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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/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 int 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 0;
 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         /* The existing code assumes virtual address is 48-bit in the canonical
 50          * address checks; exit if it is ever changed */
 51         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
 52         if (best && ((best->eax & 0xff00) >> 8) != 48 &&
 53                 ((best->eax & 0xff00) >> 8) != 0)
 54                 return -EINVAL;
 55 
 56         kvm_pmu_cpuid_update(vcpu);
 57         return 0;
 58 }
 59 
 60 static int is_efer_nx(void)
 61 {
 62         unsigned long long efer = 0;
 63 
 64         rdmsrl_safe(MSR_EFER, &efer);
 65         return efer & EFER_NX;
 66 }
 67 
 68 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
 69 {
 70         int i;
 71         struct kvm_cpuid_entry2 *e, *entry;
 72 
 73         entry = NULL;
 74         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
 75                 e = &vcpu->arch.cpuid_entries[i];
 76                 if (e->function == 0x80000001) {
 77                         entry = e;
 78                         break;
 79                 }
 80         }
 81         if (entry && (entry->edx & (1 << 20)) && !is_efer_nx()) {
 82                 entry->edx &= ~(1 << 20);
 83                 printk(KERN_INFO "kvm: guest NX capability removed\n");
 84         }
 85 }
 86 
 87 /* when an old userspace process fills a new kernel module */
 88 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
 89                              struct kvm_cpuid *cpuid,
 90                              struct kvm_cpuid_entry __user *entries)
 91 {
 92         int r, i;
 93         struct kvm_cpuid_entry *cpuid_entries;
 94 
 95         r = -E2BIG;
 96         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 97                 goto out;
 98         r = -ENOMEM;
 99         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
100         if (!cpuid_entries)
101                 goto out;
102         r = -EFAULT;
103         if (copy_from_user(cpuid_entries, entries,
104                            cpuid->nent * sizeof(struct kvm_cpuid_entry)))
105                 goto out_free;
106         for (i = 0; i < cpuid->nent; i++) {
107                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
108                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
109                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
110                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
111                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
112                 vcpu->arch.cpuid_entries[i].index = 0;
113                 vcpu->arch.cpuid_entries[i].flags = 0;
114                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
115                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
116                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
117         }
118         vcpu->arch.cpuid_nent = cpuid->nent;
119         cpuid_fix_nx_cap(vcpu);
120         kvm_apic_set_version(vcpu);
121         kvm_x86_ops->cpuid_update(vcpu);
122         r = kvm_update_cpuid(vcpu);
123 
124 out_free:
125         vfree(cpuid_entries);
126 out:
127         return r;
128 }
129 
130 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
131                               struct kvm_cpuid2 *cpuid,
132                               struct kvm_cpuid_entry2 __user *entries)
133 {
134         int r;
135 
136         r = -E2BIG;
137         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
138                 goto out;
139         r = -EFAULT;
140         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
141                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
142                 goto out;
143         vcpu->arch.cpuid_nent = cpuid->nent;
144         kvm_apic_set_version(vcpu);
145         kvm_x86_ops->cpuid_update(vcpu);
146         r = kvm_update_cpuid(vcpu);
147 out:
148         return r;
149 }
150 
151 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
152                               struct kvm_cpuid2 *cpuid,
153                               struct kvm_cpuid_entry2 __user *entries)
154 {
155         int r;
156 
157         r = -E2BIG;
158         if (cpuid->nent < vcpu->arch.cpuid_nent)
159                 goto out;
160         r = -EFAULT;
161         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
162                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
163                 goto out;
164         return 0;
165 
166 out:
167         cpuid->nent = vcpu->arch.cpuid_nent;
168         return r;
169 }
170 
171 static void cpuid_mask(u32 *word, int wordnum)
172 {
173         *word &= boot_cpu_data.x86_capability[wordnum];
174 }
175 
176 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
177                            u32 index)
178 {
179         entry->function = function;
180         entry->index = index;
181         cpuid_count(entry->function, entry->index,
182                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
183         entry->flags = 0;
184 }
185 
186 static bool supported_xcr0_bit(unsigned bit)
187 {
188         u64 mask = ((u64)1 << bit);
189 
190         return mask & (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) & host_xcr0;
191 }
192 
193 #define F(x) bit(X86_FEATURE_##x)
194 
195 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
196                          u32 index, int *nent, int maxnent)
197 {
198         int r;
199         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
200 #ifdef CONFIG_X86_64
201         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
202                                 ? F(GBPAGES) : 0;
203         unsigned f_lm = F(LM);
204 #else
205         unsigned f_gbpages = 0;
206         unsigned f_lm = 0;
207 #endif
208         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
209         unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
210 
211         /* cpuid 1.edx */
212         const u32 kvm_supported_word0_x86_features =
213                 F(FPU) | F(VME) | F(DE) | F(PSE) |
214                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
215                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
216                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
217                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLSH) |
218                 0 /* Reserved, DS, ACPI */ | F(MMX) |
219                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
220                 0 /* HTT, TM, Reserved, PBE */;
221         /* cpuid 0x80000001.edx */
222         const u32 kvm_supported_word1_x86_features =
223                 F(FPU) | F(VME) | F(DE) | F(PSE) |
224                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
225                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
226                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
227                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
228                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
229                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
230                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
231         /* cpuid 1.ecx */
232         const u32 kvm_supported_word4_x86_features =
233                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
234                 0 /* DS-CPL, VMX, SMX, EST */ |
235                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
236                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
237                 F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
238                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
239                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
240                 F(F16C) | F(RDRAND);
241         /* cpuid 0x80000001.ecx */
242         const u32 kvm_supported_word6_x86_features =
243                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
244                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
245                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
246                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
247 
248         /* cpuid 0xC0000001.edx */
249         const u32 kvm_supported_word5_x86_features =
250                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
251                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
252                 F(PMM) | F(PMM_EN);
253 
254         /* cpuid 7.0.ebx */
255         const u32 kvm_supported_word9_x86_features =
256                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
257                 F(BMI2) | F(ERMS) | f_invpcid | F(RTM);
258 
259         /* all calls to cpuid_count() should be made on the same cpu */
260         get_cpu();
261 
262         r = -E2BIG;
263 
264         if (*nent >= maxnent)
265                 goto out;
266 
267         do_cpuid_1_ent(entry, function, index);
268         ++*nent;
269 
270         switch (function) {
271         case 0:
272                 entry->eax = min(entry->eax, (u32)0xd);
273                 break;
274         case 1:
275                 entry->edx &= kvm_supported_word0_x86_features;
276                 cpuid_mask(&entry->edx, 0);
277                 entry->ecx &= kvm_supported_word4_x86_features;
278                 cpuid_mask(&entry->ecx, 4);
279                 /* we support x2apic emulation even if host does not support
280                  * it since we emulate x2apic in software */
281                 entry->ecx |= F(X2APIC);
282                 break;
283         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
284          * may return different values. This forces us to get_cpu() before
285          * issuing the first command, and also to emulate this annoying behavior
286          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
287         case 2: {
288                 int t, times = entry->eax & 0xff;
289 
290                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
291                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
292                 for (t = 1; t < times; ++t) {
293                         if (*nent >= maxnent)
294                                 goto out;
295 
296                         do_cpuid_1_ent(&entry[t], function, 0);
297                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
298                         ++*nent;
299                 }
300                 break;
301         }
302         /* function 4 has additional index. */
303         case 4: {
304                 int i, cache_type;
305 
306                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
307                 /* read more entries until cache_type is zero */
308                 for (i = 1; ; ++i) {
309                         if (*nent >= maxnent)
310                                 goto out;
311 
312                         cache_type = entry[i - 1].eax & 0x1f;
313                         if (!cache_type)
314                                 break;
315                         do_cpuid_1_ent(&entry[i], function, i);
316                         entry[i].flags |=
317                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
318                         ++*nent;
319                 }
320                 break;
321         }
322         case 7: {
323                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
324                 /* Mask ebx against host capability word 9 */
325                 if (index == 0) {
326                         entry->ebx &= kvm_supported_word9_x86_features;
327                         cpuid_mask(&entry->ebx, 9);
328                         // TSC_ADJUST is emulated
329                         entry->ebx |= F(TSC_ADJUST);
330                 } else
331                         entry->ebx = 0;
332                 entry->eax = 0;
333                 entry->ecx = 0;
334                 entry->edx = 0;
335                 break;
336         }
337         case 9:
338                 break;
339         case 0xa: { /* Architectural Performance Monitoring */
340                 struct x86_pmu_capability cap;
341                 union cpuid10_eax eax;
342                 union cpuid10_edx edx;
343 
344                 perf_get_x86_pmu_capability(&cap);
345 
346                 /*
347                  * Only support guest architectural pmu on a host
348                  * with architectural pmu.
349                  */
350                 if (!cap.version)
351                         memset(&cap, 0, sizeof(cap));
352 
353                 eax.split.version_id = min(cap.version, 2);
354                 eax.split.num_counters = cap.num_counters_gp;
355                 eax.split.bit_width = cap.bit_width_gp;
356                 eax.split.mask_length = cap.events_mask_len;
357 
358                 edx.split.num_counters_fixed = cap.num_counters_fixed;
359                 edx.split.bit_width_fixed = cap.bit_width_fixed;
360                 edx.split.reserved = 0;
361 
362                 entry->eax = eax.full;
363                 entry->ebx = cap.events_mask;
364                 entry->ecx = 0;
365                 entry->edx = edx.full;
366                 break;
367         }
368         /* function 0xb has additional index. */
369         case 0xb: {
370                 int i, level_type;
371 
372                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
373                 /* read more entries until level_type is zero */
374                 for (i = 1; ; ++i) {
375                         if (*nent >= maxnent)
376                                 goto out;
377 
378                         level_type = entry[i - 1].ecx & 0xff00;
379                         if (!level_type)
380                                 break;
381                         do_cpuid_1_ent(&entry[i], function, i);
382                         entry[i].flags |=
383                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
384                         ++*nent;
385                 }
386                 break;
387         }
388         case 0xd: {
389                 int idx, i;
390 
391                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
392                 for (idx = 1, i = 1; idx < 64; ++idx) {
393                         if (*nent >= maxnent)
394                                 goto out;
395 
396                         do_cpuid_1_ent(&entry[i], function, idx);
397                         if (entry[i].eax == 0 || !supported_xcr0_bit(idx))
398                                 continue;
399                         entry[i].flags |=
400                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
401                         ++*nent;
402                         ++i;
403                 }
404                 break;
405         }
406         case KVM_CPUID_SIGNATURE: {
407                 static const char signature[12] = "KVMKVMKVM\0\0";
408                 const u32 *sigptr = (const u32 *)signature;
409                 entry->eax = KVM_CPUID_FEATURES;
410                 entry->ebx = sigptr[0];
411                 entry->ecx = sigptr[1];
412                 entry->edx = sigptr[2];
413                 break;
414         }
415         case KVM_CPUID_FEATURES:
416                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
417                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
418                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
419                              (1 << KVM_FEATURE_ASYNC_PF) |
420                              (1 << KVM_FEATURE_PV_EOI) |
421                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
422                              (1 << KVM_FEATURE_PV_UNHALT);
423 
424                 if (sched_info_on())
425                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
426 
427                 entry->ebx = 0;
428                 entry->ecx = 0;
429                 entry->edx = 0;
430                 break;
431         case 0x80000000:
432                 entry->eax = min(entry->eax, 0x8000001a);
433                 break;
434         case 0x80000001:
435                 entry->edx &= kvm_supported_word1_x86_features;
436                 cpuid_mask(&entry->edx, 1);
437                 entry->ecx &= kvm_supported_word6_x86_features;
438                 cpuid_mask(&entry->ecx, 6);
439                 break;
440         case 0x80000007: /* Advanced power management */
441                 /* invariant TSC is CPUID.80000007H:EDX[8] */
442                 entry->edx &= (1 << 8);
443                 /* mask against host */
444                 entry->edx &= boot_cpu_data.x86_power;
445                 entry->eax = entry->ebx = entry->ecx = 0;
446                 break;
447         case 0x80000008: {
448                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
449                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
450                 unsigned phys_as = entry->eax & 0xff;
451 
452                 if (!g_phys_as)
453                         g_phys_as = phys_as;
454                 entry->eax = g_phys_as | (virt_as << 8);
455                 entry->ebx = entry->edx = 0;
456                 break;
457         }
458         case 0x80000019:
459                 entry->ecx = entry->edx = 0;
460                 break;
461         case 0x8000001a:
462                 break;
463         case 0x8000001d:
464                 break;
465         /*Add support for Centaur's CPUID instruction*/
466         case 0xC0000000:
467                 /*Just support up to 0xC0000004 now*/
468                 entry->eax = min(entry->eax, 0xC0000004);
469                 break;
470         case 0xC0000001:
471                 entry->edx &= kvm_supported_word5_x86_features;
472                 cpuid_mask(&entry->edx, 5);
473                 break;
474         case 3: /* Processor serial number */
475         case 5: /* MONITOR/MWAIT */
476         case 6: /* Thermal management */
477         case 0xC0000002:
478         case 0xC0000003:
479         case 0xC0000004:
480         default:
481                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
482                 break;
483         }
484 
485         kvm_x86_ops->set_supported_cpuid(function, entry);
486 
487         r = 0;
488 
489 out:
490         put_cpu();
491 
492         return r;
493 }
494 
495 #undef F
496 
497 struct kvm_cpuid_param {
498         u32 func;
499         u32 idx;
500         bool has_leaf_count;
501         bool (*qualifier)(const struct kvm_cpuid_param *param);
502 };
503 
504 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
505 {
506         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
507 }
508 
509 int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
510                                       struct kvm_cpuid_entry2 __user *entries)
511 {
512         struct kvm_cpuid_entry2 *cpuid_entries;
513         int limit, nent = 0, r = -E2BIG, i;
514         u32 func;
515         static const struct kvm_cpuid_param param[] = {
516                 { .func = 0, .has_leaf_count = true },
517                 { .func = 0x80000000, .has_leaf_count = true },
518                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
519                 { .func = KVM_CPUID_SIGNATURE },
520                 { .func = KVM_CPUID_FEATURES },
521         };
522 
523         if (cpuid->nent < 1)
524                 goto out;
525         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
526                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
527         r = -ENOMEM;
528         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
529         if (!cpuid_entries)
530                 goto out;
531 
532         r = 0;
533         for (i = 0; i < ARRAY_SIZE(param); i++) {
534                 const struct kvm_cpuid_param *ent = &param[i];
535 
536                 if (ent->qualifier && !ent->qualifier(ent))
537                         continue;
538 
539                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
540                                 &nent, cpuid->nent);
541 
542                 if (r)
543                         goto out_free;
544 
545                 if (!ent->has_leaf_count)
546                         continue;
547 
548                 limit = cpuid_entries[nent - 1].eax;
549                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
550                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
551                                      &nent, cpuid->nent);
552 
553                 if (r)
554                         goto out_free;
555         }
556 
557         r = -EFAULT;
558         if (copy_to_user(entries, cpuid_entries,
559                          nent * sizeof(struct kvm_cpuid_entry2)))
560                 goto out_free;
561         cpuid->nent = nent;
562         r = 0;
563 
564 out_free:
565         vfree(cpuid_entries);
566 out:
567         return r;
568 }
569 
570 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
571 {
572         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
573         int j, nent = vcpu->arch.cpuid_nent;
574 
575         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
576         /* when no next entry is found, the current entry[i] is reselected */
577         for (j = i + 1; ; j = (j + 1) % nent) {
578                 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
579                 if (ej->function == e->function) {
580                         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
581                         return j;
582                 }
583         }
584         return 0; /* silence gcc, even though control never reaches here */
585 }
586 
587 /* find an entry with matching function, matching index (if needed), and that
588  * should be read next (if it's stateful) */
589 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
590         u32 function, u32 index)
591 {
592         if (e->function != function)
593                 return 0;
594         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
595                 return 0;
596         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
597             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
598                 return 0;
599         return 1;
600 }
601 
602 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
603                                               u32 function, u32 index)
604 {
605         int i;
606         struct kvm_cpuid_entry2 *best = NULL;
607 
608         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
609                 struct kvm_cpuid_entry2 *e;
610 
611                 e = &vcpu->arch.cpuid_entries[i];
612                 if (is_matching_cpuid_entry(e, function, index)) {
613                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
614                                 move_to_next_stateful_cpuid_entry(vcpu, i);
615                         best = e;
616                         break;
617                 }
618         }
619         return best;
620 }
621 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
622 
623 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
624 {
625         struct kvm_cpuid_entry2 *best;
626 
627         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
628         if (!best || best->eax < 0x80000008)
629                 goto not_found;
630         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
631         if (best)
632                 return best->eax & 0xff;
633 not_found:
634         return 36;
635 }
636 
637 /*
638  * If no match is found, check whether we exceed the vCPU's limit
639  * and return the content of the highest valid _standard_ leaf instead.
640  * This is to satisfy the CPUID specification.
641  */
642 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
643                                                   u32 function, u32 index)
644 {
645         struct kvm_cpuid_entry2 *maxlevel;
646 
647         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
648         if (!maxlevel || maxlevel->eax >= function)
649                 return NULL;
650         if (function & 0x80000000) {
651                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
652                 if (!maxlevel)
653                         return NULL;
654         }
655         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
656 }
657 
658 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
659 {
660         u32 function = *eax, index = *ecx;
661         struct kvm_cpuid_entry2 *best;
662 
663         best = kvm_find_cpuid_entry(vcpu, function, index);
664 
665         if (!best)
666                 best = check_cpuid_limit(vcpu, function, index);
667 
668         if (best) {
669                 *eax = best->eax;
670                 *ebx = best->ebx;
671                 *ecx = best->ecx;
672                 *edx = best->edx;
673         } else
674                 *eax = *ebx = *ecx = *edx = 0;
675 }
676 EXPORT_SYMBOL_GPL(kvm_cpuid);
677 
678 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
679 {
680         u32 function, eax, ebx, ecx, edx;
681 
682         function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
683         ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
684         kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
685         kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
686         kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
687         kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
688         kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
689         kvm_x86_ops->skip_emulated_instruction(vcpu);
690         trace_kvm_cpuid(function, eax, ebx, ecx, edx);
691 }
692 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);
693 

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