Merge tag 'pm-for-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux-3.10.git] / arch / x86 / kvm / cpuid.c
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/module.h>
17 #include <linux/vmalloc.h>
18 #include <linux/uaccess.h>
19 #include <asm/user.h>
20 #include <asm/xsave.h>
21 #include "cpuid.h"
22 #include "lapic.h"
23 #include "mmu.h"
24 #include "trace.h"
25
26 void kvm_update_cpuid(struct kvm_vcpu *vcpu)
27 {
28         struct kvm_cpuid_entry2 *best;
29         struct kvm_lapic *apic = vcpu->arch.apic;
30
31         best = kvm_find_cpuid_entry(vcpu, 1, 0);
32         if (!best)
33                 return;
34
35         /* Update OSXSAVE bit */
36         if (cpu_has_xsave && best->function == 0x1) {
37                 best->ecx &= ~(bit(X86_FEATURE_OSXSAVE));
38                 if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
39                         best->ecx |= bit(X86_FEATURE_OSXSAVE);
40         }
41
42         if (apic) {
43                 if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER))
44                         apic->lapic_timer.timer_mode_mask = 3 << 17;
45                 else
46                         apic->lapic_timer.timer_mode_mask = 1 << 17;
47         }
48
49         kvm_pmu_cpuid_update(vcpu);
50 }
51
52 static int is_efer_nx(void)
53 {
54         unsigned long long efer = 0;
55
56         rdmsrl_safe(MSR_EFER, &efer);
57         return efer & EFER_NX;
58 }
59
60 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
61 {
62         int i;
63         struct kvm_cpuid_entry2 *e, *entry;
64
65         entry = NULL;
66         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
67                 e = &vcpu->arch.cpuid_entries[i];
68                 if (e->function == 0x80000001) {
69                         entry = e;
70                         break;
71                 }
72         }
73         if (entry && (entry->edx & (1 << 20)) && !is_efer_nx()) {
74                 entry->edx &= ~(1 << 20);
75                 printk(KERN_INFO "kvm: guest NX capability removed\n");
76         }
77 }
78
79 /* when an old userspace process fills a new kernel module */
80 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
81                              struct kvm_cpuid *cpuid,
82                              struct kvm_cpuid_entry __user *entries)
83 {
84         int r, i;
85         struct kvm_cpuid_entry *cpuid_entries;
86
87         r = -E2BIG;
88         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
89                 goto out;
90         r = -ENOMEM;
91         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
92         if (!cpuid_entries)
93                 goto out;
94         r = -EFAULT;
95         if (copy_from_user(cpuid_entries, entries,
96                            cpuid->nent * sizeof(struct kvm_cpuid_entry)))
97                 goto out_free;
98         for (i = 0; i < cpuid->nent; i++) {
99                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
100                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
101                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
102                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
103                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
104                 vcpu->arch.cpuid_entries[i].index = 0;
105                 vcpu->arch.cpuid_entries[i].flags = 0;
106                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
107                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
108                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
109         }
110         vcpu->arch.cpuid_nent = cpuid->nent;
111         cpuid_fix_nx_cap(vcpu);
112         r = 0;
113         kvm_apic_set_version(vcpu);
114         kvm_x86_ops->cpuid_update(vcpu);
115         kvm_update_cpuid(vcpu);
116
117 out_free:
118         vfree(cpuid_entries);
119 out:
120         return r;
121 }
122
123 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
124                               struct kvm_cpuid2 *cpuid,
125                               struct kvm_cpuid_entry2 __user *entries)
126 {
127         int r;
128
129         r = -E2BIG;
130         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
131                 goto out;
132         r = -EFAULT;
133         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
134                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
135                 goto out;
136         vcpu->arch.cpuid_nent = cpuid->nent;
137         kvm_apic_set_version(vcpu);
138         kvm_x86_ops->cpuid_update(vcpu);
139         kvm_update_cpuid(vcpu);
140         return 0;
141
142 out:
143         return r;
144 }
145
146 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
147                               struct kvm_cpuid2 *cpuid,
148                               struct kvm_cpuid_entry2 __user *entries)
149 {
150         int r;
151
152         r = -E2BIG;
153         if (cpuid->nent < vcpu->arch.cpuid_nent)
154                 goto out;
155         r = -EFAULT;
156         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
157                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
158                 goto out;
159         return 0;
160
161 out:
162         cpuid->nent = vcpu->arch.cpuid_nent;
163         return r;
164 }
165
166 static void cpuid_mask(u32 *word, int wordnum)
167 {
168         *word &= boot_cpu_data.x86_capability[wordnum];
169 }
170
171 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
172                            u32 index)
173 {
174         entry->function = function;
175         entry->index = index;
176         cpuid_count(entry->function, entry->index,
177                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
178         entry->flags = 0;
179 }
180
181 static bool supported_xcr0_bit(unsigned bit)
182 {
183         u64 mask = ((u64)1 << bit);
184
185         return mask & (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) & host_xcr0;
186 }
187
188 #define F(x) bit(X86_FEATURE_##x)
189
190 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
191                          u32 index, int *nent, int maxnent)
192 {
193         int r;
194         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
195 #ifdef CONFIG_X86_64
196         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
197                                 ? F(GBPAGES) : 0;
198         unsigned f_lm = F(LM);
199 #else
200         unsigned f_gbpages = 0;
201         unsigned f_lm = 0;
202 #endif
203         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
204
205         /* cpuid 1.edx */
206         const u32 kvm_supported_word0_x86_features =
207                 F(FPU) | F(VME) | F(DE) | F(PSE) |
208                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
209                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
210                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
211                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLSH) |
212                 0 /* Reserved, DS, ACPI */ | F(MMX) |
213                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
214                 0 /* HTT, TM, Reserved, PBE */;
215         /* cpuid 0x80000001.edx */
216         const u32 kvm_supported_word1_x86_features =
217                 F(FPU) | F(VME) | F(DE) | F(PSE) |
218                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
219                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
220                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
221                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
222                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
223                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
224                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
225         /* cpuid 1.ecx */
226         const u32 kvm_supported_word4_x86_features =
227                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
228                 0 /* DS-CPL, VMX, SMX, EST */ |
229                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
230                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
231                 0 /* Reserved, DCA */ | F(XMM4_1) |
232                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
233                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
234                 F(F16C) | F(RDRAND);
235         /* cpuid 0x80000001.ecx */
236         const u32 kvm_supported_word6_x86_features =
237                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
238                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
239                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
240                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
241
242         /* cpuid 0xC0000001.edx */
243         const u32 kvm_supported_word5_x86_features =
244                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
245                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
246                 F(PMM) | F(PMM_EN);
247
248         /* cpuid 7.0.ebx */
249         const u32 kvm_supported_word9_x86_features =
250                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
251                 F(BMI2) | F(ERMS) | F(RTM);
252
253         /* all calls to cpuid_count() should be made on the same cpu */
254         get_cpu();
255
256         r = -E2BIG;
257
258         if (*nent >= maxnent)
259                 goto out;
260
261         do_cpuid_1_ent(entry, function, index);
262         ++*nent;
263
264         switch (function) {
265         case 0:
266                 entry->eax = min(entry->eax, (u32)0xd);
267                 break;
268         case 1:
269                 entry->edx &= kvm_supported_word0_x86_features;
270                 cpuid_mask(&entry->edx, 0);
271                 entry->ecx &= kvm_supported_word4_x86_features;
272                 cpuid_mask(&entry->ecx, 4);
273                 /* we support x2apic emulation even if host does not support
274                  * it since we emulate x2apic in software */
275                 entry->ecx |= F(X2APIC);
276                 break;
277         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
278          * may return different values. This forces us to get_cpu() before
279          * issuing the first command, and also to emulate this annoying behavior
280          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
281         case 2: {
282                 int t, times = entry->eax & 0xff;
283
284                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
285                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
286                 for (t = 1; t < times; ++t) {
287                         if (*nent >= maxnent)
288                                 goto out;
289
290                         do_cpuid_1_ent(&entry[t], function, 0);
291                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
292                         ++*nent;
293                 }
294                 break;
295         }
296         /* function 4 has additional index. */
297         case 4: {
298                 int i, cache_type;
299
300                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
301                 /* read more entries until cache_type is zero */
302                 for (i = 1; ; ++i) {
303                         if (*nent >= maxnent)
304                                 goto out;
305
306                         cache_type = entry[i - 1].eax & 0x1f;
307                         if (!cache_type)
308                                 break;
309                         do_cpuid_1_ent(&entry[i], function, i);
310                         entry[i].flags |=
311                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
312                         ++*nent;
313                 }
314                 break;
315         }
316         case 7: {
317                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
318                 /* Mask ebx against host capbability word 9 */
319                 if (index == 0) {
320                         entry->ebx &= kvm_supported_word9_x86_features;
321                         cpuid_mask(&entry->ebx, 9);
322                 } else
323                         entry->ebx = 0;
324                 entry->eax = 0;
325                 entry->ecx = 0;
326                 entry->edx = 0;
327                 break;
328         }
329         case 9:
330                 break;
331         case 0xa: { /* Architectural Performance Monitoring */
332                 struct x86_pmu_capability cap;
333                 union cpuid10_eax eax;
334                 union cpuid10_edx edx;
335
336                 perf_get_x86_pmu_capability(&cap);
337
338                 /*
339                  * Only support guest architectural pmu on a host
340                  * with architectural pmu.
341                  */
342                 if (!cap.version)
343                         memset(&cap, 0, sizeof(cap));
344
345                 eax.split.version_id = min(cap.version, 2);
346                 eax.split.num_counters = cap.num_counters_gp;
347                 eax.split.bit_width = cap.bit_width_gp;
348                 eax.split.mask_length = cap.events_mask_len;
349
350                 edx.split.num_counters_fixed = cap.num_counters_fixed;
351                 edx.split.bit_width_fixed = cap.bit_width_fixed;
352                 edx.split.reserved = 0;
353
354                 entry->eax = eax.full;
355                 entry->ebx = cap.events_mask;
356                 entry->ecx = 0;
357                 entry->edx = edx.full;
358                 break;
359         }
360         /* function 0xb has additional index. */
361         case 0xb: {
362                 int i, level_type;
363
364                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
365                 /* read more entries until level_type is zero */
366                 for (i = 1; ; ++i) {
367                         if (*nent >= maxnent)
368                                 goto out;
369
370                         level_type = entry[i - 1].ecx & 0xff00;
371                         if (!level_type)
372                                 break;
373                         do_cpuid_1_ent(&entry[i], function, i);
374                         entry[i].flags |=
375                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
376                         ++*nent;
377                 }
378                 break;
379         }
380         case 0xd: {
381                 int idx, i;
382
383                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
384                 for (idx = 1, i = 1; idx < 64; ++idx) {
385                         if (*nent >= maxnent)
386                                 goto out;
387
388                         do_cpuid_1_ent(&entry[i], function, idx);
389                         if (entry[i].eax == 0 || !supported_xcr0_bit(idx))
390                                 continue;
391                         entry[i].flags |=
392                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
393                         ++*nent;
394                         ++i;
395                 }
396                 break;
397         }
398         case KVM_CPUID_SIGNATURE: {
399                 char signature[12] = "KVMKVMKVM\0\0";
400                 u32 *sigptr = (u32 *)signature;
401                 entry->eax = KVM_CPUID_FEATURES;
402                 entry->ebx = sigptr[0];
403                 entry->ecx = sigptr[1];
404                 entry->edx = sigptr[2];
405                 break;
406         }
407         case KVM_CPUID_FEATURES:
408                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
409                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
410                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
411                              (1 << KVM_FEATURE_ASYNC_PF) |
412                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
413
414                 if (sched_info_on())
415                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
416
417                 entry->ebx = 0;
418                 entry->ecx = 0;
419                 entry->edx = 0;
420                 break;
421         case 0x80000000:
422                 entry->eax = min(entry->eax, 0x8000001a);
423                 break;
424         case 0x80000001:
425                 entry->edx &= kvm_supported_word1_x86_features;
426                 cpuid_mask(&entry->edx, 1);
427                 entry->ecx &= kvm_supported_word6_x86_features;
428                 cpuid_mask(&entry->ecx, 6);
429                 break;
430         case 0x80000008: {
431                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
432                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
433                 unsigned phys_as = entry->eax & 0xff;
434
435                 if (!g_phys_as)
436                         g_phys_as = phys_as;
437                 entry->eax = g_phys_as | (virt_as << 8);
438                 entry->ebx = entry->edx = 0;
439                 break;
440         }
441         case 0x80000019:
442                 entry->ecx = entry->edx = 0;
443                 break;
444         case 0x8000001a:
445                 break;
446         case 0x8000001d:
447                 break;
448         /*Add support for Centaur's CPUID instruction*/
449         case 0xC0000000:
450                 /*Just support up to 0xC0000004 now*/
451                 entry->eax = min(entry->eax, 0xC0000004);
452                 break;
453         case 0xC0000001:
454                 entry->edx &= kvm_supported_word5_x86_features;
455                 cpuid_mask(&entry->edx, 5);
456                 break;
457         case 3: /* Processor serial number */
458         case 5: /* MONITOR/MWAIT */
459         case 6: /* Thermal management */
460         case 0x80000007: /* Advanced power management */
461         case 0xC0000002:
462         case 0xC0000003:
463         case 0xC0000004:
464         default:
465                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
466                 break;
467         }
468
469         kvm_x86_ops->set_supported_cpuid(function, entry);
470
471         r = 0;
472
473 out:
474         put_cpu();
475
476         return r;
477 }
478
479 #undef F
480
481 struct kvm_cpuid_param {
482         u32 func;
483         u32 idx;
484         bool has_leaf_count;
485         bool (*qualifier)(struct kvm_cpuid_param *param);
486 };
487
488 static bool is_centaur_cpu(struct kvm_cpuid_param *param)
489 {
490         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
491 }
492
493 int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
494                                       struct kvm_cpuid_entry2 __user *entries)
495 {
496         struct kvm_cpuid_entry2 *cpuid_entries;
497         int limit, nent = 0, r = -E2BIG, i;
498         u32 func;
499         static struct kvm_cpuid_param param[] = {
500                 { .func = 0, .has_leaf_count = true },
501                 { .func = 0x80000000, .has_leaf_count = true },
502                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
503                 { .func = KVM_CPUID_SIGNATURE },
504                 { .func = KVM_CPUID_FEATURES },
505         };
506
507         if (cpuid->nent < 1)
508                 goto out;
509         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
510                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
511         r = -ENOMEM;
512         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
513         if (!cpuid_entries)
514                 goto out;
515
516         r = 0;
517         for (i = 0; i < ARRAY_SIZE(param); i++) {
518                 struct kvm_cpuid_param *ent = &param[i];
519
520                 if (ent->qualifier && !ent->qualifier(ent))
521                         continue;
522
523                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
524                                 &nent, cpuid->nent);
525
526                 if (r)
527                         goto out_free;
528
529                 if (!ent->has_leaf_count)
530                         continue;
531
532                 limit = cpuid_entries[nent - 1].eax;
533                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
534                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
535                                      &nent, cpuid->nent);
536
537                 if (r)
538                         goto out_free;
539         }
540
541         r = -EFAULT;
542         if (copy_to_user(entries, cpuid_entries,
543                          nent * sizeof(struct kvm_cpuid_entry2)))
544                 goto out_free;
545         cpuid->nent = nent;
546         r = 0;
547
548 out_free:
549         vfree(cpuid_entries);
550 out:
551         return r;
552 }
553
554 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
555 {
556         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
557         int j, nent = vcpu->arch.cpuid_nent;
558
559         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
560         /* when no next entry is found, the current entry[i] is reselected */
561         for (j = i + 1; ; j = (j + 1) % nent) {
562                 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
563                 if (ej->function == e->function) {
564                         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
565                         return j;
566                 }
567         }
568         return 0; /* silence gcc, even though control never reaches here */
569 }
570
571 /* find an entry with matching function, matching index (if needed), and that
572  * should be read next (if it's stateful) */
573 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
574         u32 function, u32 index)
575 {
576         if (e->function != function)
577                 return 0;
578         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
579                 return 0;
580         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
581             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
582                 return 0;
583         return 1;
584 }
585
586 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
587                                               u32 function, u32 index)
588 {
589         int i;
590         struct kvm_cpuid_entry2 *best = NULL;
591
592         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
593                 struct kvm_cpuid_entry2 *e;
594
595                 e = &vcpu->arch.cpuid_entries[i];
596                 if (is_matching_cpuid_entry(e, function, index)) {
597                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
598                                 move_to_next_stateful_cpuid_entry(vcpu, i);
599                         best = e;
600                         break;
601                 }
602         }
603         return best;
604 }
605 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
606
607 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
608 {
609         struct kvm_cpuid_entry2 *best;
610
611         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
612         if (!best || best->eax < 0x80000008)
613                 goto not_found;
614         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
615         if (best)
616                 return best->eax & 0xff;
617 not_found:
618         return 36;
619 }
620
621 /*
622  * If no match is found, check whether we exceed the vCPU's limit
623  * and return the content of the highest valid _standard_ leaf instead.
624  * This is to satisfy the CPUID specification.
625  */
626 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
627                                                   u32 function, u32 index)
628 {
629         struct kvm_cpuid_entry2 *maxlevel;
630
631         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
632         if (!maxlevel || maxlevel->eax >= function)
633                 return NULL;
634         if (function & 0x80000000) {
635                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
636                 if (!maxlevel)
637                         return NULL;
638         }
639         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
640 }
641
642 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
643 {
644         u32 function, index;
645         struct kvm_cpuid_entry2 *best;
646
647         function = kvm_register_read(vcpu, VCPU_REGS_RAX);
648         index = kvm_register_read(vcpu, VCPU_REGS_RCX);
649         kvm_register_write(vcpu, VCPU_REGS_RAX, 0);
650         kvm_register_write(vcpu, VCPU_REGS_RBX, 0);
651         kvm_register_write(vcpu, VCPU_REGS_RCX, 0);
652         kvm_register_write(vcpu, VCPU_REGS_RDX, 0);
653         best = kvm_find_cpuid_entry(vcpu, function, index);
654
655         if (!best)
656                 best = check_cpuid_limit(vcpu, function, index);
657
658         if (best) {
659                 kvm_register_write(vcpu, VCPU_REGS_RAX, best->eax);
660                 kvm_register_write(vcpu, VCPU_REGS_RBX, best->ebx);
661                 kvm_register_write(vcpu, VCPU_REGS_RCX, best->ecx);
662                 kvm_register_write(vcpu, VCPU_REGS_RDX, best->edx);
663         }
664         kvm_x86_ops->skip_emulated_instruction(vcpu);
665         trace_kvm_cpuid(function,
666                         kvm_register_read(vcpu, VCPU_REGS_RAX),
667                         kvm_register_read(vcpu, VCPU_REGS_RBX),
668                         kvm_register_read(vcpu, VCPU_REGS_RCX),
669                         kvm_register_read(vcpu, VCPU_REGS_RDX));
670 }
671 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);