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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 <asm/processor.h>
 20 #include <asm/user.h>
 21 #include <asm/fpu/xstate.h>
 22 #include "cpuid.h"
 23 #include "lapic.h"
 24 #include "mmu.h"
 25 #include "trace.h"
 26 #include "pmu.h"
 27 
 28 static u32 xstate_required_size(u64 xstate_bv, bool compacted)
 29 {
 30         int feature_bit = 0;
 31         u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
 32 
 33         xstate_bv &= XFEATURE_MASK_EXTEND;
 34         while (xstate_bv) {
 35                 if (xstate_bv & 0x1) {
 36                         u32 eax, ebx, ecx, edx, offset;
 37                         cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
 38                         offset = compacted ? ret : ebx;
 39                         ret = max(ret, offset + eax);
 40                 }
 41 
 42                 xstate_bv >>= 1;
 43                 feature_bit++;
 44         }
 45 
 46         return ret;
 47 }
 48 
 49 bool kvm_mpx_supported(void)
 50 {
 51         return ((host_xcr0 & (XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR))
 52                  && kvm_x86_ops->mpx_supported());
 53 }
 54 EXPORT_SYMBOL_GPL(kvm_mpx_supported);
 55 
 56 u64 kvm_supported_xcr0(void)
 57 {
 58         u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
 59 
 60         if (!kvm_mpx_supported())
 61                 xcr0 &= ~(XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR);
 62 
 63         return xcr0;
 64 }
 65 
 66 #define F(x) bit(X86_FEATURE_##x)
 67 
 68 /* These are scattered features in cpufeatures.h. */
 69 #define KVM_CPUID_BIT_AVX512_4VNNIW     2
 70 #define KVM_CPUID_BIT_AVX512_4FMAPS     3
 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         kvm_x86_ops->fpu_activate(vcpu);
127 
128         /*
129          * The existing code assumes virtual address is 48-bit in the canonical
130          * address checks; exit if it is ever changed.
131          */
132         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
133         if (best && ((best->eax & 0xff00) >> 8) != 48 &&
134                 ((best->eax & 0xff00) >> 8) != 0)
135                 return -EINVAL;
136 
137         /* Update physical-address width */
138         vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
139 
140         kvm_pmu_refresh(vcpu);
141         return 0;
142 }
143 
144 static int is_efer_nx(void)
145 {
146         unsigned long long efer = 0;
147 
148         rdmsrl_safe(MSR_EFER, &efer);
149         return efer & EFER_NX;
150 }
151 
152 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
153 {
154         int i;
155         struct kvm_cpuid_entry2 *e, *entry;
156 
157         entry = NULL;
158         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
159                 e = &vcpu->arch.cpuid_entries[i];
160                 if (e->function == 0x80000001) {
161                         entry = e;
162                         break;
163                 }
164         }
165         if (entry && (entry->edx & F(NX)) && !is_efer_nx()) {
166                 entry->edx &= ~F(NX);
167                 printk(KERN_INFO "kvm: guest NX capability removed\n");
168         }
169 }
170 
171 int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
172 {
173         struct kvm_cpuid_entry2 *best;
174 
175         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
176         if (!best || best->eax < 0x80000008)
177                 goto not_found;
178         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
179         if (best)
180                 return best->eax & 0xff;
181 not_found:
182         return 36;
183 }
184 EXPORT_SYMBOL_GPL(cpuid_query_maxphyaddr);
185 
186 /* when an old userspace process fills a new kernel module */
187 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
188                              struct kvm_cpuid *cpuid,
189                              struct kvm_cpuid_entry __user *entries)
190 {
191         int r, i;
192         struct kvm_cpuid_entry *cpuid_entries = NULL;
193 
194         r = -E2BIG;
195         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
196                 goto out;
197         r = -ENOMEM;
198         if (cpuid->nent) {
199                 cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) *
200                                         cpuid->nent);
201                 if (!cpuid_entries)
202                         goto out;
203                 r = -EFAULT;
204                 if (copy_from_user(cpuid_entries, entries,
205                                    cpuid->nent * sizeof(struct kvm_cpuid_entry)))
206                         goto out;
207         }
208         for (i = 0; i < cpuid->nent; i++) {
209                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
210                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
211                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
212                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
213                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
214                 vcpu->arch.cpuid_entries[i].index = 0;
215                 vcpu->arch.cpuid_entries[i].flags = 0;
216                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
217                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
218                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
219         }
220         vcpu->arch.cpuid_nent = cpuid->nent;
221         cpuid_fix_nx_cap(vcpu);
222         kvm_apic_set_version(vcpu);
223         kvm_x86_ops->cpuid_update(vcpu);
224         r = kvm_update_cpuid(vcpu);
225 
226 out:
227         vfree(cpuid_entries);
228         return r;
229 }
230 
231 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
232                               struct kvm_cpuid2 *cpuid,
233                               struct kvm_cpuid_entry2 __user *entries)
234 {
235         int r;
236 
237         r = -E2BIG;
238         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
239                 goto out;
240         r = -EFAULT;
241         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
242                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
243                 goto out;
244         vcpu->arch.cpuid_nent = cpuid->nent;
245         kvm_apic_set_version(vcpu);
246         kvm_x86_ops->cpuid_update(vcpu);
247         r = kvm_update_cpuid(vcpu);
248 out:
249         return r;
250 }
251 
252 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
253                               struct kvm_cpuid2 *cpuid,
254                               struct kvm_cpuid_entry2 __user *entries)
255 {
256         int r;
257 
258         r = -E2BIG;
259         if (cpuid->nent < vcpu->arch.cpuid_nent)
260                 goto out;
261         r = -EFAULT;
262         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
263                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
264                 goto out;
265         return 0;
266 
267 out:
268         cpuid->nent = vcpu->arch.cpuid_nent;
269         return r;
270 }
271 
272 static void cpuid_mask(u32 *word, int wordnum)
273 {
274         *word &= boot_cpu_data.x86_capability[wordnum];
275 }
276 
277 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
278                            u32 index)
279 {
280         entry->function = function;
281         entry->index = index;
282         cpuid_count(entry->function, entry->index,
283                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
284         entry->flags = 0;
285 }
286 
287 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
288                                    u32 func, u32 index, int *nent, int maxnent)
289 {
290         switch (func) {
291         case 0:
292                 entry->eax = 1;         /* only one leaf currently */
293                 ++*nent;
294                 break;
295         case 1:
296                 entry->ecx = F(MOVBE);
297                 ++*nent;
298                 break;
299         default:
300                 break;
301         }
302 
303         entry->function = func;
304         entry->index = index;
305 
306         return 0;
307 }
308 
309 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
310                                  u32 index, int *nent, int maxnent)
311 {
312         int r;
313         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
314 #ifdef CONFIG_X86_64
315         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
316                                 ? F(GBPAGES) : 0;
317         unsigned f_lm = F(LM);
318 #else
319         unsigned f_gbpages = 0;
320         unsigned f_lm = 0;
321 #endif
322         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
323         unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
324         unsigned f_mpx = kvm_mpx_supported() ? F(MPX) : 0;
325         unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
326 
327         /* cpuid 1.edx */
328         const u32 kvm_cpuid_1_edx_x86_features =
329                 F(FPU) | F(VME) | F(DE) | F(PSE) |
330                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
331                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
332                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
333                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
334                 0 /* Reserved, DS, ACPI */ | F(MMX) |
335                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
336                 0 /* HTT, TM, Reserved, PBE */;
337         /* cpuid 0x80000001.edx */
338         const u32 kvm_cpuid_8000_0001_edx_x86_features =
339                 F(FPU) | F(VME) | F(DE) | F(PSE) |
340                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
341                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
342                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
343                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
344                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
345                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
346                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
347         /* cpuid 1.ecx */
348         const u32 kvm_cpuid_1_ecx_x86_features =
349                 /* NOTE: MONITOR (and MWAIT) are emulated as NOP,
350                  * but *not* advertised to guests via CPUID ! */
351                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
352                 0 /* DS-CPL, VMX, SMX, EST */ |
353                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
354                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
355                 F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
356                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
357                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
358                 F(F16C) | F(RDRAND);
359         /* cpuid 0x80000001.ecx */
360         const u32 kvm_cpuid_8000_0001_ecx_x86_features =
361                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
362                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
363                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
364                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
365 
366         /* cpuid 0xC0000001.edx */
367         const u32 kvm_cpuid_C000_0001_edx_x86_features =
368                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
369                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
370                 F(PMM) | F(PMM_EN);
371 
372         /* cpuid 7.0.ebx */
373         const u32 kvm_cpuid_7_0_ebx_x86_features =
374                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
375                 F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
376                 F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
377                 F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
378                 F(SHA_NI) | F(AVX512BW) | F(AVX512VL);
379 
380         /* cpuid 0xD.1.eax */
381         const u32 kvm_cpuid_D_1_eax_x86_features =
382                 F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
383 
384         /* cpuid 7.0.ecx*/
385         const u32 kvm_cpuid_7_0_ecx_x86_features =
386                 F(AVX512VBMI) | F(PKU) | 0 /*OSPKE*/;
387 
388         /* cpuid 7.0.edx*/
389         const u32 kvm_cpuid_7_0_edx_x86_features =
390                 KF(AVX512_4VNNIW) | KF(AVX512_4FMAPS);
391 
392         /* all calls to cpuid_count() should be made on the same cpu */
393         get_cpu();
394 
395         r = -E2BIG;
396 
397         if (*nent >= maxnent)
398                 goto out;
399 
400         do_cpuid_1_ent(entry, function, index);
401         ++*nent;
402 
403         switch (function) {
404         case 0:
405                 entry->eax = min(entry->eax, (u32)0xd);
406                 break;
407         case 1:
408                 entry->edx &= kvm_cpuid_1_edx_x86_features;
409                 cpuid_mask(&entry->edx, CPUID_1_EDX);
410                 entry->ecx &= kvm_cpuid_1_ecx_x86_features;
411                 cpuid_mask(&entry->ecx, CPUID_1_ECX);
412                 /* we support x2apic emulation even if host does not support
413                  * it since we emulate x2apic in software */
414                 entry->ecx |= F(X2APIC);
415                 break;
416         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
417          * may return different values. This forces us to get_cpu() before
418          * issuing the first command, and also to emulate this annoying behavior
419          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
420         case 2: {
421                 int t, times = entry->eax & 0xff;
422 
423                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
424                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
425                 for (t = 1; t < times; ++t) {
426                         if (*nent >= maxnent)
427                                 goto out;
428 
429                         do_cpuid_1_ent(&entry[t], function, 0);
430                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
431                         ++*nent;
432                 }
433                 break;
434         }
435         /* function 4 has additional index. */
436         case 4: {
437                 int i, cache_type;
438 
439                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
440                 /* read more entries until cache_type is zero */
441                 for (i = 1; ; ++i) {
442                         if (*nent >= maxnent)
443                                 goto out;
444 
445                         cache_type = entry[i - 1].eax & 0x1f;
446                         if (!cache_type)
447                                 break;
448                         do_cpuid_1_ent(&entry[i], function, i);
449                         entry[i].flags |=
450                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
451                         ++*nent;
452                 }
453                 break;
454         }
455         case 6: /* Thermal management */
456                 entry->eax = 0x4; /* allow ARAT */
457                 entry->ebx = 0;
458                 entry->ecx = 0;
459                 entry->edx = 0;
460                 break;
461         case 7: {
462                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
463                 /* Mask ebx against host capability word 9 */
464                 if (index == 0) {
465                         entry->ebx &= kvm_cpuid_7_0_ebx_x86_features;
466                         cpuid_mask(&entry->ebx, CPUID_7_0_EBX);
467                         // TSC_ADJUST is emulated
468                         entry->ebx |= F(TSC_ADJUST);
469                         entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
470                         cpuid_mask(&entry->ecx, CPUID_7_ECX);
471                         /* PKU is not yet implemented for shadow paging. */
472                         if (!tdp_enabled)
473                                 entry->ecx &= ~F(PKU);
474                         entry->edx &= kvm_cpuid_7_0_edx_x86_features;
475                         entry->edx &= get_scattered_cpuid_leaf(7, 0, CPUID_EDX);
476                 } else {
477                         entry->ebx = 0;
478                         entry->ecx = 0;
479                         entry->edx = 0;
480                 }
481                 entry->eax = 0;
482                 break;
483         }
484         case 9:
485                 break;
486         case 0xa: { /* Architectural Performance Monitoring */
487                 struct x86_pmu_capability cap;
488                 union cpuid10_eax eax;
489                 union cpuid10_edx edx;
490 
491                 perf_get_x86_pmu_capability(&cap);
492 
493                 /*
494                  * Only support guest architectural pmu on a host
495                  * with architectural pmu.
496                  */
497                 if (!cap.version)
498                         memset(&cap, 0, sizeof(cap));
499 
500                 eax.split.version_id = min(cap.version, 2);
501                 eax.split.num_counters = cap.num_counters_gp;
502                 eax.split.bit_width = cap.bit_width_gp;
503                 eax.split.mask_length = cap.events_mask_len;
504 
505                 edx.split.num_counters_fixed = cap.num_counters_fixed;
506                 edx.split.bit_width_fixed = cap.bit_width_fixed;
507                 edx.split.reserved = 0;
508 
509                 entry->eax = eax.full;
510                 entry->ebx = cap.events_mask;
511                 entry->ecx = 0;
512                 entry->edx = edx.full;
513                 break;
514         }
515         /* function 0xb has additional index. */
516         case 0xb: {
517                 int i, level_type;
518 
519                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
520                 /* read more entries until level_type is zero */
521                 for (i = 1; ; ++i) {
522                         if (*nent >= maxnent)
523                                 goto out;
524 
525                         level_type = entry[i - 1].ecx & 0xff00;
526                         if (!level_type)
527                                 break;
528                         do_cpuid_1_ent(&entry[i], function, i);
529                         entry[i].flags |=
530                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
531                         ++*nent;
532                 }
533                 break;
534         }
535         case 0xd: {
536                 int idx, i;
537                 u64 supported = kvm_supported_xcr0();
538 
539                 entry->eax &= supported;
540                 entry->ebx = xstate_required_size(supported, false);
541                 entry->ecx = entry->ebx;
542                 entry->edx &= supported >> 32;
543                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
544                 if (!supported)
545                         break;
546 
547                 for (idx = 1, i = 1; idx < 64; ++idx) {
548                         u64 mask = ((u64)1 << idx);
549                         if (*nent >= maxnent)
550                                 goto out;
551 
552                         do_cpuid_1_ent(&entry[i], function, idx);
553                         if (idx == 1) {
554                                 entry[i].eax &= kvm_cpuid_D_1_eax_x86_features;
555                                 cpuid_mask(&entry[i].eax, CPUID_D_1_EAX);
556                                 entry[i].ebx = 0;
557                                 if (entry[i].eax & (F(XSAVES)|F(XSAVEC)))
558                                         entry[i].ebx =
559                                                 xstate_required_size(supported,
560                                                                      true);
561                         } else {
562                                 if (entry[i].eax == 0 || !(supported & mask))
563                                         continue;
564                                 if (WARN_ON_ONCE(entry[i].ecx & 1))
565                                         continue;
566                         }
567                         entry[i].ecx = 0;
568                         entry[i].edx = 0;
569                         entry[i].flags |=
570                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
571                         ++*nent;
572                         ++i;
573                 }
574                 break;
575         }
576         case KVM_CPUID_SIGNATURE: {
577                 static const char signature[12] = "KVMKVMKVM\0\0";
578                 const u32 *sigptr = (const u32 *)signature;
579                 entry->eax = KVM_CPUID_FEATURES;
580                 entry->ebx = sigptr[0];
581                 entry->ecx = sigptr[1];
582                 entry->edx = sigptr[2];
583                 break;
584         }
585         case KVM_CPUID_FEATURES:
586                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
587                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
588                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
589                              (1 << KVM_FEATURE_ASYNC_PF) |
590                              (1 << KVM_FEATURE_PV_EOI) |
591                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
592                              (1 << KVM_FEATURE_PV_UNHALT);
593 
594                 if (sched_info_on())
595                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
596 
597                 entry->ebx = 0;
598                 entry->ecx = 0;
599                 entry->edx = 0;
600                 break;
601         case 0x80000000:
602                 entry->eax = min(entry->eax, 0x8000001a);
603                 break;
604         case 0x80000001:
605                 entry->edx &= kvm_cpuid_8000_0001_edx_x86_features;
606                 cpuid_mask(&entry->edx, CPUID_8000_0001_EDX);
607                 entry->ecx &= kvm_cpuid_8000_0001_ecx_x86_features;
608                 cpuid_mask(&entry->ecx, CPUID_8000_0001_ECX);
609                 break;
610         case 0x80000007: /* Advanced power management */
611                 /* invariant TSC is CPUID.80000007H:EDX[8] */
612                 entry->edx &= (1 << 8);
613                 /* mask against host */
614                 entry->edx &= boot_cpu_data.x86_power;
615                 entry->eax = entry->ebx = entry->ecx = 0;
616                 break;
617         case 0x80000008: {
618                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
619                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
620                 unsigned phys_as = entry->eax & 0xff;
621 
622                 if (!g_phys_as)
623                         g_phys_as = phys_as;
624                 entry->eax = g_phys_as | (virt_as << 8);
625                 entry->ebx = entry->edx = 0;
626                 break;
627         }
628         case 0x80000019:
629                 entry->ecx = entry->edx = 0;
630                 break;
631         case 0x8000001a:
632                 break;
633         case 0x8000001d:
634                 break;
635         /*Add support for Centaur's CPUID instruction*/
636         case 0xC0000000:
637                 /*Just support up to 0xC0000004 now*/
638                 entry->eax = min(entry->eax, 0xC0000004);
639                 break;
640         case 0xC0000001:
641                 entry->edx &= kvm_cpuid_C000_0001_edx_x86_features;
642                 cpuid_mask(&entry->edx, CPUID_C000_0001_EDX);
643                 break;
644         case 3: /* Processor serial number */
645         case 5: /* MONITOR/MWAIT */
646         case 0xC0000002:
647         case 0xC0000003:
648         case 0xC0000004:
649         default:
650                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
651                 break;
652         }
653 
654         kvm_x86_ops->set_supported_cpuid(function, entry);
655 
656         r = 0;
657 
658 out:
659         put_cpu();
660 
661         return r;
662 }
663 
664 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
665                         u32 idx, int *nent, int maxnent, unsigned int type)
666 {
667         if (type == KVM_GET_EMULATED_CPUID)
668                 return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
669 
670         return __do_cpuid_ent(entry, func, idx, nent, maxnent);
671 }
672 
673 #undef F
674 
675 struct kvm_cpuid_param {
676         u32 func;
677         u32 idx;
678         bool has_leaf_count;
679         bool (*qualifier)(const struct kvm_cpuid_param *param);
680 };
681 
682 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
683 {
684         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
685 }
686 
687 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
688                                  __u32 num_entries, unsigned int ioctl_type)
689 {
690         int i;
691         __u32 pad[3];
692 
693         if (ioctl_type != KVM_GET_EMULATED_CPUID)
694                 return false;
695 
696         /*
697          * We want to make sure that ->padding is being passed clean from
698          * userspace in case we want to use it for something in the future.
699          *
700          * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
701          * have to give ourselves satisfied only with the emulated side. /me
702          * sheds a tear.
703          */
704         for (i = 0; i < num_entries; i++) {
705                 if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
706                         return true;
707 
708                 if (pad[0] || pad[1] || pad[2])
709                         return true;
710         }
711         return false;
712 }
713 
714 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
715                             struct kvm_cpuid_entry2 __user *entries,
716                             unsigned int type)
717 {
718         struct kvm_cpuid_entry2 *cpuid_entries;
719         int limit, nent = 0, r = -E2BIG, i;
720         u32 func;
721         static const struct kvm_cpuid_param param[] = {
722                 { .func = 0, .has_leaf_count = true },
723                 { .func = 0x80000000, .has_leaf_count = true },
724                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
725                 { .func = KVM_CPUID_SIGNATURE },
726                 { .func = KVM_CPUID_FEATURES },
727         };
728 
729         if (cpuid->nent < 1)
730                 goto out;
731         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
732                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
733 
734         if (sanity_check_entries(entries, cpuid->nent, type))
735                 return -EINVAL;
736 
737         r = -ENOMEM;
738         cpuid_entries = vzalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
739         if (!cpuid_entries)
740                 goto out;
741 
742         r = 0;
743         for (i = 0; i < ARRAY_SIZE(param); i++) {
744                 const struct kvm_cpuid_param *ent = &param[i];
745 
746                 if (ent->qualifier && !ent->qualifier(ent))
747                         continue;
748 
749                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
750                                 &nent, cpuid->nent, type);
751 
752                 if (r)
753                         goto out_free;
754 
755                 if (!ent->has_leaf_count)
756                         continue;
757 
758                 limit = cpuid_entries[nent - 1].eax;
759                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
760                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
761                                      &nent, cpuid->nent, type);
762 
763                 if (r)
764                         goto out_free;
765         }
766 
767         r = -EFAULT;
768         if (copy_to_user(entries, cpuid_entries,
769                          nent * sizeof(struct kvm_cpuid_entry2)))
770                 goto out_free;
771         cpuid->nent = nent;
772         r = 0;
773 
774 out_free:
775         vfree(cpuid_entries);
776 out:
777         return r;
778 }
779 
780 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
781 {
782         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
783         int j, nent = vcpu->arch.cpuid_nent;
784 
785         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
786         /* when no next entry is found, the current entry[i] is reselected */
787         for (j = i + 1; ; j = (j + 1) % nent) {
788                 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
789                 if (ej->function == e->function) {
790                         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
791                         return j;
792                 }
793         }
794         return 0; /* silence gcc, even though control never reaches here */
795 }
796 
797 /* find an entry with matching function, matching index (if needed), and that
798  * should be read next (if it's stateful) */
799 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
800         u32 function, u32 index)
801 {
802         if (e->function != function)
803                 return 0;
804         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
805                 return 0;
806         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
807             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
808                 return 0;
809         return 1;
810 }
811 
812 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
813                                               u32 function, u32 index)
814 {
815         int i;
816         struct kvm_cpuid_entry2 *best = NULL;
817 
818         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
819                 struct kvm_cpuid_entry2 *e;
820 
821                 e = &vcpu->arch.cpuid_entries[i];
822                 if (is_matching_cpuid_entry(e, function, index)) {
823                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
824                                 move_to_next_stateful_cpuid_entry(vcpu, i);
825                         best = e;
826                         break;
827                 }
828         }
829         return best;
830 }
831 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
832 
833 /*
834  * If no match is found, check whether we exceed the vCPU's limit
835  * and return the content of the highest valid _standard_ leaf instead.
836  * This is to satisfy the CPUID specification.
837  */
838 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
839                                                   u32 function, u32 index)
840 {
841         struct kvm_cpuid_entry2 *maxlevel;
842 
843         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
844         if (!maxlevel || maxlevel->eax >= function)
845                 return NULL;
846         if (function & 0x80000000) {
847                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
848                 if (!maxlevel)
849                         return NULL;
850         }
851         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
852 }
853 
854 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
855 {
856         u32 function = *eax, index = *ecx;
857         struct kvm_cpuid_entry2 *best;
858 
859         best = kvm_find_cpuid_entry(vcpu, function, index);
860 
861         if (!best)
862                 best = check_cpuid_limit(vcpu, function, index);
863 
864         if (best) {
865                 *eax = best->eax;
866                 *ebx = best->ebx;
867                 *ecx = best->ecx;
868                 *edx = best->edx;
869         } else
870                 *eax = *ebx = *ecx = *edx = 0;
871         trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
872 }
873 EXPORT_SYMBOL_GPL(kvm_cpuid);
874 
875 int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
876 {
877         u32 eax, ebx, ecx, edx;
878 
879         eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
880         ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
881         kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
882         kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
883         kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
884         kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
885         kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
886         return kvm_skip_emulated_instruction(vcpu);
887 }
888 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);
889 

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