e28d798f72777e7f17fd0b8e474b73b7d11d199d
[firefly-linux-kernel-4.4.55.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 static u32 xstate_required_size(u64 xstate_bv)
27 {
28         int feature_bit = 0;
29         u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
30
31         xstate_bv &= XSTATE_EXTEND_MASK;
32         while (xstate_bv) {
33                 if (xstate_bv & 0x1) {
34                         u32 eax, ebx, ecx, edx;
35                         cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
36                         ret = max(ret, eax + ebx);
37                 }
38
39                 xstate_bv >>= 1;
40                 feature_bit++;
41         }
42
43         return ret;
44 }
45
46 u64 kvm_supported_xcr0(void)
47 {
48         u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
49
50         if (!kvm_x86_ops->mpx_supported())
51                 xcr0 &= ~(XSTATE_BNDREGS | XSTATE_BNDCSR);
52
53         return xcr0;
54 }
55
56 int kvm_update_cpuid(struct kvm_vcpu *vcpu)
57 {
58         struct kvm_cpuid_entry2 *best;
59         struct kvm_lapic *apic = vcpu->arch.apic;
60
61         best = kvm_find_cpuid_entry(vcpu, 1, 0);
62         if (!best)
63                 return 0;
64
65         /* Update OSXSAVE bit */
66         if (cpu_has_xsave && best->function == 0x1) {
67                 best->ecx &= ~(bit(X86_FEATURE_OSXSAVE));
68                 if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
69                         best->ecx |= bit(X86_FEATURE_OSXSAVE);
70         }
71
72         if (apic) {
73                 if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER))
74                         apic->lapic_timer.timer_mode_mask = 3 << 17;
75                 else
76                         apic->lapic_timer.timer_mode_mask = 1 << 17;
77         }
78
79         best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
80         if (!best) {
81                 vcpu->arch.guest_supported_xcr0 = 0;
82                 vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
83         } else {
84                 vcpu->arch.guest_supported_xcr0 =
85                         (best->eax | ((u64)best->edx << 32)) &
86                         kvm_supported_xcr0();
87                 vcpu->arch.guest_xstate_size = best->ebx =
88                         xstate_required_size(vcpu->arch.xcr0);
89         }
90
91         /*
92          * The existing code assumes virtual address is 48-bit in the canonical
93          * address checks; exit if it is ever changed.
94          */
95         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
96         if (best && ((best->eax & 0xff00) >> 8) != 48 &&
97                 ((best->eax & 0xff00) >> 8) != 0)
98                 return -EINVAL;
99
100         kvm_pmu_cpuid_update(vcpu);
101         return 0;
102 }
103
104 static int is_efer_nx(void)
105 {
106         unsigned long long efer = 0;
107
108         rdmsrl_safe(MSR_EFER, &efer);
109         return efer & EFER_NX;
110 }
111
112 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
113 {
114         int i;
115         struct kvm_cpuid_entry2 *e, *entry;
116
117         entry = NULL;
118         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
119                 e = &vcpu->arch.cpuid_entries[i];
120                 if (e->function == 0x80000001) {
121                         entry = e;
122                         break;
123                 }
124         }
125         if (entry && (entry->edx & bit(X86_FEATURE_NX)) && !is_efer_nx()) {
126                 entry->edx &= ~bit(X86_FEATURE_NX);
127                 printk(KERN_INFO "kvm: guest NX capability removed\n");
128         }
129 }
130
131 /* when an old userspace process fills a new kernel module */
132 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
133                              struct kvm_cpuid *cpuid,
134                              struct kvm_cpuid_entry __user *entries)
135 {
136         int r, i;
137         struct kvm_cpuid_entry *cpuid_entries;
138
139         r = -E2BIG;
140         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
141                 goto out;
142         r = -ENOMEM;
143         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
144         if (!cpuid_entries)
145                 goto out;
146         r = -EFAULT;
147         if (copy_from_user(cpuid_entries, entries,
148                            cpuid->nent * sizeof(struct kvm_cpuid_entry)))
149                 goto out_free;
150         for (i = 0; i < cpuid->nent; i++) {
151                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
152                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
153                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
154                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
155                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
156                 vcpu->arch.cpuid_entries[i].index = 0;
157                 vcpu->arch.cpuid_entries[i].flags = 0;
158                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
159                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
160                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
161         }
162         vcpu->arch.cpuid_nent = cpuid->nent;
163         cpuid_fix_nx_cap(vcpu);
164         kvm_apic_set_version(vcpu);
165         kvm_x86_ops->cpuid_update(vcpu);
166         r = kvm_update_cpuid(vcpu);
167
168 out_free:
169         vfree(cpuid_entries);
170 out:
171         return r;
172 }
173
174 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
175                               struct kvm_cpuid2 *cpuid,
176                               struct kvm_cpuid_entry2 __user *entries)
177 {
178         int r;
179
180         r = -E2BIG;
181         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
182                 goto out;
183         r = -EFAULT;
184         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
185                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
186                 goto out;
187         vcpu->arch.cpuid_nent = cpuid->nent;
188         kvm_apic_set_version(vcpu);
189         kvm_x86_ops->cpuid_update(vcpu);
190         r = kvm_update_cpuid(vcpu);
191 out:
192         return r;
193 }
194
195 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
196                               struct kvm_cpuid2 *cpuid,
197                               struct kvm_cpuid_entry2 __user *entries)
198 {
199         int r;
200
201         r = -E2BIG;
202         if (cpuid->nent < vcpu->arch.cpuid_nent)
203                 goto out;
204         r = -EFAULT;
205         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
206                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
207                 goto out;
208         return 0;
209
210 out:
211         cpuid->nent = vcpu->arch.cpuid_nent;
212         return r;
213 }
214
215 static void cpuid_mask(u32 *word, int wordnum)
216 {
217         *word &= boot_cpu_data.x86_capability[wordnum];
218 }
219
220 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
221                            u32 index)
222 {
223         entry->function = function;
224         entry->index = index;
225         cpuid_count(entry->function, entry->index,
226                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
227         entry->flags = 0;
228 }
229
230 #define F(x) bit(X86_FEATURE_##x)
231
232 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
233                                    u32 func, u32 index, int *nent, int maxnent)
234 {
235         switch (func) {
236         case 0:
237                 entry->eax = 1;         /* only one leaf currently */
238                 ++*nent;
239                 break;
240         case 1:
241                 entry->ecx = F(MOVBE);
242                 ++*nent;
243                 break;
244         default:
245                 break;
246         }
247
248         entry->function = func;
249         entry->index = index;
250
251         return 0;
252 }
253
254 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
255                                  u32 index, int *nent, int maxnent)
256 {
257         int r;
258         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
259 #ifdef CONFIG_X86_64
260         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
261                                 ? F(GBPAGES) : 0;
262         unsigned f_lm = F(LM);
263 #else
264         unsigned f_gbpages = 0;
265         unsigned f_lm = 0;
266 #endif
267         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
268         unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
269         unsigned f_mpx = kvm_x86_ops->mpx_supported() ? F(MPX) : 0;
270
271         /* cpuid 1.edx */
272         const u32 kvm_supported_word0_x86_features =
273                 F(FPU) | F(VME) | F(DE) | F(PSE) |
274                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
275                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
276                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
277                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
278                 0 /* Reserved, DS, ACPI */ | F(MMX) |
279                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
280                 0 /* HTT, TM, Reserved, PBE */;
281         /* cpuid 0x80000001.edx */
282         const u32 kvm_supported_word1_x86_features =
283                 F(FPU) | F(VME) | F(DE) | F(PSE) |
284                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
285                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
286                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
287                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
288                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
289                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
290                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
291         /* cpuid 1.ecx */
292         const u32 kvm_supported_word4_x86_features =
293                 /* NOTE: MONITOR (and MWAIT) are emulated as NOP,
294                  * but *not* advertised to guests via CPUID ! */
295                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
296                 0 /* DS-CPL, VMX, SMX, EST */ |
297                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
298                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
299                 F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
300                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
301                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
302                 F(F16C) | F(RDRAND);
303         /* cpuid 0x80000001.ecx */
304         const u32 kvm_supported_word6_x86_features =
305                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
306                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
307                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
308                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
309
310         /* cpuid 0xC0000001.edx */
311         const u32 kvm_supported_word5_x86_features =
312                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
313                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
314                 F(PMM) | F(PMM_EN);
315
316         /* cpuid 7.0.ebx */
317         const u32 kvm_supported_word9_x86_features =
318                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
319                 F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
320                 F(ADX) | F(SMAP);
321
322         /* all calls to cpuid_count() should be made on the same cpu */
323         get_cpu();
324
325         r = -E2BIG;
326
327         if (*nent >= maxnent)
328                 goto out;
329
330         do_cpuid_1_ent(entry, function, index);
331         ++*nent;
332
333         switch (function) {
334         case 0:
335                 entry->eax = min(entry->eax, (u32)0xd);
336                 break;
337         case 1:
338                 entry->edx &= kvm_supported_word0_x86_features;
339                 cpuid_mask(&entry->edx, 0);
340                 entry->ecx &= kvm_supported_word4_x86_features;
341                 cpuid_mask(&entry->ecx, 4);
342                 /* we support x2apic emulation even if host does not support
343                  * it since we emulate x2apic in software */
344                 entry->ecx |= F(X2APIC);
345                 break;
346         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
347          * may return different values. This forces us to get_cpu() before
348          * issuing the first command, and also to emulate this annoying behavior
349          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
350         case 2: {
351                 int t, times = entry->eax & 0xff;
352
353                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
354                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
355                 for (t = 1; t < times; ++t) {
356                         if (*nent >= maxnent)
357                                 goto out;
358
359                         do_cpuid_1_ent(&entry[t], function, 0);
360                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
361                         ++*nent;
362                 }
363                 break;
364         }
365         /* function 4 has additional index. */
366         case 4: {
367                 int i, cache_type;
368
369                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
370                 /* read more entries until cache_type is zero */
371                 for (i = 1; ; ++i) {
372                         if (*nent >= maxnent)
373                                 goto out;
374
375                         cache_type = entry[i - 1].eax & 0x1f;
376                         if (!cache_type)
377                                 break;
378                         do_cpuid_1_ent(&entry[i], function, i);
379                         entry[i].flags |=
380                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
381                         ++*nent;
382                 }
383                 break;
384         }
385         case 7: {
386                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
387                 /* Mask ebx against host capability word 9 */
388                 if (index == 0) {
389                         entry->ebx &= kvm_supported_word9_x86_features;
390                         cpuid_mask(&entry->ebx, 9);
391                         // TSC_ADJUST is emulated
392                         entry->ebx |= F(TSC_ADJUST);
393                 } else
394                         entry->ebx = 0;
395                 entry->eax = 0;
396                 entry->ecx = 0;
397                 entry->edx = 0;
398                 break;
399         }
400         case 9:
401                 break;
402         case 0xa: { /* Architectural Performance Monitoring */
403                 struct x86_pmu_capability cap;
404                 union cpuid10_eax eax;
405                 union cpuid10_edx edx;
406
407                 perf_get_x86_pmu_capability(&cap);
408
409                 /*
410                  * Only support guest architectural pmu on a host
411                  * with architectural pmu.
412                  */
413                 if (!cap.version)
414                         memset(&cap, 0, sizeof(cap));
415
416                 eax.split.version_id = min(cap.version, 2);
417                 eax.split.num_counters = cap.num_counters_gp;
418                 eax.split.bit_width = cap.bit_width_gp;
419                 eax.split.mask_length = cap.events_mask_len;
420
421                 edx.split.num_counters_fixed = cap.num_counters_fixed;
422                 edx.split.bit_width_fixed = cap.bit_width_fixed;
423                 edx.split.reserved = 0;
424
425                 entry->eax = eax.full;
426                 entry->ebx = cap.events_mask;
427                 entry->ecx = 0;
428                 entry->edx = edx.full;
429                 break;
430         }
431         /* function 0xb has additional index. */
432         case 0xb: {
433                 int i, level_type;
434
435                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
436                 /* read more entries until level_type is zero */
437                 for (i = 1; ; ++i) {
438                         if (*nent >= maxnent)
439                                 goto out;
440
441                         level_type = entry[i - 1].ecx & 0xff00;
442                         if (!level_type)
443                                 break;
444                         do_cpuid_1_ent(&entry[i], function, i);
445                         entry[i].flags |=
446                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
447                         ++*nent;
448                 }
449                 break;
450         }
451         case 0xd: {
452                 int idx, i;
453                 u64 supported = kvm_supported_xcr0();
454
455                 entry->eax &= supported;
456                 entry->edx &= supported >> 32;
457                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
458                 for (idx = 1, i = 1; idx < 64; ++idx) {
459                         u64 mask = ((u64)1 << idx);
460                         if (*nent >= maxnent)
461                                 goto out;
462
463                         do_cpuid_1_ent(&entry[i], function, idx);
464                         if (entry[i].eax == 0 || !(supported & mask))
465                                 continue;
466                         entry[i].flags |=
467                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
468                         ++*nent;
469                         ++i;
470                 }
471                 break;
472         }
473         case KVM_CPUID_SIGNATURE: {
474                 static const char signature[12] = "KVMKVMKVM\0\0";
475                 const u32 *sigptr = (const u32 *)signature;
476                 entry->eax = KVM_CPUID_FEATURES;
477                 entry->ebx = sigptr[0];
478                 entry->ecx = sigptr[1];
479                 entry->edx = sigptr[2];
480                 break;
481         }
482         case KVM_CPUID_FEATURES:
483                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
484                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
485                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
486                              (1 << KVM_FEATURE_ASYNC_PF) |
487                              (1 << KVM_FEATURE_PV_EOI) |
488                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
489                              (1 << KVM_FEATURE_PV_UNHALT);
490
491                 if (sched_info_on())
492                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
493
494                 entry->ebx = 0;
495                 entry->ecx = 0;
496                 entry->edx = 0;
497                 break;
498         case 0x80000000:
499                 entry->eax = min(entry->eax, 0x8000001a);
500                 break;
501         case 0x80000001:
502                 entry->edx &= kvm_supported_word1_x86_features;
503                 cpuid_mask(&entry->edx, 1);
504                 entry->ecx &= kvm_supported_word6_x86_features;
505                 cpuid_mask(&entry->ecx, 6);
506                 break;
507         case 0x80000007: /* Advanced power management */
508                 /* invariant TSC is CPUID.80000007H:EDX[8] */
509                 entry->edx &= (1 << 8);
510                 /* mask against host */
511                 entry->edx &= boot_cpu_data.x86_power;
512                 entry->eax = entry->ebx = entry->ecx = 0;
513                 break;
514         case 0x80000008: {
515                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
516                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
517                 unsigned phys_as = entry->eax & 0xff;
518
519                 if (!g_phys_as)
520                         g_phys_as = phys_as;
521                 entry->eax = g_phys_as | (virt_as << 8);
522                 entry->ebx = entry->edx = 0;
523                 break;
524         }
525         case 0x80000019:
526                 entry->ecx = entry->edx = 0;
527                 break;
528         case 0x8000001a:
529                 break;
530         case 0x8000001d:
531                 break;
532         /*Add support for Centaur's CPUID instruction*/
533         case 0xC0000000:
534                 /*Just support up to 0xC0000004 now*/
535                 entry->eax = min(entry->eax, 0xC0000004);
536                 break;
537         case 0xC0000001:
538                 entry->edx &= kvm_supported_word5_x86_features;
539                 cpuid_mask(&entry->edx, 5);
540                 break;
541         case 3: /* Processor serial number */
542         case 5: /* MONITOR/MWAIT */
543         case 6: /* Thermal management */
544         case 0xC0000002:
545         case 0xC0000003:
546         case 0xC0000004:
547         default:
548                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
549                 break;
550         }
551
552         kvm_x86_ops->set_supported_cpuid(function, entry);
553
554         r = 0;
555
556 out:
557         put_cpu();
558
559         return r;
560 }
561
562 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
563                         u32 idx, int *nent, int maxnent, unsigned int type)
564 {
565         if (type == KVM_GET_EMULATED_CPUID)
566                 return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
567
568         return __do_cpuid_ent(entry, func, idx, nent, maxnent);
569 }
570
571 #undef F
572
573 struct kvm_cpuid_param {
574         u32 func;
575         u32 idx;
576         bool has_leaf_count;
577         bool (*qualifier)(const struct kvm_cpuid_param *param);
578 };
579
580 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
581 {
582         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
583 }
584
585 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
586                                  __u32 num_entries, unsigned int ioctl_type)
587 {
588         int i;
589         __u32 pad[3];
590
591         if (ioctl_type != KVM_GET_EMULATED_CPUID)
592                 return false;
593
594         /*
595          * We want to make sure that ->padding is being passed clean from
596          * userspace in case we want to use it for something in the future.
597          *
598          * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
599          * have to give ourselves satisfied only with the emulated side. /me
600          * sheds a tear.
601          */
602         for (i = 0; i < num_entries; i++) {
603                 if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
604                         return true;
605
606                 if (pad[0] || pad[1] || pad[2])
607                         return true;
608         }
609         return false;
610 }
611
612 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
613                             struct kvm_cpuid_entry2 __user *entries,
614                             unsigned int type)
615 {
616         struct kvm_cpuid_entry2 *cpuid_entries;
617         int limit, nent = 0, r = -E2BIG, i;
618         u32 func;
619         static const struct kvm_cpuid_param param[] = {
620                 { .func = 0, .has_leaf_count = true },
621                 { .func = 0x80000000, .has_leaf_count = true },
622                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
623                 { .func = KVM_CPUID_SIGNATURE },
624                 { .func = KVM_CPUID_FEATURES },
625         };
626
627         if (cpuid->nent < 1)
628                 goto out;
629         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
630                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
631
632         if (sanity_check_entries(entries, cpuid->nent, type))
633                 return -EINVAL;
634
635         r = -ENOMEM;
636         cpuid_entries = vzalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
637         if (!cpuid_entries)
638                 goto out;
639
640         r = 0;
641         for (i = 0; i < ARRAY_SIZE(param); i++) {
642                 const struct kvm_cpuid_param *ent = &param[i];
643
644                 if (ent->qualifier && !ent->qualifier(ent))
645                         continue;
646
647                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
648                                 &nent, cpuid->nent, type);
649
650                 if (r)
651                         goto out_free;
652
653                 if (!ent->has_leaf_count)
654                         continue;
655
656                 limit = cpuid_entries[nent - 1].eax;
657                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
658                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
659                                      &nent, cpuid->nent, type);
660
661                 if (r)
662                         goto out_free;
663         }
664
665         r = -EFAULT;
666         if (copy_to_user(entries, cpuid_entries,
667                          nent * sizeof(struct kvm_cpuid_entry2)))
668                 goto out_free;
669         cpuid->nent = nent;
670         r = 0;
671
672 out_free:
673         vfree(cpuid_entries);
674 out:
675         return r;
676 }
677
678 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
679 {
680         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
681         int j, nent = vcpu->arch.cpuid_nent;
682
683         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
684         /* when no next entry is found, the current entry[i] is reselected */
685         for (j = i + 1; ; j = (j + 1) % nent) {
686                 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
687                 if (ej->function == e->function) {
688                         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
689                         return j;
690                 }
691         }
692         return 0; /* silence gcc, even though control never reaches here */
693 }
694
695 /* find an entry with matching function, matching index (if needed), and that
696  * should be read next (if it's stateful) */
697 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
698         u32 function, u32 index)
699 {
700         if (e->function != function)
701                 return 0;
702         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
703                 return 0;
704         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
705             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
706                 return 0;
707         return 1;
708 }
709
710 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
711                                               u32 function, u32 index)
712 {
713         int i;
714         struct kvm_cpuid_entry2 *best = NULL;
715
716         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
717                 struct kvm_cpuid_entry2 *e;
718
719                 e = &vcpu->arch.cpuid_entries[i];
720                 if (is_matching_cpuid_entry(e, function, index)) {
721                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
722                                 move_to_next_stateful_cpuid_entry(vcpu, i);
723                         best = e;
724                         break;
725                 }
726         }
727         return best;
728 }
729 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
730
731 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
732 {
733         struct kvm_cpuid_entry2 *best;
734
735         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
736         if (!best || best->eax < 0x80000008)
737                 goto not_found;
738         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
739         if (best)
740                 return best->eax & 0xff;
741 not_found:
742         return 36;
743 }
744 EXPORT_SYMBOL_GPL(cpuid_maxphyaddr);
745
746 /*
747  * If no match is found, check whether we exceed the vCPU's limit
748  * and return the content of the highest valid _standard_ leaf instead.
749  * This is to satisfy the CPUID specification.
750  */
751 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
752                                                   u32 function, u32 index)
753 {
754         struct kvm_cpuid_entry2 *maxlevel;
755
756         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
757         if (!maxlevel || maxlevel->eax >= function)
758                 return NULL;
759         if (function & 0x80000000) {
760                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
761                 if (!maxlevel)
762                         return NULL;
763         }
764         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
765 }
766
767 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
768 {
769         u32 function = *eax, index = *ecx;
770         struct kvm_cpuid_entry2 *best;
771
772         best = kvm_find_cpuid_entry(vcpu, function, index);
773
774         if (!best)
775                 best = check_cpuid_limit(vcpu, function, index);
776
777         if (best) {
778                 *eax = best->eax;
779                 *ebx = best->ebx;
780                 *ecx = best->ecx;
781                 *edx = best->edx;
782         } else
783                 *eax = *ebx = *ecx = *edx = 0;
784         trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
785 }
786 EXPORT_SYMBOL_GPL(kvm_cpuid);
787
788 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
789 {
790         u32 function, eax, ebx, ecx, edx;
791
792         function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
793         ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
794         kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
795         kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
796         kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
797         kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
798         kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
799         kvm_x86_ops->skip_emulated_instruction(vcpu);
800 }
801 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);