xref: /openbmc/linux/arch/x86/kvm/cpuid.c (revision b34e08d5)
1 /*
2  * Kernel-based Virtual Machine driver for Linux
3  * cpuid support routines
4  *
5  * derived from arch/x86/kvm/x86.c
6  *
7  * Copyright 2011 Red Hat, Inc. and/or its affiliates.
8  * Copyright IBM Corporation, 2008
9  *
10  * This work is licensed under the terms of the GNU GPL, version 2.  See
11  * the COPYING file in the top-level directory.
12  *
13  */
14 
15 #include <linux/kvm_host.h>
16 #include <linux/module.h>
17 #include <linux/vmalloc.h>
18 #include <linux/uaccess.h>
19 #include <asm/user.h>
20 #include <asm/xsave.h>
21 #include "cpuid.h"
22 #include "lapic.h"
23 #include "mmu.h"
24 #include "trace.h"
25 
26 static u32 xstate_required_size(u64 xstate_bv)
27 {
28 	int feature_bit = 0;
29 	u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
30 
31 	xstate_bv &= XSTATE_EXTEND_MASK;
32 	while (xstate_bv) {
33 		if (xstate_bv & 0x1) {
34 		        u32 eax, ebx, ecx, edx;
35 		        cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
36 			ret = max(ret, eax + ebx);
37 		}
38 
39 		xstate_bv >>= 1;
40 		feature_bit++;
41 	}
42 
43 	return ret;
44 }
45 
46 u64 kvm_supported_xcr0(void)
47 {
48 	u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
49 
50 	if (!kvm_x86_ops->mpx_supported())
51 		xcr0 &= ~(XSTATE_BNDREGS | XSTATE_BNDCSR);
52 
53 	return xcr0;
54 }
55 
56 void kvm_update_cpuid(struct kvm_vcpu *vcpu)
57 {
58 	struct kvm_cpuid_entry2 *best;
59 	struct kvm_lapic *apic = vcpu->arch.apic;
60 
61 	best = kvm_find_cpuid_entry(vcpu, 1, 0);
62 	if (!best)
63 		return;
64 
65 	/* Update OSXSAVE bit */
66 	if (cpu_has_xsave && best->function == 0x1) {
67 		best->ecx &= ~(bit(X86_FEATURE_OSXSAVE));
68 		if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
69 			best->ecx |= bit(X86_FEATURE_OSXSAVE);
70 	}
71 
72 	if (apic) {
73 		if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER))
74 			apic->lapic_timer.timer_mode_mask = 3 << 17;
75 		else
76 			apic->lapic_timer.timer_mode_mask = 1 << 17;
77 	}
78 
79 	best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
80 	if (!best) {
81 		vcpu->arch.guest_supported_xcr0 = 0;
82 		vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
83 	} else {
84 		vcpu->arch.guest_supported_xcr0 =
85 			(best->eax | ((u64)best->edx << 32)) &
86 			kvm_supported_xcr0();
87 		vcpu->arch.guest_xstate_size = best->ebx =
88 			xstate_required_size(vcpu->arch.xcr0);
89 	}
90 
91 	kvm_pmu_cpuid_update(vcpu);
92 }
93 
94 static int is_efer_nx(void)
95 {
96 	unsigned long long efer = 0;
97 
98 	rdmsrl_safe(MSR_EFER, &efer);
99 	return efer & EFER_NX;
100 }
101 
102 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
103 {
104 	int i;
105 	struct kvm_cpuid_entry2 *e, *entry;
106 
107 	entry = NULL;
108 	for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
109 		e = &vcpu->arch.cpuid_entries[i];
110 		if (e->function == 0x80000001) {
111 			entry = e;
112 			break;
113 		}
114 	}
115 	if (entry && (entry->edx & (1 << 20)) && !is_efer_nx()) {
116 		entry->edx &= ~(1 << 20);
117 		printk(KERN_INFO "kvm: guest NX capability removed\n");
118 	}
119 }
120 
121 /* when an old userspace process fills a new kernel module */
122 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
123 			     struct kvm_cpuid *cpuid,
124 			     struct kvm_cpuid_entry __user *entries)
125 {
126 	int r, i;
127 	struct kvm_cpuid_entry *cpuid_entries;
128 
129 	r = -E2BIG;
130 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
131 		goto out;
132 	r = -ENOMEM;
133 	cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
134 	if (!cpuid_entries)
135 		goto out;
136 	r = -EFAULT;
137 	if (copy_from_user(cpuid_entries, entries,
138 			   cpuid->nent * sizeof(struct kvm_cpuid_entry)))
139 		goto out_free;
140 	for (i = 0; i < cpuid->nent; i++) {
141 		vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
142 		vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
143 		vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
144 		vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
145 		vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
146 		vcpu->arch.cpuid_entries[i].index = 0;
147 		vcpu->arch.cpuid_entries[i].flags = 0;
148 		vcpu->arch.cpuid_entries[i].padding[0] = 0;
149 		vcpu->arch.cpuid_entries[i].padding[1] = 0;
150 		vcpu->arch.cpuid_entries[i].padding[2] = 0;
151 	}
152 	vcpu->arch.cpuid_nent = cpuid->nent;
153 	cpuid_fix_nx_cap(vcpu);
154 	r = 0;
155 	kvm_apic_set_version(vcpu);
156 	kvm_x86_ops->cpuid_update(vcpu);
157 	kvm_update_cpuid(vcpu);
158 
159 out_free:
160 	vfree(cpuid_entries);
161 out:
162 	return r;
163 }
164 
165 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
166 			      struct kvm_cpuid2 *cpuid,
167 			      struct kvm_cpuid_entry2 __user *entries)
168 {
169 	int r;
170 
171 	r = -E2BIG;
172 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
173 		goto out;
174 	r = -EFAULT;
175 	if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
176 			   cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
177 		goto out;
178 	vcpu->arch.cpuid_nent = cpuid->nent;
179 	kvm_apic_set_version(vcpu);
180 	kvm_x86_ops->cpuid_update(vcpu);
181 	kvm_update_cpuid(vcpu);
182 	return 0;
183 
184 out:
185 	return r;
186 }
187 
188 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
189 			      struct kvm_cpuid2 *cpuid,
190 			      struct kvm_cpuid_entry2 __user *entries)
191 {
192 	int r;
193 
194 	r = -E2BIG;
195 	if (cpuid->nent < vcpu->arch.cpuid_nent)
196 		goto out;
197 	r = -EFAULT;
198 	if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
199 			 vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
200 		goto out;
201 	return 0;
202 
203 out:
204 	cpuid->nent = vcpu->arch.cpuid_nent;
205 	return r;
206 }
207 
208 static void cpuid_mask(u32 *word, int wordnum)
209 {
210 	*word &= boot_cpu_data.x86_capability[wordnum];
211 }
212 
213 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
214 			   u32 index)
215 {
216 	entry->function = function;
217 	entry->index = index;
218 	cpuid_count(entry->function, entry->index,
219 		    &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
220 	entry->flags = 0;
221 }
222 
223 #define F(x) bit(X86_FEATURE_##x)
224 
225 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
226 				   u32 func, u32 index, int *nent, int maxnent)
227 {
228 	switch (func) {
229 	case 0:
230 		entry->eax = 1;		/* only one leaf currently */
231 		++*nent;
232 		break;
233 	case 1:
234 		entry->ecx = F(MOVBE);
235 		++*nent;
236 		break;
237 	default:
238 		break;
239 	}
240 
241 	entry->function = func;
242 	entry->index = index;
243 
244 	return 0;
245 }
246 
247 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
248 				 u32 index, int *nent, int maxnent)
249 {
250 	int r;
251 	unsigned f_nx = is_efer_nx() ? F(NX) : 0;
252 #ifdef CONFIG_X86_64
253 	unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
254 				? F(GBPAGES) : 0;
255 	unsigned f_lm = F(LM);
256 #else
257 	unsigned f_gbpages = 0;
258 	unsigned f_lm = 0;
259 #endif
260 	unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
261 	unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
262 	unsigned f_mpx = kvm_x86_ops->mpx_supported() ? F(MPX) : 0;
263 
264 	/* cpuid 1.edx */
265 	const u32 kvm_supported_word0_x86_features =
266 		F(FPU) | F(VME) | F(DE) | F(PSE) |
267 		F(TSC) | F(MSR) | F(PAE) | F(MCE) |
268 		F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
269 		F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
270 		F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
271 		0 /* Reserved, DS, ACPI */ | F(MMX) |
272 		F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
273 		0 /* HTT, TM, Reserved, PBE */;
274 	/* cpuid 0x80000001.edx */
275 	const u32 kvm_supported_word1_x86_features =
276 		F(FPU) | F(VME) | F(DE) | F(PSE) |
277 		F(TSC) | F(MSR) | F(PAE) | F(MCE) |
278 		F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
279 		F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
280 		F(PAT) | F(PSE36) | 0 /* Reserved */ |
281 		f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
282 		F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
283 		0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
284 	/* cpuid 1.ecx */
285 	const u32 kvm_supported_word4_x86_features =
286 		F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
287 		0 /* DS-CPL, VMX, SMX, EST */ |
288 		0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
289 		F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
290 		F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
291 		F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
292 		0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
293 		F(F16C) | F(RDRAND);
294 	/* cpuid 0x80000001.ecx */
295 	const u32 kvm_supported_word6_x86_features =
296 		F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
297 		F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
298 		F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
299 		0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
300 
301 	/* cpuid 0xC0000001.edx */
302 	const u32 kvm_supported_word5_x86_features =
303 		F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
304 		F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
305 		F(PMM) | F(PMM_EN);
306 
307 	/* cpuid 7.0.ebx */
308 	const u32 kvm_supported_word9_x86_features =
309 		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
310 		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
311 		F(ADX);
312 
313 	/* all calls to cpuid_count() should be made on the same cpu */
314 	get_cpu();
315 
316 	r = -E2BIG;
317 
318 	if (*nent >= maxnent)
319 		goto out;
320 
321 	do_cpuid_1_ent(entry, function, index);
322 	++*nent;
323 
324 	switch (function) {
325 	case 0:
326 		entry->eax = min(entry->eax, (u32)0xd);
327 		break;
328 	case 1:
329 		entry->edx &= kvm_supported_word0_x86_features;
330 		cpuid_mask(&entry->edx, 0);
331 		entry->ecx &= kvm_supported_word4_x86_features;
332 		cpuid_mask(&entry->ecx, 4);
333 		/* we support x2apic emulation even if host does not support
334 		 * it since we emulate x2apic in software */
335 		entry->ecx |= F(X2APIC);
336 		break;
337 	/* function 2 entries are STATEFUL. That is, repeated cpuid commands
338 	 * may return different values. This forces us to get_cpu() before
339 	 * issuing the first command, and also to emulate this annoying behavior
340 	 * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
341 	case 2: {
342 		int t, times = entry->eax & 0xff;
343 
344 		entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
345 		entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
346 		for (t = 1; t < times; ++t) {
347 			if (*nent >= maxnent)
348 				goto out;
349 
350 			do_cpuid_1_ent(&entry[t], function, 0);
351 			entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
352 			++*nent;
353 		}
354 		break;
355 	}
356 	/* function 4 has additional index. */
357 	case 4: {
358 		int i, cache_type;
359 
360 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
361 		/* read more entries until cache_type is zero */
362 		for (i = 1; ; ++i) {
363 			if (*nent >= maxnent)
364 				goto out;
365 
366 			cache_type = entry[i - 1].eax & 0x1f;
367 			if (!cache_type)
368 				break;
369 			do_cpuid_1_ent(&entry[i], function, i);
370 			entry[i].flags |=
371 			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
372 			++*nent;
373 		}
374 		break;
375 	}
376 	case 7: {
377 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
378 		/* Mask ebx against host capability word 9 */
379 		if (index == 0) {
380 			entry->ebx &= kvm_supported_word9_x86_features;
381 			cpuid_mask(&entry->ebx, 9);
382 			// TSC_ADJUST is emulated
383 			entry->ebx |= F(TSC_ADJUST);
384 		} else
385 			entry->ebx = 0;
386 		entry->eax = 0;
387 		entry->ecx = 0;
388 		entry->edx = 0;
389 		break;
390 	}
391 	case 9:
392 		break;
393 	case 0xa: { /* Architectural Performance Monitoring */
394 		struct x86_pmu_capability cap;
395 		union cpuid10_eax eax;
396 		union cpuid10_edx edx;
397 
398 		perf_get_x86_pmu_capability(&cap);
399 
400 		/*
401 		 * Only support guest architectural pmu on a host
402 		 * with architectural pmu.
403 		 */
404 		if (!cap.version)
405 			memset(&cap, 0, sizeof(cap));
406 
407 		eax.split.version_id = min(cap.version, 2);
408 		eax.split.num_counters = cap.num_counters_gp;
409 		eax.split.bit_width = cap.bit_width_gp;
410 		eax.split.mask_length = cap.events_mask_len;
411 
412 		edx.split.num_counters_fixed = cap.num_counters_fixed;
413 		edx.split.bit_width_fixed = cap.bit_width_fixed;
414 		edx.split.reserved = 0;
415 
416 		entry->eax = eax.full;
417 		entry->ebx = cap.events_mask;
418 		entry->ecx = 0;
419 		entry->edx = edx.full;
420 		break;
421 	}
422 	/* function 0xb has additional index. */
423 	case 0xb: {
424 		int i, level_type;
425 
426 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
427 		/* read more entries until level_type is zero */
428 		for (i = 1; ; ++i) {
429 			if (*nent >= maxnent)
430 				goto out;
431 
432 			level_type = entry[i - 1].ecx & 0xff00;
433 			if (!level_type)
434 				break;
435 			do_cpuid_1_ent(&entry[i], function, i);
436 			entry[i].flags |=
437 			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
438 			++*nent;
439 		}
440 		break;
441 	}
442 	case 0xd: {
443 		int idx, i;
444 		u64 supported = kvm_supported_xcr0();
445 
446 		entry->eax &= supported;
447 		entry->edx &= supported >> 32;
448 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
449 		for (idx = 1, i = 1; idx < 64; ++idx) {
450 			u64 mask = ((u64)1 << idx);
451 			if (*nent >= maxnent)
452 				goto out;
453 
454 			do_cpuid_1_ent(&entry[i], function, idx);
455 			if (entry[i].eax == 0 || !(supported & mask))
456 				continue;
457 			entry[i].flags |=
458 			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
459 			++*nent;
460 			++i;
461 		}
462 		break;
463 	}
464 	case KVM_CPUID_SIGNATURE: {
465 		static const char signature[12] = "KVMKVMKVM\0\0";
466 		const u32 *sigptr = (const u32 *)signature;
467 		entry->eax = KVM_CPUID_FEATURES;
468 		entry->ebx = sigptr[0];
469 		entry->ecx = sigptr[1];
470 		entry->edx = sigptr[2];
471 		break;
472 	}
473 	case KVM_CPUID_FEATURES:
474 		entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
475 			     (1 << KVM_FEATURE_NOP_IO_DELAY) |
476 			     (1 << KVM_FEATURE_CLOCKSOURCE2) |
477 			     (1 << KVM_FEATURE_ASYNC_PF) |
478 			     (1 << KVM_FEATURE_PV_EOI) |
479 			     (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
480 			     (1 << KVM_FEATURE_PV_UNHALT);
481 
482 		if (sched_info_on())
483 			entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
484 
485 		entry->ebx = 0;
486 		entry->ecx = 0;
487 		entry->edx = 0;
488 		break;
489 	case 0x80000000:
490 		entry->eax = min(entry->eax, 0x8000001a);
491 		break;
492 	case 0x80000001:
493 		entry->edx &= kvm_supported_word1_x86_features;
494 		cpuid_mask(&entry->edx, 1);
495 		entry->ecx &= kvm_supported_word6_x86_features;
496 		cpuid_mask(&entry->ecx, 6);
497 		break;
498 	case 0x80000008: {
499 		unsigned g_phys_as = (entry->eax >> 16) & 0xff;
500 		unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
501 		unsigned phys_as = entry->eax & 0xff;
502 
503 		if (!g_phys_as)
504 			g_phys_as = phys_as;
505 		entry->eax = g_phys_as | (virt_as << 8);
506 		entry->ebx = entry->edx = 0;
507 		break;
508 	}
509 	case 0x80000019:
510 		entry->ecx = entry->edx = 0;
511 		break;
512 	case 0x8000001a:
513 		break;
514 	case 0x8000001d:
515 		break;
516 	/*Add support for Centaur's CPUID instruction*/
517 	case 0xC0000000:
518 		/*Just support up to 0xC0000004 now*/
519 		entry->eax = min(entry->eax, 0xC0000004);
520 		break;
521 	case 0xC0000001:
522 		entry->edx &= kvm_supported_word5_x86_features;
523 		cpuid_mask(&entry->edx, 5);
524 		break;
525 	case 3: /* Processor serial number */
526 	case 5: /* MONITOR/MWAIT */
527 	case 6: /* Thermal management */
528 	case 0x80000007: /* Advanced power management */
529 	case 0xC0000002:
530 	case 0xC0000003:
531 	case 0xC0000004:
532 	default:
533 		entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
534 		break;
535 	}
536 
537 	kvm_x86_ops->set_supported_cpuid(function, entry);
538 
539 	r = 0;
540 
541 out:
542 	put_cpu();
543 
544 	return r;
545 }
546 
547 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
548 			u32 idx, int *nent, int maxnent, unsigned int type)
549 {
550 	if (type == KVM_GET_EMULATED_CPUID)
551 		return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
552 
553 	return __do_cpuid_ent(entry, func, idx, nent, maxnent);
554 }
555 
556 #undef F
557 
558 struct kvm_cpuid_param {
559 	u32 func;
560 	u32 idx;
561 	bool has_leaf_count;
562 	bool (*qualifier)(const struct kvm_cpuid_param *param);
563 };
564 
565 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
566 {
567 	return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
568 }
569 
570 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
571 				 __u32 num_entries, unsigned int ioctl_type)
572 {
573 	int i;
574 	__u32 pad[3];
575 
576 	if (ioctl_type != KVM_GET_EMULATED_CPUID)
577 		return false;
578 
579 	/*
580 	 * We want to make sure that ->padding is being passed clean from
581 	 * userspace in case we want to use it for something in the future.
582 	 *
583 	 * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
584 	 * have to give ourselves satisfied only with the emulated side. /me
585 	 * sheds a tear.
586 	 */
587 	for (i = 0; i < num_entries; i++) {
588 		if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
589 			return true;
590 
591 		if (pad[0] || pad[1] || pad[2])
592 			return true;
593 	}
594 	return false;
595 }
596 
597 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
598 			    struct kvm_cpuid_entry2 __user *entries,
599 			    unsigned int type)
600 {
601 	struct kvm_cpuid_entry2 *cpuid_entries;
602 	int limit, nent = 0, r = -E2BIG, i;
603 	u32 func;
604 	static const struct kvm_cpuid_param param[] = {
605 		{ .func = 0, .has_leaf_count = true },
606 		{ .func = 0x80000000, .has_leaf_count = true },
607 		{ .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
608 		{ .func = KVM_CPUID_SIGNATURE },
609 		{ .func = KVM_CPUID_FEATURES },
610 	};
611 
612 	if (cpuid->nent < 1)
613 		goto out;
614 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
615 		cpuid->nent = KVM_MAX_CPUID_ENTRIES;
616 
617 	if (sanity_check_entries(entries, cpuid->nent, type))
618 		return -EINVAL;
619 
620 	r = -ENOMEM;
621 	cpuid_entries = vzalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
622 	if (!cpuid_entries)
623 		goto out;
624 
625 	r = 0;
626 	for (i = 0; i < ARRAY_SIZE(param); i++) {
627 		const struct kvm_cpuid_param *ent = &param[i];
628 
629 		if (ent->qualifier && !ent->qualifier(ent))
630 			continue;
631 
632 		r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
633 				&nent, cpuid->nent, type);
634 
635 		if (r)
636 			goto out_free;
637 
638 		if (!ent->has_leaf_count)
639 			continue;
640 
641 		limit = cpuid_entries[nent - 1].eax;
642 		for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
643 			r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
644 				     &nent, cpuid->nent, type);
645 
646 		if (r)
647 			goto out_free;
648 	}
649 
650 	r = -EFAULT;
651 	if (copy_to_user(entries, cpuid_entries,
652 			 nent * sizeof(struct kvm_cpuid_entry2)))
653 		goto out_free;
654 	cpuid->nent = nent;
655 	r = 0;
656 
657 out_free:
658 	vfree(cpuid_entries);
659 out:
660 	return r;
661 }
662 
663 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
664 {
665 	struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
666 	int j, nent = vcpu->arch.cpuid_nent;
667 
668 	e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
669 	/* when no next entry is found, the current entry[i] is reselected */
670 	for (j = i + 1; ; j = (j + 1) % nent) {
671 		struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
672 		if (ej->function == e->function) {
673 			ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
674 			return j;
675 		}
676 	}
677 	return 0; /* silence gcc, even though control never reaches here */
678 }
679 
680 /* find an entry with matching function, matching index (if needed), and that
681  * should be read next (if it's stateful) */
682 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
683 	u32 function, u32 index)
684 {
685 	if (e->function != function)
686 		return 0;
687 	if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
688 		return 0;
689 	if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
690 	    !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
691 		return 0;
692 	return 1;
693 }
694 
695 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
696 					      u32 function, u32 index)
697 {
698 	int i;
699 	struct kvm_cpuid_entry2 *best = NULL;
700 
701 	for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
702 		struct kvm_cpuid_entry2 *e;
703 
704 		e = &vcpu->arch.cpuid_entries[i];
705 		if (is_matching_cpuid_entry(e, function, index)) {
706 			if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
707 				move_to_next_stateful_cpuid_entry(vcpu, i);
708 			best = e;
709 			break;
710 		}
711 	}
712 	return best;
713 }
714 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
715 
716 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
717 {
718 	struct kvm_cpuid_entry2 *best;
719 
720 	best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
721 	if (!best || best->eax < 0x80000008)
722 		goto not_found;
723 	best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
724 	if (best)
725 		return best->eax & 0xff;
726 not_found:
727 	return 36;
728 }
729 
730 /*
731  * If no match is found, check whether we exceed the vCPU's limit
732  * and return the content of the highest valid _standard_ leaf instead.
733  * This is to satisfy the CPUID specification.
734  */
735 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
736                                                   u32 function, u32 index)
737 {
738 	struct kvm_cpuid_entry2 *maxlevel;
739 
740 	maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
741 	if (!maxlevel || maxlevel->eax >= function)
742 		return NULL;
743 	if (function & 0x80000000) {
744 		maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
745 		if (!maxlevel)
746 			return NULL;
747 	}
748 	return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
749 }
750 
751 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
752 {
753 	u32 function = *eax, index = *ecx;
754 	struct kvm_cpuid_entry2 *best;
755 
756 	best = kvm_find_cpuid_entry(vcpu, function, index);
757 
758 	if (!best)
759 		best = check_cpuid_limit(vcpu, function, index);
760 
761 	if (best) {
762 		*eax = best->eax;
763 		*ebx = best->ebx;
764 		*ecx = best->ecx;
765 		*edx = best->edx;
766 	} else
767 		*eax = *ebx = *ecx = *edx = 0;
768 	trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
769 }
770 EXPORT_SYMBOL_GPL(kvm_cpuid);
771 
772 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
773 {
774 	u32 function, eax, ebx, ecx, edx;
775 
776 	function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
777 	ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
778 	kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
779 	kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
780 	kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
781 	kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
782 	kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
783 	kvm_x86_ops->skip_emulated_instruction(vcpu);
784 }
785 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);
786