xref: /openbmc/linux/arch/x86/kvm/cpuid.c (revision 4e1a33b1)
1 /*
2  * Kernel-based Virtual Machine driver for Linux
3  * cpuid support routines
4  *
5  * derived from arch/x86/kvm/x86.c
6  *
7  * Copyright 2011 Red Hat, Inc. and/or its affiliates.
8  * Copyright IBM Corporation, 2008
9  *
10  * This work is licensed under the terms of the GNU GPL, version 2.  See
11  * the COPYING file in the top-level directory.
12  *
13  */
14 
15 #include <linux/kvm_host.h>
16 #include <linux/export.h>
17 #include <linux/vmalloc.h>
18 #include <linux/uaccess.h>
19 #include <asm/processor.h>
20 #include <asm/user.h>
21 #include <asm/fpu/xstate.h>
22 #include "cpuid.h"
23 #include "lapic.h"
24 #include "mmu.h"
25 #include "trace.h"
26 #include "pmu.h"
27 
28 static u32 xstate_required_size(u64 xstate_bv, bool compacted)
29 {
30 	int feature_bit = 0;
31 	u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
32 
33 	xstate_bv &= XFEATURE_MASK_EXTEND;
34 	while (xstate_bv) {
35 		if (xstate_bv & 0x1) {
36 		        u32 eax, ebx, ecx, edx, offset;
37 		        cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
38 			offset = compacted ? ret : ebx;
39 			ret = max(ret, offset + eax);
40 		}
41 
42 		xstate_bv >>= 1;
43 		feature_bit++;
44 	}
45 
46 	return ret;
47 }
48 
49 bool kvm_mpx_supported(void)
50 {
51 	return ((host_xcr0 & (XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR))
52 		 && kvm_x86_ops->mpx_supported());
53 }
54 EXPORT_SYMBOL_GPL(kvm_mpx_supported);
55 
56 u64 kvm_supported_xcr0(void)
57 {
58 	u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
59 
60 	if (!kvm_mpx_supported())
61 		xcr0 &= ~(XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR);
62 
63 	return xcr0;
64 }
65 
66 #define F(x) bit(X86_FEATURE_##x)
67 
68 /* These are scattered features in cpufeatures.h. */
69 #define KVM_CPUID_BIT_AVX512_4VNNIW     2
70 #define KVM_CPUID_BIT_AVX512_4FMAPS     3
71 #define KF(x) bit(KVM_CPUID_BIT_##x)
72 
73 int kvm_update_cpuid(struct kvm_vcpu *vcpu)
74 {
75 	struct kvm_cpuid_entry2 *best;
76 	struct kvm_lapic *apic = vcpu->arch.apic;
77 
78 	best = kvm_find_cpuid_entry(vcpu, 1, 0);
79 	if (!best)
80 		return 0;
81 
82 	/* Update OSXSAVE bit */
83 	if (boot_cpu_has(X86_FEATURE_XSAVE) && best->function == 0x1) {
84 		best->ecx &= ~F(OSXSAVE);
85 		if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
86 			best->ecx |= F(OSXSAVE);
87 	}
88 
89 	best->edx &= ~F(APIC);
90 	if (vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE)
91 		best->edx |= F(APIC);
92 
93 	if (apic) {
94 		if (best->ecx & F(TSC_DEADLINE_TIMER))
95 			apic->lapic_timer.timer_mode_mask = 3 << 17;
96 		else
97 			apic->lapic_timer.timer_mode_mask = 1 << 17;
98 	}
99 
100 	best = kvm_find_cpuid_entry(vcpu, 7, 0);
101 	if (best) {
102 		/* Update OSPKE bit */
103 		if (boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7) {
104 			best->ecx &= ~F(OSPKE);
105 			if (kvm_read_cr4_bits(vcpu, X86_CR4_PKE))
106 				best->ecx |= F(OSPKE);
107 		}
108 	}
109 
110 	best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
111 	if (!best) {
112 		vcpu->arch.guest_supported_xcr0 = 0;
113 		vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
114 	} else {
115 		vcpu->arch.guest_supported_xcr0 =
116 			(best->eax | ((u64)best->edx << 32)) &
117 			kvm_supported_xcr0();
118 		vcpu->arch.guest_xstate_size = best->ebx =
119 			xstate_required_size(vcpu->arch.xcr0, false);
120 	}
121 
122 	best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
123 	if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
124 		best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
125 
126 	/*
127 	 * The existing code assumes virtual address is 48-bit in the canonical
128 	 * address checks; exit if it is ever changed.
129 	 */
130 	best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
131 	if (best && ((best->eax & 0xff00) >> 8) != 48 &&
132 		((best->eax & 0xff00) >> 8) != 0)
133 		return -EINVAL;
134 
135 	/* Update physical-address width */
136 	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
137 
138 	kvm_pmu_refresh(vcpu);
139 	return 0;
140 }
141 
142 static int is_efer_nx(void)
143 {
144 	unsigned long long efer = 0;
145 
146 	rdmsrl_safe(MSR_EFER, &efer);
147 	return efer & EFER_NX;
148 }
149 
150 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
151 {
152 	int i;
153 	struct kvm_cpuid_entry2 *e, *entry;
154 
155 	entry = NULL;
156 	for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
157 		e = &vcpu->arch.cpuid_entries[i];
158 		if (e->function == 0x80000001) {
159 			entry = e;
160 			break;
161 		}
162 	}
163 	if (entry && (entry->edx & F(NX)) && !is_efer_nx()) {
164 		entry->edx &= ~F(NX);
165 		printk(KERN_INFO "kvm: guest NX capability removed\n");
166 	}
167 }
168 
169 int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
170 {
171 	struct kvm_cpuid_entry2 *best;
172 
173 	best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
174 	if (!best || best->eax < 0x80000008)
175 		goto not_found;
176 	best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
177 	if (best)
178 		return best->eax & 0xff;
179 not_found:
180 	return 36;
181 }
182 EXPORT_SYMBOL_GPL(cpuid_query_maxphyaddr);
183 
184 /* when an old userspace process fills a new kernel module */
185 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
186 			     struct kvm_cpuid *cpuid,
187 			     struct kvm_cpuid_entry __user *entries)
188 {
189 	int r, i;
190 	struct kvm_cpuid_entry *cpuid_entries = NULL;
191 
192 	r = -E2BIG;
193 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
194 		goto out;
195 	r = -ENOMEM;
196 	if (cpuid->nent) {
197 		cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) *
198 					cpuid->nent);
199 		if (!cpuid_entries)
200 			goto out;
201 		r = -EFAULT;
202 		if (copy_from_user(cpuid_entries, entries,
203 				   cpuid->nent * sizeof(struct kvm_cpuid_entry)))
204 			goto out;
205 	}
206 	for (i = 0; i < cpuid->nent; i++) {
207 		vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
208 		vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
209 		vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
210 		vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
211 		vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
212 		vcpu->arch.cpuid_entries[i].index = 0;
213 		vcpu->arch.cpuid_entries[i].flags = 0;
214 		vcpu->arch.cpuid_entries[i].padding[0] = 0;
215 		vcpu->arch.cpuid_entries[i].padding[1] = 0;
216 		vcpu->arch.cpuid_entries[i].padding[2] = 0;
217 	}
218 	vcpu->arch.cpuid_nent = cpuid->nent;
219 	cpuid_fix_nx_cap(vcpu);
220 	kvm_apic_set_version(vcpu);
221 	kvm_x86_ops->cpuid_update(vcpu);
222 	r = kvm_update_cpuid(vcpu);
223 
224 out:
225 	vfree(cpuid_entries);
226 	return r;
227 }
228 
229 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
230 			      struct kvm_cpuid2 *cpuid,
231 			      struct kvm_cpuid_entry2 __user *entries)
232 {
233 	int r;
234 
235 	r = -E2BIG;
236 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
237 		goto out;
238 	r = -EFAULT;
239 	if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
240 			   cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
241 		goto out;
242 	vcpu->arch.cpuid_nent = cpuid->nent;
243 	kvm_apic_set_version(vcpu);
244 	kvm_x86_ops->cpuid_update(vcpu);
245 	r = kvm_update_cpuid(vcpu);
246 out:
247 	return r;
248 }
249 
250 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
251 			      struct kvm_cpuid2 *cpuid,
252 			      struct kvm_cpuid_entry2 __user *entries)
253 {
254 	int r;
255 
256 	r = -E2BIG;
257 	if (cpuid->nent < vcpu->arch.cpuid_nent)
258 		goto out;
259 	r = -EFAULT;
260 	if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
261 			 vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
262 		goto out;
263 	return 0;
264 
265 out:
266 	cpuid->nent = vcpu->arch.cpuid_nent;
267 	return r;
268 }
269 
270 static void cpuid_mask(u32 *word, int wordnum)
271 {
272 	*word &= boot_cpu_data.x86_capability[wordnum];
273 }
274 
275 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
276 			   u32 index)
277 {
278 	entry->function = function;
279 	entry->index = index;
280 	cpuid_count(entry->function, entry->index,
281 		    &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
282 	entry->flags = 0;
283 }
284 
285 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
286 				   u32 func, u32 index, int *nent, int maxnent)
287 {
288 	switch (func) {
289 	case 0:
290 		entry->eax = 1;		/* only one leaf currently */
291 		++*nent;
292 		break;
293 	case 1:
294 		entry->ecx = F(MOVBE);
295 		++*nent;
296 		break;
297 	default:
298 		break;
299 	}
300 
301 	entry->function = func;
302 	entry->index = index;
303 
304 	return 0;
305 }
306 
307 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
308 				 u32 index, int *nent, int maxnent)
309 {
310 	int r;
311 	unsigned f_nx = is_efer_nx() ? F(NX) : 0;
312 #ifdef CONFIG_X86_64
313 	unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
314 				? F(GBPAGES) : 0;
315 	unsigned f_lm = F(LM);
316 #else
317 	unsigned f_gbpages = 0;
318 	unsigned f_lm = 0;
319 #endif
320 	unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
321 	unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
322 	unsigned f_mpx = kvm_mpx_supported() ? F(MPX) : 0;
323 	unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
324 
325 	/* cpuid 1.edx */
326 	const u32 kvm_cpuid_1_edx_x86_features =
327 		F(FPU) | F(VME) | F(DE) | F(PSE) |
328 		F(TSC) | F(MSR) | F(PAE) | F(MCE) |
329 		F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
330 		F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
331 		F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
332 		0 /* Reserved, DS, ACPI */ | F(MMX) |
333 		F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
334 		0 /* HTT, TM, Reserved, PBE */;
335 	/* cpuid 0x80000001.edx */
336 	const u32 kvm_cpuid_8000_0001_edx_x86_features =
337 		F(FPU) | F(VME) | F(DE) | F(PSE) |
338 		F(TSC) | F(MSR) | F(PAE) | F(MCE) |
339 		F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
340 		F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
341 		F(PAT) | F(PSE36) | 0 /* Reserved */ |
342 		f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
343 		F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
344 		0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
345 	/* cpuid 1.ecx */
346 	const u32 kvm_cpuid_1_ecx_x86_features =
347 		/* NOTE: MONITOR (and MWAIT) are emulated as NOP,
348 		 * but *not* advertised to guests via CPUID ! */
349 		F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
350 		0 /* DS-CPL, VMX, SMX, EST */ |
351 		0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
352 		F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
353 		F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
354 		F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
355 		0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
356 		F(F16C) | F(RDRAND);
357 	/* cpuid 0x80000001.ecx */
358 	const u32 kvm_cpuid_8000_0001_ecx_x86_features =
359 		F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
360 		F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
361 		F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
362 		0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
363 
364 	/* cpuid 0xC0000001.edx */
365 	const u32 kvm_cpuid_C000_0001_edx_x86_features =
366 		F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
367 		F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
368 		F(PMM) | F(PMM_EN);
369 
370 	/* cpuid 7.0.ebx */
371 	const u32 kvm_cpuid_7_0_ebx_x86_features =
372 		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
373 		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
374 		F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
375 		F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
376 		F(SHA_NI) | F(AVX512BW) | F(AVX512VL);
377 
378 	/* cpuid 0xD.1.eax */
379 	const u32 kvm_cpuid_D_1_eax_x86_features =
380 		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
381 
382 	/* cpuid 7.0.ecx*/
383 	const u32 kvm_cpuid_7_0_ecx_x86_features =
384 		F(AVX512VBMI) | F(PKU) | 0 /*OSPKE*/ | F(AVX512_VPOPCNTDQ);
385 
386 	/* cpuid 7.0.edx*/
387 	const u32 kvm_cpuid_7_0_edx_x86_features =
388 		KF(AVX512_4VNNIW) | KF(AVX512_4FMAPS);
389 
390 	/* all calls to cpuid_count() should be made on the same cpu */
391 	get_cpu();
392 
393 	r = -E2BIG;
394 
395 	if (*nent >= maxnent)
396 		goto out;
397 
398 	do_cpuid_1_ent(entry, function, index);
399 	++*nent;
400 
401 	switch (function) {
402 	case 0:
403 		entry->eax = min(entry->eax, (u32)0xd);
404 		break;
405 	case 1:
406 		entry->edx &= kvm_cpuid_1_edx_x86_features;
407 		cpuid_mask(&entry->edx, CPUID_1_EDX);
408 		entry->ecx &= kvm_cpuid_1_ecx_x86_features;
409 		cpuid_mask(&entry->ecx, CPUID_1_ECX);
410 		/* we support x2apic emulation even if host does not support
411 		 * it since we emulate x2apic in software */
412 		entry->ecx |= F(X2APIC);
413 		break;
414 	/* function 2 entries are STATEFUL. That is, repeated cpuid commands
415 	 * may return different values. This forces us to get_cpu() before
416 	 * issuing the first command, and also to emulate this annoying behavior
417 	 * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
418 	case 2: {
419 		int t, times = entry->eax & 0xff;
420 
421 		entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
422 		entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
423 		for (t = 1; t < times; ++t) {
424 			if (*nent >= maxnent)
425 				goto out;
426 
427 			do_cpuid_1_ent(&entry[t], function, 0);
428 			entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
429 			++*nent;
430 		}
431 		break;
432 	}
433 	/* function 4 has additional index. */
434 	case 4: {
435 		int i, cache_type;
436 
437 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
438 		/* read more entries until cache_type is zero */
439 		for (i = 1; ; ++i) {
440 			if (*nent >= maxnent)
441 				goto out;
442 
443 			cache_type = entry[i - 1].eax & 0x1f;
444 			if (!cache_type)
445 				break;
446 			do_cpuid_1_ent(&entry[i], function, i);
447 			entry[i].flags |=
448 			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
449 			++*nent;
450 		}
451 		break;
452 	}
453 	case 6: /* Thermal management */
454 		entry->eax = 0x4; /* allow ARAT */
455 		entry->ebx = 0;
456 		entry->ecx = 0;
457 		entry->edx = 0;
458 		break;
459 	case 7: {
460 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
461 		/* Mask ebx against host capability word 9 */
462 		if (index == 0) {
463 			entry->ebx &= kvm_cpuid_7_0_ebx_x86_features;
464 			cpuid_mask(&entry->ebx, CPUID_7_0_EBX);
465 			// TSC_ADJUST is emulated
466 			entry->ebx |= F(TSC_ADJUST);
467 			entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
468 			cpuid_mask(&entry->ecx, CPUID_7_ECX);
469 			/* PKU is not yet implemented for shadow paging. */
470 			if (!tdp_enabled)
471 				entry->ecx &= ~F(PKU);
472 			entry->edx &= kvm_cpuid_7_0_edx_x86_features;
473 			entry->edx &= get_scattered_cpuid_leaf(7, 0, CPUID_EDX);
474 		} else {
475 			entry->ebx = 0;
476 			entry->ecx = 0;
477 			entry->edx = 0;
478 		}
479 		entry->eax = 0;
480 		break;
481 	}
482 	case 9:
483 		break;
484 	case 0xa: { /* Architectural Performance Monitoring */
485 		struct x86_pmu_capability cap;
486 		union cpuid10_eax eax;
487 		union cpuid10_edx edx;
488 
489 		perf_get_x86_pmu_capability(&cap);
490 
491 		/*
492 		 * Only support guest architectural pmu on a host
493 		 * with architectural pmu.
494 		 */
495 		if (!cap.version)
496 			memset(&cap, 0, sizeof(cap));
497 
498 		eax.split.version_id = min(cap.version, 2);
499 		eax.split.num_counters = cap.num_counters_gp;
500 		eax.split.bit_width = cap.bit_width_gp;
501 		eax.split.mask_length = cap.events_mask_len;
502 
503 		edx.split.num_counters_fixed = cap.num_counters_fixed;
504 		edx.split.bit_width_fixed = cap.bit_width_fixed;
505 		edx.split.reserved = 0;
506 
507 		entry->eax = eax.full;
508 		entry->ebx = cap.events_mask;
509 		entry->ecx = 0;
510 		entry->edx = edx.full;
511 		break;
512 	}
513 	/* function 0xb has additional index. */
514 	case 0xb: {
515 		int i, level_type;
516 
517 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
518 		/* read more entries until level_type is zero */
519 		for (i = 1; ; ++i) {
520 			if (*nent >= maxnent)
521 				goto out;
522 
523 			level_type = entry[i - 1].ecx & 0xff00;
524 			if (!level_type)
525 				break;
526 			do_cpuid_1_ent(&entry[i], function, i);
527 			entry[i].flags |=
528 			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
529 			++*nent;
530 		}
531 		break;
532 	}
533 	case 0xd: {
534 		int idx, i;
535 		u64 supported = kvm_supported_xcr0();
536 
537 		entry->eax &= supported;
538 		entry->ebx = xstate_required_size(supported, false);
539 		entry->ecx = entry->ebx;
540 		entry->edx &= supported >> 32;
541 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
542 		if (!supported)
543 			break;
544 
545 		for (idx = 1, i = 1; idx < 64; ++idx) {
546 			u64 mask = ((u64)1 << idx);
547 			if (*nent >= maxnent)
548 				goto out;
549 
550 			do_cpuid_1_ent(&entry[i], function, idx);
551 			if (idx == 1) {
552 				entry[i].eax &= kvm_cpuid_D_1_eax_x86_features;
553 				cpuid_mask(&entry[i].eax, CPUID_D_1_EAX);
554 				entry[i].ebx = 0;
555 				if (entry[i].eax & (F(XSAVES)|F(XSAVEC)))
556 					entry[i].ebx =
557 						xstate_required_size(supported,
558 								     true);
559 			} else {
560 				if (entry[i].eax == 0 || !(supported & mask))
561 					continue;
562 				if (WARN_ON_ONCE(entry[i].ecx & 1))
563 					continue;
564 			}
565 			entry[i].ecx = 0;
566 			entry[i].edx = 0;
567 			entry[i].flags |=
568 			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
569 			++*nent;
570 			++i;
571 		}
572 		break;
573 	}
574 	case KVM_CPUID_SIGNATURE: {
575 		static const char signature[12] = "KVMKVMKVM\0\0";
576 		const u32 *sigptr = (const u32 *)signature;
577 		entry->eax = KVM_CPUID_FEATURES;
578 		entry->ebx = sigptr[0];
579 		entry->ecx = sigptr[1];
580 		entry->edx = sigptr[2];
581 		break;
582 	}
583 	case KVM_CPUID_FEATURES:
584 		entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
585 			     (1 << KVM_FEATURE_NOP_IO_DELAY) |
586 			     (1 << KVM_FEATURE_CLOCKSOURCE2) |
587 			     (1 << KVM_FEATURE_ASYNC_PF) |
588 			     (1 << KVM_FEATURE_PV_EOI) |
589 			     (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
590 			     (1 << KVM_FEATURE_PV_UNHALT);
591 
592 		if (sched_info_on())
593 			entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
594 
595 		entry->ebx = 0;
596 		entry->ecx = 0;
597 		entry->edx = 0;
598 		break;
599 	case 0x80000000:
600 		entry->eax = min(entry->eax, 0x8000001a);
601 		break;
602 	case 0x80000001:
603 		entry->edx &= kvm_cpuid_8000_0001_edx_x86_features;
604 		cpuid_mask(&entry->edx, CPUID_8000_0001_EDX);
605 		entry->ecx &= kvm_cpuid_8000_0001_ecx_x86_features;
606 		cpuid_mask(&entry->ecx, CPUID_8000_0001_ECX);
607 		break;
608 	case 0x80000007: /* Advanced power management */
609 		/* invariant TSC is CPUID.80000007H:EDX[8] */
610 		entry->edx &= (1 << 8);
611 		/* mask against host */
612 		entry->edx &= boot_cpu_data.x86_power;
613 		entry->eax = entry->ebx = entry->ecx = 0;
614 		break;
615 	case 0x80000008: {
616 		unsigned g_phys_as = (entry->eax >> 16) & 0xff;
617 		unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
618 		unsigned phys_as = entry->eax & 0xff;
619 
620 		if (!g_phys_as)
621 			g_phys_as = phys_as;
622 		entry->eax = g_phys_as | (virt_as << 8);
623 		entry->ebx = entry->edx = 0;
624 		break;
625 	}
626 	case 0x80000019:
627 		entry->ecx = entry->edx = 0;
628 		break;
629 	case 0x8000001a:
630 		break;
631 	case 0x8000001d:
632 		break;
633 	/*Add support for Centaur's CPUID instruction*/
634 	case 0xC0000000:
635 		/*Just support up to 0xC0000004 now*/
636 		entry->eax = min(entry->eax, 0xC0000004);
637 		break;
638 	case 0xC0000001:
639 		entry->edx &= kvm_cpuid_C000_0001_edx_x86_features;
640 		cpuid_mask(&entry->edx, CPUID_C000_0001_EDX);
641 		break;
642 	case 3: /* Processor serial number */
643 	case 5: /* MONITOR/MWAIT */
644 	case 0xC0000002:
645 	case 0xC0000003:
646 	case 0xC0000004:
647 	default:
648 		entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
649 		break;
650 	}
651 
652 	kvm_x86_ops->set_supported_cpuid(function, entry);
653 
654 	r = 0;
655 
656 out:
657 	put_cpu();
658 
659 	return r;
660 }
661 
662 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
663 			u32 idx, int *nent, int maxnent, unsigned int type)
664 {
665 	if (type == KVM_GET_EMULATED_CPUID)
666 		return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
667 
668 	return __do_cpuid_ent(entry, func, idx, nent, maxnent);
669 }
670 
671 #undef F
672 
673 struct kvm_cpuid_param {
674 	u32 func;
675 	u32 idx;
676 	bool has_leaf_count;
677 	bool (*qualifier)(const struct kvm_cpuid_param *param);
678 };
679 
680 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
681 {
682 	return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
683 }
684 
685 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
686 				 __u32 num_entries, unsigned int ioctl_type)
687 {
688 	int i;
689 	__u32 pad[3];
690 
691 	if (ioctl_type != KVM_GET_EMULATED_CPUID)
692 		return false;
693 
694 	/*
695 	 * We want to make sure that ->padding is being passed clean from
696 	 * userspace in case we want to use it for something in the future.
697 	 *
698 	 * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
699 	 * have to give ourselves satisfied only with the emulated side. /me
700 	 * sheds a tear.
701 	 */
702 	for (i = 0; i < num_entries; i++) {
703 		if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
704 			return true;
705 
706 		if (pad[0] || pad[1] || pad[2])
707 			return true;
708 	}
709 	return false;
710 }
711 
712 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
713 			    struct kvm_cpuid_entry2 __user *entries,
714 			    unsigned int type)
715 {
716 	struct kvm_cpuid_entry2 *cpuid_entries;
717 	int limit, nent = 0, r = -E2BIG, i;
718 	u32 func;
719 	static const struct kvm_cpuid_param param[] = {
720 		{ .func = 0, .has_leaf_count = true },
721 		{ .func = 0x80000000, .has_leaf_count = true },
722 		{ .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
723 		{ .func = KVM_CPUID_SIGNATURE },
724 		{ .func = KVM_CPUID_FEATURES },
725 	};
726 
727 	if (cpuid->nent < 1)
728 		goto out;
729 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
730 		cpuid->nent = KVM_MAX_CPUID_ENTRIES;
731 
732 	if (sanity_check_entries(entries, cpuid->nent, type))
733 		return -EINVAL;
734 
735 	r = -ENOMEM;
736 	cpuid_entries = vzalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
737 	if (!cpuid_entries)
738 		goto out;
739 
740 	r = 0;
741 	for (i = 0; i < ARRAY_SIZE(param); i++) {
742 		const struct kvm_cpuid_param *ent = &param[i];
743 
744 		if (ent->qualifier && !ent->qualifier(ent))
745 			continue;
746 
747 		r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
748 				&nent, cpuid->nent, type);
749 
750 		if (r)
751 			goto out_free;
752 
753 		if (!ent->has_leaf_count)
754 			continue;
755 
756 		limit = cpuid_entries[nent - 1].eax;
757 		for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
758 			r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
759 				     &nent, cpuid->nent, type);
760 
761 		if (r)
762 			goto out_free;
763 	}
764 
765 	r = -EFAULT;
766 	if (copy_to_user(entries, cpuid_entries,
767 			 nent * sizeof(struct kvm_cpuid_entry2)))
768 		goto out_free;
769 	cpuid->nent = nent;
770 	r = 0;
771 
772 out_free:
773 	vfree(cpuid_entries);
774 out:
775 	return r;
776 }
777 
778 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
779 {
780 	struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
781 	int j, nent = vcpu->arch.cpuid_nent;
782 
783 	e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
784 	/* when no next entry is found, the current entry[i] is reselected */
785 	for (j = i + 1; ; j = (j + 1) % nent) {
786 		struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
787 		if (ej->function == e->function) {
788 			ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
789 			return j;
790 		}
791 	}
792 	return 0; /* silence gcc, even though control never reaches here */
793 }
794 
795 /* find an entry with matching function, matching index (if needed), and that
796  * should be read next (if it's stateful) */
797 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
798 	u32 function, u32 index)
799 {
800 	if (e->function != function)
801 		return 0;
802 	if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
803 		return 0;
804 	if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
805 	    !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
806 		return 0;
807 	return 1;
808 }
809 
810 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
811 					      u32 function, u32 index)
812 {
813 	int i;
814 	struct kvm_cpuid_entry2 *best = NULL;
815 
816 	for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
817 		struct kvm_cpuid_entry2 *e;
818 
819 		e = &vcpu->arch.cpuid_entries[i];
820 		if (is_matching_cpuid_entry(e, function, index)) {
821 			if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
822 				move_to_next_stateful_cpuid_entry(vcpu, i);
823 			best = e;
824 			break;
825 		}
826 	}
827 	return best;
828 }
829 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
830 
831 /*
832  * If no match is found, check whether we exceed the vCPU's limit
833  * and return the content of the highest valid _standard_ leaf instead.
834  * This is to satisfy the CPUID specification.
835  */
836 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
837                                                   u32 function, u32 index)
838 {
839 	struct kvm_cpuid_entry2 *maxlevel;
840 
841 	maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
842 	if (!maxlevel || maxlevel->eax >= function)
843 		return NULL;
844 	if (function & 0x80000000) {
845 		maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
846 		if (!maxlevel)
847 			return NULL;
848 	}
849 	return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
850 }
851 
852 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
853 {
854 	u32 function = *eax, index = *ecx;
855 	struct kvm_cpuid_entry2 *best;
856 
857 	best = kvm_find_cpuid_entry(vcpu, function, index);
858 
859 	if (!best)
860 		best = check_cpuid_limit(vcpu, function, index);
861 
862 	if (best) {
863 		*eax = best->eax;
864 		*ebx = best->ebx;
865 		*ecx = best->ecx;
866 		*edx = best->edx;
867 	} else
868 		*eax = *ebx = *ecx = *edx = 0;
869 	trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
870 }
871 EXPORT_SYMBOL_GPL(kvm_cpuid);
872 
873 int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
874 {
875 	u32 eax, ebx, ecx, edx;
876 
877 	eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
878 	ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
879 	kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
880 	kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
881 	kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
882 	kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
883 	kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
884 	return kvm_skip_emulated_instruction(vcpu);
885 }
886 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);
887