1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Kernel-based Virtual Machine driver for Linux
4 * cpuid support routines
5 *
6 * derived from arch/x86/kvm/x86.c
7 *
8 * Copyright 2011 Red Hat, Inc. and/or its affiliates.
9 * Copyright IBM Corporation, 2008
10 */
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13 #include <linux/kvm_host.h>
14 #include "linux/lockdep.h"
15 #include <linux/export.h>
16 #include <linux/vmalloc.h>
17 #include <linux/uaccess.h>
18 #include <linux/sched/stat.h>
19
20 #include <asm/processor.h>
21 #include <asm/user.h>
22 #include <asm/fpu/xstate.h>
23 #include <asm/sgx.h>
24 #include <asm/cpuid/api.h>
25 #include "cpuid.h"
26 #include "lapic.h"
27 #include "mmu.h"
28 #include "trace.h"
29 #include "pmu.h"
30 #include "xen.h"
31
32 /*
33 * Unlike "struct cpuinfo_x86.x86_capability", kvm_cpu_caps doesn't need to be
34 * aligned to sizeof(unsigned long) because it's not accessed via bitops.
35 */
36 u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
37 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_cpu_caps);
38
39 struct cpuid_xstate_sizes {
40 u32 eax;
41 u32 ebx;
42 u32 ecx;
43 };
44
45 static struct cpuid_xstate_sizes xstate_sizes[XFEATURE_MAX] __ro_after_init;
46
kvm_init_xstate_sizes(void)47 void __init kvm_init_xstate_sizes(void)
48 {
49 u32 ign;
50 int i;
51
52 for (i = XFEATURE_YMM; i < ARRAY_SIZE(xstate_sizes); i++) {
53 struct cpuid_xstate_sizes *xs = &xstate_sizes[i];
54
55 cpuid_count(0xD, i, &xs->eax, &xs->ebx, &xs->ecx, &ign);
56 }
57 }
58
xstate_required_size(u64 xstate_bv,bool compacted)59 u32 xstate_required_size(u64 xstate_bv, bool compacted)
60 {
61 u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
62 int i;
63
64 xstate_bv &= XFEATURE_MASK_EXTEND;
65 for (i = XFEATURE_YMM; i < ARRAY_SIZE(xstate_sizes) && xstate_bv; i++) {
66 struct cpuid_xstate_sizes *xs = &xstate_sizes[i];
67 u32 offset;
68
69 if (!(xstate_bv & BIT_ULL(i)))
70 continue;
71
72 /* ECX[1]: 64B alignment in compacted form */
73 if (compacted)
74 offset = (xs->ecx & 0x2) ? ALIGN(ret, 64) : ret;
75 else
76 offset = xs->ebx;
77 ret = max(ret, offset + xs->eax);
78 xstate_bv &= ~BIT_ULL(i);
79 }
80
81 return ret;
82 }
83
kvm_find_cpuid_entry2(struct kvm_cpuid_entry2 * entries,int nent,u32 function,u64 index)84 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry2(
85 struct kvm_cpuid_entry2 *entries, int nent, u32 function, u64 index)
86 {
87 struct kvm_cpuid_entry2 *e;
88 int i;
89
90 /*
91 * KVM has a semi-arbitrary rule that querying the guest's CPUID model
92 * with IRQs disabled is disallowed. The CPUID model can legitimately
93 * have over one hundred entries, i.e. the lookup is slow, and IRQs are
94 * typically disabled in KVM only when KVM is in a performance critical
95 * path, e.g. the core VM-Enter/VM-Exit run loop. Nothing will break
96 * if this rule is violated, this assertion is purely to flag potential
97 * performance issues. If this fires, consider moving the lookup out
98 * of the hotpath, e.g. by caching information during CPUID updates.
99 */
100 lockdep_assert_irqs_enabled();
101
102 for (i = 0; i < nent; i++) {
103 e = &entries[i];
104
105 if (e->function != function)
106 continue;
107
108 /*
109 * If the index isn't significant, use the first entry with a
110 * matching function. It's userspace's responsibility to not
111 * provide "duplicate" entries in all cases.
112 */
113 if (!(e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) || e->index == index)
114 return e;
115
116
117 /*
118 * Similarly, use the first matching entry if KVM is doing a
119 * lookup (as opposed to emulating CPUID) for a function that's
120 * architecturally defined as not having a significant index.
121 */
122 if (index == KVM_CPUID_INDEX_NOT_SIGNIFICANT) {
123 /*
124 * Direct lookups from KVM should not diverge from what
125 * KVM defines internally (the architectural behavior).
126 */
127 WARN_ON_ONCE(cpuid_function_is_indexed(function));
128 return e;
129 }
130 }
131
132 return NULL;
133 }
134 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_find_cpuid_entry2);
135
kvm_check_cpuid(struct kvm_vcpu * vcpu)136 static int kvm_check_cpuid(struct kvm_vcpu *vcpu)
137 {
138 struct kvm_cpuid_entry2 *best;
139 u64 xfeatures;
140
141 /*
142 * The existing code assumes virtual address is 48-bit or 57-bit in the
143 * canonical address checks; exit if it is ever changed.
144 */
145 best = kvm_find_cpuid_entry(vcpu, 0x80000008);
146 if (best) {
147 int vaddr_bits = (best->eax & 0xff00) >> 8;
148
149 if (vaddr_bits != 48 && vaddr_bits != 57 && vaddr_bits != 0)
150 return -EINVAL;
151 }
152
153 /*
154 * Exposing dynamic xfeatures to the guest requires additional
155 * enabling in the FPU, e.g. to expand the guest XSAVE state size.
156 */
157 best = kvm_find_cpuid_entry_index(vcpu, 0xd, 0);
158 if (!best)
159 return 0;
160
161 xfeatures = best->eax | ((u64)best->edx << 32);
162 xfeatures &= XFEATURE_MASK_USER_DYNAMIC;
163 if (!xfeatures)
164 return 0;
165
166 return fpu_enable_guest_xfd_features(&vcpu->arch.guest_fpu, xfeatures);
167 }
168
169 static u32 kvm_apply_cpuid_pv_features_quirk(struct kvm_vcpu *vcpu);
170 static void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu);
171
172 /* Check whether the supplied CPUID data is equal to what is already set for the vCPU. */
kvm_cpuid_check_equal(struct kvm_vcpu * vcpu,struct kvm_cpuid_entry2 * e2,int nent)173 static int kvm_cpuid_check_equal(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
174 int nent)
175 {
176 struct kvm_cpuid_entry2 *orig;
177 int i;
178
179 /*
180 * Apply runtime CPUID updates to the incoming CPUID entries to avoid
181 * false positives due mismatches on KVM-owned feature flags.
182 *
183 * Note! @e2 and @nent track the _old_ CPUID entries!
184 */
185 kvm_update_cpuid_runtime(vcpu);
186 kvm_apply_cpuid_pv_features_quirk(vcpu);
187
188 if (nent != vcpu->arch.cpuid_nent)
189 return -EINVAL;
190
191 for (i = 0; i < nent; i++) {
192 orig = &vcpu->arch.cpuid_entries[i];
193 if (e2[i].function != orig->function ||
194 e2[i].index != orig->index ||
195 e2[i].flags != orig->flags ||
196 e2[i].eax != orig->eax || e2[i].ebx != orig->ebx ||
197 e2[i].ecx != orig->ecx || e2[i].edx != orig->edx)
198 return -EINVAL;
199 }
200
201 return 0;
202 }
203
kvm_get_hypervisor_cpuid(struct kvm_vcpu * vcpu,const char * sig)204 static struct kvm_hypervisor_cpuid kvm_get_hypervisor_cpuid(struct kvm_vcpu *vcpu,
205 const char *sig)
206 {
207 struct kvm_hypervisor_cpuid cpuid = {};
208 struct kvm_cpuid_entry2 *entry;
209 u32 base;
210
211 for_each_possible_cpuid_base_hypervisor(base) {
212 entry = kvm_find_cpuid_entry(vcpu, base);
213
214 if (entry) {
215 u32 signature[3];
216
217 signature[0] = entry->ebx;
218 signature[1] = entry->ecx;
219 signature[2] = entry->edx;
220
221 if (!memcmp(signature, sig, sizeof(signature))) {
222 cpuid.base = base;
223 cpuid.limit = entry->eax;
224 break;
225 }
226 }
227 }
228
229 return cpuid;
230 }
231
kvm_apply_cpuid_pv_features_quirk(struct kvm_vcpu * vcpu)232 static u32 kvm_apply_cpuid_pv_features_quirk(struct kvm_vcpu *vcpu)
233 {
234 struct kvm_hypervisor_cpuid kvm_cpuid;
235 struct kvm_cpuid_entry2 *best;
236
237 kvm_cpuid = kvm_get_hypervisor_cpuid(vcpu, KVM_SIGNATURE);
238 if (!kvm_cpuid.base)
239 return 0;
240
241 best = kvm_find_cpuid_entry(vcpu, kvm_cpuid.base | KVM_CPUID_FEATURES);
242 if (!best)
243 return 0;
244
245 if (kvm_hlt_in_guest(vcpu->kvm))
246 best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT);
247
248 return best->eax;
249 }
250
251 /*
252 * Calculate guest's supported XCR0 taking into account guest CPUID data and
253 * KVM's supported XCR0 (comprised of host's XCR0 and KVM_SUPPORTED_XCR0).
254 */
cpuid_get_supported_xcr0(struct kvm_vcpu * vcpu)255 static u64 cpuid_get_supported_xcr0(struct kvm_vcpu *vcpu)
256 {
257 struct kvm_cpuid_entry2 *best;
258
259 best = kvm_find_cpuid_entry_index(vcpu, 0xd, 0);
260 if (!best)
261 return 0;
262
263 return (best->eax | ((u64)best->edx << 32)) & kvm_caps.supported_xcr0;
264 }
265
cpuid_get_supported_xss(struct kvm_vcpu * vcpu)266 static u64 cpuid_get_supported_xss(struct kvm_vcpu *vcpu)
267 {
268 struct kvm_cpuid_entry2 *best;
269
270 best = kvm_find_cpuid_entry_index(vcpu, 0xd, 1);
271 if (!best)
272 return 0;
273
274 return (best->ecx | ((u64)best->edx << 32)) & kvm_caps.supported_xss;
275 }
276
kvm_update_feature_runtime(struct kvm_vcpu * vcpu,struct kvm_cpuid_entry2 * entry,unsigned int x86_feature,bool has_feature)277 static __always_inline void kvm_update_feature_runtime(struct kvm_vcpu *vcpu,
278 struct kvm_cpuid_entry2 *entry,
279 unsigned int x86_feature,
280 bool has_feature)
281 {
282 cpuid_entry_change(entry, x86_feature, has_feature);
283 guest_cpu_cap_change(vcpu, x86_feature, has_feature);
284 }
285
kvm_update_cpuid_runtime(struct kvm_vcpu * vcpu)286 static void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
287 {
288 struct kvm_cpuid_entry2 *best;
289
290 vcpu->arch.cpuid_dynamic_bits_dirty = false;
291
292 best = kvm_find_cpuid_entry(vcpu, 1);
293 if (best) {
294 kvm_update_feature_runtime(vcpu, best, X86_FEATURE_OSXSAVE,
295 kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE));
296
297 kvm_update_feature_runtime(vcpu, best, X86_FEATURE_APIC,
298 vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE);
299
300 if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT))
301 kvm_update_feature_runtime(vcpu, best, X86_FEATURE_MWAIT,
302 vcpu->arch.ia32_misc_enable_msr &
303 MSR_IA32_MISC_ENABLE_MWAIT);
304 }
305
306 best = kvm_find_cpuid_entry_index(vcpu, 7, 0);
307 if (best)
308 kvm_update_feature_runtime(vcpu, best, X86_FEATURE_OSPKE,
309 kvm_is_cr4_bit_set(vcpu, X86_CR4_PKE));
310
311
312 best = kvm_find_cpuid_entry_index(vcpu, 0xD, 0);
313 if (best)
314 best->ebx = xstate_required_size(vcpu->arch.xcr0, false);
315
316 best = kvm_find_cpuid_entry_index(vcpu, 0xD, 1);
317 if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
318 cpuid_entry_has(best, X86_FEATURE_XSAVEC)))
319 best->ebx = xstate_required_size(vcpu->arch.xcr0 |
320 vcpu->arch.ia32_xss, true);
321 }
322
kvm_cpuid_has_hyperv(struct kvm_vcpu * vcpu)323 static bool kvm_cpuid_has_hyperv(struct kvm_vcpu *vcpu)
324 {
325 #ifdef CONFIG_KVM_HYPERV
326 struct kvm_cpuid_entry2 *entry;
327
328 entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_INTERFACE);
329 return entry && entry->eax == HYPERV_CPUID_SIGNATURE_EAX;
330 #else
331 return false;
332 #endif
333 }
334
guest_cpuid_is_amd_or_hygon(struct kvm_vcpu * vcpu)335 static bool guest_cpuid_is_amd_or_hygon(struct kvm_vcpu *vcpu)
336 {
337 struct kvm_cpuid_entry2 *entry;
338
339 entry = kvm_find_cpuid_entry(vcpu, 0);
340 if (!entry)
341 return false;
342
343 return is_guest_vendor_amd(entry->ebx, entry->ecx, entry->edx) ||
344 is_guest_vendor_hygon(entry->ebx, entry->ecx, entry->edx);
345 }
346
347 /*
348 * This isn't truly "unsafe", but except for the cpu_caps initialization code,
349 * all register lookups should use __cpuid_entry_get_reg(), which provides
350 * compile-time validation of the input.
351 */
cpuid_get_reg_unsafe(struct kvm_cpuid_entry2 * entry,u32 reg)352 static u32 cpuid_get_reg_unsafe(struct kvm_cpuid_entry2 *entry, u32 reg)
353 {
354 switch (reg) {
355 case CPUID_EAX:
356 return entry->eax;
357 case CPUID_EBX:
358 return entry->ebx;
359 case CPUID_ECX:
360 return entry->ecx;
361 case CPUID_EDX:
362 return entry->edx;
363 default:
364 WARN_ON_ONCE(1);
365 return 0;
366 }
367 }
368
369 static int cpuid_func_emulated(struct kvm_cpuid_entry2 *entry, u32 func,
370 bool include_partially_emulated);
371
kvm_vcpu_after_set_cpuid(struct kvm_vcpu * vcpu)372 void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
373 {
374 struct kvm_lapic *apic = vcpu->arch.apic;
375 struct kvm_cpuid_entry2 *best;
376 struct kvm_cpuid_entry2 *entry;
377 bool allow_gbpages;
378 int i;
379
380 memset(vcpu->arch.cpu_caps, 0, sizeof(vcpu->arch.cpu_caps));
381 BUILD_BUG_ON(ARRAY_SIZE(reverse_cpuid) != NR_KVM_CPU_CAPS);
382
383 /*
384 * Reset guest capabilities to userspace's guest CPUID definition, i.e.
385 * honor userspace's definition for features that don't require KVM or
386 * hardware management/support (or that KVM simply doesn't care about).
387 */
388 for (i = 0; i < NR_KVM_CPU_CAPS; i++) {
389 const struct cpuid_reg cpuid = reverse_cpuid[i];
390 struct kvm_cpuid_entry2 emulated;
391
392 if (!cpuid.function)
393 continue;
394
395 entry = kvm_find_cpuid_entry_index(vcpu, cpuid.function, cpuid.index);
396 if (!entry)
397 continue;
398
399 cpuid_func_emulated(&emulated, cpuid.function, true);
400
401 /*
402 * A vCPU has a feature if it's supported by KVM and is enabled
403 * in guest CPUID. Note, this includes features that are
404 * supported by KVM but aren't advertised to userspace!
405 */
406 vcpu->arch.cpu_caps[i] = kvm_cpu_caps[i] |
407 cpuid_get_reg_unsafe(&emulated, cpuid.reg);
408 vcpu->arch.cpu_caps[i] &= cpuid_get_reg_unsafe(entry, cpuid.reg);
409 }
410
411 kvm_update_cpuid_runtime(vcpu);
412
413 /*
414 * If TDP is enabled, let the guest use GBPAGES if they're supported in
415 * hardware. The hardware page walker doesn't let KVM disable GBPAGES,
416 * i.e. won't treat them as reserved, and KVM doesn't redo the GVA->GPA
417 * walk for performance and complexity reasons. Not to mention KVM
418 * _can't_ solve the problem because GVA->GPA walks aren't visible to
419 * KVM once a TDP translation is installed. Mimic hardware behavior so
420 * that KVM's is at least consistent, i.e. doesn't randomly inject #PF.
421 * If TDP is disabled, honor *only* guest CPUID as KVM has full control
422 * and can install smaller shadow pages if the host lacks 1GiB support.
423 */
424 allow_gbpages = tdp_enabled ? boot_cpu_has(X86_FEATURE_GBPAGES) :
425 guest_cpu_cap_has(vcpu, X86_FEATURE_GBPAGES);
426 guest_cpu_cap_change(vcpu, X86_FEATURE_GBPAGES, allow_gbpages);
427
428 best = kvm_find_cpuid_entry(vcpu, 1);
429 if (best && apic) {
430 if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER))
431 apic->lapic_timer.timer_mode_mask = 3 << 17;
432 else
433 apic->lapic_timer.timer_mode_mask = 1 << 17;
434
435 kvm_apic_set_version(vcpu);
436 }
437
438 vcpu->arch.guest_supported_xcr0 = cpuid_get_supported_xcr0(vcpu);
439 vcpu->arch.guest_supported_xss = cpuid_get_supported_xss(vcpu);
440
441 vcpu->arch.pv_cpuid.features = kvm_apply_cpuid_pv_features_quirk(vcpu);
442
443 vcpu->arch.is_amd_compatible = guest_cpuid_is_amd_or_hygon(vcpu);
444 vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
445 vcpu->arch.reserved_gpa_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
446
447 kvm_pmu_refresh(vcpu);
448
449 #define __kvm_cpu_cap_has(UNUSED_, f) kvm_cpu_cap_has(f)
450 vcpu->arch.cr4_guest_rsvd_bits = __cr4_reserved_bits(__kvm_cpu_cap_has, UNUSED_) |
451 __cr4_reserved_bits(guest_cpu_cap_has, vcpu);
452 #undef __kvm_cpu_cap_has
453
454 kvm_hv_set_cpuid(vcpu, kvm_cpuid_has_hyperv(vcpu));
455
456 /* Invoke the vendor callback only after the above state is updated. */
457 kvm_x86_call(vcpu_after_set_cpuid)(vcpu);
458
459 /*
460 * Except for the MMU, which needs to do its thing any vendor specific
461 * adjustments to the reserved GPA bits.
462 */
463 kvm_mmu_after_set_cpuid(vcpu);
464
465 kvm_make_request(KVM_REQ_RECALC_INTERCEPTS, vcpu);
466 }
467
cpuid_query_maxphyaddr(struct kvm_vcpu * vcpu)468 int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
469 {
470 struct kvm_cpuid_entry2 *best;
471
472 best = kvm_find_cpuid_entry(vcpu, 0x80000000);
473 if (!best || best->eax < 0x80000008)
474 goto not_found;
475 best = kvm_find_cpuid_entry(vcpu, 0x80000008);
476 if (best)
477 return best->eax & 0xff;
478 not_found:
479 return 36;
480 }
481
cpuid_query_maxguestphyaddr(struct kvm_vcpu * vcpu)482 int cpuid_query_maxguestphyaddr(struct kvm_vcpu *vcpu)
483 {
484 struct kvm_cpuid_entry2 *best;
485
486 best = kvm_find_cpuid_entry(vcpu, 0x80000000);
487 if (!best || best->eax < 0x80000008)
488 goto not_found;
489 best = kvm_find_cpuid_entry(vcpu, 0x80000008);
490 if (best)
491 return (best->eax >> 16) & 0xff;
492 not_found:
493 return 0;
494 }
495
496 /*
497 * This "raw" version returns the reserved GPA bits without any adjustments for
498 * encryption technologies that usurp bits. The raw mask should be used if and
499 * only if hardware does _not_ strip the usurped bits, e.g. in virtual MTRRs.
500 */
kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu * vcpu)501 u64 kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu *vcpu)
502 {
503 return rsvd_bits(cpuid_maxphyaddr(vcpu), 63);
504 }
505
kvm_set_cpuid(struct kvm_vcpu * vcpu,struct kvm_cpuid_entry2 * e2,int nent)506 static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
507 int nent)
508 {
509 u32 vcpu_caps[NR_KVM_CPU_CAPS];
510 int r;
511
512 /*
513 * Apply pending runtime CPUID updates to the current CPUID entries to
514 * avoid false positives due to mismatches on KVM-owned feature flags.
515 */
516 if (vcpu->arch.cpuid_dynamic_bits_dirty)
517 kvm_update_cpuid_runtime(vcpu);
518
519 /*
520 * Swap the existing (old) entries with the incoming (new) entries in
521 * order to massage the new entries, e.g. to account for dynamic bits
522 * that KVM controls, without losing the current guest CPUID, which KVM
523 * needs to preserve in order to unwind on failure.
524 *
525 * Similarly, save the vCPU's current cpu_caps so that the capabilities
526 * can be updated alongside the CPUID entries when performing runtime
527 * updates. Full initialization is done if and only if the vCPU hasn't
528 * run, i.e. only if userspace is potentially changing CPUID features.
529 */
530 swap(vcpu->arch.cpuid_entries, e2);
531 swap(vcpu->arch.cpuid_nent, nent);
532
533 memcpy(vcpu_caps, vcpu->arch.cpu_caps, sizeof(vcpu_caps));
534 BUILD_BUG_ON(sizeof(vcpu_caps) != sizeof(vcpu->arch.cpu_caps));
535
536 /*
537 * KVM does not correctly handle changing guest CPUID after KVM_RUN, as
538 * MAXPHYADDR, GBPAGES support, AMD reserved bit behavior, etc.. aren't
539 * tracked in kvm_mmu_page_role. As a result, KVM may miss guest page
540 * faults due to reusing SPs/SPTEs. In practice no sane VMM mucks with
541 * the core vCPU model on the fly. It would've been better to forbid any
542 * KVM_SET_CPUID{,2} calls after KVM_RUN altogether but unfortunately
543 * some VMMs (e.g. QEMU) reuse vCPU fds for CPU hotplug/unplug and do
544 * KVM_SET_CPUID{,2} again. To support this legacy behavior, check
545 * whether the supplied CPUID data is equal to what's already set.
546 */
547 if (kvm_vcpu_has_run(vcpu)) {
548 r = kvm_cpuid_check_equal(vcpu, e2, nent);
549 if (r)
550 goto err;
551 goto success;
552 }
553
554 #ifdef CONFIG_KVM_HYPERV
555 if (kvm_cpuid_has_hyperv(vcpu)) {
556 r = kvm_hv_vcpu_init(vcpu);
557 if (r)
558 goto err;
559 }
560 #endif
561
562 r = kvm_check_cpuid(vcpu);
563 if (r)
564 goto err;
565
566 #ifdef CONFIG_KVM_XEN
567 vcpu->arch.xen.cpuid = kvm_get_hypervisor_cpuid(vcpu, XEN_SIGNATURE);
568 #endif
569 kvm_vcpu_after_set_cpuid(vcpu);
570
571 success:
572 kvfree(e2);
573 return 0;
574
575 err:
576 memcpy(vcpu->arch.cpu_caps, vcpu_caps, sizeof(vcpu_caps));
577 swap(vcpu->arch.cpuid_entries, e2);
578 swap(vcpu->arch.cpuid_nent, nent);
579 return r;
580 }
581
582 /* when an old userspace process fills a new kernel module */
kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu * vcpu,struct kvm_cpuid * cpuid,struct kvm_cpuid_entry __user * entries)583 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
584 struct kvm_cpuid *cpuid,
585 struct kvm_cpuid_entry __user *entries)
586 {
587 int r, i;
588 struct kvm_cpuid_entry *e = NULL;
589 struct kvm_cpuid_entry2 *e2 = NULL;
590
591 if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
592 return -E2BIG;
593
594 if (cpuid->nent) {
595 e = vmemdup_array_user(entries, cpuid->nent, sizeof(*e));
596 if (IS_ERR(e))
597 return PTR_ERR(e);
598
599 e2 = kvmalloc_array(cpuid->nent, sizeof(*e2), GFP_KERNEL_ACCOUNT);
600 if (!e2) {
601 r = -ENOMEM;
602 goto out_free_cpuid;
603 }
604 }
605 for (i = 0; i < cpuid->nent; i++) {
606 e2[i].function = e[i].function;
607 e2[i].eax = e[i].eax;
608 e2[i].ebx = e[i].ebx;
609 e2[i].ecx = e[i].ecx;
610 e2[i].edx = e[i].edx;
611 e2[i].index = 0;
612 e2[i].flags = 0;
613 e2[i].padding[0] = 0;
614 e2[i].padding[1] = 0;
615 e2[i].padding[2] = 0;
616 }
617
618 r = kvm_set_cpuid(vcpu, e2, cpuid->nent);
619 if (r)
620 kvfree(e2);
621
622 out_free_cpuid:
623 kvfree(e);
624
625 return r;
626 }
627
kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu * vcpu,struct kvm_cpuid2 * cpuid,struct kvm_cpuid_entry2 __user * entries)628 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
629 struct kvm_cpuid2 *cpuid,
630 struct kvm_cpuid_entry2 __user *entries)
631 {
632 struct kvm_cpuid_entry2 *e2 = NULL;
633 int r;
634
635 if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
636 return -E2BIG;
637
638 if (cpuid->nent) {
639 e2 = vmemdup_array_user(entries, cpuid->nent, sizeof(*e2));
640 if (IS_ERR(e2))
641 return PTR_ERR(e2);
642 }
643
644 r = kvm_set_cpuid(vcpu, e2, cpuid->nent);
645 if (r)
646 kvfree(e2);
647
648 return r;
649 }
650
kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu * vcpu,struct kvm_cpuid2 * cpuid,struct kvm_cpuid_entry2 __user * entries)651 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
652 struct kvm_cpuid2 *cpuid,
653 struct kvm_cpuid_entry2 __user *entries)
654 {
655 if (cpuid->nent < vcpu->arch.cpuid_nent)
656 return -E2BIG;
657
658 if (vcpu->arch.cpuid_dynamic_bits_dirty)
659 kvm_update_cpuid_runtime(vcpu);
660
661 if (copy_to_user(entries, vcpu->arch.cpuid_entries,
662 vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
663 return -EFAULT;
664
665 cpuid->nent = vcpu->arch.cpuid_nent;
666 return 0;
667 }
668
raw_cpuid_get(struct cpuid_reg cpuid)669 static __always_inline u32 raw_cpuid_get(struct cpuid_reg cpuid)
670 {
671 struct kvm_cpuid_entry2 entry;
672 u32 base;
673
674 /*
675 * KVM only supports features defined by Intel (0x0), AMD (0x80000000),
676 * and Centaur (0xc0000000). WARN if a feature for new vendor base is
677 * defined, as this and other code would need to be updated.
678 */
679 base = cpuid.function & 0xffff0000;
680 if (WARN_ON_ONCE(base && base != 0x80000000 && base != 0xc0000000))
681 return 0;
682
683 if (cpuid_eax(base) < cpuid.function)
684 return 0;
685
686 cpuid_count(cpuid.function, cpuid.index,
687 &entry.eax, &entry.ebx, &entry.ecx, &entry.edx);
688
689 return *__cpuid_entry_get_reg(&entry, cpuid.reg);
690 }
691
692 /*
693 * For kernel-defined leafs, mask KVM's supported feature set with the kernel's
694 * capabilities as well as raw CPUID. For KVM-defined leafs, consult only raw
695 * CPUID, as KVM is the one and only authority (in the kernel).
696 */
697 #define kvm_cpu_cap_init(leaf, feature_initializers...) \
698 do { \
699 const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32); \
700 const u32 __maybe_unused kvm_cpu_cap_init_in_progress = leaf; \
701 const u32 *kernel_cpu_caps = boot_cpu_data.x86_capability; \
702 u32 kvm_cpu_cap_passthrough = 0; \
703 u32 kvm_cpu_cap_synthesized = 0; \
704 u32 kvm_cpu_cap_emulated = 0; \
705 u32 kvm_cpu_cap_features = 0; \
706 \
707 feature_initializers \
708 \
709 kvm_cpu_caps[leaf] = kvm_cpu_cap_features; \
710 \
711 if (leaf < NCAPINTS) \
712 kvm_cpu_caps[leaf] &= kernel_cpu_caps[leaf]; \
713 \
714 kvm_cpu_caps[leaf] |= kvm_cpu_cap_passthrough; \
715 kvm_cpu_caps[leaf] &= (raw_cpuid_get(cpuid) | \
716 kvm_cpu_cap_synthesized); \
717 kvm_cpu_caps[leaf] |= kvm_cpu_cap_emulated; \
718 } while (0)
719
720 /*
721 * Assert that the feature bit being declared, e.g. via F(), is in the CPUID
722 * word that's being initialized. Exempt 0x8000_0001.EDX usage of 0x1.EDX
723 * features, as AMD duplicated many 0x1.EDX features into 0x8000_0001.EDX.
724 */
725 #define KVM_VALIDATE_CPU_CAP_USAGE(name) \
726 do { \
727 u32 __leaf = __feature_leaf(X86_FEATURE_##name); \
728 \
729 BUILD_BUG_ON(__leaf != kvm_cpu_cap_init_in_progress); \
730 } while (0)
731
732 #define F(name) \
733 ({ \
734 KVM_VALIDATE_CPU_CAP_USAGE(name); \
735 kvm_cpu_cap_features |= feature_bit(name); \
736 })
737
738 /* Scattered Flag - For features that are scattered by cpufeatures.h. */
739 #define SCATTERED_F(name) \
740 ({ \
741 BUILD_BUG_ON(X86_FEATURE_##name >= MAX_CPU_FEATURES); \
742 KVM_VALIDATE_CPU_CAP_USAGE(name); \
743 if (boot_cpu_has(X86_FEATURE_##name)) \
744 F(name); \
745 })
746
747 /* Features that KVM supports only on 64-bit kernels. */
748 #define X86_64_F(name) \
749 ({ \
750 KVM_VALIDATE_CPU_CAP_USAGE(name); \
751 if (IS_ENABLED(CONFIG_X86_64)) \
752 F(name); \
753 })
754
755 /*
756 * Emulated Feature - For features that KVM emulates in software irrespective
757 * of host CPU/kernel support.
758 */
759 #define EMULATED_F(name) \
760 ({ \
761 kvm_cpu_cap_emulated |= feature_bit(name); \
762 F(name); \
763 })
764
765 /*
766 * Synthesized Feature - For features that are synthesized into boot_cpu_data,
767 * i.e. may not be present in the raw CPUID, but can still be advertised to
768 * userspace. Primarily used for mitigation related feature flags.
769 */
770 #define SYNTHESIZED_F(name) \
771 ({ \
772 kvm_cpu_cap_synthesized |= feature_bit(name); \
773 F(name); \
774 })
775
776 /*
777 * Passthrough Feature - For features that KVM supports based purely on raw
778 * hardware CPUID, i.e. that KVM virtualizes even if the host kernel doesn't
779 * use the feature. Simply force set the feature in KVM's capabilities, raw
780 * CPUID support will be factored in by kvm_cpu_cap_mask().
781 */
782 #define PASSTHROUGH_F(name) \
783 ({ \
784 kvm_cpu_cap_passthrough |= feature_bit(name); \
785 F(name); \
786 })
787
788 /*
789 * Aliased Features - For features in 0x8000_0001.EDX that are duplicates of
790 * identical 0x1.EDX features, and thus are aliased from 0x1 to 0x8000_0001.
791 */
792 #define ALIASED_1_EDX_F(name) \
793 ({ \
794 BUILD_BUG_ON(__feature_leaf(X86_FEATURE_##name) != CPUID_1_EDX); \
795 BUILD_BUG_ON(kvm_cpu_cap_init_in_progress != CPUID_8000_0001_EDX); \
796 kvm_cpu_cap_features |= feature_bit(name); \
797 })
798
799 /*
800 * Vendor Features - For features that KVM supports, but are added in later
801 * because they require additional vendor enabling.
802 */
803 #define VENDOR_F(name) \
804 ({ \
805 KVM_VALIDATE_CPU_CAP_USAGE(name); \
806 })
807
808 /*
809 * Runtime Features - For features that KVM dynamically sets/clears at runtime,
810 * e.g. when CR4 changes, but which are never advertised to userspace.
811 */
812 #define RUNTIME_F(name) \
813 ({ \
814 KVM_VALIDATE_CPU_CAP_USAGE(name); \
815 })
816
817 /*
818 * Undefine the MSR bit macro to avoid token concatenation issues when
819 * processing X86_FEATURE_SPEC_CTRL_SSBD.
820 */
821 #undef SPEC_CTRL_SSBD
822
823 /* DS is defined by ptrace-abi.h on 32-bit builds. */
824 #undef DS
825
kvm_set_cpu_caps(void)826 void kvm_set_cpu_caps(void)
827 {
828 memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps));
829
830 BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) >
831 sizeof(boot_cpu_data.x86_capability));
832
833 kvm_cpu_cap_init(CPUID_1_ECX,
834 F(XMM3),
835 F(PCLMULQDQ),
836 VENDOR_F(DTES64),
837 /*
838 * NOTE: MONITOR (and MWAIT) are emulated as NOP, but *not*
839 * advertised to guests via CPUID! MWAIT is also technically a
840 * runtime flag thanks to IA32_MISC_ENABLES; mark it as such so
841 * that KVM is aware that it's a known, unadvertised flag.
842 */
843 RUNTIME_F(MWAIT),
844 /* DS-CPL */
845 VENDOR_F(VMX),
846 /* SMX, EST */
847 /* TM2 */
848 F(SSSE3),
849 /* CNXT-ID */
850 /* Reserved */
851 F(FMA),
852 F(CX16),
853 /* xTPR Update */
854 F(PDCM),
855 F(PCID),
856 /* Reserved, DCA */
857 F(XMM4_1),
858 F(XMM4_2),
859 EMULATED_F(X2APIC),
860 F(MOVBE),
861 F(POPCNT),
862 EMULATED_F(TSC_DEADLINE_TIMER),
863 F(AES),
864 F(XSAVE),
865 RUNTIME_F(OSXSAVE),
866 F(AVX),
867 F(F16C),
868 F(RDRAND),
869 EMULATED_F(HYPERVISOR),
870 );
871
872 kvm_cpu_cap_init(CPUID_1_EDX,
873 F(FPU),
874 F(VME),
875 F(DE),
876 F(PSE),
877 F(TSC),
878 F(MSR),
879 F(PAE),
880 F(MCE),
881 F(CX8),
882 F(APIC),
883 /* Reserved */
884 F(SEP),
885 F(MTRR),
886 F(PGE),
887 F(MCA),
888 F(CMOV),
889 F(PAT),
890 F(PSE36),
891 /* PSN */
892 F(CLFLUSH),
893 /* Reserved */
894 VENDOR_F(DS),
895 /* ACPI */
896 F(MMX),
897 F(FXSR),
898 F(XMM),
899 F(XMM2),
900 F(SELFSNOOP),
901 /* HTT, TM, Reserved, PBE */
902 );
903
904 kvm_cpu_cap_init(CPUID_7_0_EBX,
905 F(FSGSBASE),
906 EMULATED_F(TSC_ADJUST),
907 F(SGX),
908 F(BMI1),
909 F(HLE),
910 F(AVX2),
911 F(FDP_EXCPTN_ONLY),
912 F(SMEP),
913 F(BMI2),
914 F(ERMS),
915 F(INVPCID),
916 F(RTM),
917 F(ZERO_FCS_FDS),
918 VENDOR_F(MPX),
919 F(AVX512F),
920 F(AVX512DQ),
921 F(RDSEED),
922 F(ADX),
923 F(SMAP),
924 F(AVX512IFMA),
925 F(CLFLUSHOPT),
926 F(CLWB),
927 VENDOR_F(INTEL_PT),
928 F(AVX512PF),
929 F(AVX512ER),
930 F(AVX512CD),
931 F(SHA_NI),
932 F(AVX512BW),
933 F(AVX512VL),
934 );
935
936 kvm_cpu_cap_init(CPUID_7_ECX,
937 F(AVX512VBMI),
938 PASSTHROUGH_F(LA57),
939 F(PKU),
940 RUNTIME_F(OSPKE),
941 F(RDPID),
942 F(AVX512_VPOPCNTDQ),
943 F(UMIP),
944 F(AVX512_VBMI2),
945 F(GFNI),
946 F(VAES),
947 F(VPCLMULQDQ),
948 F(AVX512_VNNI),
949 F(AVX512_BITALG),
950 F(CLDEMOTE),
951 F(MOVDIRI),
952 F(MOVDIR64B),
953 VENDOR_F(WAITPKG),
954 F(SGX_LC),
955 F(BUS_LOCK_DETECT),
956 X86_64_F(SHSTK),
957 );
958
959 /*
960 * PKU not yet implemented for shadow paging and requires OSPKE
961 * to be set on the host. Clear it if that is not the case
962 */
963 if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
964 kvm_cpu_cap_clear(X86_FEATURE_PKU);
965
966 /*
967 * Shadow Stacks aren't implemented in the Shadow MMU. Shadow Stack
968 * accesses require "magic" Writable=0,Dirty=1 protection, which KVM
969 * doesn't know how to emulate or map.
970 */
971 if (!tdp_enabled)
972 kvm_cpu_cap_clear(X86_FEATURE_SHSTK);
973
974 kvm_cpu_cap_init(CPUID_7_EDX,
975 F(AVX512_4VNNIW),
976 F(AVX512_4FMAPS),
977 F(SPEC_CTRL),
978 F(SPEC_CTRL_SSBD),
979 EMULATED_F(ARCH_CAPABILITIES),
980 F(INTEL_STIBP),
981 F(MD_CLEAR),
982 F(AVX512_VP2INTERSECT),
983 F(FSRM),
984 F(SERIALIZE),
985 F(TSXLDTRK),
986 F(AVX512_FP16),
987 F(AMX_TILE),
988 F(AMX_INT8),
989 F(AMX_BF16),
990 F(FLUSH_L1D),
991 F(IBT),
992 );
993
994 /*
995 * Disable support for IBT and SHSTK if KVM is configured to emulate
996 * accesses to reserved GPAs, as KVM's emulator doesn't support IBT or
997 * SHSTK, nor does KVM handle Shadow Stack #PFs (see above).
998 */
999 if (allow_smaller_maxphyaddr) {
1000 kvm_cpu_cap_clear(X86_FEATURE_SHSTK);
1001 kvm_cpu_cap_clear(X86_FEATURE_IBT);
1002 }
1003
1004 if (boot_cpu_has(X86_FEATURE_AMD_IBPB_RET) &&
1005 boot_cpu_has(X86_FEATURE_AMD_IBPB) &&
1006 boot_cpu_has(X86_FEATURE_AMD_IBRS))
1007 kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL);
1008 if (boot_cpu_has(X86_FEATURE_STIBP))
1009 kvm_cpu_cap_set(X86_FEATURE_INTEL_STIBP);
1010 if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
1011 kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD);
1012
1013 kvm_cpu_cap_init(CPUID_7_1_EAX,
1014 F(SHA512),
1015 F(SM3),
1016 F(SM4),
1017 F(AVX_VNNI),
1018 F(AVX512_BF16),
1019 F(CMPCCXADD),
1020 F(FZRM),
1021 F(FSRS),
1022 F(FSRC),
1023 F(WRMSRNS),
1024 X86_64_F(LKGS),
1025 F(AMX_FP16),
1026 F(AVX_IFMA),
1027 F(LAM),
1028 );
1029
1030 kvm_cpu_cap_init(CPUID_7_1_ECX,
1031 SCATTERED_F(MSR_IMM),
1032 );
1033
1034 kvm_cpu_cap_init(CPUID_7_1_EDX,
1035 F(AVX_VNNI_INT8),
1036 F(AVX_NE_CONVERT),
1037 F(AMX_COMPLEX),
1038 F(AVX_VNNI_INT16),
1039 F(PREFETCHITI),
1040 F(AVX10),
1041 );
1042
1043 kvm_cpu_cap_init(CPUID_7_2_EDX,
1044 F(INTEL_PSFD),
1045 F(IPRED_CTRL),
1046 F(RRSBA_CTRL),
1047 F(DDPD_U),
1048 F(BHI_CTRL),
1049 F(MCDT_NO),
1050 );
1051
1052 kvm_cpu_cap_init(CPUID_D_1_EAX,
1053 F(XSAVEOPT),
1054 F(XSAVEC),
1055 F(XGETBV1),
1056 F(XSAVES),
1057 X86_64_F(XFD),
1058 );
1059
1060 kvm_cpu_cap_init(CPUID_12_EAX,
1061 SCATTERED_F(SGX1),
1062 SCATTERED_F(SGX2),
1063 SCATTERED_F(SGX_EDECCSSA),
1064 );
1065
1066 kvm_cpu_cap_init(CPUID_24_0_EBX,
1067 F(AVX10_128),
1068 F(AVX10_256),
1069 F(AVX10_512),
1070 );
1071
1072 kvm_cpu_cap_init(CPUID_8000_0001_ECX,
1073 F(LAHF_LM),
1074 F(CMP_LEGACY),
1075 VENDOR_F(SVM),
1076 /* ExtApicSpace */
1077 F(CR8_LEGACY),
1078 F(ABM),
1079 F(SSE4A),
1080 F(MISALIGNSSE),
1081 F(3DNOWPREFETCH),
1082 F(OSVW),
1083 /* IBS */
1084 F(XOP),
1085 /* SKINIT, WDT, LWP */
1086 F(FMA4),
1087 F(TBM),
1088 F(TOPOEXT),
1089 VENDOR_F(PERFCTR_CORE),
1090 );
1091
1092 kvm_cpu_cap_init(CPUID_8000_0001_EDX,
1093 ALIASED_1_EDX_F(FPU),
1094 ALIASED_1_EDX_F(VME),
1095 ALIASED_1_EDX_F(DE),
1096 ALIASED_1_EDX_F(PSE),
1097 ALIASED_1_EDX_F(TSC),
1098 ALIASED_1_EDX_F(MSR),
1099 ALIASED_1_EDX_F(PAE),
1100 ALIASED_1_EDX_F(MCE),
1101 ALIASED_1_EDX_F(CX8),
1102 ALIASED_1_EDX_F(APIC),
1103 /* Reserved */
1104 F(SYSCALL),
1105 ALIASED_1_EDX_F(MTRR),
1106 ALIASED_1_EDX_F(PGE),
1107 ALIASED_1_EDX_F(MCA),
1108 ALIASED_1_EDX_F(CMOV),
1109 ALIASED_1_EDX_F(PAT),
1110 ALIASED_1_EDX_F(PSE36),
1111 /* Reserved */
1112 F(NX),
1113 /* Reserved */
1114 F(MMXEXT),
1115 ALIASED_1_EDX_F(MMX),
1116 ALIASED_1_EDX_F(FXSR),
1117 F(FXSR_OPT),
1118 X86_64_F(GBPAGES),
1119 F(RDTSCP),
1120 /* Reserved */
1121 X86_64_F(LM),
1122 F(3DNOWEXT),
1123 F(3DNOW),
1124 );
1125
1126 if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64))
1127 kvm_cpu_cap_set(X86_FEATURE_GBPAGES);
1128
1129 kvm_cpu_cap_init(CPUID_8000_0007_EDX,
1130 SCATTERED_F(CONSTANT_TSC),
1131 );
1132
1133 kvm_cpu_cap_init(CPUID_8000_0008_EBX,
1134 F(CLZERO),
1135 F(XSAVEERPTR),
1136 F(WBNOINVD),
1137 F(AMD_IBPB),
1138 F(AMD_IBRS),
1139 F(AMD_SSBD),
1140 F(VIRT_SSBD),
1141 F(AMD_SSB_NO),
1142 F(AMD_STIBP),
1143 F(AMD_STIBP_ALWAYS_ON),
1144 F(AMD_IBRS_SAME_MODE),
1145 PASSTHROUGH_F(EFER_LMSLE_MBZ),
1146 F(AMD_PSFD),
1147 F(AMD_IBPB_RET),
1148 );
1149
1150 /*
1151 * AMD has separate bits for each SPEC_CTRL bit.
1152 * arch/x86/kernel/cpu/bugs.c is kind enough to
1153 * record that in cpufeatures so use them.
1154 */
1155 if (boot_cpu_has(X86_FEATURE_IBPB)) {
1156 kvm_cpu_cap_set(X86_FEATURE_AMD_IBPB);
1157 if (boot_cpu_has(X86_FEATURE_SPEC_CTRL) &&
1158 !boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB))
1159 kvm_cpu_cap_set(X86_FEATURE_AMD_IBPB_RET);
1160 }
1161 if (boot_cpu_has(X86_FEATURE_IBRS))
1162 kvm_cpu_cap_set(X86_FEATURE_AMD_IBRS);
1163 if (boot_cpu_has(X86_FEATURE_STIBP))
1164 kvm_cpu_cap_set(X86_FEATURE_AMD_STIBP);
1165 if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
1166 kvm_cpu_cap_set(X86_FEATURE_AMD_SSBD);
1167 if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
1168 kvm_cpu_cap_set(X86_FEATURE_AMD_SSB_NO);
1169 /*
1170 * The preference is to use SPEC CTRL MSR instead of the
1171 * VIRT_SPEC MSR.
1172 */
1173 if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) &&
1174 !boot_cpu_has(X86_FEATURE_AMD_SSBD))
1175 kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
1176
1177 /* All SVM features required additional vendor module enabling. */
1178 kvm_cpu_cap_init(CPUID_8000_000A_EDX,
1179 VENDOR_F(NPT),
1180 VENDOR_F(VMCBCLEAN),
1181 VENDOR_F(FLUSHBYASID),
1182 VENDOR_F(NRIPS),
1183 VENDOR_F(TSCRATEMSR),
1184 VENDOR_F(V_VMSAVE_VMLOAD),
1185 VENDOR_F(LBRV),
1186 VENDOR_F(PAUSEFILTER),
1187 VENDOR_F(PFTHRESHOLD),
1188 VENDOR_F(VGIF),
1189 VENDOR_F(VNMI),
1190 VENDOR_F(SVME_ADDR_CHK),
1191 );
1192
1193 kvm_cpu_cap_init(CPUID_8000_001F_EAX,
1194 VENDOR_F(SME),
1195 VENDOR_F(SEV),
1196 /* VM_PAGE_FLUSH */
1197 VENDOR_F(SEV_ES),
1198 F(SME_COHERENT),
1199 );
1200
1201 kvm_cpu_cap_init(CPUID_8000_0021_EAX,
1202 F(NO_NESTED_DATA_BP),
1203 F(WRMSR_XX_BASE_NS),
1204 /*
1205 * Synthesize "LFENCE is serializing" into the AMD-defined entry
1206 * in KVM's supported CPUID, i.e. if the feature is reported as
1207 * supported by the kernel. LFENCE_RDTSC was a Linux-defined
1208 * synthetic feature long before AMD joined the bandwagon, e.g.
1209 * LFENCE is serializing on most CPUs that support SSE2. On
1210 * CPUs that don't support AMD's leaf, ANDing with the raw host
1211 * CPUID will drop the flags, and reporting support in AMD's
1212 * leaf can make it easier for userspace to detect the feature.
1213 */
1214 SYNTHESIZED_F(LFENCE_RDTSC),
1215 /* SmmPgCfgLock */
1216 /* 4: Resv */
1217 SYNTHESIZED_F(VERW_CLEAR),
1218 F(NULL_SEL_CLR_BASE),
1219 /* UpperAddressIgnore */
1220 F(AUTOIBRS),
1221 F(PREFETCHI),
1222 EMULATED_F(NO_SMM_CTL_MSR),
1223 /* PrefetchCtlMsr */
1224 /* GpOnUserCpuid */
1225 /* EPSF */
1226 SYNTHESIZED_F(SBPB),
1227 SYNTHESIZED_F(IBPB_BRTYPE),
1228 SYNTHESIZED_F(SRSO_NO),
1229 F(SRSO_USER_KERNEL_NO),
1230 );
1231
1232 kvm_cpu_cap_init(CPUID_8000_0021_ECX,
1233 SYNTHESIZED_F(TSA_SQ_NO),
1234 SYNTHESIZED_F(TSA_L1_NO),
1235 );
1236
1237 kvm_cpu_cap_init(CPUID_8000_0022_EAX,
1238 F(PERFMON_V2),
1239 );
1240
1241 if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
1242 kvm_cpu_cap_set(X86_FEATURE_NULL_SEL_CLR_BASE);
1243
1244 kvm_cpu_cap_init(CPUID_C000_0001_EDX,
1245 F(XSTORE),
1246 F(XSTORE_EN),
1247 F(XCRYPT),
1248 F(XCRYPT_EN),
1249 F(ACE2),
1250 F(ACE2_EN),
1251 F(PHE),
1252 F(PHE_EN),
1253 F(PMM),
1254 F(PMM_EN),
1255 );
1256
1257 /*
1258 * Hide RDTSCP and RDPID if either feature is reported as supported but
1259 * probing MSR_TSC_AUX failed. This is purely a sanity check and
1260 * should never happen, but the guest will likely crash if RDTSCP or
1261 * RDPID is misreported, and KVM has botched MSR_TSC_AUX emulation in
1262 * the past. For example, the sanity check may fire if this instance of
1263 * KVM is running as L1 on top of an older, broken KVM.
1264 */
1265 if (WARN_ON((kvm_cpu_cap_has(X86_FEATURE_RDTSCP) ||
1266 kvm_cpu_cap_has(X86_FEATURE_RDPID)) &&
1267 !kvm_is_supported_user_return_msr(MSR_TSC_AUX))) {
1268 kvm_cpu_cap_clear(X86_FEATURE_RDTSCP);
1269 kvm_cpu_cap_clear(X86_FEATURE_RDPID);
1270 }
1271 }
1272 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_set_cpu_caps);
1273
1274 #undef F
1275 #undef SCATTERED_F
1276 #undef X86_64_F
1277 #undef EMULATED_F
1278 #undef SYNTHESIZED_F
1279 #undef PASSTHROUGH_F
1280 #undef ALIASED_1_EDX_F
1281 #undef VENDOR_F
1282 #undef RUNTIME_F
1283
1284 struct kvm_cpuid_array {
1285 struct kvm_cpuid_entry2 *entries;
1286 int maxnent;
1287 int nent;
1288 };
1289
get_next_cpuid(struct kvm_cpuid_array * array)1290 static struct kvm_cpuid_entry2 *get_next_cpuid(struct kvm_cpuid_array *array)
1291 {
1292 if (array->nent >= array->maxnent)
1293 return NULL;
1294
1295 return &array->entries[array->nent++];
1296 }
1297
do_host_cpuid(struct kvm_cpuid_array * array,u32 function,u32 index)1298 static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array,
1299 u32 function, u32 index)
1300 {
1301 struct kvm_cpuid_entry2 *entry = get_next_cpuid(array);
1302
1303 if (!entry)
1304 return NULL;
1305
1306 memset(entry, 0, sizeof(*entry));
1307 entry->function = function;
1308 entry->index = index;
1309 switch (function & 0xC0000000) {
1310 case 0x40000000:
1311 /* Hypervisor leaves are always synthesized by __do_cpuid_func. */
1312 return entry;
1313
1314 case 0x80000000:
1315 /*
1316 * 0x80000021 is sometimes synthesized by __do_cpuid_func, which
1317 * would result in out-of-bounds calls to do_host_cpuid.
1318 */
1319 {
1320 static int max_cpuid_80000000;
1321 if (!READ_ONCE(max_cpuid_80000000))
1322 WRITE_ONCE(max_cpuid_80000000, cpuid_eax(0x80000000));
1323 if (function > READ_ONCE(max_cpuid_80000000))
1324 return entry;
1325 }
1326 break;
1327
1328 default:
1329 break;
1330 }
1331
1332 cpuid_count(entry->function, entry->index,
1333 &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
1334
1335 if (cpuid_function_is_indexed(function))
1336 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
1337
1338 return entry;
1339 }
1340
cpuid_func_emulated(struct kvm_cpuid_entry2 * entry,u32 func,bool include_partially_emulated)1341 static int cpuid_func_emulated(struct kvm_cpuid_entry2 *entry, u32 func,
1342 bool include_partially_emulated)
1343 {
1344 memset(entry, 0, sizeof(*entry));
1345
1346 entry->function = func;
1347 entry->index = 0;
1348 entry->flags = 0;
1349
1350 switch (func) {
1351 case 0:
1352 entry->eax = 7;
1353 return 1;
1354 case 1:
1355 entry->ecx = feature_bit(MOVBE);
1356 /*
1357 * KVM allows userspace to enumerate MONITOR+MWAIT support to
1358 * the guest, but the MWAIT feature flag is never advertised
1359 * to userspace because MONITOR+MWAIT aren't virtualized by
1360 * hardware, can't be faithfully emulated in software (KVM
1361 * emulates them as NOPs), and allowing the guest to execute
1362 * them natively requires enabling a per-VM capability.
1363 */
1364 if (include_partially_emulated)
1365 entry->ecx |= feature_bit(MWAIT);
1366 return 1;
1367 case 7:
1368 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
1369 entry->eax = 0;
1370 if (kvm_cpu_cap_has(X86_FEATURE_RDTSCP))
1371 entry->ecx = feature_bit(RDPID);
1372 return 1;
1373 default:
1374 return 0;
1375 }
1376 }
1377
__do_cpuid_func_emulated(struct kvm_cpuid_array * array,u32 func)1378 static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
1379 {
1380 if (array->nent >= array->maxnent)
1381 return -E2BIG;
1382
1383 array->nent += cpuid_func_emulated(&array->entries[array->nent], func, false);
1384 return 0;
1385 }
1386
__do_cpuid_func(struct kvm_cpuid_array * array,u32 function)1387 static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
1388 {
1389 struct kvm_cpuid_entry2 *entry;
1390 int r, i, max_idx;
1391
1392 /* all calls to cpuid_count() should be made on the same cpu */
1393 get_cpu();
1394
1395 r = -E2BIG;
1396
1397 entry = do_host_cpuid(array, function, 0);
1398 if (!entry)
1399 goto out;
1400
1401 switch (function) {
1402 case 0:
1403 /* Limited to the highest leaf implemented in KVM. */
1404 entry->eax = min(entry->eax, 0x24U);
1405 break;
1406 case 1:
1407 cpuid_entry_override(entry, CPUID_1_EDX);
1408 cpuid_entry_override(entry, CPUID_1_ECX);
1409 break;
1410 case 2:
1411 /*
1412 * On ancient CPUs, function 2 entries are STATEFUL. That is,
1413 * CPUID(function=2, index=0) may return different results each
1414 * time, with the least-significant byte in EAX enumerating the
1415 * number of times software should do CPUID(2, 0).
1416 *
1417 * Modern CPUs, i.e. every CPU KVM has *ever* run on are less
1418 * idiotic. Intel's SDM states that EAX & 0xff "will always
1419 * return 01H. Software should ignore this value and not
1420 * interpret it as an informational descriptor", while AMD's
1421 * APM states that CPUID(2) is reserved.
1422 *
1423 * WARN if a frankenstein CPU that supports virtualization and
1424 * a stateful CPUID.0x2 is encountered.
1425 */
1426 WARN_ON_ONCE((entry->eax & 0xff) > 1);
1427 break;
1428 /* functions 4 and 0x8000001d have additional index. */
1429 case 4:
1430 case 0x8000001d:
1431 /*
1432 * Read entries until the cache type in the previous entry is
1433 * zero, i.e. indicates an invalid entry.
1434 */
1435 for (i = 1; entry->eax & 0x1f; ++i) {
1436 entry = do_host_cpuid(array, function, i);
1437 if (!entry)
1438 goto out;
1439 }
1440 break;
1441 case 6: /* Thermal management */
1442 entry->eax = 0x4; /* allow ARAT */
1443 entry->ebx = 0;
1444 entry->ecx = 0;
1445 entry->edx = 0;
1446 break;
1447 /* function 7 has additional index. */
1448 case 7:
1449 max_idx = entry->eax = min(entry->eax, 2u);
1450 cpuid_entry_override(entry, CPUID_7_0_EBX);
1451 cpuid_entry_override(entry, CPUID_7_ECX);
1452 cpuid_entry_override(entry, CPUID_7_EDX);
1453
1454 /* KVM only supports up to 0x7.2, capped above via min(). */
1455 if (max_idx >= 1) {
1456 entry = do_host_cpuid(array, function, 1);
1457 if (!entry)
1458 goto out;
1459
1460 cpuid_entry_override(entry, CPUID_7_1_EAX);
1461 cpuid_entry_override(entry, CPUID_7_1_ECX);
1462 cpuid_entry_override(entry, CPUID_7_1_EDX);
1463 entry->ebx = 0;
1464 }
1465 if (max_idx >= 2) {
1466 entry = do_host_cpuid(array, function, 2);
1467 if (!entry)
1468 goto out;
1469
1470 cpuid_entry_override(entry, CPUID_7_2_EDX);
1471 entry->ecx = 0;
1472 entry->ebx = 0;
1473 entry->eax = 0;
1474 }
1475 break;
1476 case 0xa: { /* Architectural Performance Monitoring */
1477 union cpuid10_eax eax = { };
1478 union cpuid10_edx edx = { };
1479
1480 if (!enable_pmu || !static_cpu_has(X86_FEATURE_ARCH_PERFMON)) {
1481 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1482 break;
1483 }
1484
1485 eax.split.version_id = kvm_pmu_cap.version;
1486 eax.split.num_counters = kvm_pmu_cap.num_counters_gp;
1487 eax.split.bit_width = kvm_pmu_cap.bit_width_gp;
1488 eax.split.mask_length = kvm_pmu_cap.events_mask_len;
1489 edx.split.num_counters_fixed = kvm_pmu_cap.num_counters_fixed;
1490 edx.split.bit_width_fixed = kvm_pmu_cap.bit_width_fixed;
1491
1492 if (kvm_pmu_cap.version)
1493 edx.split.anythread_deprecated = 1;
1494
1495 entry->eax = eax.full;
1496 entry->ebx = kvm_pmu_cap.events_mask;
1497 entry->ecx = 0;
1498 entry->edx = edx.full;
1499 break;
1500 }
1501 case 0x1f:
1502 case 0xb:
1503 /*
1504 * No topology; a valid topology is indicated by the presence
1505 * of subleaf 1.
1506 */
1507 entry->eax = entry->ebx = entry->ecx = 0;
1508 break;
1509 case 0xd: {
1510 u64 permitted_xcr0 = kvm_get_filtered_xcr0();
1511 u64 permitted_xss = kvm_caps.supported_xss;
1512
1513 entry->eax &= permitted_xcr0;
1514 entry->ebx = xstate_required_size(permitted_xcr0, false);
1515 entry->ecx = entry->ebx;
1516 entry->edx &= permitted_xcr0 >> 32;
1517 if (!permitted_xcr0)
1518 break;
1519
1520 entry = do_host_cpuid(array, function, 1);
1521 if (!entry)
1522 goto out;
1523
1524 cpuid_entry_override(entry, CPUID_D_1_EAX);
1525 if (entry->eax & (feature_bit(XSAVES) | feature_bit(XSAVEC)))
1526 entry->ebx = xstate_required_size(permitted_xcr0 | permitted_xss,
1527 true);
1528 else {
1529 WARN_ON_ONCE(permitted_xss != 0);
1530 entry->ebx = 0;
1531 }
1532 entry->ecx &= permitted_xss;
1533 entry->edx &= permitted_xss >> 32;
1534
1535 for (i = 2; i < 64; ++i) {
1536 bool s_state;
1537 if (permitted_xcr0 & BIT_ULL(i))
1538 s_state = false;
1539 else if (permitted_xss & BIT_ULL(i))
1540 s_state = true;
1541 else
1542 continue;
1543
1544 entry = do_host_cpuid(array, function, i);
1545 if (!entry)
1546 goto out;
1547
1548 /*
1549 * The supported check above should have filtered out
1550 * invalid sub-leafs. Only valid sub-leafs should
1551 * reach this point, and they should have a non-zero
1552 * save state size. Furthermore, check whether the
1553 * processor agrees with permitted_xcr0/permitted_xss
1554 * on whether this is an XCR0- or IA32_XSS-managed area.
1555 */
1556 if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 0x1) != s_state)) {
1557 --array->nent;
1558 continue;
1559 }
1560
1561 if (!kvm_cpu_cap_has(X86_FEATURE_XFD))
1562 entry->ecx &= ~BIT_ULL(2);
1563 entry->edx = 0;
1564 }
1565 break;
1566 }
1567 case 0x12:
1568 /* Intel SGX */
1569 if (!kvm_cpu_cap_has(X86_FEATURE_SGX)) {
1570 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1571 break;
1572 }
1573
1574 /*
1575 * Index 0: Sub-features, MISCSELECT (a.k.a extended features)
1576 * and max enclave sizes. The SGX sub-features and MISCSELECT
1577 * are restricted by kernel and KVM capabilities (like most
1578 * feature flags), while enclave size is unrestricted.
1579 */
1580 cpuid_entry_override(entry, CPUID_12_EAX);
1581 entry->ebx &= SGX_MISC_EXINFO;
1582
1583 entry = do_host_cpuid(array, function, 1);
1584 if (!entry)
1585 goto out;
1586
1587 /*
1588 * Index 1: SECS.ATTRIBUTES. ATTRIBUTES are restricted a la
1589 * feature flags. Advertise all supported flags, including
1590 * privileged attributes that require explicit opt-in from
1591 * userspace. ATTRIBUTES.XFRM is not adjusted as userspace is
1592 * expected to derive it from supported XCR0.
1593 */
1594 entry->eax &= SGX_ATTR_PRIV_MASK | SGX_ATTR_UNPRIV_MASK;
1595 entry->ebx &= 0;
1596 break;
1597 /* Intel PT */
1598 case 0x14:
1599 if (!kvm_cpu_cap_has(X86_FEATURE_INTEL_PT)) {
1600 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1601 break;
1602 }
1603
1604 for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) {
1605 if (!do_host_cpuid(array, function, i))
1606 goto out;
1607 }
1608 break;
1609 /* Intel AMX TILE */
1610 case 0x1d:
1611 if (!kvm_cpu_cap_has(X86_FEATURE_AMX_TILE)) {
1612 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1613 break;
1614 }
1615
1616 for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) {
1617 if (!do_host_cpuid(array, function, i))
1618 goto out;
1619 }
1620 break;
1621 case 0x1e: /* TMUL information */
1622 if (!kvm_cpu_cap_has(X86_FEATURE_AMX_TILE)) {
1623 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1624 break;
1625 }
1626 break;
1627 case 0x24: {
1628 u8 avx10_version;
1629
1630 if (!kvm_cpu_cap_has(X86_FEATURE_AVX10)) {
1631 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1632 break;
1633 }
1634
1635 /*
1636 * The AVX10 version is encoded in EBX[7:0]. Note, the version
1637 * is guaranteed to be >=1 if AVX10 is supported. Note #2, the
1638 * version needs to be captured before overriding EBX features!
1639 */
1640 avx10_version = min_t(u8, entry->ebx & 0xff, 1);
1641 cpuid_entry_override(entry, CPUID_24_0_EBX);
1642 entry->ebx |= avx10_version;
1643
1644 entry->eax = 0;
1645 entry->ecx = 0;
1646 entry->edx = 0;
1647 break;
1648 }
1649 case KVM_CPUID_SIGNATURE: {
1650 const u32 *sigptr = (const u32 *)KVM_SIGNATURE;
1651 entry->eax = KVM_CPUID_FEATURES;
1652 entry->ebx = sigptr[0];
1653 entry->ecx = sigptr[1];
1654 entry->edx = sigptr[2];
1655 break;
1656 }
1657 case KVM_CPUID_FEATURES:
1658 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
1659 (1 << KVM_FEATURE_NOP_IO_DELAY) |
1660 (1 << KVM_FEATURE_CLOCKSOURCE2) |
1661 (1 << KVM_FEATURE_ASYNC_PF) |
1662 (1 << KVM_FEATURE_PV_EOI) |
1663 (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
1664 (1 << KVM_FEATURE_PV_UNHALT) |
1665 (1 << KVM_FEATURE_PV_TLB_FLUSH) |
1666 (1 << KVM_FEATURE_ASYNC_PF_VMEXIT) |
1667 (1 << KVM_FEATURE_PV_SEND_IPI) |
1668 (1 << KVM_FEATURE_POLL_CONTROL) |
1669 (1 << KVM_FEATURE_PV_SCHED_YIELD) |
1670 (1 << KVM_FEATURE_ASYNC_PF_INT);
1671
1672 if (sched_info_on())
1673 entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
1674
1675 entry->ebx = 0;
1676 entry->ecx = 0;
1677 entry->edx = 0;
1678 break;
1679 case 0x80000000:
1680 entry->eax = min(entry->eax, 0x80000022);
1681 /*
1682 * Serializing LFENCE is reported in a multitude of ways, and
1683 * NullSegClearsBase is not reported in CPUID on Zen2; help
1684 * userspace by providing the CPUID leaf ourselves.
1685 *
1686 * However, only do it if the host has CPUID leaf 0x8000001d.
1687 * QEMU thinks that it can query the host blindly for that
1688 * CPUID leaf if KVM reports that it supports 0x8000001d or
1689 * above. The processor merrily returns values from the
1690 * highest Intel leaf which QEMU tries to use as the guest's
1691 * 0x8000001d. Even worse, this can result in an infinite
1692 * loop if said highest leaf has no subleaves indexed by ECX.
1693 */
1694 if (entry->eax >= 0x8000001d &&
1695 (static_cpu_has(X86_FEATURE_LFENCE_RDTSC)
1696 || !static_cpu_has_bug(X86_BUG_NULL_SEG)))
1697 entry->eax = max(entry->eax, 0x80000021);
1698 break;
1699 case 0x80000001:
1700 entry->ebx &= ~GENMASK(27, 16);
1701 cpuid_entry_override(entry, CPUID_8000_0001_EDX);
1702 cpuid_entry_override(entry, CPUID_8000_0001_ECX);
1703 break;
1704 case 0x80000005:
1705 /* Pass host L1 cache and TLB info. */
1706 break;
1707 case 0x80000006:
1708 /* Drop reserved bits, pass host L2 cache and TLB info. */
1709 entry->edx &= ~GENMASK(17, 16);
1710 break;
1711 case 0x80000007: /* Advanced power management */
1712 cpuid_entry_override(entry, CPUID_8000_0007_EDX);
1713
1714 /* mask against host */
1715 entry->edx &= boot_cpu_data.x86_power;
1716 entry->eax = entry->ebx = entry->ecx = 0;
1717 break;
1718 case 0x80000008: {
1719 /*
1720 * GuestPhysAddrSize (EAX[23:16]) is intended for software
1721 * use.
1722 *
1723 * KVM's ABI is to report the effective MAXPHYADDR for the
1724 * guest in PhysAddrSize (phys_as), and the maximum
1725 * *addressable* GPA in GuestPhysAddrSize (g_phys_as).
1726 *
1727 * GuestPhysAddrSize is valid if and only if TDP is enabled,
1728 * in which case the max GPA that can be addressed by KVM may
1729 * be less than the max GPA that can be legally generated by
1730 * the guest, e.g. if MAXPHYADDR>48 but the CPU doesn't
1731 * support 5-level TDP.
1732 */
1733 unsigned int virt_as = max((entry->eax >> 8) & 0xff, 48U);
1734 unsigned int phys_as, g_phys_as;
1735
1736 /*
1737 * If TDP (NPT) is disabled use the adjusted host MAXPHYADDR as
1738 * the guest operates in the same PA space as the host, i.e.
1739 * reductions in MAXPHYADDR for memory encryption affect shadow
1740 * paging, too.
1741 *
1742 * If TDP is enabled, use the raw bare metal MAXPHYADDR as
1743 * reductions to the HPAs do not affect GPAs. The max
1744 * addressable GPA is the same as the max effective GPA, except
1745 * that it's capped at 48 bits if 5-level TDP isn't supported
1746 * (hardware processes bits 51:48 only when walking the fifth
1747 * level page table).
1748 */
1749 if (!tdp_enabled) {
1750 phys_as = boot_cpu_data.x86_phys_bits;
1751 g_phys_as = 0;
1752 } else {
1753 phys_as = entry->eax & 0xff;
1754 g_phys_as = phys_as;
1755 if (kvm_mmu_get_max_tdp_level() < 5)
1756 g_phys_as = min(g_phys_as, 48U);
1757 }
1758
1759 entry->eax = phys_as | (virt_as << 8) | (g_phys_as << 16);
1760 entry->ecx &= ~(GENMASK(31, 16) | GENMASK(11, 8));
1761 entry->edx = 0;
1762 cpuid_entry_override(entry, CPUID_8000_0008_EBX);
1763 break;
1764 }
1765 case 0x8000000A:
1766 if (!kvm_cpu_cap_has(X86_FEATURE_SVM)) {
1767 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1768 break;
1769 }
1770 entry->eax = 1; /* SVM revision 1 */
1771 entry->ebx = 8; /* Lets support 8 ASIDs in case we add proper
1772 ASID emulation to nested SVM */
1773 entry->ecx = 0; /* Reserved */
1774 cpuid_entry_override(entry, CPUID_8000_000A_EDX);
1775 break;
1776 case 0x80000019:
1777 entry->ecx = entry->edx = 0;
1778 break;
1779 case 0x8000001a:
1780 entry->eax &= GENMASK(2, 0);
1781 entry->ebx = entry->ecx = entry->edx = 0;
1782 break;
1783 case 0x8000001e:
1784 /* Do not return host topology information. */
1785 entry->eax = entry->ebx = entry->ecx = 0;
1786 entry->edx = 0; /* reserved */
1787 break;
1788 case 0x8000001F:
1789 if (!kvm_cpu_cap_has(X86_FEATURE_SEV)) {
1790 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1791 } else {
1792 cpuid_entry_override(entry, CPUID_8000_001F_EAX);
1793 /* Clear NumVMPL since KVM does not support VMPL. */
1794 entry->ebx &= ~GENMASK(31, 12);
1795 /*
1796 * Enumerate '0' for "PA bits reduction", the adjusted
1797 * MAXPHYADDR is enumerated directly (see 0x80000008).
1798 */
1799 entry->ebx &= ~GENMASK(11, 6);
1800 }
1801 break;
1802 case 0x80000020:
1803 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1804 break;
1805 case 0x80000021:
1806 entry->ebx = entry->edx = 0;
1807 cpuid_entry_override(entry, CPUID_8000_0021_EAX);
1808 cpuid_entry_override(entry, CPUID_8000_0021_ECX);
1809 break;
1810 /* AMD Extended Performance Monitoring and Debug */
1811 case 0x80000022: {
1812 union cpuid_0x80000022_ebx ebx = { };
1813
1814 entry->ecx = entry->edx = 0;
1815 if (!enable_pmu || !kvm_cpu_cap_has(X86_FEATURE_PERFMON_V2)) {
1816 entry->eax = entry->ebx = 0;
1817 break;
1818 }
1819
1820 cpuid_entry_override(entry, CPUID_8000_0022_EAX);
1821
1822 ebx.split.num_core_pmc = kvm_pmu_cap.num_counters_gp;
1823 entry->ebx = ebx.full;
1824 break;
1825 }
1826 /*Add support for Centaur's CPUID instruction*/
1827 case 0xC0000000:
1828 /*Just support up to 0xC0000004 now*/
1829 entry->eax = min(entry->eax, 0xC0000004);
1830 break;
1831 case 0xC0000001:
1832 cpuid_entry_override(entry, CPUID_C000_0001_EDX);
1833 break;
1834 case 3: /* Processor serial number */
1835 case 5: /* MONITOR/MWAIT */
1836 case 0xC0000002:
1837 case 0xC0000003:
1838 case 0xC0000004:
1839 default:
1840 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
1841 break;
1842 }
1843
1844 r = 0;
1845
1846 out:
1847 put_cpu();
1848
1849 return r;
1850 }
1851
do_cpuid_func(struct kvm_cpuid_array * array,u32 func,unsigned int type)1852 static int do_cpuid_func(struct kvm_cpuid_array *array, u32 func,
1853 unsigned int type)
1854 {
1855 if (type == KVM_GET_EMULATED_CPUID)
1856 return __do_cpuid_func_emulated(array, func);
1857
1858 return __do_cpuid_func(array, func);
1859 }
1860
1861 #define CENTAUR_CPUID_SIGNATURE 0xC0000000
1862
get_cpuid_func(struct kvm_cpuid_array * array,u32 func,unsigned int type)1863 static int get_cpuid_func(struct kvm_cpuid_array *array, u32 func,
1864 unsigned int type)
1865 {
1866 u32 limit;
1867 int r;
1868
1869 if (func == CENTAUR_CPUID_SIGNATURE &&
1870 boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR &&
1871 boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN)
1872 return 0;
1873
1874 r = do_cpuid_func(array, func, type);
1875 if (r)
1876 return r;
1877
1878 limit = array->entries[array->nent - 1].eax;
1879 for (func = func + 1; func <= limit; ++func) {
1880 r = do_cpuid_func(array, func, type);
1881 if (r)
1882 break;
1883 }
1884
1885 return r;
1886 }
1887
sanity_check_entries(struct kvm_cpuid_entry2 __user * entries,__u32 num_entries,unsigned int ioctl_type)1888 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
1889 __u32 num_entries, unsigned int ioctl_type)
1890 {
1891 int i;
1892 __u32 pad[3];
1893
1894 if (ioctl_type != KVM_GET_EMULATED_CPUID)
1895 return false;
1896
1897 /*
1898 * We want to make sure that ->padding is being passed clean from
1899 * userspace in case we want to use it for something in the future.
1900 *
1901 * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
1902 * have to give ourselves satisfied only with the emulated side. /me
1903 * sheds a tear.
1904 */
1905 for (i = 0; i < num_entries; i++) {
1906 if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
1907 return true;
1908
1909 if (pad[0] || pad[1] || pad[2])
1910 return true;
1911 }
1912 return false;
1913 }
1914
kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 * cpuid,struct kvm_cpuid_entry2 __user * entries,unsigned int type)1915 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
1916 struct kvm_cpuid_entry2 __user *entries,
1917 unsigned int type)
1918 {
1919 static const u32 funcs[] = {
1920 0, 0x80000000, CENTAUR_CPUID_SIGNATURE, KVM_CPUID_SIGNATURE,
1921 };
1922
1923 struct kvm_cpuid_array array = {
1924 .nent = 0,
1925 };
1926 int r, i;
1927
1928 if (cpuid->nent < 1)
1929 return -E2BIG;
1930 if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
1931 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
1932
1933 if (sanity_check_entries(entries, cpuid->nent, type))
1934 return -EINVAL;
1935
1936 array.entries = kvcalloc(cpuid->nent, sizeof(struct kvm_cpuid_entry2), GFP_KERNEL);
1937 if (!array.entries)
1938 return -ENOMEM;
1939
1940 array.maxnent = cpuid->nent;
1941
1942 for (i = 0; i < ARRAY_SIZE(funcs); i++) {
1943 r = get_cpuid_func(&array, funcs[i], type);
1944 if (r)
1945 goto out_free;
1946 }
1947 cpuid->nent = array.nent;
1948
1949 if (copy_to_user(entries, array.entries,
1950 array.nent * sizeof(struct kvm_cpuid_entry2)))
1951 r = -EFAULT;
1952
1953 out_free:
1954 kvfree(array.entries);
1955 return r;
1956 }
1957
1958 /*
1959 * Intel CPUID semantics treats any query for an out-of-range leaf as if the
1960 * highest basic leaf (i.e. CPUID.0H:EAX) were requested. AMD CPUID semantics
1961 * returns all zeroes for any undefined leaf, whether or not the leaf is in
1962 * range. Centaur/VIA follows Intel semantics.
1963 *
1964 * A leaf is considered out-of-range if its function is higher than the maximum
1965 * supported leaf of its associated class or if its associated class does not
1966 * exist.
1967 *
1968 * There are three primary classes to be considered, with their respective
1969 * ranges described as "<base> - <top>[,<base2> - <top2>] inclusive. A primary
1970 * class exists if a guest CPUID entry for its <base> leaf exists. For a given
1971 * class, CPUID.<base>.EAX contains the max supported leaf for the class.
1972 *
1973 * - Basic: 0x00000000 - 0x3fffffff, 0x50000000 - 0x7fffffff
1974 * - Hypervisor: 0x40000000 - 0x4fffffff
1975 * - Extended: 0x80000000 - 0xbfffffff
1976 * - Centaur: 0xc0000000 - 0xcfffffff
1977 *
1978 * The Hypervisor class is further subdivided into sub-classes that each act as
1979 * their own independent class associated with a 0x100 byte range. E.g. if Qemu
1980 * is advertising support for both HyperV and KVM, the resulting Hypervisor
1981 * CPUID sub-classes are:
1982 *
1983 * - HyperV: 0x40000000 - 0x400000ff
1984 * - KVM: 0x40000100 - 0x400001ff
1985 */
1986 static struct kvm_cpuid_entry2 *
get_out_of_range_cpuid_entry(struct kvm_vcpu * vcpu,u32 * fn_ptr,u32 index)1987 get_out_of_range_cpuid_entry(struct kvm_vcpu *vcpu, u32 *fn_ptr, u32 index)
1988 {
1989 struct kvm_cpuid_entry2 *basic, *class;
1990 u32 function = *fn_ptr;
1991
1992 basic = kvm_find_cpuid_entry(vcpu, 0);
1993 if (!basic)
1994 return NULL;
1995
1996 if (is_guest_vendor_amd(basic->ebx, basic->ecx, basic->edx) ||
1997 is_guest_vendor_hygon(basic->ebx, basic->ecx, basic->edx))
1998 return NULL;
1999
2000 if (function >= 0x40000000 && function <= 0x4fffffff)
2001 class = kvm_find_cpuid_entry(vcpu, function & 0xffffff00);
2002 else if (function >= 0xc0000000)
2003 class = kvm_find_cpuid_entry(vcpu, 0xc0000000);
2004 else
2005 class = kvm_find_cpuid_entry(vcpu, function & 0x80000000);
2006
2007 if (class && function <= class->eax)
2008 return NULL;
2009
2010 /*
2011 * Leaf specific adjustments are also applied when redirecting to the
2012 * max basic entry, e.g. if the max basic leaf is 0xb but there is no
2013 * entry for CPUID.0xb.index (see below), then the output value for EDX
2014 * needs to be pulled from CPUID.0xb.1.
2015 */
2016 *fn_ptr = basic->eax;
2017
2018 /*
2019 * The class does not exist or the requested function is out of range;
2020 * the effective CPUID entry is the max basic leaf. Note, the index of
2021 * the original requested leaf is observed!
2022 */
2023 return kvm_find_cpuid_entry_index(vcpu, basic->eax, index);
2024 }
2025
kvm_cpuid(struct kvm_vcpu * vcpu,u32 * eax,u32 * ebx,u32 * ecx,u32 * edx,bool exact_only)2026 bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
2027 u32 *ecx, u32 *edx, bool exact_only)
2028 {
2029 u32 orig_function = *eax, function = *eax, index = *ecx;
2030 struct kvm_cpuid_entry2 *entry;
2031 bool exact, used_max_basic = false;
2032
2033 if (vcpu->arch.cpuid_dynamic_bits_dirty)
2034 kvm_update_cpuid_runtime(vcpu);
2035
2036 entry = kvm_find_cpuid_entry_index(vcpu, function, index);
2037 exact = !!entry;
2038
2039 if (!entry && !exact_only) {
2040 entry = get_out_of_range_cpuid_entry(vcpu, &function, index);
2041 used_max_basic = !!entry;
2042 }
2043
2044 if (entry) {
2045 *eax = entry->eax;
2046 *ebx = entry->ebx;
2047 *ecx = entry->ecx;
2048 *edx = entry->edx;
2049 if (function == 7 && index == 0) {
2050 u64 data;
2051 if ((*ebx & (feature_bit(RTM) | feature_bit(HLE))) &&
2052 !kvm_msr_read(vcpu, MSR_IA32_TSX_CTRL, &data) &&
2053 (data & TSX_CTRL_CPUID_CLEAR))
2054 *ebx &= ~(feature_bit(RTM) | feature_bit(HLE));
2055 } else if (function == 0x80000007) {
2056 if (kvm_hv_invtsc_suppressed(vcpu))
2057 *edx &= ~feature_bit(CONSTANT_TSC);
2058 } else if (IS_ENABLED(CONFIG_KVM_XEN) &&
2059 kvm_xen_is_tsc_leaf(vcpu, function)) {
2060 /*
2061 * Update guest TSC frequency information if necessary.
2062 * Ignore failures, there is no sane value that can be
2063 * provided if KVM can't get the TSC frequency.
2064 */
2065 if (kvm_check_request(KVM_REQ_CLOCK_UPDATE, vcpu))
2066 kvm_guest_time_update(vcpu);
2067
2068 if (index == 1) {
2069 *ecx = vcpu->arch.pvclock_tsc_mul;
2070 *edx = vcpu->arch.pvclock_tsc_shift;
2071 } else if (index == 2) {
2072 *eax = vcpu->arch.hw_tsc_khz;
2073 }
2074 }
2075 } else {
2076 *eax = *ebx = *ecx = *edx = 0;
2077 /*
2078 * When leaf 0BH or 1FH is defined, CL is pass-through
2079 * and EDX is always the x2APIC ID, even for undefined
2080 * subleaves. Index 1 will exist iff the leaf is
2081 * implemented, so we pass through CL iff leaf 1
2082 * exists. EDX can be copied from any existing index.
2083 */
2084 if (function == 0xb || function == 0x1f) {
2085 entry = kvm_find_cpuid_entry_index(vcpu, function, 1);
2086 if (entry) {
2087 *ecx = index & 0xff;
2088 *edx = entry->edx;
2089 }
2090 }
2091 }
2092 trace_kvm_cpuid(orig_function, index, *eax, *ebx, *ecx, *edx, exact,
2093 used_max_basic);
2094 return exact;
2095 }
2096 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_cpuid);
2097
kvm_emulate_cpuid(struct kvm_vcpu * vcpu)2098 int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
2099 {
2100 u32 eax, ebx, ecx, edx;
2101
2102 if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0))
2103 return 1;
2104
2105 eax = kvm_rax_read(vcpu);
2106 ecx = kvm_rcx_read(vcpu);
2107 kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, false);
2108 kvm_rax_write(vcpu, eax);
2109 kvm_rbx_write(vcpu, ebx);
2110 kvm_rcx_write(vcpu, ecx);
2111 kvm_rdx_write(vcpu, edx);
2112 return kvm_skip_emulated_instruction(vcpu);
2113 }
2114 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_emulate_cpuid);
2115