1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * KVM paravirt_ops implementation
4 *
5 * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
6 * Copyright IBM Corporation, 2007
7 * Authors: Anthony Liguori <aliguori@us.ibm.com>
8 */
9
10 #define pr_fmt(fmt) "kvm-guest: " fmt
11
12 #include <linux/context_tracking.h>
13 #include <linux/init.h>
14 #include <linux/irq.h>
15 #include <linux/kernel.h>
16 #include <linux/kvm_para.h>
17 #include <linux/cpu.h>
18 #include <linux/mm.h>
19 #include <linux/highmem.h>
20 #include <linux/hardirq.h>
21 #include <linux/notifier.h>
22 #include <linux/reboot.h>
23 #include <linux/hash.h>
24 #include <linux/sched.h>
25 #include <linux/slab.h>
26 #include <linux/kprobes.h>
27 #include <linux/nmi.h>
28 #include <linux/swait.h>
29 #include <linux/syscore_ops.h>
30 #include <linux/cc_platform.h>
31 #include <linux/efi.h>
32 #include <asm/timer.h>
33 #include <asm/cpu.h>
34 #include <asm/traps.h>
35 #include <asm/desc.h>
36 #include <asm/tlbflush.h>
37 #include <asm/apic.h>
38 #include <asm/apicdef.h>
39 #include <asm/hypervisor.h>
40 #include <asm/tlb.h>
41 #include <asm/cpuidle_haltpoll.h>
42 #include <asm/ptrace.h>
43 #include <asm/reboot.h>
44 #include <asm/svm.h>
45 #include <asm/e820/api.h>
46
47 DEFINE_STATIC_KEY_FALSE_RO(kvm_async_pf_enabled);
48
49 static int kvmapf = 1;
50
51 static int __init parse_no_kvmapf(char *arg)
52 {
53 kvmapf = 0;
54 return 0;
55 }
56
57 early_param("no-kvmapf", parse_no_kvmapf);
58
59 static int steal_acc = 1;
60 static int __init parse_no_stealacc(char *arg)
61 {
62 steal_acc = 0;
63 return 0;
64 }
65
66 early_param("no-steal-acc", parse_no_stealacc);
67
68 static DEFINE_PER_CPU_READ_MOSTLY(bool, async_pf_enabled);
69 static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
70 DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64) __visible;
71 static int has_steal_clock = 0;
72
73 static int has_guest_poll = 0;
74 /*
75 * No need for any "IO delay" on KVM
76 */
77 static void kvm_io_delay(void)
78 {
79 }
80
81 #define KVM_TASK_SLEEP_HASHBITS 8
82 #define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
83
84 struct kvm_task_sleep_node {
85 struct hlist_node link;
86 struct swait_queue_head wq;
87 u32 token;
88 int cpu;
89 };
90
91 static struct kvm_task_sleep_head {
92 raw_spinlock_t lock;
93 struct hlist_head list;
94 } async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
95
96 static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
97 u32 token)
98 {
99 struct hlist_node *p;
100
101 hlist_for_each(p, &b->list) {
102 struct kvm_task_sleep_node *n =
103 hlist_entry(p, typeof(*n), link);
104 if (n->token == token)
105 return n;
106 }
107
108 return NULL;
109 }
110
111 static bool kvm_async_pf_queue_task(u32 token, struct kvm_task_sleep_node *n)
112 {
113 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
114 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
115 struct kvm_task_sleep_node *e;
116
117 raw_spin_lock(&b->lock);
118 e = _find_apf_task(b, token);
119 if (e) {
120 /* dummy entry exist -> wake up was delivered ahead of PF */
121 hlist_del(&e->link);
122 raw_spin_unlock(&b->lock);
123 kfree(e);
124 return false;
125 }
126
127 n->token = token;
128 n->cpu = smp_processor_id();
129 init_swait_queue_head(&n->wq);
130 hlist_add_head(&n->link, &b->list);
131 raw_spin_unlock(&b->lock);
132 return true;
133 }
134
135 /*
136 * kvm_async_pf_task_wait_schedule - Wait for pagefault to be handled
137 * @token: Token to identify the sleep node entry
138 *
139 * Invoked from the async pagefault handling code or from the VM exit page
140 * fault handler. In both cases RCU is watching.
141 */
142 void kvm_async_pf_task_wait_schedule(u32 token)
143 {
144 struct kvm_task_sleep_node n;
145 DECLARE_SWAITQUEUE(wait);
146
147 lockdep_assert_irqs_disabled();
148
149 if (!kvm_async_pf_queue_task(token, &n))
150 return;
151
152 for (;;) {
153 prepare_to_swait_exclusive(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
154 if (hlist_unhashed(&n.link))
155 break;
156
157 local_irq_enable();
158 schedule();
159 local_irq_disable();
160 }
161 finish_swait(&n.wq, &wait);
162 }
163 EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait_schedule);
164
165 static void apf_task_wake_one(struct kvm_task_sleep_node *n)
166 {
167 hlist_del_init(&n->link);
168 if (swq_has_sleeper(&n->wq))
169 swake_up_one(&n->wq);
170 }
171
172 static void apf_task_wake_all(void)
173 {
174 int i;
175
176 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
177 struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
178 struct kvm_task_sleep_node *n;
179 struct hlist_node *p, *next;
180
181 raw_spin_lock(&b->lock);
182 hlist_for_each_safe(p, next, &b->list) {
183 n = hlist_entry(p, typeof(*n), link);
184 if (n->cpu == smp_processor_id())
185 apf_task_wake_one(n);
186 }
187 raw_spin_unlock(&b->lock);
188 }
189 }
190
191 void kvm_async_pf_task_wake(u32 token)
192 {
193 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
194 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
195 struct kvm_task_sleep_node *n, *dummy = NULL;
196
197 if (token == ~0) {
198 apf_task_wake_all();
199 return;
200 }
201
202 again:
203 raw_spin_lock(&b->lock);
204 n = _find_apf_task(b, token);
205 if (!n) {
206 /*
207 * Async #PF not yet handled, add a dummy entry for the token.
208 * Allocating the token must be down outside of the raw lock
209 * as the allocator is preemptible on PREEMPT_RT kernels.
210 */
211 if (!dummy) {
212 raw_spin_unlock(&b->lock);
213 dummy = kzalloc(sizeof(*dummy), GFP_ATOMIC);
214
215 /*
216 * Continue looping on allocation failure, eventually
217 * the async #PF will be handled and allocating a new
218 * node will be unnecessary.
219 */
220 if (!dummy)
221 cpu_relax();
222
223 /*
224 * Recheck for async #PF completion before enqueueing
225 * the dummy token to avoid duplicate list entries.
226 */
227 goto again;
228 }
229 dummy->token = token;
230 dummy->cpu = smp_processor_id();
231 init_swait_queue_head(&dummy->wq);
232 hlist_add_head(&dummy->link, &b->list);
233 dummy = NULL;
234 } else {
235 apf_task_wake_one(n);
236 }
237 raw_spin_unlock(&b->lock);
238
239 /* A dummy token might be allocated and ultimately not used. */
240 kfree(dummy);
241 }
242 EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
243
244 noinstr u32 kvm_read_and_reset_apf_flags(void)
245 {
246 u32 flags = 0;
247
248 if (__this_cpu_read(async_pf_enabled)) {
249 flags = __this_cpu_read(apf_reason.flags);
250 __this_cpu_write(apf_reason.flags, 0);
251 }
252
253 return flags;
254 }
255 EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags);
256
257 noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
258 {
259 u32 flags = kvm_read_and_reset_apf_flags();
260 irqentry_state_t state;
261
262 if (!flags)
263 return false;
264
265 state = irqentry_enter(regs);
266 instrumentation_begin();
267
268 /*
269 * If the host managed to inject an async #PF into an interrupt
270 * disabled region, then die hard as this is not going to end well
271 * and the host side is seriously broken.
272 */
273 if (unlikely(!(regs->flags & X86_EFLAGS_IF)))
274 panic("Host injected async #PF in interrupt disabled region\n");
275
276 if (flags & KVM_PV_REASON_PAGE_NOT_PRESENT) {
277 if (unlikely(!(user_mode(regs))))
278 panic("Host injected async #PF in kernel mode\n");
279 /* Page is swapped out by the host. */
280 kvm_async_pf_task_wait_schedule(token);
281 } else {
282 WARN_ONCE(1, "Unexpected async PF flags: %x\n", flags);
283 }
284
285 instrumentation_end();
286 irqentry_exit(regs, state);
287 return true;
288 }
289
290 DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_asyncpf_interrupt)
291 {
292 struct pt_regs *old_regs = set_irq_regs(regs);
293 u32 token;
294
295 apic_eoi();
296
297 inc_irq_stat(irq_hv_callback_count);
298
299 if (__this_cpu_read(async_pf_enabled)) {
300 token = __this_cpu_read(apf_reason.token);
301 kvm_async_pf_task_wake(token);
302 __this_cpu_write(apf_reason.token, 0);
303 wrmsrl(MSR_KVM_ASYNC_PF_ACK, 1);
304 }
305
306 set_irq_regs(old_regs);
307 }
308
309 static void __init paravirt_ops_setup(void)
310 {
311 pv_info.name = "KVM";
312
313 if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
314 pv_ops.cpu.io_delay = kvm_io_delay;
315
316 #ifdef CONFIG_X86_IO_APIC
317 no_timer_check = 1;
318 #endif
319 }
320
321 static void kvm_register_steal_time(void)
322 {
323 int cpu = smp_processor_id();
324 struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
325
326 if (!has_steal_clock)
327 return;
328
329 wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
330 pr_debug("stealtime: cpu %d, msr %llx\n", cpu,
331 (unsigned long long) slow_virt_to_phys(st));
332 }
333
334 static DEFINE_PER_CPU_DECRYPTED(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
335
336 static notrace __maybe_unused void kvm_guest_apic_eoi_write(void)
337 {
338 /**
339 * This relies on __test_and_clear_bit to modify the memory
340 * in a way that is atomic with respect to the local CPU.
341 * The hypervisor only accesses this memory from the local CPU so
342 * there's no need for lock or memory barriers.
343 * An optimization barrier is implied in apic write.
344 */
345 if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi)))
346 return;
347 apic_native_eoi();
348 }
349
350 static void kvm_guest_cpu_init(void)
351 {
352 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
353 u64 pa;
354
355 WARN_ON_ONCE(!static_branch_likely(&kvm_async_pf_enabled));
356
357 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
358 pa |= KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT;
359
360 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT))
361 pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;
362
363 wrmsrl(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);
364
365 wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
366 __this_cpu_write(async_pf_enabled, true);
367 pr_debug("setup async PF for cpu %d\n", smp_processor_id());
368 }
369
370 if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
371 unsigned long pa;
372
373 /* Size alignment is implied but just to make it explicit. */
374 BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
375 __this_cpu_write(kvm_apic_eoi, 0);
376 pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi))
377 | KVM_MSR_ENABLED;
378 wrmsrl(MSR_KVM_PV_EOI_EN, pa);
379 }
380
381 if (has_steal_clock)
382 kvm_register_steal_time();
383 }
384
385 static void kvm_pv_disable_apf(void)
386 {
387 if (!__this_cpu_read(async_pf_enabled))
388 return;
389
390 wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
391 __this_cpu_write(async_pf_enabled, false);
392
393 pr_debug("disable async PF for cpu %d\n", smp_processor_id());
394 }
395
396 static void kvm_disable_steal_time(void)
397 {
398 if (!has_steal_clock)
399 return;
400
401 wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
402 }
403
404 static u64 kvm_steal_clock(int cpu)
405 {
406 u64 steal;
407 struct kvm_steal_time *src;
408 int version;
409
410 src = &per_cpu(steal_time, cpu);
411 do {
412 version = src->version;
413 virt_rmb();
414 steal = src->steal;
415 virt_rmb();
416 } while ((version & 1) || (version != src->version));
417
418 return steal;
419 }
420
421 static inline void __set_percpu_decrypted(void *ptr, unsigned long size)
422 {
423 early_set_memory_decrypted((unsigned long) ptr, size);
424 }
425
426 /*
427 * Iterate through all possible CPUs and map the memory region pointed
428 * by apf_reason, steal_time and kvm_apic_eoi as decrypted at once.
429 *
430 * Note: we iterate through all possible CPUs to ensure that CPUs
431 * hotplugged will have their per-cpu variable already mapped as
432 * decrypted.
433 */
434 static void __init sev_map_percpu_data(void)
435 {
436 int cpu;
437
438 if (cc_vendor != CC_VENDOR_AMD ||
439 !cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
440 return;
441
442 for_each_possible_cpu(cpu) {
443 __set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason));
444 __set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time));
445 __set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi));
446 }
447 }
448
449 static void kvm_guest_cpu_offline(bool shutdown)
450 {
451 kvm_disable_steal_time();
452 if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
453 wrmsrl(MSR_KVM_PV_EOI_EN, 0);
454 if (kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL))
455 wrmsrl(MSR_KVM_MIGRATION_CONTROL, 0);
456 kvm_pv_disable_apf();
457 if (!shutdown)
458 apf_task_wake_all();
459 kvmclock_disable();
460 }
461
462 static int kvm_cpu_online(unsigned int cpu)
463 {
464 unsigned long flags;
465
466 local_irq_save(flags);
467 kvm_guest_cpu_init();
468 local_irq_restore(flags);
469 return 0;
470 }
471
472 #ifdef CONFIG_SMP
473
474 static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask);
475
476 static bool pv_tlb_flush_supported(void)
477 {
478 return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
479 !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
480 kvm_para_has_feature(KVM_FEATURE_STEAL_TIME) &&
481 !boot_cpu_has(X86_FEATURE_MWAIT) &&
482 (num_possible_cpus() != 1));
483 }
484
485 static bool pv_ipi_supported(void)
486 {
487 return (kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI) &&
488 (num_possible_cpus() != 1));
489 }
490
491 static bool pv_sched_yield_supported(void)
492 {
493 return (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) &&
494 !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
495 kvm_para_has_feature(KVM_FEATURE_STEAL_TIME) &&
496 !boot_cpu_has(X86_FEATURE_MWAIT) &&
497 (num_possible_cpus() != 1));
498 }
499
500 #define KVM_IPI_CLUSTER_SIZE (2 * BITS_PER_LONG)
501
502 static void __send_ipi_mask(const struct cpumask *mask, int vector)
503 {
504 unsigned long flags;
505 int cpu, min = 0, max = 0;
506 #ifdef CONFIG_X86_64
507 __uint128_t ipi_bitmap = 0;
508 #else
509 u64 ipi_bitmap = 0;
510 #endif
511 u32 apic_id, icr;
512 long ret;
513
514 if (cpumask_empty(mask))
515 return;
516
517 local_irq_save(flags);
518
519 switch (vector) {
520 default:
521 icr = APIC_DM_FIXED | vector;
522 break;
523 case NMI_VECTOR:
524 icr = APIC_DM_NMI;
525 break;
526 }
527
528 for_each_cpu(cpu, mask) {
529 apic_id = per_cpu(x86_cpu_to_apicid, cpu);
530 if (!ipi_bitmap) {
531 min = max = apic_id;
532 } else if (apic_id < min && max - apic_id < KVM_IPI_CLUSTER_SIZE) {
533 ipi_bitmap <<= min - apic_id;
534 min = apic_id;
535 } else if (apic_id > min && apic_id < min + KVM_IPI_CLUSTER_SIZE) {
536 max = apic_id < max ? max : apic_id;
537 } else {
538 ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
539 (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
540 WARN_ONCE(ret < 0, "kvm-guest: failed to send PV IPI: %ld",
541 ret);
542 min = max = apic_id;
543 ipi_bitmap = 0;
544 }
545 __set_bit(apic_id - min, (unsigned long *)&ipi_bitmap);
546 }
547
548 if (ipi_bitmap) {
549 ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
550 (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
551 WARN_ONCE(ret < 0, "kvm-guest: failed to send PV IPI: %ld",
552 ret);
553 }
554
555 local_irq_restore(flags);
556 }
557
558 static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
559 {
560 __send_ipi_mask(mask, vector);
561 }
562
563 static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
564 {
565 unsigned int this_cpu = smp_processor_id();
566 struct cpumask *new_mask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
567 const struct cpumask *local_mask;
568
569 cpumask_copy(new_mask, mask);
570 cpumask_clear_cpu(this_cpu, new_mask);
571 local_mask = new_mask;
572 __send_ipi_mask(local_mask, vector);
573 }
574
575 static int __init setup_efi_kvm_sev_migration(void)
576 {
577 efi_char16_t efi_sev_live_migration_enabled[] = L"SevLiveMigrationEnabled";
578 efi_guid_t efi_variable_guid = AMD_SEV_MEM_ENCRYPT_GUID;
579 efi_status_t status;
580 unsigned long size;
581 bool enabled;
582
583 if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) ||
584 !kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL))
585 return 0;
586
587 if (!efi_enabled(EFI_BOOT))
588 return 0;
589
590 if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
591 pr_info("%s : EFI runtime services are not enabled\n", __func__);
592 return 0;
593 }
594
595 size = sizeof(enabled);
596
597 /* Get variable contents into buffer */
598 status = efi.get_variable(efi_sev_live_migration_enabled,
599 &efi_variable_guid, NULL, &size, &enabled);
600
601 if (status == EFI_NOT_FOUND) {
602 pr_info("%s : EFI live migration variable not found\n", __func__);
603 return 0;
604 }
605
606 if (status != EFI_SUCCESS) {
607 pr_info("%s : EFI variable retrieval failed\n", __func__);
608 return 0;
609 }
610
611 if (enabled == 0) {
612 pr_info("%s: live migration disabled in EFI\n", __func__);
613 return 0;
614 }
615
616 pr_info("%s : live migration enabled in EFI\n", __func__);
617 wrmsrl(MSR_KVM_MIGRATION_CONTROL, KVM_MIGRATION_READY);
618
619 return 1;
620 }
621
622 late_initcall(setup_efi_kvm_sev_migration);
623
624 /*
625 * Set the IPI entry points
626 */
627 static __init void kvm_setup_pv_ipi(void)
628 {
629 apic_update_callback(send_IPI_mask, kvm_send_ipi_mask);
630 apic_update_callback(send_IPI_mask_allbutself, kvm_send_ipi_mask_allbutself);
631 pr_info("setup PV IPIs\n");
632 }
633
634 static void kvm_smp_send_call_func_ipi(const struct cpumask *mask)
635 {
636 int cpu;
637
638 native_send_call_func_ipi(mask);
639
640 /* Make sure other vCPUs get a chance to run if they need to. */
641 for_each_cpu(cpu, mask) {
642 if (!idle_cpu(cpu) && vcpu_is_preempted(cpu)) {
643 kvm_hypercall1(KVM_HC_SCHED_YIELD, per_cpu(x86_cpu_to_apicid, cpu));
644 break;
645 }
646 }
647 }
648
649 static void kvm_flush_tlb_multi(const struct cpumask *cpumask,
650 const struct flush_tlb_info *info)
651 {
652 u8 state;
653 int cpu;
654 struct kvm_steal_time *src;
655 struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
656
657 cpumask_copy(flushmask, cpumask);
658 /*
659 * We have to call flush only on online vCPUs. And
660 * queue flush_on_enter for pre-empted vCPUs
661 */
662 for_each_cpu(cpu, flushmask) {
663 /*
664 * The local vCPU is never preempted, so we do not explicitly
665 * skip check for local vCPU - it will never be cleared from
666 * flushmask.
667 */
668 src = &per_cpu(steal_time, cpu);
669 state = READ_ONCE(src->preempted);
670 if ((state & KVM_VCPU_PREEMPTED)) {
671 if (try_cmpxchg(&src->preempted, &state,
672 state | KVM_VCPU_FLUSH_TLB))
673 __cpumask_clear_cpu(cpu, flushmask);
674 }
675 }
676
677 native_flush_tlb_multi(flushmask, info);
678 }
679
680 static __init int kvm_alloc_cpumask(void)
681 {
682 int cpu;
683
684 if (!kvm_para_available() || nopv)
685 return 0;
686
687 if (pv_tlb_flush_supported() || pv_ipi_supported())
688 for_each_possible_cpu(cpu) {
689 zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu),
690 GFP_KERNEL, cpu_to_node(cpu));
691 }
692
693 return 0;
694 }
695 arch_initcall(kvm_alloc_cpumask);
696
697 static void __init kvm_smp_prepare_boot_cpu(void)
698 {
699 /*
700 * Map the per-cpu variables as decrypted before kvm_guest_cpu_init()
701 * shares the guest physical address with the hypervisor.
702 */
703 sev_map_percpu_data();
704
705 kvm_guest_cpu_init();
706 native_smp_prepare_boot_cpu();
707 kvm_spinlock_init();
708 }
709
710 static int kvm_cpu_down_prepare(unsigned int cpu)
711 {
712 unsigned long flags;
713
714 local_irq_save(flags);
715 kvm_guest_cpu_offline(false);
716 local_irq_restore(flags);
717 return 0;
718 }
719
720 #endif
721
722 static int kvm_suspend(void)
723 {
724 u64 val = 0;
725
726 kvm_guest_cpu_offline(false);
727
728 #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
729 if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
730 rdmsrl(MSR_KVM_POLL_CONTROL, val);
731 has_guest_poll = !(val & 1);
732 #endif
733 return 0;
734 }
735
736 static void kvm_resume(void)
737 {
738 kvm_cpu_online(raw_smp_processor_id());
739
740 #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
741 if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL) && has_guest_poll)
742 wrmsrl(MSR_KVM_POLL_CONTROL, 0);
743 #endif
744 }
745
746 static struct syscore_ops kvm_syscore_ops = {
747 .suspend = kvm_suspend,
748 .resume = kvm_resume,
749 };
750
751 static void kvm_pv_guest_cpu_reboot(void *unused)
752 {
753 kvm_guest_cpu_offline(true);
754 }
755
756 static int kvm_pv_reboot_notify(struct notifier_block *nb,
757 unsigned long code, void *unused)
758 {
759 if (code == SYS_RESTART)
760 on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
761 return NOTIFY_DONE;
762 }
763
764 static struct notifier_block kvm_pv_reboot_nb = {
765 .notifier_call = kvm_pv_reboot_notify,
766 };
767
768 /*
769 * After a PV feature is registered, the host will keep writing to the
770 * registered memory location. If the guest happens to shutdown, this memory
771 * won't be valid. In cases like kexec, in which you install a new kernel, this
772 * means a random memory location will be kept being written.
773 */
774 #ifdef CONFIG_CRASH_DUMP
775 static void kvm_crash_shutdown(struct pt_regs *regs)
776 {
777 kvm_guest_cpu_offline(true);
778 native_machine_crash_shutdown(regs);
779 }
780 #endif
781
782 #if defined(CONFIG_X86_32) || !defined(CONFIG_SMP)
783 bool __kvm_vcpu_is_preempted(long cpu);
784
785 __visible bool __kvm_vcpu_is_preempted(long cpu)
786 {
787 struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
788
789 return !!(src->preempted & KVM_VCPU_PREEMPTED);
790 }
791 PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
792
793 #else
794
795 #include <asm/asm-offsets.h>
796
797 extern bool __raw_callee_save___kvm_vcpu_is_preempted(long);
798
799 /*
800 * Hand-optimize version for x86-64 to avoid 8 64-bit register saving and
801 * restoring to/from the stack.
802 */
803 #define PV_VCPU_PREEMPTED_ASM \
804 "movq __per_cpu_offset(,%rdi,8), %rax\n\t" \
805 "cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax)\n\t" \
806 "setne %al\n\t"
807
808 DEFINE_ASM_FUNC(__raw_callee_save___kvm_vcpu_is_preempted,
809 PV_VCPU_PREEMPTED_ASM, .text);
810 #endif
811
812 static void __init kvm_guest_init(void)
813 {
814 int i;
815
816 paravirt_ops_setup();
817 register_reboot_notifier(&kvm_pv_reboot_nb);
818 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
819 raw_spin_lock_init(&async_pf_sleepers[i].lock);
820
821 if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
822 has_steal_clock = 1;
823 static_call_update(pv_steal_clock, kvm_steal_clock);
824
825 pv_ops.lock.vcpu_is_preempted =
826 PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
827 }
828
829 if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
830 apic_update_callback(eoi, kvm_guest_apic_eoi_write);
831
832 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
833 static_branch_enable(&kvm_async_pf_enabled);
834 sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_kvm_asyncpf_interrupt);
835 }
836
837 #ifdef CONFIG_SMP
838 if (pv_tlb_flush_supported()) {
839 pv_ops.mmu.flush_tlb_multi = kvm_flush_tlb_multi;
840 pv_ops.mmu.tlb_remove_table = tlb_remove_table;
841 pr_info("KVM setup pv remote TLB flush\n");
842 }
843
844 smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
845 if (pv_sched_yield_supported()) {
846 smp_ops.send_call_func_ipi = kvm_smp_send_call_func_ipi;
847 pr_info("setup PV sched yield\n");
848 }
849 if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",
850 kvm_cpu_online, kvm_cpu_down_prepare) < 0)
851 pr_err("failed to install cpu hotplug callbacks\n");
852 #else
853 sev_map_percpu_data();
854 kvm_guest_cpu_init();
855 #endif
856
857 #ifdef CONFIG_CRASH_DUMP
858 machine_ops.crash_shutdown = kvm_crash_shutdown;
859 #endif
860
861 register_syscore_ops(&kvm_syscore_ops);
862
863 /*
864 * Hard lockup detection is enabled by default. Disable it, as guests
865 * can get false positives too easily, for example if the host is
866 * overcommitted.
867 */
868 hardlockup_detector_disable();
869 }
870
871 static noinline uint32_t __kvm_cpuid_base(void)
872 {
873 if (boot_cpu_data.cpuid_level < 0)
874 return 0; /* So we don't blow up on old processors */
875
876 if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
877 return hypervisor_cpuid_base(KVM_SIGNATURE, 0);
878
879 return 0;
880 }
881
882 static inline uint32_t kvm_cpuid_base(void)
883 {
884 static int kvm_cpuid_base = -1;
885
886 if (kvm_cpuid_base == -1)
887 kvm_cpuid_base = __kvm_cpuid_base();
888
889 return kvm_cpuid_base;
890 }
891
892 bool kvm_para_available(void)
893 {
894 return kvm_cpuid_base() != 0;
895 }
896 EXPORT_SYMBOL_GPL(kvm_para_available);
897
898 unsigned int kvm_arch_para_features(void)
899 {
900 return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
901 }
902
903 unsigned int kvm_arch_para_hints(void)
904 {
905 return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES);
906 }
907 EXPORT_SYMBOL_GPL(kvm_arch_para_hints);
908
909 static uint32_t __init kvm_detect(void)
910 {
911 return kvm_cpuid_base();
912 }
913
914 static void __init kvm_apic_init(void)
915 {
916 #ifdef CONFIG_SMP
917 if (pv_ipi_supported())
918 kvm_setup_pv_ipi();
919 #endif
920 }
921
922 static bool __init kvm_msi_ext_dest_id(void)
923 {
924 return kvm_para_has_feature(KVM_FEATURE_MSI_EXT_DEST_ID);
925 }
926
927 static void kvm_sev_hc_page_enc_status(unsigned long pfn, int npages, bool enc)
928 {
929 kvm_sev_hypercall3(KVM_HC_MAP_GPA_RANGE, pfn << PAGE_SHIFT, npages,
930 KVM_MAP_GPA_RANGE_ENC_STAT(enc) | KVM_MAP_GPA_RANGE_PAGE_SZ_4K);
931 }
932
933 static void __init kvm_init_platform(void)
934 {
935 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) &&
936 kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL)) {
937 unsigned long nr_pages;
938 int i;
939
940 pv_ops.mmu.notify_page_enc_status_changed =
941 kvm_sev_hc_page_enc_status;
942
943 /*
944 * Reset the host's shared pages list related to kernel
945 * specific page encryption status settings before we load a
946 * new kernel by kexec. Reset the page encryption status
947 * during early boot instead of just before kexec to avoid SMP
948 * races during kvm_pv_guest_cpu_reboot().
949 * NOTE: We cannot reset the complete shared pages list
950 * here as we need to retain the UEFI/OVMF firmware
951 * specific settings.
952 */
953
954 for (i = 0; i < e820_table->nr_entries; i++) {
955 struct e820_entry *entry = &e820_table->entries[i];
956
957 if (entry->type != E820_TYPE_RAM)
958 continue;
959
960 nr_pages = DIV_ROUND_UP(entry->size, PAGE_SIZE);
961
962 kvm_sev_hypercall3(KVM_HC_MAP_GPA_RANGE, entry->addr,
963 nr_pages,
964 KVM_MAP_GPA_RANGE_ENCRYPTED | KVM_MAP_GPA_RANGE_PAGE_SZ_4K);
965 }
966
967 /*
968 * Ensure that _bss_decrypted section is marked as decrypted in the
969 * shared pages list.
970 */
971 early_set_mem_enc_dec_hypercall((unsigned long)__start_bss_decrypted,
972 __end_bss_decrypted - __start_bss_decrypted, 0);
973
974 /*
975 * If not booted using EFI, enable Live migration support.
976 */
977 if (!efi_enabled(EFI_BOOT))
978 wrmsrl(MSR_KVM_MIGRATION_CONTROL,
979 KVM_MIGRATION_READY);
980 }
981 kvmclock_init();
982 x86_platform.apic_post_init = kvm_apic_init;
983 }
984
985 #if defined(CONFIG_AMD_MEM_ENCRYPT)
986 static void kvm_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
987 {
988 /* RAX and CPL are already in the GHCB */
989 ghcb_set_rbx(ghcb, regs->bx);
990 ghcb_set_rcx(ghcb, regs->cx);
991 ghcb_set_rdx(ghcb, regs->dx);
992 ghcb_set_rsi(ghcb, regs->si);
993 }
994
995 static bool kvm_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
996 {
997 /* No checking of the return state needed */
998 return true;
999 }
1000 #endif
1001
1002 const __initconst struct hypervisor_x86 x86_hyper_kvm = {
1003 .name = "KVM",
1004 .detect = kvm_detect,
1005 .type = X86_HYPER_KVM,
1006 .init.guest_late_init = kvm_guest_init,
1007 .init.x2apic_available = kvm_para_available,
1008 .init.msi_ext_dest_id = kvm_msi_ext_dest_id,
1009 .init.init_platform = kvm_init_platform,
1010 #if defined(CONFIG_AMD_MEM_ENCRYPT)
1011 .runtime.sev_es_hcall_prepare = kvm_sev_es_hcall_prepare,
1012 .runtime.sev_es_hcall_finish = kvm_sev_es_hcall_finish,
1013 #endif
1014 };
1015
1016 static __init int activate_jump_labels(void)
1017 {
1018 if (has_steal_clock) {
1019 static_key_slow_inc(¶virt_steal_enabled);
1020 if (steal_acc)
1021 static_key_slow_inc(¶virt_steal_rq_enabled);
1022 }
1023
1024 return 0;
1025 }
1026 arch_initcall(activate_jump_labels);
1027
1028 #ifdef CONFIG_PARAVIRT_SPINLOCKS
1029
1030 /* Kick a cpu by its apicid. Used to wake up a halted vcpu */
1031 static void kvm_kick_cpu(int cpu)
1032 {
1033 unsigned long flags = 0;
1034 u32 apicid;
1035
1036 apicid = per_cpu(x86_cpu_to_apicid, cpu);
1037 kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
1038 }
1039
1040 #include <asm/qspinlock.h>
1041
1042 static void kvm_wait(u8 *ptr, u8 val)
1043 {
1044 if (in_nmi())
1045 return;
1046
1047 /*
1048 * halt until it's our turn and kicked. Note that we do safe halt
1049 * for irq enabled case to avoid hang when lock info is overwritten
1050 * in irq spinlock slowpath and no spurious interrupt occur to save us.
1051 */
1052 if (irqs_disabled()) {
1053 if (READ_ONCE(*ptr) == val)
1054 halt();
1055 } else {
1056 local_irq_disable();
1057
1058 /* safe_halt() will enable IRQ */
1059 if (READ_ONCE(*ptr) == val)
1060 safe_halt();
1061 else
1062 local_irq_enable();
1063 }
1064 }
1065
1066 /*
1067 * Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
1068 */
1069 void __init kvm_spinlock_init(void)
1070 {
1071 /*
1072 * In case host doesn't support KVM_FEATURE_PV_UNHALT there is still an
1073 * advantage of keeping virt_spin_lock_key enabled: virt_spin_lock() is
1074 * preferred over native qspinlock when vCPU is preempted.
1075 */
1076 if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT)) {
1077 pr_info("PV spinlocks disabled, no host support\n");
1078 return;
1079 }
1080
1081 /*
1082 * Disable PV spinlocks and use native qspinlock when dedicated pCPUs
1083 * are available.
1084 */
1085 if (kvm_para_has_hint(KVM_HINTS_REALTIME)) {
1086 pr_info("PV spinlocks disabled with KVM_HINTS_REALTIME hints\n");
1087 goto out;
1088 }
1089
1090 if (num_possible_cpus() == 1) {
1091 pr_info("PV spinlocks disabled, single CPU\n");
1092 goto out;
1093 }
1094
1095 if (nopvspin) {
1096 pr_info("PV spinlocks disabled, forced by \"nopvspin\" parameter\n");
1097 goto out;
1098 }
1099
1100 pr_info("PV spinlocks enabled\n");
1101
1102 __pv_init_lock_hash();
1103 pv_ops.lock.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
1104 pv_ops.lock.queued_spin_unlock =
1105 PV_CALLEE_SAVE(__pv_queued_spin_unlock);
1106 pv_ops.lock.wait = kvm_wait;
1107 pv_ops.lock.kick = kvm_kick_cpu;
1108
1109 /*
1110 * When PV spinlock is enabled which is preferred over
1111 * virt_spin_lock(), virt_spin_lock_key's value is meaningless.
1112 * Just disable it anyway.
1113 */
1114 out:
1115 static_branch_disable(&virt_spin_lock_key);
1116 }
1117
1118 #endif /* CONFIG_PARAVIRT_SPINLOCKS */
1119
1120 #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
1121
1122 static void kvm_disable_host_haltpoll(void *i)
1123 {
1124 wrmsrl(MSR_KVM_POLL_CONTROL, 0);
1125 }
1126
1127 static void kvm_enable_host_haltpoll(void *i)
1128 {
1129 wrmsrl(MSR_KVM_POLL_CONTROL, 1);
1130 }
1131
1132 void arch_haltpoll_enable(unsigned int cpu)
1133 {
1134 if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
1135 pr_err_once("host does not support poll control\n");
1136 pr_err_once("host upgrade recommended\n");
1137 return;
1138 }
1139
1140 /* Enable guest halt poll disables host halt poll */
1141 smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
1142 }
1143 EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
1144
1145 void arch_haltpoll_disable(unsigned int cpu)
1146 {
1147 if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
1148 return;
1149
1150 /* Disable guest halt poll enables host halt poll */
1151 smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
1152 }
1153 EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
1154 #endif
1155
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