6555 to unknown reasons. Further architecture-specific information is
6556 available in hardware_entry_failure_reason.
6557
6558 ::
6559
6560 /* KVM_EXIT_EXCEPTION */
6561 struct {
6562 __u32 exception;
6563 __u32 error_code;
6564 } ex;
6565
6566 Unused.
6567
6568 ::
6569
6570 /* KVM_EXIT_IO */
6571 struct {
6572 #define KVM_EXIT_IO_IN 0
6573 #define KVM_EXIT_IO_OUT 1
6574 __u8 direction;
6575 __u8 size; /* bytes */
6576 __u16 port;
6577 __u32 count;
6578 __u64 data_offset; /* relative to kvm_run start */
6579 } io;
6580
6581 If exit_reason is KVM_EXIT_IO, then the vcpu has
6582 executed a port I/O instruction which could not be satisfied by kvm.
6583 data_offset describes where the data is located (KVM_EXIT_IO_OUT) or
6584 where kvm expects application code to place the data for the next
6585 KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array.
6586
6587 ::
6588
6589 /* KVM_EXIT_DEBUG */
6590 struct {
6591 struct kvm_debug_exit_arch arch;
6592 } debug;
6593
6594 If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event
6595 for which architecture specific information is returned.
6596
6597 ::
6598
6599 /* KVM_EXIT_MMIO */
6600 struct {
6601 __u64 phys_addr;
6602 __u8 data[8];
6603 __u32 len;
6604 __u8 is_write;
6605 } mmio;
6606
6607 If exit_reason is KVM_EXIT_MMIO, then the vcpu has
6608 executed a memory-mapped I/O instruction which could not be satisfied
6609 by kvm. The 'data' member contains the written data if 'is_write' is
6610 true, and should be filled by application code otherwise.
6611
6612 The 'data' member contains, in its first 'len' bytes, the value as it would
6613 appear if the VCPU performed a load or store of the appropriate width directly
6614 to the byte array.
6615
6616 .. note::
6617
6618 For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN,
6619 KVM_EXIT_EPR, KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding
6620 operations are complete (and guest state is consistent) only after userspace
6621 has re-entered the kernel with KVM_RUN. The kernel side will first finish
6622 incomplete operations and then check for pending signals.
6623
6624 The pending state of the operation is not preserved in state which is
6625 visible to userspace, thus userspace should ensure that the operation is
6626 completed before performing a live migration. Userspace can re-enter the
6627 guest with an unmasked signal pending or with the immediate_exit field set
6628 to complete pending operations without allowing any further instructions
6629 to be executed.
6630
6631 ::
6632
6633 /* KVM_EXIT_HYPERCALL */
6634 struct {
6635 __u64 nr;
6636 __u64 args[6];
6637 __u64 ret;
6638 __u64 flags;
6639 } hypercall;
6640
6641
6642 It is strongly recommended that userspace use ``KVM_EXIT_IO`` (x86) or
6643 ``KVM_EXIT_MMIO`` (all except s390) to implement functionality that
6644 requires a guest to interact with host userspace.
6645
6646 .. note:: KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO.
6647
6648 For arm64:
6649 ----------
6650
6651 SMCCC exits can be enabled depending on the configuration of the SMCCC
6652 filter. See the Documentation/virt/kvm/devices/vm.rst
6653 ``KVM_ARM_SMCCC_FILTER`` for more details.
6654
6655 ``nr`` contains the function ID of the guest's SMCCC call. Userspace is
6656 expected to use the ``KVM_GET_ONE_REG`` ioctl to retrieve the call
6657 parameters from the vCPU's GPRs.
6658
6659 Definition of ``flags``:
6660 - ``KVM_HYPERCALL_EXIT_SMC``: Indicates that the guest used the SMC
6661 conduit to initiate the SMCCC call. If this bit is 0 then the guest
6662 used the HVC conduit for the SMCCC call.
6663
6664 - ``KVM_HYPERCALL_EXIT_16BIT``: Indicates that the guest used a 16bit
6665 instruction to initiate the SMCCC call. If this bit is 0 then the
6666 guest used a 32bit instruction. An AArch64 guest always has this
6667 bit set to 0.
6668
6669 At the point of exit, PC points to the instruction immediately following
6670 the trapping instruction.
6671
6672 ::
6673
6674 /* KVM_EXIT_TPR_ACCESS */
6675 struct {
6676 __u64 rip;
6677 __u32 is_write;
6678 __u32 pad;
6679 } tpr_access;
6680
6681 To be documented (KVM_TPR_ACCESS_REPORTING).
6682
6683 ::
6684
6685 /* KVM_EXIT_S390_SIEIC */
6686 struct {
6687 __u8 icptcode;
6688 __u64 mask; /* psw upper half */
6689 __u64 addr; /* psw lower half */
6690 __u16 ipa;
6691 __u32 ipb;
6692 } s390_sieic;
6693
6694 s390 specific.
6695
6696 ::
6697
6698 /* KVM_EXIT_S390_RESET */
6699 #define KVM_S390_RESET_POR 1
6700 #define KVM_S390_RESET_CLEAR 2
6701 #define KVM_S390_RESET_SUBSYSTEM 4
6702 #define KVM_S390_RESET_CPU_INIT 8
6703 #define KVM_S390_RESET_IPL 16
6704 __u64 s390_reset_flags;
6705
6706 s390 specific.
6707
6708 ::
6709
6710 /* KVM_EXIT_S390_UCONTROL */
6711 struct {
6712 __u64 trans_exc_code;
6713 __u32 pgm_code;
6714 } s390_ucontrol;
6715
6716 s390 specific. A page fault has occurred for a user controlled virtual
6717 machine (KVM_VM_S390_UNCONTROL) on its host page table that cannot be
6718 resolved by the kernel.
6719 The program code and the translation exception code that were placed
6720 in the cpu's lowcore are presented here as defined by the z Architecture
6721 Principles of Operation Book in the Chapter for Dynamic Address Translation
6722 (DAT)
6723
6724 ::
6725
6726 /* KVM_EXIT_DCR */
6727 struct {
6728 __u32 dcrn;
6729 __u32 data;
6730 __u8 is_write;
6731 } dcr;
6732
6733 Deprecated - was used for 440 KVM.
6734
6735 ::
6736
6737 /* KVM_EXIT_OSI */
6738 struct {
6739 __u64 gprs[32];
6740 } osi;
6741
6742 MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch
6743 hypercalls and exit with this exit struct that contains all the guest gprs.
6744
6745 If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall.
6746 Userspace can now handle the hypercall and when it's done modify the gprs as
6747 necessary. Upon guest entry all guest GPRs will then be replaced by the values
6748 in this struct.
6749
6750 ::
6751
6752 /* KVM_EXIT_PAPR_HCALL */
6753 struct {
6754 __u64 nr;
6755 __u64 ret;
6756 __u64 args[9];
6757 } papr_hcall;
6758
6759 This is used on 64-bit PowerPC when emulating a pSeries partition,
6760 e.g. with the 'pseries' machine type in qemu. It occurs when the
6761 guest does a hypercall using the 'sc 1' instruction. The 'nr' field
6762 contains the hypercall number (from the guest R3), and 'args' contains
6763 the arguments (from the guest R4 - R12). Userspace should put the
6764 return code in 'ret' and any extra returned values in args[].
6765 The possible hypercalls are defined in the Power Architecture Platform
6766 Requirements (PAPR) document available from www.power.org (free
6767 developer registration required to access it).
6768
6769 ::
6770
6771 /* KVM_EXIT_S390_TSCH */
6772 struct {
6773 __u16 subchannel_id;
6774 __u16 subchannel_nr;
6775 __u32 io_int_parm;
6776 __u32 io_int_word;
6777 __u32 ipb;
6778 __u8 dequeued;
6779 } s390_tsch;
6780
6781 s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled
6782 and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O
6783 interrupt for the target subchannel has been dequeued and subchannel_id,
6784 subchannel_nr, io_int_parm and io_int_word contain the parameters for that
6785 interrupt. ipb is needed for instruction parameter decoding.
6786
6787 ::
6788
6789 /* KVM_EXIT_EPR */
6790 struct {
6791 __u32 epr;
6792 } epr;
6793
6794 On FSL BookE PowerPC chips, the interrupt controller has a fast patch
6795 interrupt acknowledge path to the core. When the core successfully
6796 delivers an interrupt, it automatically populates the EPR register with
6797 the interrupt vector number and acknowledges the interrupt inside
6798 the interrupt controller.
6799
6800 In case the interrupt controller lives in user space, we need to do
6801 the interrupt acknowledge cycle through it to fetch the next to be
6802 delivered interrupt vector using this exit.
6803
6804 It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an
6805 external interrupt has just been delivered into the guest. User space
6806 should put the acknowledged interrupt vector into the 'epr' field.
6807
6808 ::
6809
6810 /* KVM_EXIT_SYSTEM_EVENT */
6811 struct {
6812 #define KVM_SYSTEM_EVENT_SHUTDOWN 1
6813 #define KVM_SYSTEM_EVENT_RESET 2
6814 #define KVM_SYSTEM_EVENT_CRASH 3
6815 #define KVM_SYSTEM_EVENT_WAKEUP 4
6816 #define KVM_SYSTEM_EVENT_SUSPEND 5
6817 #define KVM_SYSTEM_EVENT_SEV_TERM 6
6818 __u32 type;
6819 __u32 ndata;
6820 __u64 data[16];
6821 } system_event;
6822
6823 If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered
6824 a system-level event using some architecture specific mechanism (hypercall
6825 or some special instruction). In case of ARM64, this is triggered using
6826 HVC instruction based PSCI call from the vcpu.
6827
6828 The 'type' field describes the system-level event type.
6829 Valid values for 'type' are:
6830
6831 - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the
6832 VM. Userspace is not obliged to honour this, and if it does honour
6833 this does not need to destroy the VM synchronously (ie it may call
6834 KVM_RUN again before shutdown finally occurs).
6835 - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM.
6836 As with SHUTDOWN, userspace can choose to ignore the request, or
6837 to schedule the reset to occur in the future and may call KVM_RUN again.
6838 - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest
6839 has requested a crash condition maintenance. Userspace can choose
6840 to ignore the request, or to gather VM memory core dump and/or
6841 reset/shutdown of the VM.
6842 - KVM_SYSTEM_EVENT_SEV_TERM -- an AMD SEV guest requested termination.
6843 The guest physical address of the guest's GHCB is stored in `data[0]`.
6844 - KVM_SYSTEM_EVENT_WAKEUP -- the exiting vCPU is in a suspended state and
6845 KVM has recognized a wakeup event. Userspace may honor this event by
6846 marking the exiting vCPU as runnable, or deny it and call KVM_RUN again.
6847 - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested a suspension of
6848 the VM.
6849
6850 If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain
6851 architecture specific information for the system-level event. Only
6852 the first `ndata` items (possibly zero) of the data array are valid.
6853
6854 - for arm64, data[0] is set to KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 if
6855 the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI
6856 specification.
6857
6858 - for RISC-V, data[0] is set to the value of the second argument of the
6859 ``sbi_system_reset`` call.
6860
6861 Previous versions of Linux defined a `flags` member in this struct. The
6862 field is now aliased to `data[0]`. Userspace can assume that it is only
6863 written if ndata is greater than 0.
6864
6865 For arm/arm64:
6866 --------------
6867
6868 KVM_SYSTEM_EVENT_SUSPEND exits are enabled with the
6869 KVM_CAP_ARM_SYSTEM_SUSPEND VM capability. If a guest invokes the PSCI
6870 SYSTEM_SUSPEND function, KVM will exit to userspace with this event
6871 type.
6872
6873 It is the sole responsibility of userspace to implement the PSCI
6874 SYSTEM_SUSPEND call according to ARM DEN0022D.b 5.19 "SYSTEM_SUSPEND".
6875 KVM does not change the vCPU's state before exiting to userspace, so
6876 the call parameters are left in-place in the vCPU registers.
6877
6878 Userspace is _required_ to take action for such an exit. It must
6879 either:
6880
6881 - Honor the guest request to suspend the VM. Userspace can request
6882 in-kernel emulation of suspension by setting the calling vCPU's
6883 state to KVM_MP_STATE_SUSPENDED. Userspace must configure the vCPU's
6884 state according to the parameters passed to the PSCI function when
6885 the calling vCPU is resumed. See ARM DEN0022D.b 5.19.1 "Intended use"
6886 for details on the function parameters.
6887
6888 - Deny the guest request to suspend the VM. See ARM DEN0022D.b 5.19.2
6889 "Caller responsibilities" for possible return values.
6890
6891 ::
6892
6893 /* KVM_EXIT_IOAPIC_EOI */
6894 struct {
6895 __u8 vector;
6896 } eoi;
6897
6898 Indicates that the VCPU's in-kernel local APIC received an EOI for a
6899 level-triggered IOAPIC interrupt. This exit only triggers when the
6900 IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled);
6901 the userspace IOAPIC should process the EOI and retrigger the interrupt if
6902 it is still asserted. Vector is the LAPIC interrupt vector for which the
6903 EOI was received.
6904
6905 ::
6906
6907 struct kvm_hyperv_exit {
6908 #define KVM_EXIT_HYPERV_SYNIC 1
6909 #define KVM_EXIT_HYPERV_HCALL 2
6910 #define KVM_EXIT_HYPERV_SYNDBG 3
6911 __u32 type;
6912 __u32 pad1;
6913 union {
6914 struct {
6915 __u32 msr;
6916 __u32 pad2;
6917 __u64 control;
6918 __u64 evt_page;
6919 __u64 msg_page;
6920 } synic;
6921 struct {
6922 __u64 input;
6923 __u64 result;
6924 __u64 params[2];
6925 } hcall;
6926 struct {
6927 __u32 msr;
6928 __u32 pad2;
6929 __u64 control;
6930 __u64 status;
6931 __u64 send_page;
6932 __u64 recv_page;
6933 __u64 pending_page;
6934 } syndbg;
6935 } u;
6936 };
6937 /* KVM_EXIT_HYPERV */
6938 struct kvm_hyperv_exit hyperv;
6939
6940 Indicates that the VCPU exits into userspace to process some tasks
6941 related to Hyper-V emulation.
6942
6943 Valid values for 'type' are:
6944
6945 - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about
6946
6947 Hyper-V SynIC state change. Notification is used to remap SynIC
6948 event/message pages and to enable/disable SynIC messages/events processing
6949 in userspace.
6950
6951 - KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about
6952
6953 Hyper-V Synthetic debugger state change. Notification is used to either update
6954 the pending_page location or to send a control command (send the buffer located
6955 in send_page or recv a buffer to recv_page).
6956
6957 ::
6958
6959 /* KVM_EXIT_ARM_NISV */
6960 struct {
6961 __u64 esr_iss;
6962 __u64 fault_ipa;
6963 } arm_nisv;
6964
6965 Used on arm64 systems. If a guest accesses memory not in a memslot,
6966 KVM will typically return to userspace and ask it to do MMIO emulation on its
6967 behalf. However, for certain classes of instructions, no instruction decode
6968 (direction, length of memory access) is provided, and fetching and decoding
6969 the instruction from the VM is overly complicated to live in the kernel.
6970
6971 Historically, when this situation occurred, KVM would print a warning and kill
6972 the VM. KVM assumed that if the guest accessed non-memslot memory, it was
6973 trying to do I/O, which just couldn't be emulated, and the warning message was
6974 phrased accordingly. However, what happened more often was that a guest bug
6975 caused access outside the guest memory areas which should lead to a more
6976 meaningful warning message and an external abort in the guest, if the access
6977 did not fall within an I/O window.
6978
6979 Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable
6980 this capability at VM creation. Once this is done, these types of errors will
6981 instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from
6982 the ESR_EL2 in the esr_iss field, and the faulting IPA in the fault_ipa field.
6983 Userspace can either fix up the access if it's actually an I/O access by
6984 decoding the instruction from guest memory (if it's very brave) and continue
6985 executing the guest, or it can decide to suspend, dump, or restart the guest.
6986
6987 Note that KVM does not skip the faulting instruction as it does for
6988 KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state
6989 if it decides to decode and emulate the instruction.
6990
6991 This feature isn't available to protected VMs, as userspace does not
6992 have access to the state that is required to perform the emulation.
6993 Instead, a data abort exception is directly injected in the guest.
6994 Note that although KVM_CAP_ARM_NISV_TO_USER will be reported if
6995 queried outside of a protected VM context, the feature will not be
6996 exposed if queried on a protected VM file descriptor.
6997
6998 ::
6999
7000 /* KVM_EXIT_X86_RDMSR / KVM_EXIT_X86_WRMSR */
7001 struct {
7002 __u8 error; /* user -> kernel */
7003 __u8 pad[7];
7004 __u32 reason; /* kernel -> user */
7005 __u32 index; /* kernel -> user */
7006 __u64 data; /* kernel <-> user */
7007 } msr;
7008
7009 Used on x86 systems. When the VM capability KVM_CAP_X86_USER_SPACE_MSR is
7010 enabled, MSR accesses to registers that would invoke a #GP by KVM kernel code
7011 may instead trigger a KVM_EXIT_X86_RDMSR exit for reads and KVM_EXIT_X86_WRMSR
7012 exit for writes.
7013
7014 The "reason" field specifies why the MSR interception occurred. Userspace will
7015 only receive MSR exits when a particular reason was requested during through
7016 ENABLE_CAP. Currently valid exit reasons are:
7017
7018 ============================ ========================================
7019 KVM_MSR_EXIT_REASON_UNKNOWN access to MSR that is unknown to KVM
7020 KVM_MSR_EXIT_REASON_INVAL access to invalid MSRs or reserved bits
7021 KVM_MSR_EXIT_REASON_FILTER access blocked by KVM_X86_SET_MSR_FILTER
7022 ============================ ========================================
7023
7024 For KVM_EXIT_X86_RDMSR, the "index" field tells userspace which MSR the guest
7025 wants to read. To respond to this request with a successful read, userspace
7026 writes the respective data into the "data" field and must continue guest
7027 execution to ensure the read data is transferred into guest register state.
7028
7029 If the RDMSR request was unsuccessful, userspace indicates that with a "1" in
7030 the "error" field. This will inject a #GP into the guest when the VCPU is
7031 executed again.
7032
7033 For KVM_EXIT_X86_WRMSR, the "index" field tells userspace which MSR the guest
7034 wants to write. Once finished processing the event, userspace must continue
7035 vCPU execution. If the MSR write was unsuccessful, userspace also sets the
7036 "error" field to "1".
7037
7038 See KVM_X86_SET_MSR_FILTER for details on the interaction with MSR filtering.
7039
7040 ::
7041
7042
7043 struct kvm_xen_exit {
7044 #define KVM_EXIT_XEN_HCALL 1
7045 __u32 type;
7046 union {
7047 struct {
7048 __u32 longmode;
7049 __u32 cpl;
7050 __u64 input;
7051 __u64 result;
7052 __u64 params[6];
7053 } hcall;
7054 } u;
7055 };
7056 /* KVM_EXIT_XEN */
7057 struct kvm_hyperv_exit xen;
7058
7059 Indicates that the VCPU exits into userspace to process some tasks
7060 related to Xen emulation.
7061
7062 Valid values for 'type' are:
7063
7064 - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall.
7065 Userspace is expected to place the hypercall result into the appropriate
7066 field before invoking KVM_RUN again.
7067
7068 ::
7069
7070 /* KVM_EXIT_RISCV_SBI */
7071 struct {
7072 unsigned long extension_id;
7073 unsigned long function_id;
7074 unsigned long args[6];
7075 unsigned long ret[2];
7076 } riscv_sbi;
7077
7078 If exit reason is KVM_EXIT_RISCV_SBI then it indicates that the VCPU has
7079 done a SBI call which is not handled by KVM RISC-V kernel module. The details
7080 of the SBI call are available in 'riscv_sbi' member of kvm_run structure. The
7081 'extension_id' field of 'riscv_sbi' represents SBI extension ID whereas the
7082 'function_id' field represents function ID of given SBI extension. The 'args'
7083 array field of 'riscv_sbi' represents parameters for the SBI call and 'ret'
7084 array field represents return values. The userspace should update the return
7085 values of SBI call before resuming the VCPU. For more details on RISC-V SBI
7086 spec refer, https://github.com/riscv/riscv-sbi-doc.
7087
7088 ::
7089
7090 /* KVM_EXIT_MEMORY_FAULT */
7091 struct {
7092 #define KVM_MEMORY_EXIT_FLAG_PRIVATE (1ULL << 3)
7093 __u64 flags;
7094 __u64 gpa;
7095 __u64 size;
7096 } memory_fault;
7097
7098 KVM_EXIT_MEMORY_FAULT indicates the vCPU has encountered a memory fault that
7099 could not be resolved by KVM. The 'gpa' and 'size' (in bytes) describe the
7100 guest physical address range [gpa, gpa + size) of the fault. The 'flags' field
7101 describes properties of the faulting access that are likely pertinent:
7102
7103 - KVM_MEMORY_EXIT_FLAG_PRIVATE - When set, indicates the memory fault occurred
7104 on a private memory access. When clear, indicates the fault occurred on a
7105 shared access.
7106
7107 Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that it
7108 accompanies a return code of '-1', not '0'! errno will always be set to EFAULT
7109 or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT, userspace should assume
7110 kvm_run.exit_reason is stale/undefined for all other error numbers.
7111
7112 ::
7113
7114 /* KVM_EXIT_NOTIFY */
7115 struct {
7116 #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0)
7117 __u32 flags;
7118 } notify;
7119
7120 Used on x86 systems. When the VM capability KVM_CAP_X86_NOTIFY_VMEXIT is
7121 enabled, a VM exit generated if no event window occurs in VM non-root mode
7122 for a specified amount of time. Once KVM_X86_NOTIFY_VMEXIT_USER is set when
7123 enabling the cap, it would exit to userspace with the exit reason
7124 KVM_EXIT_NOTIFY for further handling. The "flags" field contains more
7125 detailed info.
7126
7127 The valid value for 'flags' is:
7128
7129 - KVM_NOTIFY_CONTEXT_INVALID -- the VM context is corrupted and not valid
7130 in VMCS. It would run into unknown result if resume the target VM.
7131
7132 ::
7133
7134 /* Fix the size of the union. */
7135 char padding[256];
7136 };
7137
7138 /*
7139 * shared registers between kvm and userspace.
7140 * kvm_valid_regs specifies the register classes set by the host
7141 * kvm_dirty_regs specified the register classes dirtied by userspace
7142 * struct kvm_sync_regs is architecture specific, as well as the
7143 * bits for kvm_valid_regs and kvm_dirty_regs
7144 */
7145 __u64 kvm_valid_regs;
7146 __u64 kvm_dirty_regs;
7147 union {
7148 struct kvm_sync_regs regs;
7149 char padding[SYNC_REGS_SIZE_BYTES];
7150 } s;
7151
7152 If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access
7153 certain guest registers without having to call SET/GET_*REGS. Thus we can
7154 avoid some system call overhead if userspace has to handle the exit.
7155 Userspace can query the validity of the structure by checking
7156 kvm_valid_regs for specific bits. These bits are architecture specific
7157 and usually define the validity of a groups of registers. (e.g. one bit
7158 for general purpose registers)
7159
7160 Please note that the kernel is allowed to use the kvm_run structure as the
7161 primary storage for certain register types. Therefore, the kernel may use the
7162 values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set.
7163
7164
7165 6. Capabilities that can be enabled on vCPUs
7166 ============================================
7167
7168 There are certain capabilities that change the behavior of the virtual CPU or
7169 the virtual machine when enabled. To enable them, please see section 4.37.
7170 Below you can find a list of capabilities and what their effect on the vCPU or
7171 the virtual machine is when enabling them.
7172
7173 The following information is provided along with the description:
7174
7175 Architectures:
7176 which instruction set architectures provide this ioctl.
7177 x86 includes both i386 and x86_64.
7178
7179 Target:
7180 whether this is a per-vcpu or per-vm capability.
7181
7182 Parameters:
7183 what parameters are accepted by the capability.
7184
7185 Returns:
7186 the return value. General error numbers (EBADF, ENOMEM, EINVAL)
7187 are not detailed, but errors with specific meanings are.
7188
7189
7190 6.1 KVM_CAP_PPC_OSI
7191 -------------------
7192
7193 :Architectures: ppc
7194 :Target: vcpu
7195 :Parameters: none
7196 :Returns: 0 on success; -1 on error
7197
7198 This capability enables interception of OSI hypercalls that otherwise would
7199 be treated as normal system calls to be injected into the guest. OSI hypercalls
7200 were invented by Mac-on-Linux to have a standardized communication mechanism
7201 between the guest and the host.
7202
7203 When this capability is enabled, KVM_EXIT_OSI can occur.
7204
7205
7206 6.2 KVM_CAP_PPC_PAPR
7207 --------------------
7208
7209 :Architectures: ppc
7210 :Target: vcpu
7211 :Parameters: none
7212 :Returns: 0 on success; -1 on error
7213
7214 This capability enables interception of PAPR hypercalls. PAPR hypercalls are
7215 done using the hypercall instruction "sc 1".
7216
7217 It also sets the guest privilege level to "supervisor" mode. Usually the guest
7218 runs in "hypervisor" privilege mode with a few missing features.
7219
7220 In addition to the above, it changes the semantics of SDR1. In this mode, the
7221 HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the
7222 HTAB invisible to the guest.
7223
7224 When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur.
7225
7226
7227 6.3 KVM_CAP_SW_TLB
7228 ------------------
7229
7230 :Architectures: ppc
7231 :Target: vcpu
7232 :Parameters: args[0] is the address of a struct kvm_config_tlb
7233 :Returns: 0 on success; -1 on error
7234
7235 ::
7236
7237 struct kvm_config_tlb {
7238 __u64 params;
7239 __u64 array;
7240 __u32 mmu_type;
7241 __u32 array_len;
7242 };
7243
7244 Configures the virtual CPU's TLB array, establishing a shared memory area
7245 between userspace and KVM. The "params" and "array" fields are userspace
7246 addresses of mmu-type-specific data structures. The "array_len" field is an
7247 safety mechanism, and should be set to the size in bytes of the memory that
7248 userspace has reserved for the array. It must be at least the size dictated
7249 by "mmu_type" and "params".
7250
7251 While KVM_RUN is active, the shared region is under control of KVM. Its
7252 contents are undefined, and any modification by userspace results in
7253 boundedly undefined behavior.
7254
7255 On return from KVM_RUN, the shared region will reflect the current state of
7256 the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB
7257 to tell KVM which entries have been changed, prior to calling KVM_RUN again
7258 on this vcpu.
7259
7260 For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV:
7261
7262 - The "params" field is of type "struct kvm_book3e_206_tlb_params".
7263 - The "array" field points to an array of type "struct
7264 kvm_book3e_206_tlb_entry".
7265 - The array consists of all entries in the first TLB, followed by all
7266 entries in the second TLB.
7267 - Within a TLB, entries are ordered first by increasing set number. Within a
7268 set, entries are ordered by way (increasing ESEL).
7269 - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1)
7270 where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value.
7271 - The tsize field of mas1 shall be set to 4K on TLB0, even though the
7272 hardware ignores this value for TLB0.
7273
7274 6.4 KVM_CAP_S390_CSS_SUPPORT
7275 ----------------------------
7276
7277 :Architectures: s390
7278 :Target: vcpu
7279 :Parameters: none
7280 :Returns: 0 on success; -1 on error
7281
7282 This capability enables support for handling of channel I/O instructions.
7283
7284 TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are
7285 handled in-kernel, while the other I/O instructions are passed to userspace.
7286
7287 When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST
7288 SUBCHANNEL intercepts.
7289
7290 Note that even though this capability is enabled per-vcpu, the complete
7291 virtual machine is affected.
7292
7293 6.5 KVM_CAP_PPC_EPR
7294 -------------------
7295
7296 :Architectures: ppc
7297 :Target: vcpu
7298 :Parameters: args[0] defines whether the proxy facility is active
7299 :Returns: 0 on success; -1 on error
7300
7301 This capability enables or disables the delivery of interrupts through the
7302 external proxy facility.
7303
7304 When enabled (args[0] != 0), every time the guest gets an external interrupt
7305 delivered, it automatically exits into user space with a KVM_EXIT_EPR exit
7306 to receive the topmost interrupt vector.
7307
7308 When disabled (args[0] == 0), behavior is as if this facility is unsupported.
7309
7310 When this capability is enabled, KVM_EXIT_EPR can occur.
7311
7312 6.6 KVM_CAP_IRQ_MPIC
7313 --------------------
7314
7315 :Architectures: ppc
7316 :Parameters: args[0] is the MPIC device fd;
7317 args[1] is the MPIC CPU number for this vcpu
7318
7319 This capability connects the vcpu to an in-kernel MPIC device.
7320
7321 6.7 KVM_CAP_IRQ_XICS
7322 --------------------
7323
7324 :Architectures: ppc
7325 :Target: vcpu
7326 :Parameters: args[0] is the XICS device fd;
7327 args[1] is the XICS CPU number (server ID) for this vcpu
7328
7329 This capability connects the vcpu to an in-kernel XICS device.
7330
7331 6.8 KVM_CAP_S390_IRQCHIP
7332 ------------------------
7333
7334 :Architectures: s390
7335 :Target: vm
7336 :Parameters: none
7337
7338 This capability enables the in-kernel irqchip for s390. Please refer to
7339 "4.24 KVM_CREATE_IRQCHIP" for details.
7340
7341 6.9 KVM_CAP_MIPS_FPU
7342 --------------------
7343
7344 :Architectures: mips
7345 :Target: vcpu
7346 :Parameters: args[0] is reserved for future use (should be 0).
7347
7348 This capability allows the use of the host Floating Point Unit by the guest. It
7349 allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is
7350 done the ``KVM_REG_MIPS_FPR_*`` and ``KVM_REG_MIPS_FCR_*`` registers can be
7351 accessed (depending on the current guest FPU register mode), and the Status.FR,
7352 Config5.FRE bits are accessible via the KVM API and also from the guest,
7353 depending on them being supported by the FPU.
7354
7355 6.10 KVM_CAP_MIPS_MSA
7356 ---------------------
7357
7358 :Architectures: mips
7359 :Target: vcpu
7360 :Parameters: args[0] is reserved for future use (should be 0).
7361
7362 This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest.
7363 It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest.
7364 Once this is done the ``KVM_REG_MIPS_VEC_*`` and ``KVM_REG_MIPS_MSA_*``
7365 registers can be accessed, and the Config5.MSAEn bit is accessible via the
7366 KVM API and also from the guest.
7367
7368 6.74 KVM_CAP_SYNC_REGS
7369 ----------------------
7370
7371 :Architectures: s390, x86
7372 :Target: s390: always enabled, x86: vcpu
7373 :Parameters: none
7374 :Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register
7375 sets are supported
7376 (bitfields defined in arch/x86/include/uapi/asm/kvm.h).
7377
7378 As described above in the kvm_sync_regs struct info in section 5 (kvm_run):
7379 KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers
7380 without having to call SET/GET_*REGS". This reduces overhead by eliminating
7381 repeated ioctl calls for setting and/or getting register values. This is
7382 particularly important when userspace is making synchronous guest state
7383 modifications, e.g. when emulating and/or intercepting instructions in
7384 userspace.
7385
7386 For s390 specifics, please refer to the source code.
7387
7388 For x86:
7389
7390 - the register sets to be copied out to kvm_run are selectable
7391 by userspace (rather that all sets being copied out for every exit).
7392 - vcpu_events are available in addition to regs and sregs.
7393
7394 For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to
7395 function as an input bit-array field set by userspace to indicate the
7396 specific register sets to be copied out on the next exit.
7397
7398 To indicate when userspace has modified values that should be copied into
7399 the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set.
7400 This is done using the same bitflags as for the 'kvm_valid_regs' field.
7401 If the dirty bit is not set, then the register set values will not be copied
7402 into the vCPU even if they've been modified.
7403
7404 Unused bitfields in the bitarrays must be set to zero.
7405
7406 ::
7407
7408 struct kvm_sync_regs {
7409 struct kvm_regs regs;
7410 struct kvm_sregs sregs;
7411 struct kvm_vcpu_events events;
7412 };
7413
7414 6.75 KVM_CAP_PPC_IRQ_XIVE
7415 -------------------------
7416
7417 :Architectures: ppc
7418 :Target: vcpu
7419 :Parameters: args[0] is the XIVE device fd;
7420 args[1] is the XIVE CPU number (server ID) for this vcpu
7421
7422 This capability connects the vcpu to an in-kernel XIVE device.
7423
7424 7. Capabilities that can be enabled on VMs
7425 ==========================================
7426
7427 There are certain capabilities that change the behavior of the virtual
7428 machine when enabled. To enable them, please see section 4.37. Below
7429 you can find a list of capabilities and what their effect on the VM
7430 is when enabling them.
7431
7432 The following information is provided along with the description:
7433
7434 Architectures:
7435 which instruction set architectures provide this ioctl.
7436 x86 includes both i386 and x86_64.
7437
7438 Parameters:
7439 what parameters are accepted by the capability.
7440
7441 Returns:
7442 the return value. General error numbers (EBADF, ENOMEM, EINVAL)
7443 are not detailed, but errors with specific meanings are.
7444
7445
7446 7.1 KVM_CAP_PPC_ENABLE_HCALL
7447 ----------------------------
7448
7449 :Architectures: ppc
7450 :Parameters: args[0] is the sPAPR hcall number;
7451 args[1] is 0 to disable, 1 to enable in-kernel handling
7452
7453 This capability controls whether individual sPAPR hypercalls (hcalls)
7454 get handled by the kernel or not. Enabling or disabling in-kernel
7455 handling of an hcall is effective across the VM. On creation, an
7456 initial set of hcalls are enabled for in-kernel handling, which
7457 consists of those hcalls for which in-kernel handlers were implemented
7458 before this capability was implemented. If disabled, the kernel will
7459 not to attempt to handle the hcall, but will always exit to userspace
7460 to handle it. Note that it may not make sense to enable some and
7461 disable others of a group of related hcalls, but KVM does not prevent
7462 userspace from doing that.
7463
7464 If the hcall number specified is not one that has an in-kernel
7465 implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL
7466 error.
7467
7468 7.2 KVM_CAP_S390_USER_SIGP
7469 --------------------------
7470
7471 :Architectures: s390
7472 :Parameters: none
7473
7474 This capability controls which SIGP orders will be handled completely in user
7475 space. With this capability enabled, all fast orders will be handled completely
7476 in the kernel:
7477
7478 - SENSE
7479 - SENSE RUNNING
7480 - EXTERNAL CALL
7481 - EMERGENCY SIGNAL
7482 - CONDITIONAL EMERGENCY SIGNAL
7483
7484 All other orders will be handled completely in user space.
7485
7486 Only privileged operation exceptions will be checked for in the kernel (or even
7487 in the hardware prior to interception). If this capability is not enabled, the
7488 old way of handling SIGP orders is used (partially in kernel and user space).
7489
7490 7.3 KVM_CAP_S390_VECTOR_REGISTERS
7491 ---------------------------------
7492
7493 :Architectures: s390
7494 :Parameters: none
7495 :Returns: 0 on success, negative value on error
7496
7497 Allows use of the vector registers introduced with z13 processor, and
7498 provides for the synchronization between host and user space. Will
7499 return -EINVAL if the machine does not support vectors.
7500
7501 7.4 KVM_CAP_S390_USER_STSI
7502 --------------------------
7503
7504 :Architectures: s390
7505 :Parameters: none
7506
7507 This capability allows post-handlers for the STSI instruction. After
7508 initial handling in the kernel, KVM exits to user space with
7509 KVM_EXIT_S390_STSI to allow user space to insert further data.
7510
7511 Before exiting to userspace, kvm handlers should fill in s390_stsi field of
7512 vcpu->run::
7513
7514 struct {
7515 __u64 addr;
7516 __u8 ar;
7517 __u8 reserved;
7518 __u8 fc;
7519 __u8 sel1;
7520 __u16 sel2;
7521 } s390_stsi;
7522
7523 @addr - guest address of STSI SYSIB
7524 @fc - function code
7525 @sel1 - selector 1
7526 @sel2 - selector 2
7527 @ar - access register number
7528
7529 KVM handlers should exit to userspace with rc = -EREMOTE.
7530
7531 7.5 KVM_CAP_SPLIT_IRQCHIP
7532 -------------------------
7533
7534 :Architectures: x86
7535 :Parameters: args[0] - number of routes reserved for userspace IOAPICs
7536 :Returns: 0 on success, -1 on error
7537
7538 Create a local apic for each processor in the kernel. This can be used
7539 instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the
7540 IOAPIC and PIC (and also the PIT, even though this has to be enabled
7541 separately).
7542
7543 This capability also enables in kernel routing of interrupt requests;
7544 when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are
7545 used in the IRQ routing table. The first args[0] MSI routes are reserved
7546 for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes,
7547 a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace.
7548
7549 Fails if VCPU has already been created, or if the irqchip is already in the
7550 kernel (i.e. KVM_CREATE_IRQCHIP has already been called).
7551
7552 7.6 KVM_CAP_S390_RI
7553 -------------------
7554
7555 :Architectures: s390
7556 :Parameters: none
7557
7558 Allows use of runtime-instrumentation introduced with zEC12 processor.
7559 Will return -EINVAL if the machine does not support runtime-instrumentation.
7560 Will return -EBUSY if a VCPU has already been created.
7561
7562 7.7 KVM_CAP_X2APIC_API
7563 ----------------------
7564
7565 :Architectures: x86
7566 :Parameters: args[0] - features that should be enabled
7567 :Returns: 0 on success, -EINVAL when args[0] contains invalid features
7568
7569 Valid feature flags in args[0] are::
7570
7571 #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0)
7572 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1)
7573
7574 Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of
7575 KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC,
7576 allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their
7577 respective sections.
7578
7579 KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work
7580 in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff
7581 as a broadcast even in x2APIC mode in order to support physical x2APIC
7582 without interrupt remapping. This is undesirable in logical mode,
7583 where 0xff represents CPUs 0-7 in cluster 0.
7584
7585 7.8 KVM_CAP_S390_USER_INSTR0
7586 ----------------------------
7587
7588 :Architectures: s390
7589 :Parameters: none
7590
7591 With this capability enabled, all illegal instructions 0x0000 (2 bytes) will
7592 be intercepted and forwarded to user space. User space can use this
7593 mechanism e.g. to realize 2-byte software breakpoints. The kernel will
7594 not inject an operating exception for these instructions, user space has
7595 to take care of that.
7596
7597 This capability can be enabled dynamically even if VCPUs were already
7598 created and are running.
7599
7600 7.9 KVM_CAP_S390_GS
7601 -------------------
7602
7603 :Architectures: s390
7604 :Parameters: none
7605 :Returns: 0 on success; -EINVAL if the machine does not support
7606 guarded storage; -EBUSY if a VCPU has already been created.
7607
7608 Allows use of guarded storage for the KVM guest.
7609
7610 7.10 KVM_CAP_S390_AIS
7611 ---------------------
7612
7613 :Architectures: s390
7614 :Parameters: none
7615
7616 Allow use of adapter-interruption suppression.
7617 :Returns: 0 on success; -EBUSY if a VCPU has already been created.
7618
7619 7.11 KVM_CAP_PPC_SMT
7620 --------------------
7621
7622 :Architectures: ppc
7623 :Parameters: vsmt_mode, flags
7624
7625 Enabling this capability on a VM provides userspace with a way to set
7626 the desired virtual SMT mode (i.e. the number of virtual CPUs per
7627 virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2
7628 between 1 and 8. On POWER8, vsmt_mode must also be no greater than
7629 the number of threads per subcore for the host. Currently flags must
7630 be 0. A successful call to enable this capability will result in
7631 vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is
7632 subsequently queried for the VM. This capability is only supported by
7633 HV KVM, and can only be set before any VCPUs have been created.
7634 The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT
7635 modes are available.
7636
7637 7.12 KVM_CAP_PPC_FWNMI
7638 ----------------------
7639
7640 :Architectures: ppc
7641 :Parameters: none
7642
7643 With this capability a machine check exception in the guest address
7644 space will cause KVM to exit the guest with NMI exit reason. This
7645 enables QEMU to build error log and branch to guest kernel registered
7646 machine check handling routine. Without this capability KVM will
7647 branch to guests' 0x200 interrupt vector.
7648
7649 7.13 KVM_CAP_X86_DISABLE_EXITS
7650 ------------------------------
7651
7652 :Architectures: x86
7653 :Parameters: args[0] defines which exits are disabled
7654 :Returns: 0 on success, -EINVAL when args[0] contains invalid exits
7655
7656 Valid bits in args[0] are::
7657
7658 #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0)
7659 #define KVM_X86_DISABLE_EXITS_HLT (1 << 1)
7660 #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2)
7661 #define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3)
7662
7663 Enabling this capability on a VM provides userspace with a way to no
7664 longer intercept some instructions for improved latency in some
7665 workloads, and is suggested when vCPUs are associated to dedicated
7666 physical CPUs. More bits can be added in the future; userspace can
7667 just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable
7668 all such vmexits.
7669
7670 Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits.
7671
7672 7.14 KVM_CAP_S390_HPAGE_1M
7673 --------------------------
7674
7675 :Architectures: s390
7676 :Parameters: none
7677 :Returns: 0 on success, -EINVAL if hpage module parameter was not set
7678 or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL
7679 flag set
7680
7681 With this capability the KVM support for memory backing with 1m pages
7682 through hugetlbfs can be enabled for a VM. After the capability is
7683 enabled, cmma can't be enabled anymore and pfmfi and the storage key
7684 interpretation are disabled. If cmma has already been enabled or the
7685 hpage module parameter is not set to 1, -EINVAL is returned.
7686
7687 While it is generally possible to create a huge page backed VM without
7688 this capability, the VM will not be able to run.
7689
7690 7.15 KVM_CAP_MSR_PLATFORM_INFO
7691 ------------------------------
7692
7693 :Architectures: x86
7694 :Parameters: args[0] whether feature should be enabled or not
7695
7696 With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise,
7697 a #GP would be raised when the guest tries to access. Currently, this
7698 capability does not enable write permissions of this MSR for the guest.
7699
7700 7.16 KVM_CAP_PPC_NESTED_HV
7701 --------------------------
7702
7703 :Architectures: ppc
7704 :Parameters: none
7705 :Returns: 0 on success, -EINVAL when the implementation doesn't support
7706 nested-HV virtualization.
7707
7708 HV-KVM on POWER9 and later systems allows for "nested-HV"
7709 virtualization, which provides a way for a guest VM to run guests that
7710 can run using the CPU's supervisor mode (privileged non-hypervisor
7711 state). Enabling this capability on a VM depends on the CPU having
7712 the necessary functionality and on the facility being enabled with a
7713 kvm-hv module parameter.
7714
7715 7.17 KVM_CAP_EXCEPTION_PAYLOAD
7716 ------------------------------
7717
7718 :Architectures: x86
7719 :Parameters: args[0] whether feature should be enabled or not
7720
7721 With this capability enabled, CR2 will not be modified prior to the
7722 emulated VM-exit when L1 intercepts a #PF exception that occurs in
7723 L2. Similarly, for kvm-intel only, DR6 will not be modified prior to
7724 the emulated VM-exit when L1 intercepts a #DB exception that occurs in
7725 L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or
7726 #DB) exception for L2, exception.has_payload will be set and the
7727 faulting address (or the new DR6 bits*) will be reported in the
7728 exception_payload field. Similarly, when userspace injects a #PF (or
7729 #DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set
7730 exception.has_payload and to put the faulting address - or the new DR6
7731 bits\ [#]_ - in the exception_payload field.
7732
7733 This capability also enables exception.pending in struct
7734 kvm_vcpu_events, which allows userspace to distinguish between pending
7735 and injected exceptions.
7736
7737
7738 .. [#] For the new DR6 bits, note that bit 16 is set iff the #DB exception
7739 will clear DR6.RTM.
7740
7741 7.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
7742 --------------------------------------
7743
7744 :Architectures: x86, arm64, mips
7745 :Parameters: args[0] whether feature should be enabled or not
7746
7747 Valid flags are::
7748
7749 #define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0)
7750 #define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1)
7751
7752 With KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is set, KVM_GET_DIRTY_LOG will not
7753 automatically clear and write-protect all pages that are returned as dirty.
7754 Rather, userspace will have to do this operation separately using
7755 KVM_CLEAR_DIRTY_LOG.
7756
7757 At the cost of a slightly more complicated operation, this provides better
7758 scalability and responsiveness for two reasons. First,
7759 KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather
7760 than requiring to sync a full memslot; this ensures that KVM does not
7761 take spinlocks for an extended period of time. Second, in some cases a
7762 large amount of time can pass between a call to KVM_GET_DIRTY_LOG and
7763 userspace actually using the data in the page. Pages can be modified
7764 during this time, which is inefficient for both the guest and userspace:
7765 the guest will incur a higher penalty due to write protection faults,
7766 while userspace can see false reports of dirty pages. Manual reprotection
7767 helps reducing this time, improving guest performance and reducing the
7768 number of dirty log false positives.
7769
7770 With KVM_DIRTY_LOG_INITIALLY_SET set, all the bits of the dirty bitmap
7771 will be initialized to 1 when created. This also improves performance because
7772 dirty logging can be enabled gradually in small chunks on the first call
7773 to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on
7774 KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on
7775 x86 and arm64 for now).
7776
7777 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name
7778 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make
7779 it hard or impossible to use it correctly. The availability of
7780 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed.
7781 Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT.
7782
7783 7.19 KVM_CAP_PPC_SECURE_GUEST
7784 ------------------------------
7785
7786 :Architectures: ppc
7787
7788 This capability indicates that KVM is running on a host that has
7789 ultravisor firmware and thus can support a secure guest. On such a
7790 system, a guest can ask the ultravisor to make it a secure guest,
7791 one whose memory is inaccessible to the host except for pages which
7792 are explicitly requested to be shared with the host. The ultravisor
7793 notifies KVM when a guest requests to become a secure guest, and KVM
7794 has the opportunity to veto the transition.
7795
7796 If present, this capability can be enabled for a VM, meaning that KVM
7797 will allow the transition to secure guest mode. Otherwise KVM will
7798 veto the transition.
7799
7800 7.20 KVM_CAP_HALT_POLL
7801 ----------------------
7802
7803 :Architectures: all
7804 :Target: VM
7805 :Parameters: args[0] is the maximum poll time in nanoseconds
7806 :Returns: 0 on success; -1 on error
7807
7808 KVM_CAP_HALT_POLL overrides the kvm.halt_poll_ns module parameter to set the
7809 maximum halt-polling time for all vCPUs in the target VM. This capability can
7810 be invoked at any time and any number of times to dynamically change the
7811 maximum halt-polling time.
7812
7813 See Documentation/virt/kvm/halt-polling.rst for more information on halt
7814 polling.
7815
7816 7.21 KVM_CAP_X86_USER_SPACE_MSR
7817 -------------------------------
7818
7819 :Architectures: x86
7820 :Target: VM
7821 :Parameters: args[0] contains the mask of KVM_MSR_EXIT_REASON_* events to report
7822 :Returns: 0 on success; -1 on error
7823
7824 This capability allows userspace to intercept RDMSR and WRMSR instructions if
7825 access to an MSR is denied. By default, KVM injects #GP on denied accesses.
7826
7827 When a guest requests to read or write an MSR, KVM may not implement all MSRs
7828 that are relevant to a respective system. It also does not differentiate by
7829 CPU type.
7830
7831 To allow more fine grained control over MSR handling, userspace may enable
7832 this capability. With it enabled, MSR accesses that match the mask specified in
7833 args[0] and would trigger a #GP inside the guest will instead trigger
7834 KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications. Userspace
7835 can then implement model specific MSR handling and/or user notifications
7836 to inform a user that an MSR was not emulated/virtualized by KVM.
7837
7838 The valid mask flags are:
7839
7840 ============================ ===============================================
7841 KVM_MSR_EXIT_REASON_UNKNOWN intercept accesses to unknown (to KVM) MSRs
7842 KVM_MSR_EXIT_REASON_INVAL intercept accesses that are architecturally
7843 invalid according to the vCPU model and/or mode
7844 KVM_MSR_EXIT_REASON_FILTER intercept accesses that are denied by userspace
7845 via KVM_X86_SET_MSR_FILTER
7846 ============================ ===============================================
7847
7848 7.22 KVM_CAP_X86_BUS_LOCK_EXIT
7849 -------------------------------
7850
7851 :Architectures: x86
7852 :Target: VM
7853 :Parameters: args[0] defines the policy used when bus locks detected in guest
7854 :Returns: 0 on success, -EINVAL when args[0] contains invalid bits
7855
7856 Valid bits in args[0] are::
7857
7858 #define KVM_BUS_LOCK_DETECTION_OFF (1 << 0)
7859 #define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1)
7860
7861 Enabling this capability on a VM provides userspace with a way to select a
7862 policy to handle the bus locks detected in guest. Userspace can obtain the
7863 supported modes from the result of KVM_CHECK_EXTENSION and define it through
7864 the KVM_ENABLE_CAP. The supported modes are mutually-exclusive.
7865
7866 This capability allows userspace to force VM exits on bus locks detected in the
7867 guest, irrespective whether or not the host has enabled split-lock detection
7868 (which triggers an #AC exception that KVM intercepts). This capability is
7869 intended to mitigate attacks where a malicious/buggy guest can exploit bus
7870 locks to degrade the performance of the whole system.
7871
7872 If KVM_BUS_LOCK_DETECTION_OFF is set, KVM doesn't force guest bus locks to VM
7873 exit, although the host kernel's split-lock #AC detection still applies, if
7874 enabled.
7875
7876 If KVM_BUS_LOCK_DETECTION_EXIT is set, KVM enables a CPU feature that ensures
7877 bus locks in the guest trigger a VM exit, and KVM exits to userspace for all
7878 such VM exits, e.g. to allow userspace to throttle the offending guest and/or
7879 apply some other policy-based mitigation. When exiting to userspace, KVM sets
7880 KVM_RUN_X86_BUS_LOCK in vcpu-run->flags, and conditionally sets the exit_reason
7881 to KVM_EXIT_X86_BUS_LOCK.
7882
7883 Note! Detected bus locks may be coincident with other exits to userspace, i.e.
7884 KVM_RUN_X86_BUS_LOCK should be checked regardless of the primary exit reason if
7885 userspace wants to take action on all detected bus locks.
7886
7887 7.23 KVM_CAP_PPC_DAWR1
7888 ----------------------
7889
7890 :Architectures: ppc
7891 :Parameters: none
7892 :Returns: 0 on success, -EINVAL when CPU doesn't support 2nd DAWR
7893
7894 This capability can be used to check / enable 2nd DAWR feature provided
7895 by POWER10 processor.
7896
7897
7898 7.24 KVM_CAP_VM_COPY_ENC_CONTEXT_FROM
7899 -------------------------------------
7900
7901 Architectures: x86 SEV enabled
7902 Type: vm
7903 Parameters: args[0] is the fd of the source vm
7904 Returns: 0 on success; ENOTTY on error
7905
7906 This capability enables userspace to copy encryption context from the vm
7907 indicated by the fd to the vm this is called on.
7908
7909 This is intended to support in-guest workloads scheduled by the host. This
7910 allows the in-guest workload to maintain its own NPTs and keeps the two vms
7911 from accidentally clobbering each other with interrupts and the like (separate
7912 APIC/MSRs/etc).
7913
7914 7.25 KVM_CAP_SGX_ATTRIBUTE
7915 --------------------------
7916
7917 :Architectures: x86
7918 :Target: VM
7919 :Parameters: args[0] is a file handle of a SGX attribute file in securityfs
7920 :Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested
7921 attribute is not supported by KVM.
7922
7923 KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or
7924 more privileged enclave attributes. args[0] must hold a file handle to a valid
7925 SGX attribute file corresponding to an attribute that is supported/restricted
7926 by KVM (currently only PROVISIONKEY).
7927
7928 The SGX subsystem restricts access to a subset of enclave attributes to provide
7929 additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY
7930 is restricted to deter malware from using the PROVISIONKEY to obtain a stable
7931 system fingerprint. To prevent userspace from circumventing such restrictions
7932 by running an enclave in a VM, KVM prevents access to privileged attributes by
7933 default.
7934
7935 See Documentation/arch/x86/sgx.rst for more details.
7936
7937 7.26 KVM_CAP_PPC_RPT_INVALIDATE
7938 -------------------------------
7939
7940 :Capability: KVM_CAP_PPC_RPT_INVALIDATE
7941 :Architectures: ppc
7942 :Type: vm
7943
7944 This capability indicates that the kernel is capable of handling
7945 H_RPT_INVALIDATE hcall.
7946
7947 In order to enable the use of H_RPT_INVALIDATE in the guest,
7948 user space might have to advertise it for the guest. For example,
7949 IBM pSeries (sPAPR) guest starts using it if "hcall-rpt-invalidate" is
7950 present in the "ibm,hypertas-functions" device-tree property.
7951
7952 This capability is enabled for hypervisors on platforms like POWER9
7953 that support radix MMU.
7954
7955 7.27 KVM_CAP_EXIT_ON_EMULATION_FAILURE
7956 --------------------------------------
7957
7958 :Architectures: x86
7959 :Parameters: args[0] whether the feature should be enabled or not
7960
7961 When this capability is enabled, an emulation failure will result in an exit
7962 to userspace with KVM_INTERNAL_ERROR (except when the emulator was invoked
7963 to handle a VMware backdoor instruction). Furthermore, KVM will now provide up
7964 to 15 instruction bytes for any exit to userspace resulting from an emulation
7965 failure. When these exits to userspace occur use the emulation_failure struct
7966 instead of the internal struct. They both have the same layout, but the
7967 emulation_failure struct matches the content better. It also explicitly
7968 defines the 'flags' field which is used to describe the fields in the struct
7969 that are valid (ie: if KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES is
7970 set in the 'flags' field then both 'insn_size' and 'insn_bytes' have valid data
7971 in them.)
7972
7973 7.28 KVM_CAP_ARM_MTE
7974 --------------------
7975
7976 :Architectures: arm64
7977 :Parameters: none
7978
7979 This capability indicates that KVM (and the hardware) supports exposing the
7980 Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the
7981 VMM before creating any VCPUs to allow the guest access. Note that MTE is only
7982 available to a guest running in AArch64 mode and enabling this capability will
7983 cause attempts to create AArch32 VCPUs to fail.
7984
7985 When enabled the guest is able to access tags associated with any memory given
7986 to the guest. KVM will ensure that the tags are maintained during swap or
7987 hibernation of the host; however the VMM needs to manually save/restore the
7988 tags as appropriate if the VM is migrated.
7989
7990 When this capability is enabled all memory in memslots must be mapped as
7991 ``MAP_ANONYMOUS`` or with a RAM-based file mapping (``tmpfs``, ``memfd``),
7992 attempts to create a memslot with an invalid mmap will result in an
7993 -EINVAL return.
7994
7995 When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to
7996 perform a bulk copy of tags to/from the guest.
7997
7998 7.29 KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM
7999 -------------------------------------
8000
8001 :Architectures: x86 SEV enabled
8002 :Type: vm
8003 :Parameters: args[0] is the fd of the source vm
8004 :Returns: 0 on success
8005
8006 This capability enables userspace to migrate the encryption context from the VM
8007 indicated by the fd to the VM this is called on.
8008
8009 This is intended to support intra-host migration of VMs between userspace VMMs,
8010 upgrading the VMM process without interrupting the guest.
8011
8012 7.30 KVM_CAP_PPC_AIL_MODE_3
8013 -------------------------------
8014
8015 :Capability: KVM_CAP_PPC_AIL_MODE_3
8016 :Architectures: ppc
8017 :Type: vm
8018
8019 This capability indicates that the kernel supports the mode 3 setting for the
8020 "Address Translation Mode on Interrupt" aka "Alternate Interrupt Location"
8021 resource that is controlled with the H_SET_MODE hypercall.
8022
8023 This capability allows a guest kernel to use a better-performance mode for
8024 handling interrupts and system calls.
8025
8026 7.31 KVM_CAP_DISABLE_QUIRKS2
8027 ----------------------------
8028
8029 :Capability: KVM_CAP_DISABLE_QUIRKS2
8030 :Parameters: args[0] - set of KVM quirks to disable
8031 :Architectures: x86
8032 :Type: vm
8033
8034 This capability, if enabled, will cause KVM to disable some behavior
8035 quirks.
8036
8037 Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of
8038 quirks that can be disabled in KVM.
8039
8040 The argument to KVM_ENABLE_CAP for this capability is a bitmask of
8041 quirks to disable, and must be a subset of the bitmask returned by
8042 KVM_CHECK_EXTENSION.
8043
8044 The valid bits in cap.args[0] are:
8045
8046 =================================== ============================================
8047 KVM_X86_QUIRK_LINT0_REENABLED By default, the reset value for the LVT
8048 LINT0 register is 0x700 (APIC_MODE_EXTINT).
8049 When this quirk is disabled, the reset value
8050 is 0x10000 (APIC_LVT_MASKED).
8051
8052 KVM_X86_QUIRK_CD_NW_CLEARED By default, KVM clears CR0.CD and CR0.NW on
8053 AMD CPUs to workaround buggy guest firmware
8054 that runs in perpetuity with CR0.CD, i.e.
8055 with caches in "no fill" mode.
8056
8057 When this quirk is disabled, KVM does not
8058 change the value of CR0.CD and CR0.NW.
8059
8060 KVM_X86_QUIRK_LAPIC_MMIO_HOLE By default, the MMIO LAPIC interface is
8061 available even when configured for x2APIC
8062 mode. When this quirk is disabled, KVM
8063 disables the MMIO LAPIC interface if the
8064 LAPIC is in x2APIC mode.
8065
8066 KVM_X86_QUIRK_OUT_7E_INC_RIP By default, KVM pre-increments %rip before
8067 exiting to userspace for an OUT instruction
8068 to port 0x7e. When this quirk is disabled,
8069 KVM does not pre-increment %rip before
8070 exiting to userspace.
8071
8072 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT When this quirk is disabled, KVM sets
8073 CPUID.01H:ECX[bit 3] (MONITOR/MWAIT) if
8074 IA32_MISC_ENABLE[bit 18] (MWAIT) is set.
8075 Additionally, when this quirk is disabled,
8076 KVM clears CPUID.01H:ECX[bit 3] if
8077 IA32_MISC_ENABLE[bit 18] is cleared.
8078
8079 KVM_X86_QUIRK_FIX_HYPERCALL_INSN By default, KVM rewrites guest
8080 VMMCALL/VMCALL instructions to match the
8081 vendor's hypercall instruction for the
8082 system. When this quirk is disabled, KVM
8083 will no longer rewrite invalid guest
8084 hypercall instructions. Executing the
8085 incorrect hypercall instruction will
8086 generate a #UD within the guest.
8087
8088 KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS By default, KVM emulates MONITOR/MWAIT (if
8089 they are intercepted) as NOPs regardless of
8090 whether or not MONITOR/MWAIT are supported
8091 according to guest CPUID. When this quirk
8092 is disabled and KVM_X86_DISABLE_EXITS_MWAIT
8093 is not set (MONITOR/MWAIT are intercepted),
8094 KVM will inject a #UD on MONITOR/MWAIT if
8095 they're unsupported per guest CPUID. Note,
8096 KVM will modify MONITOR/MWAIT support in
8097 guest CPUID on writes to MISC_ENABLE if
8098 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT is
8099 disabled.
8100
8101 KVM_X86_QUIRK_SLOT_ZAP_ALL By default, for KVM_X86_DEFAULT_VM VMs, KVM
8102 invalidates all SPTEs in all memslots and
8103 address spaces when a memslot is deleted or
8104 moved. When this quirk is disabled (or the
8105 VM type isn't KVM_X86_DEFAULT_VM), KVM only
8106 ensures the backing memory of the deleted
8107 or moved memslot isn't reachable, i.e KVM
8108 _may_ invalidate only SPTEs related to the
8109 memslot.
8110 =================================== ============================================
8111
8112 7.32 KVM_CAP_MAX_VCPU_ID
8113 ------------------------
8114
8115 :Architectures: x86
8116 :Target: VM
8117 :Parameters: args[0] - maximum APIC ID value set for current VM
8118 :Returns: 0 on success, -EINVAL if args[0] is beyond KVM_MAX_VCPU_IDS
8119 supported in KVM or if it has been set.
8120
8121 This capability allows userspace to specify maximum possible APIC ID
8122 assigned for current VM session prior to the creation of vCPUs, saving
8123 memory for data structures indexed by the APIC ID. Userspace is able
8124 to calculate the limit to APIC ID values from designated
8125 CPU topology.
8126
8127 The value can be changed only until KVM_ENABLE_CAP is set to a nonzero
8128 value or until a vCPU is created. Upon creation of the first vCPU,
8129 if the value was set to zero or KVM_ENABLE_CAP was not invoked, KVM
8130 uses the return value of KVM_CHECK_EXTENSION(KVM_CAP_MAX_VCPU_ID) as
8131 the maximum APIC ID.
8132
8133 7.33 KVM_CAP_X86_NOTIFY_VMEXIT
8134 ------------------------------
8135
8136 :Architectures: x86
8137 :Target: VM
8138 :Parameters: args[0] is the value of notify window as well as some flags
8139 :Returns: 0 on success, -EINVAL if args[0] contains invalid flags or notify
8140 VM exit is unsupported.
8141
8142 Bits 63:32 of args[0] are used for notify window.
8143 Bits 31:0 of args[0] are for some flags. Valid bits are::
8144
8145 #define KVM_X86_NOTIFY_VMEXIT_ENABLED (1 << 0)
8146 #define KVM_X86_NOTIFY_VMEXIT_USER (1 << 1)
8147
8148 This capability allows userspace to configure the notify VM exit on/off
8149 in per-VM scope during VM creation. Notify VM exit is disabled by default.
8150 When userspace sets KVM_X86_NOTIFY_VMEXIT_ENABLED bit in args[0], VMM will
8151 enable this feature with the notify window provided, which will generate
8152 a VM exit if no event window occurs in VM non-root mode for a specified of
8153 time (notify window).
8154
8155 If KVM_X86_NOTIFY_VMEXIT_USER is set in args[0], upon notify VM exits happen,
8156 KVM would exit to userspace for handling.
8157
8158 This capability is aimed to mitigate the threat that malicious VMs can
8159 cause CPU stuck (due to event windows don't open up) and make the CPU
8160 unavailable to host or other VMs.
8161
8162 7.34 KVM_CAP_MEMORY_FAULT_INFO
8163 ------------------------------
8164
8165 :Architectures: x86
8166 :Returns: Informational only, -EINVAL on direct KVM_ENABLE_CAP.
8167
8168 The presence of this capability indicates that KVM_RUN will fill
8169 kvm_run.memory_fault if KVM cannot resolve a guest page fault VM-Exit, e.g. if
8170 there is a valid memslot but no backing VMA for the corresponding host virtual
8171 address.
8172
8173 The information in kvm_run.memory_fault is valid if and only if KVM_RUN returns
8174 an error with errno=EFAULT or errno=EHWPOISON *and* kvm_run.exit_reason is set
8175 to KVM_EXIT_MEMORY_FAULT.
8176
8177 Note: Userspaces which attempt to resolve memory faults so that they can retry
8178 KVM_RUN are encouraged to guard against repeatedly receiving the same
8179 error/annotated fault.
8180
8181 See KVM_EXIT_MEMORY_FAULT for more information.
8182
8183 7.35 KVM_CAP_X86_APIC_BUS_CYCLES_NS
8184 -----------------------------------
8185
8186 :Architectures: x86
8187 :Target: VM
8188 :Parameters: args[0] is the desired APIC bus clock rate, in nanoseconds
8189 :Returns: 0 on success, -EINVAL if args[0] contains an invalid value for the
8190 frequency or if any vCPUs have been created, -ENXIO if a virtual
8191 local APIC has not been created using KVM_CREATE_IRQCHIP.
8192
8193 This capability sets the VM's APIC bus clock frequency, used by KVM's in-kernel
8194 virtual APIC when emulating APIC timers. KVM's default value can be retrieved
8195 by KVM_CHECK_EXTENSION.
8196
8197 Note: Userspace is responsible for correctly configuring CPUID 0x15, a.k.a. the
8198 core crystal clock frequency, if a non-zero CPUID 0x15 is exposed to the guest.
8199
8200 7.36 KVM_CAP_X86_GUEST_MODE
8201 ------------------------------
8202
8203 :Architectures: x86
8204 :Returns: Informational only, -EINVAL on direct KVM_ENABLE_CAP.
8205
8206 The presence of this capability indicates that KVM_RUN will update the
8207 KVM_RUN_X86_GUEST_MODE bit in kvm_run.flags to indicate whether the
8208 vCPU was executing nested guest code when it exited.
8209
8210 KVM exits with the register state of either the L1 or L2 guest
8211 depending on which executed at the time of an exit. Userspace must
8212 take care to differentiate between these cases.
8213
8214 8. Other capabilities.
8215 ======================
8216
8217 This section lists capabilities that give information about other
8218 features of the KVM implementation.
8219
8220 8.1 KVM_CAP_PPC_HWRNG
8221 ---------------------
8222
8223 :Architectures: ppc
8224
8225 This capability, if KVM_CHECK_EXTENSION indicates that it is
8226 available, means that the kernel has an implementation of the
8227 H_RANDOM hypercall backed by a hardware random-number generator.
8228 If present, the kernel H_RANDOM handler can be enabled for guest use
8229 with the KVM_CAP_PPC_ENABLE_HCALL capability.
8230
8231 8.2 KVM_CAP_HYPERV_SYNIC
8232 ------------------------
8233
8234 :Architectures: x86
8235
8236 This capability, if KVM_CHECK_EXTENSION indicates that it is
8237 available, means that the kernel has an implementation of the
8238 Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is
8239 used to support Windows Hyper-V based guest paravirt drivers(VMBus).
8240
8241 In order to use SynIC, it has to be activated by setting this
8242 capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this
8243 will disable the use of APIC hardware virtualization even if supported
8244 by the CPU, as it's incompatible with SynIC auto-EOI behavior.
8245
8246 8.3 KVM_CAP_PPC_MMU_RADIX
8247 -------------------------
8248
8249 :Architectures: ppc
8250
8251 This capability, if KVM_CHECK_EXTENSION indicates that it is
8252 available, means that the kernel can support guests using the
8253 radix MMU defined in Power ISA V3.00 (as implemented in the POWER9
8254 processor).
8255
8256 8.4 KVM_CAP_PPC_MMU_HASH_V3
8257 ---------------------------
8258
8259 :Architectures: ppc
8260
8261 This capability, if KVM_CHECK_EXTENSION indicates that it is
8262 available, means that the kernel can support guests using the
8263 hashed page table MMU defined in Power ISA V3.00 (as implemented in
8264 the POWER9 processor), including in-memory segment tables.
8265
8266 8.5 KVM_CAP_MIPS_VZ
8267 -------------------
8268
8269 :Architectures: mips
8270
8271 This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that
8272 it is available, means that full hardware assisted virtualization capabilities
8273 of the hardware are available for use through KVM. An appropriate
8274 KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which
8275 utilises it.
8276
8277 If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is
8278 available, it means that the VM is using full hardware assisted virtualization
8279 capabilities of the hardware. This is useful to check after creating a VM with
8280 KVM_VM_MIPS_DEFAULT.
8281
8282 The value returned by KVM_CHECK_EXTENSION should be compared against known
8283 values (see below). All other values are reserved. This is to allow for the
8284 possibility of other hardware assisted virtualization implementations which
8285 may be incompatible with the MIPS VZ ASE.
8286
8287 == ==========================================================================
8288 0 The trap & emulate implementation is in use to run guest code in user
8289 mode. Guest virtual memory segments are rearranged to fit the guest in the
8290 user mode address space.
8291
8292 1 The MIPS VZ ASE is in use, providing full hardware assisted
8293 virtualization, including standard guest virtual memory segments.
8294 == ==========================================================================
8295
8296 8.6 KVM_CAP_MIPS_TE
8297 -------------------
8298
8299 :Architectures: mips
8300
8301 This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that
8302 it is available, means that the trap & emulate implementation is available to
8303 run guest code in user mode, even if KVM_CAP_MIPS_VZ indicates that hardware
8304 assisted virtualisation is also available. KVM_VM_MIPS_TE (0) must be passed
8305 to KVM_CREATE_VM to create a VM which utilises it.
8306
8307 If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is
8308 available, it means that the VM is using trap & emulate.
8309
8310 8.7 KVM_CAP_MIPS_64BIT
8311 ----------------------
8312
8313 :Architectures: mips
8314
8315 This capability indicates the supported architecture type of the guest, i.e. the
8316 supported register and address width.
8317
8318 The values returned when this capability is checked by KVM_CHECK_EXTENSION on a
8319 kvm VM handle correspond roughly to the CP0_Config.AT register field, and should
8320 be checked specifically against known values (see below). All other values are
8321 reserved.
8322
8323 == ========================================================================
8324 0 MIPS32 or microMIPS32.
8325 Both registers and addresses are 32-bits wide.
8326 It will only be possible to run 32-bit guest code.
8327
8328 1 MIPS64 or microMIPS64 with access only to 32-bit compatibility segments.
8329 Registers are 64-bits wide, but addresses are 32-bits wide.
8330 64-bit guest code may run but cannot access MIPS64 memory segments.
8331 It will also be possible to run 32-bit guest code.
8332
8333 2 MIPS64 or microMIPS64 with access to all address segments.
8334 Both registers and addresses are 64-bits wide.
8335 It will be possible to run 64-bit or 32-bit guest code.
8336 == ========================================================================
8337
8338 8.9 KVM_CAP_ARM_USER_IRQ
8339 ------------------------
8340
8341 :Architectures: arm64
8342
8343 This capability, if KVM_CHECK_EXTENSION indicates that it is available, means
8344 that if userspace creates a VM without an in-kernel interrupt controller, it
8345 will be notified of changes to the output level of in-kernel emulated devices,
8346 which can generate virtual interrupts, presented to the VM.
8347 For such VMs, on every return to userspace, the kernel
8348 updates the vcpu's run->s.regs.device_irq_level field to represent the actual
8349 output level of the device.
8350
8351 Whenever kvm detects a change in the device output level, kvm guarantees at
8352 least one return to userspace before running the VM. This exit could either
8353 be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way,
8354 userspace can always sample the device output level and re-compute the state of
8355 the userspace interrupt controller. Userspace should always check the state
8356 of run->s.regs.device_irq_level on every kvm exit.
8357 The value in run->s.regs.device_irq_level can represent both level and edge
8358 triggered interrupt signals, depending on the device. Edge triggered interrupt
8359 signals will exit to userspace with the bit in run->s.regs.device_irq_level
8360 set exactly once per edge signal.
8361
8362 The field run->s.regs.device_irq_level is available independent of
8363 run->kvm_valid_regs or run->kvm_dirty_regs bits.
8364
8365 If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a
8366 number larger than 0 indicating the version of this capability is implemented
8367 and thereby which bits in run->s.regs.device_irq_level can signal values.
8368
8369 Currently the following bits are defined for the device_irq_level bitmap::
8370
8371 KVM_CAP_ARM_USER_IRQ >= 1:
8372
8373 KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer
8374 KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer
8375 KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal
8376
8377 Future versions of kvm may implement additional events. These will get
8378 indicated by returning a higher number from KVM_CHECK_EXTENSION and will be
8379 listed above.
8380
8381 8.10 KVM_CAP_PPC_SMT_POSSIBLE
8382 -----------------------------
8383
8384 :Architectures: ppc
8385
8386 Querying this capability returns a bitmap indicating the possible
8387 virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N
8388 (counting from the right) is set, then a virtual SMT mode of 2^N is
8389 available.
8390
8391 8.11 KVM_CAP_HYPERV_SYNIC2
8392 --------------------------
8393
8394 :Architectures: x86
8395
8396 This capability enables a newer version of Hyper-V Synthetic interrupt
8397 controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM
8398 doesn't clear SynIC message and event flags pages when they are enabled by
8399 writing to the respective MSRs.
8400
8401 8.12 KVM_CAP_HYPERV_VP_INDEX
8402 ----------------------------
8403
8404 :Architectures: x86
8405
8406 This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its
8407 value is used to denote the target vcpu for a SynIC interrupt. For
8408 compatibility, KVM initializes this msr to KVM's internal vcpu index. When this
8409 capability is absent, userspace can still query this msr's value.
8410
8411 8.13 KVM_CAP_S390_AIS_MIGRATION
8412 -------------------------------
8413
8414 :Architectures: s390
8415 :Parameters: none
8416
8417 This capability indicates if the flic device will be able to get/set the
8418 AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows
8419 to discover this without having to create a flic device.
8420
8421 8.14 KVM_CAP_S390_PSW
8422 ---------------------
8423
8424 :Architectures: s390
8425
8426 This capability indicates that the PSW is exposed via the kvm_run structure.
8427
8428 8.15 KVM_CAP_S390_GMAP
8429 ----------------------
8430
8431 :Architectures: s390
8432
8433 This capability indicates that the user space memory used as guest mapping can
8434 be anywhere in the user memory address space, as long as the memory slots are
8435 aligned and sized to a segment (1MB) boundary.
8436
8437 8.16 KVM_CAP_S390_COW
8438 ---------------------
8439
8440 :Architectures: s390
8441
8442 This capability indicates that the user space memory used as guest mapping can
8443 use copy-on-write semantics as well as dirty pages tracking via read-only page
8444 tables.
8445
8446 8.17 KVM_CAP_S390_BPB
8447 ---------------------
8448
8449 :Architectures: s390
8450
8451 This capability indicates that kvm will implement the interfaces to handle
8452 reset, migration and nested KVM for branch prediction blocking. The stfle
8453 facility 82 should not be provided to the guest without this capability.
8454
8455 8.18 KVM_CAP_HYPERV_TLBFLUSH
8456 ----------------------------
8457
8458 :Architectures: x86
8459
8460 This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush
8461 hypercalls:
8462 HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx,
8463 HvFlushVirtualAddressList, HvFlushVirtualAddressListEx.
8464
8465 8.19 KVM_CAP_ARM_INJECT_SERROR_ESR
8466 ----------------------------------
8467
8468 :Architectures: arm64
8469
8470 This capability indicates that userspace can specify (via the
8471 KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it
8472 takes a virtual SError interrupt exception.
8473 If KVM advertises this capability, userspace can only specify the ISS field for
8474 the ESR syndrome. Other parts of the ESR, such as the EC are generated by the
8475 CPU when the exception is taken. If this virtual SError is taken to EL1 using
8476 AArch64, this value will be reported in the ISS field of ESR_ELx.
8477
8478 See KVM_CAP_VCPU_EVENTS for more details.
8479
8480 8.20 KVM_CAP_HYPERV_SEND_IPI
8481 ----------------------------
8482
8483 :Architectures: x86
8484
8485 This capability indicates that KVM supports paravirtualized Hyper-V IPI send
8486 hypercalls:
8487 HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx.
8488
8489 8.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH
8490 -----------------------------------
8491
8492 :Architectures: x86
8493
8494 This capability indicates that KVM running on top of Hyper-V hypervisor
8495 enables Direct TLB flush for its guests meaning that TLB flush
8496 hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM.
8497 Due to the different ABI for hypercall parameters between Hyper-V and
8498 KVM, enabling this capability effectively disables all hypercall
8499 handling by KVM (as some KVM hypercall may be mistakenly treated as TLB
8500 flush hypercalls by Hyper-V) so userspace should disable KVM identification
8501 in CPUID and only exposes Hyper-V identification. In this case, guest
8502 thinks it's running on Hyper-V and only use Hyper-V hypercalls.
8503
8504 8.22 KVM_CAP_S390_VCPU_RESETS
8505 -----------------------------
8506
8507 :Architectures: s390
8508
8509 This capability indicates that the KVM_S390_NORMAL_RESET and
8510 KVM_S390_CLEAR_RESET ioctls are available.
8511
8512 8.23 KVM_CAP_S390_PROTECTED
8513 ---------------------------
8514
8515 :Architectures: s390
8516
8517 This capability indicates that the Ultravisor has been initialized and
8518 KVM can therefore start protected VMs.
8519 This capability governs the KVM_S390_PV_COMMAND ioctl and the
8520 KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected
8521 guests when the state change is invalid.
8522
8523 8.24 KVM_CAP_STEAL_TIME
8524 -----------------------
8525
8526 :Architectures: arm64, x86
8527
8528 This capability indicates that KVM supports steal time accounting.
8529 When steal time accounting is supported it may be enabled with
8530 architecture-specific interfaces. This capability and the architecture-
8531 specific interfaces must be consistent, i.e. if one says the feature
8532 is supported, than the other should as well and vice versa. For arm64
8533 see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL".
8534 For x86 see Documentation/virt/kvm/x86/msr.rst "MSR_KVM_STEAL_TIME".
8535
8536 8.25 KVM_CAP_S390_DIAG318
8537 -------------------------
8538
8539 :Architectures: s390
8540
8541 This capability enables a guest to set information about its control program
8542 (i.e. guest kernel type and version). The information is helpful during
8543 system/firmware service events, providing additional data about the guest
8544 environments running on the machine.
8545
8546 The information is associated with the DIAGNOSE 0x318 instruction, which sets
8547 an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and
8548 a 7-byte Control Program Version Code (CPVC). The CPNC determines what
8549 environment the control program is running in (e.g. Linux, z/VM...), and the
8550 CPVC is used for information specific to OS (e.g. Linux version, Linux
8551 distribution...)
8552
8553 If this capability is available, then the CPNC and CPVC can be synchronized
8554 between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318).
8555
8556 8.26 KVM_CAP_X86_USER_SPACE_MSR
8557 -------------------------------
8558
8559 :Architectures: x86
8560
8561 This capability indicates that KVM supports deflection of MSR reads and
8562 writes to user space. It can be enabled on a VM level. If enabled, MSR
8563 accesses that would usually trigger a #GP by KVM into the guest will
8564 instead get bounced to user space through the KVM_EXIT_X86_RDMSR and
8565 KVM_EXIT_X86_WRMSR exit notifications.
8566
8567 8.27 KVM_CAP_X86_MSR_FILTER
8568 ---------------------------
8569
8570 :Architectures: x86
8571
8572 This capability indicates that KVM supports that accesses to user defined MSRs
8573 may be rejected. With this capability exposed, KVM exports new VM ioctl
8574 KVM_X86_SET_MSR_FILTER which user space can call to specify bitmaps of MSR
8575 ranges that KVM should deny access to.
8576
8577 In combination with KVM_CAP_X86_USER_SPACE_MSR, this allows user space to
8578 trap and emulate MSRs that are outside of the scope of KVM as well as
8579 limit the attack surface on KVM's MSR emulation code.
8580
8581 8.28 KVM_CAP_ENFORCE_PV_FEATURE_CPUID
8582 -------------------------------------
8583
8584 Architectures: x86
8585
8586 When enabled, KVM will disable paravirtual features provided to the
8587 guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf
8588 (0x40000001). Otherwise, a guest may use the paravirtual features
8589 regardless of what has actually been exposed through the CPUID leaf.
8590
8591 8.29 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL
8592 ----------------------------------------------------------
8593
8594 :Architectures: x86, arm64
8595 :Parameters: args[0] - size of the dirty log ring
8596
8597 KVM is capable of tracking dirty memory using ring buffers that are
8598 mmapped into userspace; there is one dirty ring per vcpu.
8599
8600 The dirty ring is available to userspace as an array of
8601 ``struct kvm_dirty_gfn``. Each dirty entry is defined as::
8602
8603 struct kvm_dirty_gfn {
8604 __u32 flags;
8605 __u32 slot; /* as_id | slot_id */
8606 __u64 offset;
8607 };
8608
8609 The following values are defined for the flags field to define the
8610 current state of the entry::
8611
8612 #define KVM_DIRTY_GFN_F_DIRTY BIT(0)
8613 #define KVM_DIRTY_GFN_F_RESET BIT(1)
8614 #define KVM_DIRTY_GFN_F_MASK 0x3
8615
8616 Userspace should call KVM_ENABLE_CAP ioctl right after KVM_CREATE_VM
8617 ioctl to enable this capability for the new guest and set the size of
8618 the rings. Enabling the capability is only allowed before creating any
8619 vCPU, and the size of the ring must be a power of two. The larger the
8620 ring buffer, the less likely the ring is full and the VM is forced to
8621 exit to userspace. The optimal size depends on the workload, but it is
8622 recommended that it be at least 64 KiB (4096 entries).
8623
8624 Just like for dirty page bitmaps, the buffer tracks writes to
8625 all user memory regions for which the KVM_MEM_LOG_DIRTY_PAGES flag was
8626 set in KVM_SET_USER_MEMORY_REGION. Once a memory region is registered
8627 with the flag set, userspace can start harvesting dirty pages from the
8628 ring buffer.
8629
8630 An entry in the ring buffer can be unused (flag bits ``00``),
8631 dirty (flag bits ``01``) or harvested (flag bits ``1X``). The
8632 state machine for the entry is as follows::
8633
8634 dirtied harvested reset
8635 00 -----------> 01 -------------> 1X -------+
8636 ^ |
8637 | |
8638 +------------------------------------------+
8639
8640 To harvest the dirty pages, userspace accesses the mmapped ring buffer
8641 to read the dirty GFNs. If the flags has the DIRTY bit set (at this stage
8642 the RESET bit must be cleared), then it means this GFN is a dirty GFN.
8643 The userspace should harvest this GFN and mark the flags from state
8644 ``01b`` to ``1Xb`` (bit 0 will be ignored by KVM, but bit 1 must be set
8645 to show that this GFN is harvested and waiting for a reset), and move
8646 on to the next GFN. The userspace should continue to do this until the
8647 flags of a GFN have the DIRTY bit cleared, meaning that it has harvested
8648 all the dirty GFNs that were available.
8649
8650 Note that on weakly ordered architectures, userspace accesses to the
8651 ring buffer (and more specifically the 'flags' field) must be ordered,
8652 using load-acquire/store-release accessors when available, or any
8653 other memory barrier that will ensure this ordering.
8654
8655 It's not necessary for userspace to harvest the all dirty GFNs at once.
8656 However it must collect the dirty GFNs in sequence, i.e., the userspace
8657 program cannot skip one dirty GFN to collect the one next to it.
8658
8659 After processing one or more entries in the ring buffer, userspace
8660 calls the VM ioctl KVM_RESET_DIRTY_RINGS to notify the kernel about
8661 it, so that the kernel will reprotect those collected GFNs.
8662 Therefore, the ioctl must be called *before* reading the content of
8663 the dirty pages.
8664
8665 The dirty ring can get full. When it happens, the KVM_RUN of the
8666 vcpu will return with exit reason KVM_EXIT_DIRTY_LOG_FULL.
8667
8668 The dirty ring interface has a major difference comparing to the
8669 KVM_GET_DIRTY_LOG interface in that, when reading the dirty ring from
8670 userspace, it's still possible that the kernel has not yet flushed the
8671 processor's dirty page buffers into the kernel buffer (with dirty bitmaps, the
8672 flushing is done by the KVM_GET_DIRTY_LOG ioctl). To achieve that, one
8673 needs to kick the vcpu out of KVM_RUN using a signal. The resulting
8674 vmexit ensures that all dirty GFNs are flushed to the dirty rings.
8675
8676 NOTE: KVM_CAP_DIRTY_LOG_RING_ACQ_REL is the only capability that
8677 should be exposed by weakly ordered architecture, in order to indicate
8678 the additional memory ordering requirements imposed on userspace when
8679 reading the state of an entry and mutating it from DIRTY to HARVESTED.
8680 Architecture with TSO-like ordering (such as x86) are allowed to
8681 expose both KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL
8682 to userspace.
8683
8684 After enabling the dirty rings, the userspace needs to detect the
8685 capability of KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP to see whether the
8686 ring structures can be backed by per-slot bitmaps. With this capability
8687 advertised, it means the architecture can dirty guest pages without
8688 vcpu/ring context, so that some of the dirty information will still be
8689 maintained in the bitmap structure. KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP
8690 can't be enabled if the capability of KVM_CAP_DIRTY_LOG_RING_ACQ_REL
8691 hasn't been enabled, or any memslot has been existing.
8692
8693 Note that the bitmap here is only a backup of the ring structure. The
8694 use of the ring and bitmap combination is only beneficial if there is
8695 only a very small amount of memory that is dirtied out of vcpu/ring
8696 context. Otherwise, the stand-alone per-slot bitmap mechanism needs to
8697 be considered.
8698
8699 To collect dirty bits in the backup bitmap, userspace can use the same
8700 KVM_GET_DIRTY_LOG ioctl. KVM_CLEAR_DIRTY_LOG isn't needed as long as all
8701 the generation of the dirty bits is done in a single pass. Collecting
8702 the dirty bitmap should be the very last thing that the VMM does before
8703 considering the state as complete. VMM needs to ensure that the dirty
8704 state is final and avoid missing dirty pages from another ioctl ordered
8705 after the bitmap collection.
8706
8707 NOTE: Multiple examples of using the backup bitmap: (1) save vgic/its
8708 tables through command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} on
8709 KVM device "kvm-arm-vgic-its". (2) restore vgic/its tables through
8710 command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} on KVM device
8711 "kvm-arm-vgic-its". VGICv3 LPI pending status is restored. (3) save
8712 vgic3 pending table through KVM_DEV_ARM_VGIC_{GRP_CTRL, SAVE_PENDING_TABLES}
8713 command on KVM device "kvm-arm-vgic-v3".
8714
8715 8.30 KVM_CAP_XEN_HVM
8716 --------------------
8717
8718 :Architectures: x86
8719
8720 This capability indicates the features that Xen supports for hosting Xen
8721 PVHVM guests. Valid flags are::
8722
8723 #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0)
8724 #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1)
8725 #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2)
8726 #define KVM_XEN_HVM_CONFIG_RUNSTATE (1 << 3)
8727 #define KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL (1 << 4)
8728 #define KVM_XEN_HVM_CONFIG_EVTCHN_SEND (1 << 5)
8729 #define KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG (1 << 6)
8730 #define KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE (1 << 7)
8731
8732 The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG
8733 ioctl is available, for the guest to set its hypercall page.
8734
8735 If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be
8736 provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page
8737 contents, to request that KVM generate hypercall page content automatically
8738 and also enable interception of guest hypercalls with KVM_EXIT_XEN.
8739
8740 The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the
8741 KVM_XEN_HVM_SET_ATTR, KVM_XEN_HVM_GET_ATTR, KVM_XEN_VCPU_SET_ATTR and
8742 KVM_XEN_VCPU_GET_ATTR ioctls, as well as the delivery of exception vectors
8743 for event channel upcalls when the evtchn_upcall_pending field of a vcpu's
8744 vcpu_info is set.
8745
8746 The KVM_XEN_HVM_CONFIG_RUNSTATE flag indicates that the runstate-related
8747 features KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR/_CURRENT/_DATA/_ADJUST are
8748 supported by the KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR ioctls.
8749
8750 The KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL flag indicates that IRQ routing entries
8751 of the type KVM_IRQ_ROUTING_XEN_EVTCHN are supported, with the priority
8752 field set to indicate 2 level event channel delivery.
8753
8754 The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates that KVM supports
8755 injecting event channel events directly into the guest with the
8756 KVM_XEN_HVM_EVTCHN_SEND ioctl. It also indicates support for the
8757 KVM_XEN_ATTR_TYPE_EVTCHN/XEN_VERSION HVM attributes and the
8758 KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID/TIMER/UPCALL_VECTOR vCPU attributes.
8759 related to event channel delivery, timers, and the XENVER_version
8760 interception.
8761
8762 The KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG flag indicates that KVM supports
8763 the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute in the KVM_XEN_SET_ATTR
8764 and KVM_XEN_GET_ATTR ioctls. This controls whether KVM will set the
8765 XEN_RUNSTATE_UPDATE flag in guest memory mapped vcpu_runstate_info during
8766 updates of the runstate information. Note that versions of KVM which support
8767 the RUNSTATE feature above, but not the RUNSTATE_UPDATE_FLAG feature, will
8768 always set the XEN_RUNSTATE_UPDATE flag when updating the guest structure,
8769 which is perhaps counterintuitive. When this flag is advertised, KVM will
8770 behave more correctly, not using the XEN_RUNSTATE_UPDATE flag until/unless
8771 specifically enabled (by the guest making the hypercall, causing the VMM
8772 to enable the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute).
8773
8774 The KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE flag indicates that KVM supports
8775 clearing the PVCLOCK_TSC_STABLE_BIT flag in Xen pvclock sources. This will be
8776 done when the KVM_CAP_XEN_HVM ioctl sets the
8777 KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE flag.
8778
8779 8.31 KVM_CAP_PPC_MULTITCE
8780 -------------------------
8781
8782 :Capability: KVM_CAP_PPC_MULTITCE
8783 :Architectures: ppc
8784 :Type: vm
8785
8786 This capability means the kernel is capable of handling hypercalls
8787 H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user
8788 space. This significantly accelerates DMA operations for PPC KVM guests.
8789 User space should expect that its handlers for these hypercalls
8790 are not going to be called if user space previously registered LIOBN
8791 in KVM (via KVM_CREATE_SPAPR_TCE or similar calls).
8792
8793 In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest,
8794 user space might have to advertise it for the guest. For example,
8795 IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is
8796 present in the "ibm,hypertas-functions" device-tree property.
8797
8798 The hypercalls mentioned above may or may not be processed successfully
8799 in the kernel based fast path. If they can not be handled by the kernel,
8800 they will get passed on to user space. So user space still has to have
8801 an implementation for these despite the in kernel acceleration.
8802
8803 This capability is always enabled.
8804
8805 8.32 KVM_CAP_PTP_KVM
8806 --------------------
8807
8808 :Architectures: arm64
8809
8810 This capability indicates that the KVM virtual PTP service is
8811 supported in the host. A VMM can check whether the service is
8812 available to the guest on migration.
8813
8814 8.33 KVM_CAP_HYPERV_ENFORCE_CPUID
8815 ---------------------------------
8816
8817 Architectures: x86
8818
8819 When enabled, KVM will disable emulated Hyper-V features provided to the
8820 guest according to the bits Hyper-V CPUID feature leaves. Otherwise, all
8821 currently implemented Hyper-V features are provided unconditionally when
8822 Hyper-V identification is set in the HYPERV_CPUID_INTERFACE (0x40000001)
8823 leaf.
8824
8825 8.34 KVM_CAP_EXIT_HYPERCALL
8826 ---------------------------
8827
8828 :Capability: KVM_CAP_EXIT_HYPERCALL
8829 :Architectures: x86
8830 :Type: vm
8831
8832 This capability, if enabled, will cause KVM to exit to userspace
8833 with KVM_EXIT_HYPERCALL exit reason to process some hypercalls.
8834
8835 Calling KVM_CHECK_EXTENSION for this capability will return a bitmask
8836 of hypercalls that can be configured to exit to userspace.
8837 Right now, the only such hypercall is KVM_HC_MAP_GPA_RANGE.
8838
8839 The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset
8840 of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace
8841 the hypercalls whose corresponding bit is in the argument, and return
8842 ENOSYS for the others.
8843
8844 8.35 KVM_CAP_PMU_CAPABILITY
8845 ---------------------------
8846
8847 :Capability: KVM_CAP_PMU_CAPABILITY
8848 :Architectures: x86
8849 :Type: vm
8850 :Parameters: arg[0] is bitmask of PMU virtualization capabilities.
8851 :Returns: 0 on success, -EINVAL when arg[0] contains invalid bits
8852
8853 This capability alters PMU virtualization in KVM.
8854
8855 Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of
8856 PMU virtualization capabilities that can be adjusted on a VM.
8857
8858 The argument to KVM_ENABLE_CAP is also a bitmask and selects specific
8859 PMU virtualization capabilities to be applied to the VM. This can
8860 only be invoked on a VM prior to the creation of VCPUs.
8861
8862 At this time, KVM_PMU_CAP_DISABLE is the only capability. Setting
8863 this capability will disable PMU virtualization for that VM. Usermode
8864 should adjust CPUID leaf 0xA to reflect that the PMU is disabled.
8865
8866 8.36 KVM_CAP_ARM_SYSTEM_SUSPEND
8867 -------------------------------
8868
8869 :Capability: KVM_CAP_ARM_SYSTEM_SUSPEND
8870 :Architectures: arm64
8871 :Type: vm
8872
8873 When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of
8874 type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request.
8875
8876 8.37 KVM_CAP_S390_PROTECTED_DUMP
8877 --------------------------------
8878
8879 :Capability: KVM_CAP_S390_PROTECTED_DUMP
8880 :Architectures: s390
8881 :Type: vm
8882
8883 This capability indicates that KVM and the Ultravisor support dumping
8884 PV guests. The `KVM_PV_DUMP` command is available for the
8885 `KVM_S390_PV_COMMAND` ioctl and the `KVM_PV_INFO` command provides
8886 dump related UV data. Also the vcpu ioctl `KVM_S390_PV_CPU_COMMAND` is
8887 available and supports the `KVM_PV_DUMP_CPU` subcommand.
8888
8889 8.38 KVM_CAP_VM_DISABLE_NX_HUGE_PAGES
8890 -------------------------------------
8891
8892 :Capability: KVM_CAP_VM_DISABLE_NX_HUGE_PAGES
8893 :Architectures: x86
8894 :Type: vm
8895 :Parameters: arg[0] must be 0.
8896 :Returns: 0 on success, -EPERM if the userspace process does not
8897 have CAP_SYS_BOOT, -EINVAL if args[0] is not 0 or any vCPUs have been
8898 created.
8899
8900 This capability disables the NX huge pages mitigation for iTLB MULTIHIT.
8901
8902 The capability has no effect if the nx_huge_pages module parameter is not set.
8903
8904 This capability may only be set before any vCPUs are created.
8905
8906 8.39 KVM_CAP_S390_CPU_TOPOLOGY
8907 ------------------------------
8908
8909 :Capability: KVM_CAP_S390_CPU_TOPOLOGY
8910 :Architectures: s390
8911 :Type: vm
8912
8913 This capability indicates that KVM will provide the S390 CPU Topology
8914 facility which consist of the interpretation of the PTF instruction for
8915 the function code 2 along with interception and forwarding of both the
8916 PTF instruction with function codes 0 or 1 and the STSI(15,1,x)
8917 instruction to the userland hypervisor.
8918
8919 The stfle facility 11, CPU Topology facility, should not be indicated
8920 to the guest without this capability.
8921
8922 When this capability is present, KVM provides a new attribute group
8923 on vm fd, KVM_S390_VM_CPU_TOPOLOGY.
8924 This new attribute allows to get, set or clear the Modified Change
8925 Topology Report (MTCR) bit of the SCA through the kvm_device_attr
8926 structure.
8927
8928 When getting the Modified Change Topology Report value, the attr->addr
8929 must point to a byte where the value will be stored or retrieved from.
8930
8931 8.40 KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE
8932 ---------------------------------------
8933
8934 :Capability: KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE
8935 :Architectures: arm64
8936 :Type: vm
8937 :Parameters: arg[0] is the new split chunk size.
8938 :Returns: 0 on success, -EINVAL if any memslot was already created.
8939
8940 This capability sets the chunk size used in Eager Page Splitting.
8941
8942 Eager Page Splitting improves the performance of dirty-logging (used
8943 in live migrations) when guest memory is backed by huge-pages. It
8944 avoids splitting huge-pages (into PAGE_SIZE pages) on fault, by doing
8945 it eagerly when enabling dirty logging (with the
8946 KVM_MEM_LOG_DIRTY_PAGES flag for a memory region), or when using
8947 KVM_CLEAR_DIRTY_LOG.
8948
8949 The chunk size specifies how many pages to break at a time, using a
8950 single allocation for each chunk. Bigger the chunk size, more pages
8951 need to be allocated ahead of time.
8952
8953 The chunk size needs to be a valid block size. The list of acceptable
8954 block sizes is exposed in KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES as a
8955 64-bit bitmap (each bit describing a block size). The default value is
8956 0, to disable the eager page splitting.
8957
8958 8.41 KVM_CAP_VM_TYPES
8959 ---------------------
8960
8961 :Capability: KVM_CAP_MEMORY_ATTRIBUTES
8962 :Architectures: x86
8963 :Type: system ioctl
8964
8965 This capability returns a bitmap of support VM types. The 1-setting of bit @n
8966 means the VM type with value @n is supported. Possible values of @n are::
8967
8968 #define KVM_X86_DEFAULT_VM 0
8969 #define KVM_X86_SW_PROTECTED_VM 1
8970 #define KVM_X86_SEV_VM 2
8971 #define KVM_X86_SEV_ES_VM 3
8972
8973 Note, KVM_X86_SW_PROTECTED_VM is currently only for development and testing.
8974 Do not use KVM_X86_SW_PROTECTED_VM for "real" VMs, and especially not in
8975 production. The behavior and effective ABI for software-protected VMs is
8976 unstable.
8977
8978 9. Known KVM API problems
8979 =========================
8980
8981 In some cases, KVM's API has some inconsistencies or common pitfalls
8982 that userspace need to be aware of. This section details some of
8983 these issues.
8984
8985 Most of them are architecture specific, so the section is split by
8986 architecture.
8987
8988 9.1. x86
8989 --------
8990
8991 ``KVM_GET_SUPPORTED_CPUID`` issues
8992 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
8993
8994 In general, ``KVM_GET_SUPPORTED_CPUID`` is designed so that it is possible
8995 to take its result and pass it directly to ``KVM_SET_CPUID2``. This section
8996 documents some cases in which that requires some care.
8997
8998 Local APIC features
8999 ~~~~~~~~~~~~~~~~~~~
9000
9001 CPU[EAX=1]:ECX[21] (X2APIC) is reported by ``KVM_GET_SUPPORTED_CPUID``,
9002 but it can only be enabled if ``KVM_CREATE_IRQCHIP`` or
9003 ``KVM_ENABLE_CAP(KVM_CAP_IRQCHIP_SPLIT)`` are used to enable in-kernel emulation of
9004 the local APIC.
9005
9006 The same is true for the ``KVM_FEATURE_PV_UNHALT`` paravirtualized feature.
9007
9008 CPU[EAX=1]:ECX[24] (TSC_DEADLINE) is not reported by ``KVM_GET_SUPPORTED_CPUID``.
9009 It can be enabled if ``KVM_CAP_TSC_DEADLINE_TIMER`` is present and the kernel
9010 has enabled in-kernel emulation of the local APIC.
9011
9012 CPU topology
9013 ~~~~~~~~~~~~
9014
9015 Several CPUID values include topology information for the host CPU:
9016 0x0b and 0x1f for Intel systems, 0x8000001e for AMD systems. Different
9017 versions of KVM return different values for this information and userspace
9018 should not rely on it. Currently they return all zeroes.
9019
9020 If userspace wishes to set up a guest topology, it should be careful that
9021 the values of these three leaves differ for each CPU. In particular,
9022 the APIC ID is found in EDX for all subleaves of 0x0b and 0x1f, and in EAX
9023 for 0x8000001e; the latter also encodes the core id and node id in bits
9024 7:0 of EBX and ECX respectively.
9025
9026 Obsolete ioctls and capabilities
9027 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
9028
9029 KVM_CAP_DISABLE_QUIRKS does not let userspace know which quirks are actually
9030 available. Use ``KVM_CHECK_EXTENSION(KVM_CAP_DISABLE_QUIRKS2)`` instead if
9031 available.
9032
9033 Ordering of KVM_GET_*/KVM_SET_* ioctls
9034 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
9035
9036 TBD
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