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TOMOYO Linux Cross Reference
Linux/arch/x86/hyperv/ivm.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * Hyper-V Isolation VM interface with paravisor and hypervisor
  4  *
  5  * Author:
  6  *  Tianyu Lan <Tianyu.Lan@microsoft.com>
  7  */
  8 
  9 #include <linux/bitfield.h>
 10 #include <linux/hyperv.h>
 11 #include <linux/types.h>
 12 #include <linux/slab.h>
 13 #include <asm/svm.h>
 14 #include <asm/sev.h>
 15 #include <asm/io.h>
 16 #include <asm/coco.h>
 17 #include <asm/mem_encrypt.h>
 18 #include <asm/set_memory.h>
 19 #include <asm/mshyperv.h>
 20 #include <asm/hypervisor.h>
 21 #include <asm/mtrr.h>
 22 #include <asm/io_apic.h>
 23 #include <asm/realmode.h>
 24 #include <asm/e820/api.h>
 25 #include <asm/desc.h>
 26 #include <uapi/asm/vmx.h>
 27 
 28 #ifdef CONFIG_AMD_MEM_ENCRYPT
 29 
 30 #define GHCB_USAGE_HYPERV_CALL  1
 31 
 32 union hv_ghcb {
 33         struct ghcb ghcb;
 34         struct {
 35                 u64 hypercalldata[509];
 36                 u64 outputgpa;
 37                 union {
 38                         union {
 39                                 struct {
 40                                         u32 callcode        : 16;
 41                                         u32 isfast          : 1;
 42                                         u32 reserved1       : 14;
 43                                         u32 isnested        : 1;
 44                                         u32 countofelements : 12;
 45                                         u32 reserved2       : 4;
 46                                         u32 repstartindex   : 12;
 47                                         u32 reserved3       : 4;
 48                                 };
 49                                 u64 asuint64;
 50                         } hypercallinput;
 51                         union {
 52                                 struct {
 53                                         u16 callstatus;
 54                                         u16 reserved1;
 55                                         u32 elementsprocessed : 12;
 56                                         u32 reserved2         : 20;
 57                                 };
 58                                 u64 asunit64;
 59                         } hypercalloutput;
 60                 };
 61                 u64 reserved2;
 62         } hypercall;
 63 } __packed __aligned(HV_HYP_PAGE_SIZE);
 64 
 65 /* Only used in an SNP VM with the paravisor */
 66 static u16 hv_ghcb_version __ro_after_init;
 67 
 68 /* Functions only used in an SNP VM with the paravisor go here. */
 69 u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
 70 {
 71         union hv_ghcb *hv_ghcb;
 72         void **ghcb_base;
 73         unsigned long flags;
 74         u64 status;
 75 
 76         if (!hv_ghcb_pg)
 77                 return -EFAULT;
 78 
 79         WARN_ON(in_nmi());
 80 
 81         local_irq_save(flags);
 82         ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
 83         hv_ghcb = (union hv_ghcb *)*ghcb_base;
 84         if (!hv_ghcb) {
 85                 local_irq_restore(flags);
 86                 return -EFAULT;
 87         }
 88 
 89         hv_ghcb->ghcb.protocol_version = GHCB_PROTOCOL_MAX;
 90         hv_ghcb->ghcb.ghcb_usage = GHCB_USAGE_HYPERV_CALL;
 91 
 92         hv_ghcb->hypercall.outputgpa = (u64)output;
 93         hv_ghcb->hypercall.hypercallinput.asuint64 = 0;
 94         hv_ghcb->hypercall.hypercallinput.callcode = control;
 95 
 96         if (input_size)
 97                 memcpy(hv_ghcb->hypercall.hypercalldata, input, input_size);
 98 
 99         VMGEXIT();
100 
101         hv_ghcb->ghcb.ghcb_usage = 0xffffffff;
102         memset(hv_ghcb->ghcb.save.valid_bitmap, 0,
103                sizeof(hv_ghcb->ghcb.save.valid_bitmap));
104 
105         status = hv_ghcb->hypercall.hypercalloutput.callstatus;
106 
107         local_irq_restore(flags);
108 
109         return status;
110 }
111 
112 static inline u64 rd_ghcb_msr(void)
113 {
114         return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
115 }
116 
117 static inline void wr_ghcb_msr(u64 val)
118 {
119         native_wrmsrl(MSR_AMD64_SEV_ES_GHCB, val);
120 }
121 
122 static enum es_result hv_ghcb_hv_call(struct ghcb *ghcb, u64 exit_code,
123                                    u64 exit_info_1, u64 exit_info_2)
124 {
125         /* Fill in protocol and format specifiers */
126         ghcb->protocol_version = hv_ghcb_version;
127         ghcb->ghcb_usage       = GHCB_DEFAULT_USAGE;
128 
129         ghcb_set_sw_exit_code(ghcb, exit_code);
130         ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
131         ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
132 
133         VMGEXIT();
134 
135         if (ghcb->save.sw_exit_info_1 & GENMASK_ULL(31, 0))
136                 return ES_VMM_ERROR;
137         else
138                 return ES_OK;
139 }
140 
141 void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason)
142 {
143         u64 val = GHCB_MSR_TERM_REQ;
144 
145         /* Tell the hypervisor what went wrong. */
146         val |= GHCB_SEV_TERM_REASON(set, reason);
147 
148         /* Request Guest Termination from Hypervisor */
149         wr_ghcb_msr(val);
150         VMGEXIT();
151 
152         while (true)
153                 asm volatile("hlt\n" : : : "memory");
154 }
155 
156 bool hv_ghcb_negotiate_protocol(void)
157 {
158         u64 ghcb_gpa;
159         u64 val;
160 
161         /* Save ghcb page gpa. */
162         ghcb_gpa = rd_ghcb_msr();
163 
164         /* Do the GHCB protocol version negotiation */
165         wr_ghcb_msr(GHCB_MSR_SEV_INFO_REQ);
166         VMGEXIT();
167         val = rd_ghcb_msr();
168 
169         if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP)
170                 return false;
171 
172         if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN ||
173             GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX)
174                 return false;
175 
176         hv_ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val),
177                              GHCB_PROTOCOL_MAX);
178 
179         /* Write ghcb page back after negotiating protocol. */
180         wr_ghcb_msr(ghcb_gpa);
181         VMGEXIT();
182 
183         return true;
184 }
185 
186 static void hv_ghcb_msr_write(u64 msr, u64 value)
187 {
188         union hv_ghcb *hv_ghcb;
189         void **ghcb_base;
190         unsigned long flags;
191 
192         if (!hv_ghcb_pg)
193                 return;
194 
195         WARN_ON(in_nmi());
196 
197         local_irq_save(flags);
198         ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
199         hv_ghcb = (union hv_ghcb *)*ghcb_base;
200         if (!hv_ghcb) {
201                 local_irq_restore(flags);
202                 return;
203         }
204 
205         ghcb_set_rcx(&hv_ghcb->ghcb, msr);
206         ghcb_set_rax(&hv_ghcb->ghcb, lower_32_bits(value));
207         ghcb_set_rdx(&hv_ghcb->ghcb, upper_32_bits(value));
208 
209         if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 1, 0))
210                 pr_warn("Fail to write msr via ghcb %llx.\n", msr);
211 
212         local_irq_restore(flags);
213 }
214 
215 static void hv_ghcb_msr_read(u64 msr, u64 *value)
216 {
217         union hv_ghcb *hv_ghcb;
218         void **ghcb_base;
219         unsigned long flags;
220 
221         /* Check size of union hv_ghcb here. */
222         BUILD_BUG_ON(sizeof(union hv_ghcb) != HV_HYP_PAGE_SIZE);
223 
224         if (!hv_ghcb_pg)
225                 return;
226 
227         WARN_ON(in_nmi());
228 
229         local_irq_save(flags);
230         ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
231         hv_ghcb = (union hv_ghcb *)*ghcb_base;
232         if (!hv_ghcb) {
233                 local_irq_restore(flags);
234                 return;
235         }
236 
237         ghcb_set_rcx(&hv_ghcb->ghcb, msr);
238         if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 0, 0))
239                 pr_warn("Fail to read msr via ghcb %llx.\n", msr);
240         else
241                 *value = (u64)lower_32_bits(hv_ghcb->ghcb.save.rax)
242                         | ((u64)lower_32_bits(hv_ghcb->ghcb.save.rdx) << 32);
243         local_irq_restore(flags);
244 }
245 
246 /* Only used in a fully enlightened SNP VM, i.e. without the paravisor */
247 static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
248 static u8 ap_start_stack[PAGE_SIZE] __aligned(PAGE_SIZE);
249 static DEFINE_PER_CPU(struct sev_es_save_area *, hv_sev_vmsa);
250 
251 /* Functions only used in an SNP VM without the paravisor go here. */
252 
253 #define hv_populate_vmcb_seg(seg, gdtr_base)                    \
254 do {                                                            \
255         if (seg.selector) {                                     \
256                 seg.base = 0;                                   \
257                 seg.limit = HV_AP_SEGMENT_LIMIT;                \
258                 seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5);    \
259                 seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \
260         }                                                       \
261 } while (0)                                                     \
262 
263 static int snp_set_vmsa(void *va, bool vmsa)
264 {
265         u64 attrs;
266 
267         /*
268          * Running at VMPL0 allows the kernel to change the VMSA bit for a page
269          * using the RMPADJUST instruction. However, for the instruction to
270          * succeed it must target the permissions of a lesser privileged
271          * (higher numbered) VMPL level, so use VMPL1 (refer to the RMPADJUST
272          * instruction in the AMD64 APM Volume 3).
273          */
274         attrs = 1;
275         if (vmsa)
276                 attrs |= RMPADJUST_VMSA_PAGE_BIT;
277 
278         return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
279 }
280 
281 static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
282 {
283         int err;
284 
285         err = snp_set_vmsa(vmsa, false);
286         if (err)
287                 pr_err("clear VMSA page failed (%u), leaking page\n", err);
288         else
289                 free_page((unsigned long)vmsa);
290 }
291 
292 int hv_snp_boot_ap(u32 cpu, unsigned long start_ip)
293 {
294         struct sev_es_save_area *vmsa = (struct sev_es_save_area *)
295                 __get_free_page(GFP_KERNEL | __GFP_ZERO);
296         struct sev_es_save_area *cur_vmsa;
297         struct desc_ptr gdtr;
298         u64 ret, retry = 5;
299         struct hv_enable_vp_vtl *start_vp_input;
300         unsigned long flags;
301 
302         if (!vmsa)
303                 return -ENOMEM;
304 
305         native_store_gdt(&gdtr);
306 
307         vmsa->gdtr.base = gdtr.address;
308         vmsa->gdtr.limit = gdtr.size;
309 
310         asm volatile("movl %%es, %%eax;" : "=a" (vmsa->es.selector));
311         hv_populate_vmcb_seg(vmsa->es, vmsa->gdtr.base);
312 
313         asm volatile("movl %%cs, %%eax;" : "=a" (vmsa->cs.selector));
314         hv_populate_vmcb_seg(vmsa->cs, vmsa->gdtr.base);
315 
316         asm volatile("movl %%ss, %%eax;" : "=a" (vmsa->ss.selector));
317         hv_populate_vmcb_seg(vmsa->ss, vmsa->gdtr.base);
318 
319         asm volatile("movl %%ds, %%eax;" : "=a" (vmsa->ds.selector));
320         hv_populate_vmcb_seg(vmsa->ds, vmsa->gdtr.base);
321 
322         vmsa->efer = native_read_msr(MSR_EFER);
323 
324         asm volatile("movq %%cr4, %%rax;" : "=a" (vmsa->cr4));
325         asm volatile("movq %%cr3, %%rax;" : "=a" (vmsa->cr3));
326         asm volatile("movq %%cr0, %%rax;" : "=a" (vmsa->cr0));
327 
328         vmsa->xcr0 = 1;
329         vmsa->g_pat = HV_AP_INIT_GPAT_DEFAULT;
330         vmsa->rip = (u64)secondary_startup_64_no_verify;
331         vmsa->rsp = (u64)&ap_start_stack[PAGE_SIZE];
332 
333         /*
334          * Set the SNP-specific fields for this VMSA:
335          *   VMPL level
336          *   SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
337          */
338         vmsa->vmpl = 0;
339         vmsa->sev_features = sev_status >> 2;
340 
341         ret = snp_set_vmsa(vmsa, true);
342         if (!ret) {
343                 pr_err("RMPADJUST(%llx) failed: %llx\n", (u64)vmsa, ret);
344                 free_page((u64)vmsa);
345                 return ret;
346         }
347 
348         local_irq_save(flags);
349         start_vp_input = (struct hv_enable_vp_vtl *)ap_start_input_arg;
350         memset(start_vp_input, 0, sizeof(*start_vp_input));
351         start_vp_input->partition_id = -1;
352         start_vp_input->vp_index = cpu;
353         start_vp_input->target_vtl.target_vtl = ms_hyperv.vtl;
354         *(u64 *)&start_vp_input->vp_context = __pa(vmsa) | 1;
355 
356         do {
357                 ret = hv_do_hypercall(HVCALL_START_VP,
358                                       start_vp_input, NULL);
359         } while (hv_result(ret) == HV_STATUS_TIME_OUT && retry--);
360 
361         local_irq_restore(flags);
362 
363         if (!hv_result_success(ret)) {
364                 pr_err("HvCallStartVirtualProcessor failed: %llx\n", ret);
365                 snp_cleanup_vmsa(vmsa);
366                 vmsa = NULL;
367         }
368 
369         cur_vmsa = per_cpu(hv_sev_vmsa, cpu);
370         /* Free up any previous VMSA page */
371         if (cur_vmsa)
372                 snp_cleanup_vmsa(cur_vmsa);
373 
374         /* Record the current VMSA page */
375         per_cpu(hv_sev_vmsa, cpu) = vmsa;
376 
377         return ret;
378 }
379 
380 #else
381 static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
382 static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
383 #endif /* CONFIG_AMD_MEM_ENCRYPT */
384 
385 #ifdef CONFIG_INTEL_TDX_GUEST
386 static void hv_tdx_msr_write(u64 msr, u64 val)
387 {
388         struct tdx_module_args args = {
389                 .r10 = TDX_HYPERCALL_STANDARD,
390                 .r11 = EXIT_REASON_MSR_WRITE,
391                 .r12 = msr,
392                 .r13 = val,
393         };
394 
395         u64 ret = __tdx_hypercall(&args);
396 
397         WARN_ONCE(ret, "Failed to emulate MSR write: %lld\n", ret);
398 }
399 
400 static void hv_tdx_msr_read(u64 msr, u64 *val)
401 {
402         struct tdx_module_args args = {
403                 .r10 = TDX_HYPERCALL_STANDARD,
404                 .r11 = EXIT_REASON_MSR_READ,
405                 .r12 = msr,
406         };
407 
408         u64 ret = __tdx_hypercall(&args);
409 
410         if (WARN_ONCE(ret, "Failed to emulate MSR read: %lld\n", ret))
411                 *val = 0;
412         else
413                 *val = args.r11;
414 }
415 
416 u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
417 {
418         struct tdx_module_args args = { };
419 
420         args.r10 = control;
421         args.rdx = param1;
422         args.r8  = param2;
423 
424         (void)__tdx_hypercall(&args);
425 
426         return args.r11;
427 }
428 
429 #else
430 static inline void hv_tdx_msr_write(u64 msr, u64 value) {}
431 static inline void hv_tdx_msr_read(u64 msr, u64 *value) {}
432 #endif /* CONFIG_INTEL_TDX_GUEST */
433 
434 #if defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST)
435 void hv_ivm_msr_write(u64 msr, u64 value)
436 {
437         if (!ms_hyperv.paravisor_present)
438                 return;
439 
440         if (hv_isolation_type_tdx())
441                 hv_tdx_msr_write(msr, value);
442         else if (hv_isolation_type_snp())
443                 hv_ghcb_msr_write(msr, value);
444 }
445 
446 void hv_ivm_msr_read(u64 msr, u64 *value)
447 {
448         if (!ms_hyperv.paravisor_present)
449                 return;
450 
451         if (hv_isolation_type_tdx())
452                 hv_tdx_msr_read(msr, value);
453         else if (hv_isolation_type_snp())
454                 hv_ghcb_msr_read(msr, value);
455 }
456 
457 /*
458  * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
459  *
460  * In Isolation VM, all guest memory is encrypted from host and guest
461  * needs to set memory visible to host via hvcall before sharing memory
462  * with host.
463  */
464 static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
465                            enum hv_mem_host_visibility visibility)
466 {
467         struct hv_gpa_range_for_visibility *input;
468         u16 pages_processed;
469         u64 hv_status;
470         unsigned long flags;
471 
472         /* no-op if partition isolation is not enabled */
473         if (!hv_is_isolation_supported())
474                 return 0;
475 
476         if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
477                 pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
478                         HV_MAX_MODIFY_GPA_REP_COUNT);
479                 return -EINVAL;
480         }
481 
482         local_irq_save(flags);
483         input = *this_cpu_ptr(hyperv_pcpu_input_arg);
484 
485         if (unlikely(!input)) {
486                 local_irq_restore(flags);
487                 return -EINVAL;
488         }
489 
490         input->partition_id = HV_PARTITION_ID_SELF;
491         input->host_visibility = visibility;
492         input->reserved0 = 0;
493         input->reserved1 = 0;
494         memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
495         hv_status = hv_do_rep_hypercall(
496                         HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
497                         0, input, &pages_processed);
498         local_irq_restore(flags);
499 
500         if (hv_result_success(hv_status))
501                 return 0;
502         else
503                 return -EFAULT;
504 }
505 
506 /*
507  * When transitioning memory between encrypted and decrypted, the caller
508  * of set_memory_encrypted() or set_memory_decrypted() is responsible for
509  * ensuring that the memory isn't in use and isn't referenced while the
510  * transition is in progress.  The transition has multiple steps, and the
511  * memory is in an inconsistent state until all steps are complete. A
512  * reference while the state is inconsistent could result in an exception
513  * that can't be cleanly fixed up.
514  *
515  * But the Linux kernel load_unaligned_zeropad() mechanism could cause a
516  * stray reference that can't be prevented by the caller, so Linux has
517  * specific code to handle this case. But when the #VC and #VE exceptions
518  * routed to a paravisor, the specific code doesn't work. To avoid this
519  * problem, mark the pages as "not present" while the transition is in
520  * progress. If load_unaligned_zeropad() causes a stray reference, a normal
521  * page fault is generated instead of #VC or #VE, and the page-fault-based
522  * handlers for load_unaligned_zeropad() resolve the reference.  When the
523  * transition is complete, hv_vtom_set_host_visibility() marks the pages
524  * as "present" again.
525  */
526 static int hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc)
527 {
528         return set_memory_np(kbuffer, pagecount);
529 }
530 
531 /*
532  * hv_vtom_set_host_visibility - Set specified memory visible to host.
533  *
534  * In Isolation VM, all guest memory is encrypted from host and guest
535  * needs to set memory visible to host via hvcall before sharing memory
536  * with host. This function works as wrap of hv_mark_gpa_visibility()
537  * with memory base and size.
538  */
539 static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
540 {
541         enum hv_mem_host_visibility visibility = enc ?
542                         VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
543         u64 *pfn_array;
544         phys_addr_t paddr;
545         int i, pfn, err;
546         void *vaddr;
547         int ret = 0;
548 
549         pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
550         if (!pfn_array) {
551                 ret = -ENOMEM;
552                 goto err_set_memory_p;
553         }
554 
555         for (i = 0, pfn = 0; i < pagecount; i++) {
556                 /*
557                  * Use slow_virt_to_phys() because the PRESENT bit has been
558                  * temporarily cleared in the PTEs.  slow_virt_to_phys() works
559                  * without the PRESENT bit while virt_to_hvpfn() or similar
560                  * does not.
561                  */
562                 vaddr = (void *)kbuffer + (i * HV_HYP_PAGE_SIZE);
563                 paddr = slow_virt_to_phys(vaddr);
564                 pfn_array[pfn] = paddr >> HV_HYP_PAGE_SHIFT;
565                 pfn++;
566 
567                 if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
568                         ret = hv_mark_gpa_visibility(pfn, pfn_array,
569                                                      visibility);
570                         if (ret)
571                                 goto err_free_pfn_array;
572                         pfn = 0;
573                 }
574         }
575 
576 err_free_pfn_array:
577         kfree(pfn_array);
578 
579 err_set_memory_p:
580         /*
581          * Set the PTE PRESENT bits again to revert what hv_vtom_clear_present()
582          * did. Do this even if there is an error earlier in this function in
583          * order to avoid leaving the memory range in a "broken" state. Setting
584          * the PRESENT bits shouldn't fail, but return an error if it does.
585          */
586         err = set_memory_p(kbuffer, pagecount);
587         if (err && !ret)
588                 ret = err;
589 
590         return ret;
591 }
592 
593 static bool hv_vtom_tlb_flush_required(bool private)
594 {
595         /*
596          * Since hv_vtom_clear_present() marks the PTEs as "not present"
597          * and flushes the TLB, they can't be in the TLB. That makes the
598          * flush controlled by this function redundant, so return "false".
599          */
600         return false;
601 }
602 
603 static bool hv_vtom_cache_flush_required(void)
604 {
605         return false;
606 }
607 
608 static bool hv_is_private_mmio(u64 addr)
609 {
610         /*
611          * Hyper-V always provides a single IO-APIC in a guest VM.
612          * When a paravisor is used, it is emulated by the paravisor
613          * in the guest context and must be mapped private.
614          */
615         if (addr >= HV_IOAPIC_BASE_ADDRESS &&
616             addr < (HV_IOAPIC_BASE_ADDRESS + PAGE_SIZE))
617                 return true;
618 
619         /* Same with a vTPM */
620         if (addr >= VTPM_BASE_ADDRESS &&
621             addr < (VTPM_BASE_ADDRESS + PAGE_SIZE))
622                 return true;
623 
624         return false;
625 }
626 
627 void __init hv_vtom_init(void)
628 {
629         enum hv_isolation_type type = hv_get_isolation_type();
630 
631         switch (type) {
632         case HV_ISOLATION_TYPE_VBS:
633                 fallthrough;
634         /*
635          * By design, a VM using vTOM doesn't see the SEV setting,
636          * so SEV initialization is bypassed and sev_status isn't set.
637          * Set it here to indicate a vTOM VM.
638          *
639          * Note: if CONFIG_AMD_MEM_ENCRYPT is not set, sev_status is
640          * defined as 0ULL, to which we can't assigned a value.
641          */
642 #ifdef CONFIG_AMD_MEM_ENCRYPT
643         case HV_ISOLATION_TYPE_SNP:
644                 sev_status = MSR_AMD64_SNP_VTOM;
645                 cc_vendor = CC_VENDOR_AMD;
646                 break;
647 #endif
648 
649         case HV_ISOLATION_TYPE_TDX:
650                 cc_vendor = CC_VENDOR_INTEL;
651                 break;
652 
653         default:
654                 panic("hv_vtom_init: unsupported isolation type %d\n", type);
655         }
656 
657         cc_set_mask(ms_hyperv.shared_gpa_boundary);
658         physical_mask &= ms_hyperv.shared_gpa_boundary - 1;
659 
660         x86_platform.hyper.is_private_mmio = hv_is_private_mmio;
661         x86_platform.guest.enc_cache_flush_required = hv_vtom_cache_flush_required;
662         x86_platform.guest.enc_tlb_flush_required = hv_vtom_tlb_flush_required;
663         x86_platform.guest.enc_status_change_prepare = hv_vtom_clear_present;
664         x86_platform.guest.enc_status_change_finish = hv_vtom_set_host_visibility;
665 
666         /* Set WB as the default cache mode. */
667         mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
668 }
669 
670 #endif /* defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST) */
671 
672 enum hv_isolation_type hv_get_isolation_type(void)
673 {
674         if (!(ms_hyperv.priv_high & HV_ISOLATION))
675                 return HV_ISOLATION_TYPE_NONE;
676         return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
677 }
678 EXPORT_SYMBOL_GPL(hv_get_isolation_type);
679 
680 /*
681  * hv_is_isolation_supported - Check system runs in the Hyper-V
682  * isolation VM.
683  */
684 bool hv_is_isolation_supported(void)
685 {
686         if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
687                 return false;
688 
689         if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
690                 return false;
691 
692         return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
693 }
694 
695 DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
696 
697 /*
698  * hv_isolation_type_snp - Check if the system runs in an AMD SEV-SNP based
699  * isolation VM.
700  */
701 bool hv_isolation_type_snp(void)
702 {
703         return static_branch_unlikely(&isolation_type_snp);
704 }
705 
706 DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
707 /*
708  * hv_isolation_type_tdx - Check if the system runs in an Intel TDX based
709  * isolated VM.
710  */
711 bool hv_isolation_type_tdx(void)
712 {
713         return static_branch_unlikely(&isolation_type_tdx);
714 }
715 

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