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

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source code of linux/arch/x86/kvm/cpuid.c