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TOMOYO Linux Cross Reference
Linux/arch/x86/kvm/cpuid.c

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  1 /*
  2  * Kernel-based Virtual Machine driver for Linux
  3  * cpuid support routines
  4  *
  5  * derived from arch/x86/kvm/x86.c
  6  *
  7  * Copyright 2011 Red Hat, Inc. and/or its affiliates.
  8  * Copyright IBM Corporation, 2008
  9  *
 10  * This work is licensed under the terms of the GNU GPL, version 2.  See
 11  * the COPYING file in the top-level directory.
 12  *
 13  */
 14 
 15 #include <linux/kvm_host.h>
 16 #include <linux/export.h>
 17 #include <linux/vmalloc.h>
 18 #include <linux/uaccess.h>
 19 #include <linux/sched/stat.h>
 20 
 21 #include <asm/processor.h>
 22 #include <asm/user.h>
 23 #include <asm/fpu/xstate.h>
 24 #include "cpuid.h"
 25 #include "lapic.h"
 26 #include "mmu.h"
 27 #include "trace.h"
 28 #include "pmu.h"
 29 
 30 static u32 xstate_required_size(u64 xstate_bv, bool compacted)
 31 {
 32         int feature_bit = 0;
 33         u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
 34 
 35         xstate_bv &= XFEATURE_MASK_EXTEND;
 36         while (xstate_bv) {
 37                 if (xstate_bv & 0x1) {
 38                         u32 eax, ebx, ecx, edx, offset;
 39                         cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
 40                         offset = compacted ? ret : ebx;
 41                         ret = max(ret, offset + eax);
 42                 }
 43 
 44                 xstate_bv >>= 1;
 45                 feature_bit++;
 46         }
 47 
 48         return ret;
 49 }
 50 
 51 bool kvm_mpx_supported(void)
 52 {
 53         return ((host_xcr0 & (XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR))
 54                  && kvm_x86_ops->mpx_supported());
 55 }
 56 EXPORT_SYMBOL_GPL(kvm_mpx_supported);
 57 
 58 u64 kvm_supported_xcr0(void)
 59 {
 60         u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
 61 
 62         if (!kvm_mpx_supported())
 63                 xcr0 &= ~(XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR);
 64 
 65         return xcr0;
 66 }
 67 
 68 #define F(x) bit(X86_FEATURE_##x)
 69 
 70 /* For scattered features from cpufeatures.h; we currently expose none */
 71 #define KF(x) bit(KVM_CPUID_BIT_##x)
 72 
 73 int kvm_update_cpuid(struct kvm_vcpu *vcpu)
 74 {
 75         struct kvm_cpuid_entry2 *best;
 76         struct kvm_lapic *apic = vcpu->arch.apic;
 77 
 78         best = kvm_find_cpuid_entry(vcpu, 1, 0);
 79         if (!best)
 80                 return 0;
 81 
 82         /* Update OSXSAVE bit */
 83         if (boot_cpu_has(X86_FEATURE_XSAVE) && best->function == 0x1) {
 84                 best->ecx &= ~F(OSXSAVE);
 85                 if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
 86                         best->ecx |= F(OSXSAVE);
 87         }
 88 
 89         best->edx &= ~F(APIC);
 90         if (vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE)
 91                 best->edx |= F(APIC);
 92 
 93         if (apic) {
 94                 if (best->ecx & F(TSC_DEADLINE_TIMER))
 95                         apic->lapic_timer.timer_mode_mask = 3 << 17;
 96                 else
 97                         apic->lapic_timer.timer_mode_mask = 1 << 17;
 98         }
 99 
100         best = kvm_find_cpuid_entry(vcpu, 7, 0);
101         if (best) {
102                 /* Update OSPKE bit */
103                 if (boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7) {
104                         best->ecx &= ~F(OSPKE);
105                         if (kvm_read_cr4_bits(vcpu, X86_CR4_PKE))
106                                 best->ecx |= F(OSPKE);
107                 }
108         }
109 
110         best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
111         if (!best) {
112                 vcpu->arch.guest_supported_xcr0 = 0;
113                 vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
114         } else {
115                 vcpu->arch.guest_supported_xcr0 =
116                         (best->eax | ((u64)best->edx << 32)) &
117                         kvm_supported_xcr0();
118                 vcpu->arch.guest_xstate_size = best->ebx =
119                         xstate_required_size(vcpu->arch.xcr0, false);
120         }
121 
122         best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
123         if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
124                 best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
125 
126         /*
127          * The existing code assumes virtual address is 48-bit or 57-bit in the
128          * canonical address checks; exit if it is ever changed.
129          */
130         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
131         if (best) {
132                 int vaddr_bits = (best->eax & 0xff00) >> 8;
133 
134                 if (vaddr_bits != 48 && vaddr_bits != 57 && vaddr_bits != 0)
135                         return -EINVAL;
136         }
137 
138         best = kvm_find_cpuid_entry(vcpu, KVM_CPUID_FEATURES, 0);
139         if (kvm_hlt_in_guest(vcpu->kvm) && best &&
140                 (best->eax & (1 << KVM_FEATURE_PV_UNHALT)))
141                 best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT);
142 
143         /* Update physical-address width */
144         vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
145         kvm_mmu_reset_context(vcpu);
146 
147         kvm_pmu_refresh(vcpu);
148         return 0;
149 }
150 
151 static int is_efer_nx(void)
152 {
153         unsigned long long efer = 0;
154 
155         rdmsrl_safe(MSR_EFER, &efer);
156         return efer & EFER_NX;
157 }
158 
159 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
160 {
161         int i;
162         struct kvm_cpuid_entry2 *e, *entry;
163 
164         entry = NULL;
165         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
166                 e = &vcpu->arch.cpuid_entries[i];
167                 if (e->function == 0x80000001) {
168                         entry = e;
169                         break;
170                 }
171         }
172         if (entry && (entry->edx & F(NX)) && !is_efer_nx()) {
173                 entry->edx &= ~F(NX);
174                 printk(KERN_INFO "kvm: guest NX capability removed\n");
175         }
176 }
177 
178 int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
179 {
180         struct kvm_cpuid_entry2 *best;
181 
182         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
183         if (!best || best->eax < 0x80000008)
184                 goto not_found;
185         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
186         if (best)
187                 return best->eax & 0xff;
188 not_found:
189         return 36;
190 }
191 EXPORT_SYMBOL_GPL(cpuid_query_maxphyaddr);
192 
193 /* when an old userspace process fills a new kernel module */
194 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
195                              struct kvm_cpuid *cpuid,
196                              struct kvm_cpuid_entry __user *entries)
197 {
198         int r, i;
199         struct kvm_cpuid_entry *cpuid_entries = NULL;
200 
201         r = -E2BIG;
202         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
203                 goto out;
204         r = -ENOMEM;
205         if (cpuid->nent) {
206                 cpuid_entries =
207                         vmalloc(array_size(sizeof(struct kvm_cpuid_entry),
208                                            cpuid->nent));
209                 if (!cpuid_entries)
210                         goto out;
211                 r = -EFAULT;
212                 if (copy_from_user(cpuid_entries, entries,
213                                    cpuid->nent * sizeof(struct kvm_cpuid_entry)))
214                         goto out;
215         }
216         for (i = 0; i < cpuid->nent; i++) {
217                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
218                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
219                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
220                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
221                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
222                 vcpu->arch.cpuid_entries[i].index = 0;
223                 vcpu->arch.cpuid_entries[i].flags = 0;
224                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
225                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
226                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
227         }
228         vcpu->arch.cpuid_nent = cpuid->nent;
229         cpuid_fix_nx_cap(vcpu);
230         kvm_apic_set_version(vcpu);
231         kvm_x86_ops->cpuid_update(vcpu);
232         r = kvm_update_cpuid(vcpu);
233 
234 out:
235         vfree(cpuid_entries);
236         return r;
237 }
238 
239 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
240                               struct kvm_cpuid2 *cpuid,
241                               struct kvm_cpuid_entry2 __user *entries)
242 {
243         int r;
244 
245         r = -E2BIG;
246         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
247                 goto out;
248         r = -EFAULT;
249         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
250                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
251                 goto out;
252         vcpu->arch.cpuid_nent = cpuid->nent;
253         kvm_apic_set_version(vcpu);
254         kvm_x86_ops->cpuid_update(vcpu);
255         r = kvm_update_cpuid(vcpu);
256 out:
257         return r;
258 }
259 
260 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
261                               struct kvm_cpuid2 *cpuid,
262                               struct kvm_cpuid_entry2 __user *entries)
263 {
264         int r;
265 
266         r = -E2BIG;
267         if (cpuid->nent < vcpu->arch.cpuid_nent)
268                 goto out;
269         r = -EFAULT;
270         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
271                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
272                 goto out;
273         return 0;
274 
275 out:
276         cpuid->nent = vcpu->arch.cpuid_nent;
277         return r;
278 }
279 
280 static void cpuid_mask(u32 *word, int wordnum)
281 {
282         *word &= boot_cpu_data.x86_capability[wordnum];
283 }
284 
285 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
286                            u32 index)
287 {
288         entry->function = function;
289         entry->index = index;
290         cpuid_count(entry->function, entry->index,
291                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
292         entry->flags = 0;
293 }
294 
295 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
296                                    u32 func, u32 index, int *nent, int maxnent)
297 {
298         switch (func) {
299         case 0:
300                 entry->eax = 7;
301                 ++*nent;
302                 break;
303         case 1:
304                 entry->ecx = F(MOVBE);
305                 ++*nent;
306                 break;
307         case 7:
308                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
309                 if (index == 0)
310                         entry->ecx = F(RDPID);
311                 ++*nent;
312         default:
313                 break;
314         }
315 
316         entry->function = func;
317         entry->index = index;
318 
319         return 0;
320 }
321 
322 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
323                                  u32 index, int *nent, int maxnent)
324 {
325         int r;
326         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
327 #ifdef CONFIG_X86_64
328         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
329                                 ? F(GBPAGES) : 0;
330         unsigned f_lm = F(LM);
331 #else
332         unsigned f_gbpages = 0;
333         unsigned f_lm = 0;
334 #endif
335         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
336         unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
337         unsigned f_mpx = kvm_mpx_supported() ? F(MPX) : 0;
338         unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
339         unsigned f_umip = kvm_x86_ops->umip_emulated() ? F(UMIP) : 0;
340 
341         /* cpuid 1.edx */
342         const u32 kvm_cpuid_1_edx_x86_features =
343                 F(FPU) | F(VME) | F(DE) | F(PSE) |
344                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
345                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
346                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
347                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
348                 0 /* Reserved, DS, ACPI */ | F(MMX) |
349                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
350                 0 /* HTT, TM, Reserved, PBE */;
351         /* cpuid 0x80000001.edx */
352         const u32 kvm_cpuid_8000_0001_edx_x86_features =
353                 F(FPU) | F(VME) | F(DE) | F(PSE) |
354                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
355                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
356                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
357                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
358                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
359                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
360                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
361         /* cpuid 1.ecx */
362         const u32 kvm_cpuid_1_ecx_x86_features =
363                 /* NOTE: MONITOR (and MWAIT) are emulated as NOP,
364                  * but *not* advertised to guests via CPUID ! */
365                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
366                 0 /* DS-CPL, VMX, SMX, EST */ |
367                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
368                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
369                 F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
370                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
371                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
372                 F(F16C) | F(RDRAND);
373         /* cpuid 0x80000001.ecx */
374         const u32 kvm_cpuid_8000_0001_ecx_x86_features =
375                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
376                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
377                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
378                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM) |
379                 F(TOPOEXT) | F(PERFCTR_CORE);
380 
381         /* cpuid 0x80000008.ebx */
382         const u32 kvm_cpuid_8000_0008_ebx_x86_features =
383                 F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) |
384                 F(AMD_SSB_NO);
385 
386         /* cpuid 0xC0000001.edx */
387         const u32 kvm_cpuid_C000_0001_edx_x86_features =
388                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
389                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
390                 F(PMM) | F(PMM_EN);
391 
392         /* cpuid 7.0.ebx */
393         const u32 kvm_cpuid_7_0_ebx_x86_features =
394                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
395                 F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
396                 F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
397                 F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
398                 F(SHA_NI) | F(AVX512BW) | F(AVX512VL);
399 
400         /* cpuid 0xD.1.eax */
401         const u32 kvm_cpuid_D_1_eax_x86_features =
402                 F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
403 
404         /* cpuid 7.0.ecx*/
405         const u32 kvm_cpuid_7_0_ecx_x86_features =
406                 F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ |
407                 F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
408                 F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
409                 F(CLDEMOTE);
410 
411         /* cpuid 7.0.edx*/
412         const u32 kvm_cpuid_7_0_edx_x86_features =
413                 F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
414                 F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES);
415 
416         /* all calls to cpuid_count() should be made on the same cpu */
417         get_cpu();
418 
419         r = -E2BIG;
420 
421         if (*nent >= maxnent)
422                 goto out;
423 
424         do_cpuid_1_ent(entry, function, index);
425         ++*nent;
426 
427         switch (function) {
428         case 0:
429                 entry->eax = min(entry->eax, (u32)0xd);
430                 break;
431         case 1:
432                 entry->edx &= kvm_cpuid_1_edx_x86_features;
433                 cpuid_mask(&entry->edx, CPUID_1_EDX);
434                 entry->ecx &= kvm_cpuid_1_ecx_x86_features;
435                 cpuid_mask(&entry->ecx, CPUID_1_ECX);
436                 /* we support x2apic emulation even if host does not support
437                  * it since we emulate x2apic in software */
438                 entry->ecx |= F(X2APIC);
439                 break;
440         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
441          * may return different values. This forces us to get_cpu() before
442          * issuing the first command, and also to emulate this annoying behavior
443          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
444         case 2: {
445                 int t, times = entry->eax & 0xff;
446 
447                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
448                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
449                 for (t = 1; t < times; ++t) {
450                         if (*nent >= maxnent)
451                                 goto out;
452 
453                         do_cpuid_1_ent(&entry[t], function, 0);
454                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
455                         ++*nent;
456                 }
457                 break;
458         }
459         /* function 4 has additional index. */
460         case 4: {
461                 int i, cache_type;
462 
463                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
464                 /* read more entries until cache_type is zero */
465                 for (i = 1; ; ++i) {
466                         if (*nent >= maxnent)
467                                 goto out;
468 
469                         cache_type = entry[i - 1].eax & 0x1f;
470                         if (!cache_type)
471                                 break;
472                         do_cpuid_1_ent(&entry[i], function, i);
473                         entry[i].flags |=
474                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
475                         ++*nent;
476                 }
477                 break;
478         }
479         case 6: /* Thermal management */
480                 entry->eax = 0x4; /* allow ARAT */
481                 entry->ebx = 0;
482                 entry->ecx = 0;
483                 entry->edx = 0;
484                 break;
485         case 7: {
486                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
487                 /* Mask ebx against host capability word 9 */
488                 if (index == 0) {
489                         entry->ebx &= kvm_cpuid_7_0_ebx_x86_features;
490                         cpuid_mask(&entry->ebx, CPUID_7_0_EBX);
491                         // TSC_ADJUST is emulated
492                         entry->ebx |= F(TSC_ADJUST);
493                         entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
494                         cpuid_mask(&entry->ecx, CPUID_7_ECX);
495                         entry->ecx |= f_umip;
496                         /* PKU is not yet implemented for shadow paging. */
497                         if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
498                                 entry->ecx &= ~F(PKU);
499                         entry->edx &= kvm_cpuid_7_0_edx_x86_features;
500                         cpuid_mask(&entry->edx, CPUID_7_EDX);
501                         /*
502                          * We emulate ARCH_CAPABILITIES in software even
503                          * if the host doesn't support it.
504                          */
505                         entry->edx |= F(ARCH_CAPABILITIES);
506                 } else {
507                         entry->ebx = 0;
508                         entry->ecx = 0;
509                         entry->edx = 0;
510                 }
511                 entry->eax = 0;
512                 break;
513         }
514         case 9:
515                 break;
516         case 0xa: { /* Architectural Performance Monitoring */
517                 struct x86_pmu_capability cap;
518                 union cpuid10_eax eax;
519                 union cpuid10_edx edx;
520 
521                 perf_get_x86_pmu_capability(&cap);
522 
523                 /*
524                  * Only support guest architectural pmu on a host
525                  * with architectural pmu.
526                  */
527                 if (!cap.version)
528                         memset(&cap, 0, sizeof(cap));
529 
530                 eax.split.version_id = min(cap.version, 2);
531                 eax.split.num_counters = cap.num_counters_gp;
532                 eax.split.bit_width = cap.bit_width_gp;
533                 eax.split.mask_length = cap.events_mask_len;
534 
535                 edx.split.num_counters_fixed = cap.num_counters_fixed;
536                 edx.split.bit_width_fixed = cap.bit_width_fixed;
537                 edx.split.reserved = 0;
538 
539                 entry->eax = eax.full;
540                 entry->ebx = cap.events_mask;
541                 entry->ecx = 0;
542                 entry->edx = edx.full;
543                 break;
544         }
545         /* function 0xb has additional index. */
546         case 0xb: {
547                 int i, level_type;
548 
549                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
550                 /* read more entries until level_type is zero */
551                 for (i = 1; ; ++i) {
552                         if (*nent >= maxnent)
553                                 goto out;
554 
555                         level_type = entry[i - 1].ecx & 0xff00;
556                         if (!level_type)
557                                 break;
558                         do_cpuid_1_ent(&entry[i], function, i);
559                         entry[i].flags |=
560                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
561                         ++*nent;
562                 }
563                 break;
564         }
565         case 0xd: {
566                 int idx, i;
567                 u64 supported = kvm_supported_xcr0();
568 
569                 entry->eax &= supported;
570                 entry->ebx = xstate_required_size(supported, false);
571                 entry->ecx = entry->ebx;
572                 entry->edx &= supported >> 32;
573                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
574                 if (!supported)
575                         break;
576 
577                 for (idx = 1, i = 1; idx < 64; ++idx) {
578                         u64 mask = ((u64)1 << idx);
579                         if (*nent >= maxnent)
580                                 goto out;
581 
582                         do_cpuid_1_ent(&entry[i], function, idx);
583                         if (idx == 1) {
584                                 entry[i].eax &= kvm_cpuid_D_1_eax_x86_features;
585                                 cpuid_mask(&entry[i].eax, CPUID_D_1_EAX);
586                                 entry[i].ebx = 0;
587                                 if (entry[i].eax & (F(XSAVES)|F(XSAVEC)))
588                                         entry[i].ebx =
589                                                 xstate_required_size(supported,
590                                                                      true);
591                         } else {
592                                 if (entry[i].eax == 0 || !(supported & mask))
593                                         continue;
594                                 if (WARN_ON_ONCE(entry[i].ecx & 1))
595                                         continue;
596                         }
597                         entry[i].ecx = 0;
598                         entry[i].edx = 0;
599                         entry[i].flags |=
600                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
601                         ++*nent;
602                         ++i;
603                 }
604                 break;
605         }
606         case KVM_CPUID_SIGNATURE: {
607                 static const char signature[12] = "KVMKVMKVM\0\0";
608                 const u32 *sigptr = (const u32 *)signature;
609                 entry->eax = KVM_CPUID_FEATURES;
610                 entry->ebx = sigptr[0];
611                 entry->ecx = sigptr[1];
612                 entry->edx = sigptr[2];
613                 break;
614         }
615         case KVM_CPUID_FEATURES:
616                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
617                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
618                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
619                              (1 << KVM_FEATURE_ASYNC_PF) |
620                              (1 << KVM_FEATURE_PV_EOI) |
621                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
622                              (1 << KVM_FEATURE_PV_UNHALT) |
623                              (1 << KVM_FEATURE_PV_TLB_FLUSH) |
624                              (1 << KVM_FEATURE_ASYNC_PF_VMEXIT);
625 
626                 if (sched_info_on())
627                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
628 
629                 entry->ebx = 0;
630                 entry->ecx = 0;
631                 entry->edx = 0;
632                 break;
633         case 0x80000000:
634                 entry->eax = min(entry->eax, 0x8000001f);
635                 break;
636         case 0x80000001:
637                 entry->edx &= kvm_cpuid_8000_0001_edx_x86_features;
638                 cpuid_mask(&entry->edx, CPUID_8000_0001_EDX);
639                 entry->ecx &= kvm_cpuid_8000_0001_ecx_x86_features;
640                 cpuid_mask(&entry->ecx, CPUID_8000_0001_ECX);
641                 break;
642         case 0x80000007: /* Advanced power management */
643                 /* invariant TSC is CPUID.80000007H:EDX[8] */
644                 entry->edx &= (1 << 8);
645                 /* mask against host */
646                 entry->edx &= boot_cpu_data.x86_power;
647                 entry->eax = entry->ebx = entry->ecx = 0;
648                 break;
649         case 0x80000008: {
650                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
651                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
652                 unsigned phys_as = entry->eax & 0xff;
653 
654                 if (!g_phys_as)
655                         g_phys_as = phys_as;
656                 entry->eax = g_phys_as | (virt_as << 8);
657                 entry->edx = 0;
658                 /*
659                  * IBRS, IBPB and VIRT_SSBD aren't necessarily present in
660                  * hardware cpuid
661                  */
662                 if (boot_cpu_has(X86_FEATURE_AMD_IBPB))
663                         entry->ebx |= F(AMD_IBPB);
664                 if (boot_cpu_has(X86_FEATURE_AMD_IBRS))
665                         entry->ebx |= F(AMD_IBRS);
666                 if (boot_cpu_has(X86_FEATURE_VIRT_SSBD))
667                         entry->ebx |= F(VIRT_SSBD);
668                 entry->ebx &= kvm_cpuid_8000_0008_ebx_x86_features;
669                 cpuid_mask(&entry->ebx, CPUID_8000_0008_EBX);
670                 /*
671                  * The preference is to use SPEC CTRL MSR instead of the
672                  * VIRT_SPEC MSR.
673                  */
674                 if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) &&
675                     !boot_cpu_has(X86_FEATURE_AMD_SSBD))
676                         entry->ebx |= F(VIRT_SSBD);
677                 break;
678         }
679         case 0x80000019:
680                 entry->ecx = entry->edx = 0;
681                 break;
682         case 0x8000001a:
683                 break;
684         case 0x8000001d:
685                 break;
686         /*Add support for Centaur's CPUID instruction*/
687         case 0xC0000000:
688                 /*Just support up to 0xC0000004 now*/
689                 entry->eax = min(entry->eax, 0xC0000004);
690                 break;
691         case 0xC0000001:
692                 entry->edx &= kvm_cpuid_C000_0001_edx_x86_features;
693                 cpuid_mask(&entry->edx, CPUID_C000_0001_EDX);
694                 break;
695         case 3: /* Processor serial number */
696         case 5: /* MONITOR/MWAIT */
697         case 0xC0000002:
698         case 0xC0000003:
699         case 0xC0000004:
700         default:
701                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
702                 break;
703         }
704 
705         kvm_x86_ops->set_supported_cpuid(function, entry);
706 
707         r = 0;
708 
709 out:
710         put_cpu();
711 
712         return r;
713 }
714 
715 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
716                         u32 idx, int *nent, int maxnent, unsigned int type)
717 {
718         if (type == KVM_GET_EMULATED_CPUID)
719                 return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
720 
721         return __do_cpuid_ent(entry, func, idx, nent, maxnent);
722 }
723 
724 #undef F
725 
726 struct kvm_cpuid_param {
727         u32 func;
728         u32 idx;
729         bool has_leaf_count;
730         bool (*qualifier)(const struct kvm_cpuid_param *param);
731 };
732 
733 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
734 {
735         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
736 }
737 
738 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
739                                  __u32 num_entries, unsigned int ioctl_type)
740 {
741         int i;
742         __u32 pad[3];
743 
744         if (ioctl_type != KVM_GET_EMULATED_CPUID)
745                 return false;
746 
747         /*
748          * We want to make sure that ->padding is being passed clean from
749          * userspace in case we want to use it for something in the future.
750          *
751          * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
752          * have to give ourselves satisfied only with the emulated side. /me
753          * sheds a tear.
754          */
755         for (i = 0; i < num_entries; i++) {
756                 if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
757                         return true;
758 
759                 if (pad[0] || pad[1] || pad[2])
760                         return true;
761         }
762         return false;
763 }
764 
765 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
766                             struct kvm_cpuid_entry2 __user *entries,
767                             unsigned int type)
768 {
769         struct kvm_cpuid_entry2 *cpuid_entries;
770         int limit, nent = 0, r = -E2BIG, i;
771         u32 func;
772         static const struct kvm_cpuid_param param[] = {
773                 { .func = 0, .has_leaf_count = true },
774                 { .func = 0x80000000, .has_leaf_count = true },
775                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
776                 { .func = KVM_CPUID_SIGNATURE },
777                 { .func = KVM_CPUID_FEATURES },
778         };
779 
780         if (cpuid->nent < 1)
781                 goto out;
782         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
783                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
784 
785         if (sanity_check_entries(entries, cpuid->nent, type))
786                 return -EINVAL;
787 
788         r = -ENOMEM;
789         cpuid_entries = vzalloc(array_size(sizeof(struct kvm_cpuid_entry2),
790                                            cpuid->nent));
791         if (!cpuid_entries)
792                 goto out;
793 
794         r = 0;
795         for (i = 0; i < ARRAY_SIZE(param); i++) {
796                 const struct kvm_cpuid_param *ent = &param[i];
797 
798                 if (ent->qualifier && !ent->qualifier(ent))
799                         continue;
800 
801                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
802                                 &nent, cpuid->nent, type);
803 
804                 if (r)
805                         goto out_free;
806 
807                 if (!ent->has_leaf_count)
808                         continue;
809 
810                 limit = cpuid_entries[nent - 1].eax;
811                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
812                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
813                                      &nent, cpuid->nent, type);
814 
815                 if (r)
816                         goto out_free;
817         }
818 
819         r = -EFAULT;
820         if (copy_to_user(entries, cpuid_entries,
821                          nent * sizeof(struct kvm_cpuid_entry2)))
822                 goto out_free;
823         cpuid->nent = nent;
824         r = 0;
825 
826 out_free:
827         vfree(cpuid_entries);
828 out:
829         return r;
830 }
831 
832 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
833 {
834         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
835         struct kvm_cpuid_entry2 *ej;
836         int j = i;
837         int nent = vcpu->arch.cpuid_nent;
838 
839         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
840         /* when no next entry is found, the current entry[i] is reselected */
841         do {
842                 j = (j + 1) % nent;
843                 ej = &vcpu->arch.cpuid_entries[j];
844         } while (ej->function != e->function);
845 
846         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
847 
848         return j;
849 }
850 
851 /* find an entry with matching function, matching index (if needed), and that
852  * should be read next (if it's stateful) */
853 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
854         u32 function, u32 index)
855 {
856         if (e->function != function)
857                 return 0;
858         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
859                 return 0;
860         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
861             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
862                 return 0;
863         return 1;
864 }
865 
866 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
867                                               u32 function, u32 index)
868 {
869         int i;
870         struct kvm_cpuid_entry2 *best = NULL;
871 
872         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
873                 struct kvm_cpuid_entry2 *e;
874 
875                 e = &vcpu->arch.cpuid_entries[i];
876                 if (is_matching_cpuid_entry(e, function, index)) {
877                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
878                                 move_to_next_stateful_cpuid_entry(vcpu, i);
879                         best = e;
880                         break;
881                 }
882         }
883         return best;
884 }
885 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
886 
887 /*
888  * If no match is found, check whether we exceed the vCPU's limit
889  * and return the content of the highest valid _standard_ leaf instead.
890  * This is to satisfy the CPUID specification.
891  */
892 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
893                                                   u32 function, u32 index)
894 {
895         struct kvm_cpuid_entry2 *maxlevel;
896 
897         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
898         if (!maxlevel || maxlevel->eax >= function)
899                 return NULL;
900         if (function & 0x80000000) {
901                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
902                 if (!maxlevel)
903                         return NULL;
904         }
905         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
906 }
907 
908 bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
909                u32 *ecx, u32 *edx, bool check_limit)
910 {
911         u32 function = *eax, index = *ecx;
912         struct kvm_cpuid_entry2 *best;
913         bool entry_found = true;
914 
915         best = kvm_find_cpuid_entry(vcpu, function, index);
916 
917         if (!best) {
918                 entry_found = false;
919                 if (!check_limit)
920                         goto out;
921 
922                 best = check_cpuid_limit(vcpu, function, index);
923         }
924 
925 out:
926         if (best) {
927                 *eax = best->eax;
928                 *ebx = best->ebx;
929                 *ecx = best->ecx;
930                 *edx = best->edx;
931         } else
932                 *eax = *ebx = *ecx = *edx = 0;
933         trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, entry_found);
934         return entry_found;
935 }
936 EXPORT_SYMBOL_GPL(kvm_cpuid);
937 
938 int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
939 {
940         u32 eax, ebx, ecx, edx;
941 
942         if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0))
943                 return 1;
944 
945         eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
946         ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
947         kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, true);
948         kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
949         kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
950         kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
951         kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
952         return kvm_skip_emulated_instruction(vcpu);
953 }
954 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);
955 

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