// SPDX-License-Identifier: GPL-2.0-only /* * Kernel-based Virtual Machine driver for Linux * cpuid support routines * * derived from arch/x86/kvm/x86.c * * Copyright 2011 Red Hat, Inc. and/or its affiliates. * Copyright IBM Corporation, 2008 */ #include #include #include #include #include #include #include #include #include #include "cpuid.h" #include "lapic.h" #include "mmu.h" #include "trace.h" #include "pmu.h" /* * Unlike "struct cpuinfo_x86.x86_capability", kvm_cpu_caps doesn't need to be * aligned to sizeof(unsigned long) because it's not accessed via bitops. */ u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly; EXPORT_SYMBOL_GPL(kvm_cpu_caps); static u32 xstate_required_size(u64 xstate_bv, bool compacted) { int feature_bit = 0; u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET; xstate_bv &= XFEATURE_MASK_EXTEND; while (xstate_bv) { if (xstate_bv & 0x1) { u32 eax, ebx, ecx, edx, offset; cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx); offset = compacted ? ret : ebx; ret = max(ret, offset + eax); } xstate_bv >>= 1; feature_bit++; } return ret; } #define F feature_bit #define SF(name) (boot_cpu_has(X86_FEATURE_##name) ? F(name) : 0) static inline struct kvm_cpuid_entry2 *cpuid_entry2_find( struct kvm_cpuid_entry2 *entries, int nent, u32 function, u32 index) { struct kvm_cpuid_entry2 *e; int i; for (i = 0; i < nent; i++) { e = &entries[i]; if (e->function == function && (!(e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) || e->index == index)) return e; } return NULL; } static int kvm_check_cpuid(struct kvm_cpuid_entry2 *entries, int nent) { struct kvm_cpuid_entry2 *best; /* * The existing code assumes virtual address is 48-bit or 57-bit in the * canonical address checks; exit if it is ever changed. */ best = cpuid_entry2_find(entries, nent, 0x80000008, 0); if (best) { int vaddr_bits = (best->eax & 0xff00) >> 8; if (vaddr_bits != 48 && vaddr_bits != 57 && vaddr_bits != 0) return -EINVAL; } return 0; } void kvm_update_pv_runtime(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best; best = kvm_find_cpuid_entry(vcpu, KVM_CPUID_FEATURES, 0); /* * save the feature bitmap to avoid cpuid lookup for every PV * operation */ if (best) vcpu->arch.pv_cpuid.features = best->eax; } void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best; best = kvm_find_cpuid_entry(vcpu, 1, 0); if (best) { /* Update OSXSAVE bit */ if (boot_cpu_has(X86_FEATURE_XSAVE)) cpuid_entry_change(best, X86_FEATURE_OSXSAVE, kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)); cpuid_entry_change(best, X86_FEATURE_APIC, vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE); } best = kvm_find_cpuid_entry(vcpu, 7, 0); if (best && boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7) cpuid_entry_change(best, X86_FEATURE_OSPKE, kvm_read_cr4_bits(vcpu, X86_CR4_PKE)); best = kvm_find_cpuid_entry(vcpu, 0xD, 0); if (best) best->ebx = xstate_required_size(vcpu->arch.xcr0, false); best = kvm_find_cpuid_entry(vcpu, 0xD, 1); if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) || cpuid_entry_has(best, X86_FEATURE_XSAVEC))) best->ebx = xstate_required_size(vcpu->arch.xcr0, true); best = kvm_find_cpuid_entry(vcpu, KVM_CPUID_FEATURES, 0); if (kvm_hlt_in_guest(vcpu->kvm) && best && (best->eax & (1 << KVM_FEATURE_PV_UNHALT))) best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT); if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT)) { best = kvm_find_cpuid_entry(vcpu, 0x1, 0); if (best) cpuid_entry_change(best, X86_FEATURE_MWAIT, vcpu->arch.ia32_misc_enable_msr & MSR_IA32_MISC_ENABLE_MWAIT); } } EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime); static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) { struct kvm_lapic *apic = vcpu->arch.apic; struct kvm_cpuid_entry2 *best; best = kvm_find_cpuid_entry(vcpu, 1, 0); if (best && apic) { if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER)) apic->lapic_timer.timer_mode_mask = 3 << 17; else apic->lapic_timer.timer_mode_mask = 1 << 17; kvm_apic_set_version(vcpu); } best = kvm_find_cpuid_entry(vcpu, 0xD, 0); if (!best) vcpu->arch.guest_supported_xcr0 = 0; else vcpu->arch.guest_supported_xcr0 = (best->eax | ((u64)best->edx << 32)) & supported_xcr0; /* * Bits 127:0 of the allowed SECS.ATTRIBUTES (CPUID.0x12.0x1) enumerate * the supported XSAVE Feature Request Mask (XFRM), i.e. the enclave's * requested XCR0 value. The enclave's XFRM must be a subset of XCRO * at the time of EENTER, thus adjust the allowed XFRM by the guest's * supported XCR0. Similar to XCR0 handling, FP and SSE are forced to * '1' even on CPUs that don't support XSAVE. */ best = kvm_find_cpuid_entry(vcpu, 0x12, 0x1); if (best) { best->ecx &= vcpu->arch.guest_supported_xcr0 & 0xffffffff; best->edx &= vcpu->arch.guest_supported_xcr0 >> 32; best->ecx |= XFEATURE_MASK_FPSSE; } kvm_update_pv_runtime(vcpu); vcpu->arch.is_amd_compatible = guest_cpuid_is_amd_or_hygon(vcpu); vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu); vcpu->arch.reserved_gpa_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu); kvm_pmu_refresh(vcpu); vcpu->arch.cr4_guest_rsvd_bits = __cr4_reserved_bits(guest_cpuid_has, vcpu); kvm_hv_set_cpuid(vcpu); /* Invoke the vendor callback only after the above state is updated. */ static_call(kvm_x86_vcpu_after_set_cpuid)(vcpu); /* * Except for the MMU, which needs to do its thing any vendor specific * adjustments to the reserved GPA bits. */ kvm_mmu_after_set_cpuid(vcpu); } int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best; best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0); if (!best || best->eax < 0x80000008) goto not_found; best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0); if (best) return best->eax & 0xff; not_found: return 36; } /* * This "raw" version returns the reserved GPA bits without any adjustments for * encryption technologies that usurp bits. The raw mask should be used if and * only if hardware does _not_ strip the usurped bits, e.g. in virtual MTRRs. */ u64 kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu *vcpu) { return rsvd_bits(cpuid_maxphyaddr(vcpu), 63); } static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, int nent) { int r; r = kvm_check_cpuid(e2, nent); if (r) return r; kvfree(vcpu->arch.cpuid_entries); vcpu->arch.cpuid_entries = e2; vcpu->arch.cpuid_nent = nent; kvm_update_cpuid_runtime(vcpu); kvm_vcpu_after_set_cpuid(vcpu); return 0; } /* when an old userspace process fills a new kernel module */ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid *cpuid, struct kvm_cpuid_entry __user *entries) { int r, i; struct kvm_cpuid_entry *e = NULL; struct kvm_cpuid_entry2 *e2 = NULL; if (cpuid->nent > KVM_MAX_CPUID_ENTRIES) return -E2BIG; if (cpuid->nent) { e = vmemdup_user(entries, array_size(sizeof(*e), cpuid->nent)); if (IS_ERR(e)) return PTR_ERR(e); e2 = kvmalloc_array(cpuid->nent, sizeof(*e2), GFP_KERNEL_ACCOUNT); if (!e2) { r = -ENOMEM; goto out_free_cpuid; } } for (i = 0; i < cpuid->nent; i++) { e2[i].function = e[i].function; e2[i].eax = e[i].eax; e2[i].ebx = e[i].ebx; e2[i].ecx = e[i].ecx; e2[i].edx = e[i].edx; e2[i].index = 0; e2[i].flags = 0; e2[i].padding[0] = 0; e2[i].padding[1] = 0; e2[i].padding[2] = 0; } r = kvm_set_cpuid(vcpu, e2, cpuid->nent); if (r) kvfree(e2); out_free_cpuid: kvfree(e); return r; } int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, struct kvm_cpuid_entry2 __user *entries) { struct kvm_cpuid_entry2 *e2 = NULL; int r; if (cpuid->nent > KVM_MAX_CPUID_ENTRIES) return -E2BIG; if (cpuid->nent) { e2 = vmemdup_user(entries, array_size(sizeof(*e2), cpuid->nent)); if (IS_ERR(e2)) return PTR_ERR(e2); } r = kvm_set_cpuid(vcpu, e2, cpuid->nent); if (r) kvfree(e2); return r; } int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, struct kvm_cpuid_entry2 __user *entries) { int r; r = -E2BIG; if (cpuid->nent < vcpu->arch.cpuid_nent) goto out; r = -EFAULT; if (copy_to_user(entries, vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2))) goto out; return 0; out: cpuid->nent = vcpu->arch.cpuid_nent; return r; } /* Mask kvm_cpu_caps for @leaf with the raw CPUID capabilities of this CPU. */ static __always_inline void __kvm_cpu_cap_mask(unsigned int leaf) { const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32); struct kvm_cpuid_entry2 entry; reverse_cpuid_check(leaf); cpuid_count(cpuid.function, cpuid.index, &entry.eax, &entry.ebx, &entry.ecx, &entry.edx); kvm_cpu_caps[leaf] &= *__cpuid_entry_get_reg(&entry, cpuid.reg); } static __always_inline void kvm_cpu_cap_init_kvm_defined(enum kvm_only_cpuid_leafs leaf, u32 mask) { /* Use kvm_cpu_cap_mask for leafs that aren't KVM-only. */ BUILD_BUG_ON(leaf < NCAPINTS); kvm_cpu_caps[leaf] = mask; __kvm_cpu_cap_mask(leaf); } static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask) { /* Use kvm_cpu_cap_init_kvm_defined for KVM-only leafs. */ BUILD_BUG_ON(leaf >= NCAPINTS); kvm_cpu_caps[leaf] &= mask; __kvm_cpu_cap_mask(leaf); } void kvm_set_cpu_caps(void) { #ifdef CONFIG_X86_64 unsigned int f_gbpages = F(GBPAGES); unsigned int f_lm = F(LM); #else unsigned int f_gbpages = 0; unsigned int f_lm = 0; #endif memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps)); BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) > sizeof(boot_cpu_data.x86_capability)); memcpy(&kvm_cpu_caps, &boot_cpu_data.x86_capability, sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps))); kvm_cpu_cap_mask(CPUID_1_ECX, /* * NOTE: MONITOR (and MWAIT) are emulated as NOP, but *not* * advertised to guests via CPUID! */ F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ | 0 /* DS-CPL, VMX, SMX, EST */ | 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ | F(FMA) | F(CX16) | 0 /* xTPR Update */ | F(PDCM) | F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) | F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) | 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) | F(F16C) | F(RDRAND) ); /* KVM emulates x2apic in software irrespective of host support. */ kvm_cpu_cap_set(X86_FEATURE_X2APIC); kvm_cpu_cap_mask(CPUID_1_EDX, F(FPU) | F(VME) | F(DE) | F(PSE) | F(TSC) | F(MSR) | F(PAE) | F(MCE) | F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) | F(MTRR) | F(PGE) | F(MCA) | F(CMOV) | F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) | 0 /* Reserved, DS, ACPI */ | F(MMX) | F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) | 0 /* HTT, TM, Reserved, PBE */ ); kvm_cpu_cap_mask(CPUID_7_0_EBX, F(FSGSBASE) | F(SGX) | F(BMI1) | F(HLE) | F(AVX2) | F(FDP_EXCPTN_ONLY) | F(SMEP) | F(BMI2) | F(ERMS) | F(INVPCID) | F(RTM) | F(ZERO_FCS_FDS) | 0 /*MPX*/ | F(AVX512F) | F(AVX512DQ) | F(RDSEED) | F(ADX) | F(SMAP) | F(AVX512IFMA) | F(CLFLUSHOPT) | F(CLWB) | 0 /*INTEL_PT*/ | F(AVX512PF) | F(AVX512ER) | F(AVX512CD) | F(SHA_NI) | F(AVX512BW) | F(AVX512VL)); kvm_cpu_cap_mask(CPUID_7_ECX, F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) | F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) | F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) | F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/ | F(SGX_LC) | F(BUS_LOCK_DETECT) ); /* Set LA57 based on hardware capability. */ if (cpuid_ecx(7) & F(LA57)) kvm_cpu_cap_set(X86_FEATURE_LA57); /* * PKU not yet implemented for shadow paging and requires OSPKE * to be set on the host. Clear it if that is not the case */ if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE)) kvm_cpu_cap_clear(X86_FEATURE_PKU); kvm_cpu_cap_mask(CPUID_7_EDX, F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) | F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) | F(MD_CLEAR) | F(AVX512_VP2INTERSECT) | F(FSRM) | F(SERIALIZE) | F(TSXLDTRK) | F(AVX512_FP16) ); /* TSC_ADJUST and ARCH_CAPABILITIES are emulated in software. */ kvm_cpu_cap_set(X86_FEATURE_TSC_ADJUST); kvm_cpu_cap_set(X86_FEATURE_ARCH_CAPABILITIES); if (boot_cpu_has(X86_FEATURE_IBPB) && boot_cpu_has(X86_FEATURE_IBRS)) kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL); if (boot_cpu_has(X86_FEATURE_STIBP)) kvm_cpu_cap_set(X86_FEATURE_INTEL_STIBP); if (boot_cpu_has(X86_FEATURE_AMD_SSBD)) kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD); kvm_cpu_cap_mask(CPUID_7_1_EAX, F(AVX_VNNI) | F(AVX512_BF16) ); kvm_cpu_cap_init_kvm_defined(CPUID_7_2_EDX, F(INTEL_PSFD) | F(IPRED_CTRL) | F(RRSBA_CTRL) | F(DDPD_U) | F(BHI_CTRL) | F(MCDT_NO) ); kvm_cpu_cap_mask(CPUID_D_1_EAX, F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) ); kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX, SF(SGX1) | SF(SGX2) ); kvm_cpu_cap_mask(CPUID_8000_0001_ECX, F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ | F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) | F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) | 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM) | F(TOPOEXT) | F(PERFCTR_CORE) ); kvm_cpu_cap_mask(CPUID_8000_0001_EDX, F(FPU) | F(VME) | F(DE) | F(PSE) | F(TSC) | F(MSR) | F(PAE) | F(MCE) | F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) | F(MTRR) | F(PGE) | F(MCA) | F(CMOV) | F(PAT) | F(PSE36) | 0 /* Reserved */ | F(NX) | 0 /* Reserved */ | F(MMXEXT) | F(MMX) | F(FXSR) | F(FXSR_OPT) | f_gbpages | F(RDTSCP) | 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW) ); if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64)) kvm_cpu_cap_set(X86_FEATURE_GBPAGES); kvm_cpu_cap_mask(CPUID_8000_0008_EBX, F(CLZERO) | F(XSAVEERPTR) | F(WBNOINVD) | F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) | F(AMD_SSB_NO) | F(AMD_STIBP) | F(AMD_STIBP_ALWAYS_ON) ); /* * AMD has separate bits for each SPEC_CTRL bit. * arch/x86/kernel/cpu/bugs.c is kind enough to * record that in cpufeatures so use them. */ if (boot_cpu_has(X86_FEATURE_IBPB)) kvm_cpu_cap_set(X86_FEATURE_AMD_IBPB); if (boot_cpu_has(X86_FEATURE_IBRS)) kvm_cpu_cap_set(X86_FEATURE_AMD_IBRS); if (boot_cpu_has(X86_FEATURE_STIBP)) kvm_cpu_cap_set(X86_FEATURE_AMD_STIBP); if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD)) kvm_cpu_cap_set(X86_FEATURE_AMD_SSBD); if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS)) kvm_cpu_cap_set(X86_FEATURE_AMD_SSB_NO); /* * The preference is to use SPEC CTRL MSR instead of the * VIRT_SPEC MSR. */ if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) && !boot_cpu_has(X86_FEATURE_AMD_SSBD)) kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD); /* * Hide all SVM features by default, SVM will set the cap bits for * features it emulates and/or exposes for L1. */ kvm_cpu_cap_mask(CPUID_8000_000A_EDX, 0); kvm_cpu_cap_mask(CPUID_8000_001F_EAX, 0 /* SME */ | F(SEV) | 0 /* VM_PAGE_FLUSH */ | F(SEV_ES) | F(SME_COHERENT)); kvm_cpu_cap_mask(CPUID_C000_0001_EDX, F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) | F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) | F(PMM) | F(PMM_EN) ); if (cpu_feature_enabled(X86_FEATURE_SRSO_NO)) kvm_cpu_cap_set(X86_FEATURE_SRSO_NO); /* * Hide RDTSCP and RDPID if either feature is reported as supported but * probing MSR_TSC_AUX failed. This is purely a sanity check and * should never happen, but the guest will likely crash if RDTSCP or * RDPID is misreported, and KVM has botched MSR_TSC_AUX emulation in * the past. For example, the sanity check may fire if this instance of * KVM is running as L1 on top of an older, broken KVM. */ if (WARN_ON((kvm_cpu_cap_has(X86_FEATURE_RDTSCP) || kvm_cpu_cap_has(X86_FEATURE_RDPID)) && !kvm_is_supported_user_return_msr(MSR_TSC_AUX))) { kvm_cpu_cap_clear(X86_FEATURE_RDTSCP); kvm_cpu_cap_clear(X86_FEATURE_RDPID); } } EXPORT_SYMBOL_GPL(kvm_set_cpu_caps); struct kvm_cpuid_array { struct kvm_cpuid_entry2 *entries; int maxnent; int nent; }; static struct kvm_cpuid_entry2 *get_next_cpuid(struct kvm_cpuid_array *array) { if (array->nent >= array->maxnent) return NULL; return &array->entries[array->nent++]; } static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array, u32 function, u32 index) { struct kvm_cpuid_entry2 *entry = get_next_cpuid(array); if (!entry) return NULL; entry->function = function; entry->index = index; entry->flags = 0; cpuid_count(entry->function, entry->index, &entry->eax, &entry->ebx, &entry->ecx, &entry->edx); switch (function) { case 4: case 7: case 0xb: case 0xd: case 0xf: case 0x10: case 0x12: case 0x14: case 0x17: case 0x18: case 0x1f: case 0x8000001d: entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; break; } return entry; } static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func) { struct kvm_cpuid_entry2 *entry; if (array->nent >= array->maxnent) return -E2BIG; entry = &array->entries[array->nent]; entry->function = func; entry->index = 0; entry->flags = 0; switch (func) { case 0: entry->eax = 7; ++array->nent; break; case 1: entry->ecx = F(MOVBE); ++array->nent; break; case 7: entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; entry->eax = 0; if (kvm_cpu_cap_has(X86_FEATURE_RDTSCP)) entry->ecx = F(RDPID); ++array->nent; break; default: break; } return 0; } static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) { struct kvm_cpuid_entry2 *entry; int r, i, max_idx; /* all calls to cpuid_count() should be made on the same cpu */ get_cpu(); r = -E2BIG; entry = do_host_cpuid(array, function, 0); if (!entry) goto out; switch (function) { case 0: /* Limited to the highest leaf implemented in KVM. */ entry->eax = min(entry->eax, 0x1fU); break; case 1: cpuid_entry_override(entry, CPUID_1_EDX); cpuid_entry_override(entry, CPUID_1_ECX); break; case 2: /* * On ancient CPUs, function 2 entries are STATEFUL. That is, * CPUID(function=2, index=0) may return different results each * time, with the least-significant byte in EAX enumerating the * number of times software should do CPUID(2, 0). * * Modern CPUs, i.e. every CPU KVM has *ever* run on are less * idiotic. Intel's SDM states that EAX & 0xff "will always * return 01H. Software should ignore this value and not * interpret it as an informational descriptor", while AMD's * APM states that CPUID(2) is reserved. * * WARN if a frankenstein CPU that supports virtualization and * a stateful CPUID.0x2 is encountered. */ WARN_ON_ONCE((entry->eax & 0xff) > 1); break; /* functions 4 and 0x8000001d have additional index. */ case 4: case 0x8000001d: /* * Read entries until the cache type in the previous entry is * zero, i.e. indicates an invalid entry. */ for (i = 1; entry->eax & 0x1f; ++i) { entry = do_host_cpuid(array, function, i); if (!entry) goto out; } break; case 6: /* Thermal management */ entry->eax = 0x4; /* allow ARAT */ entry->ebx = 0; entry->ecx = 0; entry->edx = 0; break; /* function 7 has additional index. */ case 7: max_idx = entry->eax = min(entry->eax, 2u); cpuid_entry_override(entry, CPUID_7_0_EBX); cpuid_entry_override(entry, CPUID_7_ECX); cpuid_entry_override(entry, CPUID_7_EDX); /* KVM only supports up to 0x7.2, capped above via min(). */ if (max_idx >= 1) { entry = do_host_cpuid(array, function, 1); if (!entry) goto out; cpuid_entry_override(entry, CPUID_7_1_EAX); entry->ebx = 0; entry->ecx = 0; entry->edx = 0; } if (max_idx >= 2) { entry = do_host_cpuid(array, function, 2); if (!entry) goto out; cpuid_entry_override(entry, CPUID_7_2_EDX); entry->ecx = 0; entry->ebx = 0; entry->eax = 0; } break; case 0xa: { /* Architectural Performance Monitoring */ struct x86_pmu_capability cap; union cpuid10_eax eax; union cpuid10_edx edx; if (!static_cpu_has(X86_FEATURE_ARCH_PERFMON)) { entry->eax = entry->ebx = entry->ecx = entry->edx = 0; break; } perf_get_x86_pmu_capability(&cap); /* * Only support guest architectural pmu on a host * with architectural pmu. */ if (!cap.version) memset(&cap, 0, sizeof(cap)); eax.split.version_id = min(cap.version, 2); eax.split.num_counters = cap.num_counters_gp; eax.split.bit_width = cap.bit_width_gp; eax.split.mask_length = cap.events_mask_len; edx.split.num_counters_fixed = min(cap.num_counters_fixed, MAX_FIXED_COUNTERS); edx.split.bit_width_fixed = cap.bit_width_fixed; if (cap.version) edx.split.anythread_deprecated = 1; edx.split.reserved1 = 0; edx.split.reserved2 = 0; entry->eax = eax.full; entry->ebx = cap.events_mask; entry->ecx = 0; entry->edx = edx.full; break; } case 0x1f: case 0xb: /* * No topology; a valid topology is indicated by the presence * of subleaf 1. */ entry->eax = entry->ebx = entry->ecx = 0; break; case 0xd: entry->eax &= supported_xcr0; entry->ebx = xstate_required_size(supported_xcr0, false); entry->ecx = entry->ebx; entry->edx &= supported_xcr0 >> 32; if (!supported_xcr0) break; entry = do_host_cpuid(array, function, 1); if (!entry) goto out; cpuid_entry_override(entry, CPUID_D_1_EAX); if (entry->eax & (F(XSAVES)|F(XSAVEC))) entry->ebx = xstate_required_size(supported_xcr0 | supported_xss, true); else { WARN_ON_ONCE(supported_xss != 0); entry->ebx = 0; } entry->ecx &= supported_xss; entry->edx &= supported_xss >> 32; for (i = 2; i < 64; ++i) { bool s_state; if (supported_xcr0 & BIT_ULL(i)) s_state = false; else if (supported_xss & BIT_ULL(i)) s_state = true; else continue; entry = do_host_cpuid(array, function, i); if (!entry) goto out; /* * The supported check above should have filtered out * invalid sub-leafs. Only valid sub-leafs should * reach this point, and they should have a non-zero * save state size. Furthermore, check whether the * processor agrees with supported_xcr0/supported_xss * on whether this is an XCR0- or IA32_XSS-managed area. */ if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 0x1) != s_state)) { --array->nent; continue; } entry->edx = 0; } break; case 0x12: /* Intel SGX */ if (!kvm_cpu_cap_has(X86_FEATURE_SGX)) { entry->eax = entry->ebx = entry->ecx = entry->edx = 0; break; } /* * Index 0: Sub-features, MISCSELECT (a.k.a extended features) * and max enclave sizes. The SGX sub-features and MISCSELECT * are restricted by kernel and KVM capabilities (like most * feature flags), while enclave size is unrestricted. */ cpuid_entry_override(entry, CPUID_12_EAX); entry->ebx &= SGX_MISC_EXINFO; entry = do_host_cpuid(array, function, 1); if (!entry) goto out; /* * Index 1: SECS.ATTRIBUTES. ATTRIBUTES are restricted a la * feature flags. Advertise all supported flags, including * privileged attributes that require explicit opt-in from * userspace. ATTRIBUTES.XFRM is not adjusted as userspace is * expected to derive it from supported XCR0. */ entry->eax &= SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | SGX_ATTR_PROVISIONKEY | SGX_ATTR_EINITTOKENKEY | SGX_ATTR_KSS; entry->ebx &= 0; break; /* Intel PT */ case 0x14: if (!kvm_cpu_cap_has(X86_FEATURE_INTEL_PT)) { entry->eax = entry->ebx = entry->ecx = entry->edx = 0; break; } for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) { if (!do_host_cpuid(array, function, i)) goto out; } break; case KVM_CPUID_SIGNATURE: { static const char signature[12] = "KVMKVMKVM\0\0"; const u32 *sigptr = (const u32 *)signature; entry->eax = KVM_CPUID_FEATURES; entry->ebx = sigptr[0]; entry->ecx = sigptr[1]; entry->edx = sigptr[2]; break; } case KVM_CPUID_FEATURES: entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) | (1 << KVM_FEATURE_NOP_IO_DELAY) | (1 << KVM_FEATURE_CLOCKSOURCE2) | (1 << KVM_FEATURE_ASYNC_PF) | (1 << KVM_FEATURE_PV_EOI) | (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) | (1 << KVM_FEATURE_PV_UNHALT) | (1 << KVM_FEATURE_PV_TLB_FLUSH) | (1 << KVM_FEATURE_ASYNC_PF_VMEXIT) | (1 << KVM_FEATURE_PV_SEND_IPI) | (1 << KVM_FEATURE_POLL_CONTROL) | (1 << KVM_FEATURE_PV_SCHED_YIELD) | (1 << KVM_FEATURE_ASYNC_PF_INT); if (sched_info_on()) entry->eax |= (1 << KVM_FEATURE_STEAL_TIME); entry->ebx = 0; entry->ecx = 0; entry->edx = 0; break; case 0x80000000: entry->eax = min(entry->eax, 0x8000001f); break; case 0x80000001: entry->ebx &= ~GENMASK(27, 16); cpuid_entry_override(entry, CPUID_8000_0001_EDX); cpuid_entry_override(entry, CPUID_8000_0001_ECX); break; case 0x80000006: /* Drop reserved bits, pass host L2 cache and TLB info. */ entry->edx &= ~GENMASK(17, 16); break; case 0x80000007: /* Advanced power management */ /* invariant TSC is CPUID.80000007H:EDX[8] */ entry->edx &= (1 << 8); /* mask against host */ entry->edx &= boot_cpu_data.x86_power; entry->eax = entry->ebx = entry->ecx = 0; break; case 0x80000008: { unsigned int virt_as = max((entry->eax >> 8) & 0xff, 48U); unsigned int phys_as; /* * If TDP (NPT) is disabled use the adjusted host MAXPHYADDR as * the guest operates in the same PA space as the host, i.e. * reductions in MAXPHYADDR for memory encryption affect shadow * paging, too. * * If TDP is enabled, use the raw bare metal MAXPHYADDR as * reductions to the HPAs do not affect GPAs. */ if (!tdp_enabled) { phys_as = boot_cpu_data.x86_phys_bits; } else { phys_as = entry->eax & 0xff; } entry->eax = phys_as | (virt_as << 8); entry->ecx &= ~(GENMASK(31, 16) | GENMASK(11, 8)); entry->edx = 0; cpuid_entry_override(entry, CPUID_8000_0008_EBX); break; } case 0x8000000A: if (!kvm_cpu_cap_has(X86_FEATURE_SVM)) { entry->eax = entry->ebx = entry->ecx = entry->edx = 0; break; } entry->eax = 1; /* SVM revision 1 */ entry->ebx = 8; /* Lets support 8 ASIDs in case we add proper ASID emulation to nested SVM */ entry->ecx = 0; /* Reserved */ cpuid_entry_override(entry, CPUID_8000_000A_EDX); break; case 0x80000019: entry->ecx = entry->edx = 0; break; case 0x8000001a: entry->eax &= GENMASK(2, 0); entry->ebx = entry->ecx = entry->edx = 0; break; case 0x8000001e: /* Do not return host topology information. */ entry->eax = entry->ebx = entry->ecx = 0; entry->edx = 0; /* reserved */ break; case 0x8000001F: if (!kvm_cpu_cap_has(X86_FEATURE_SEV)) { entry->eax = entry->ebx = entry->ecx = entry->edx = 0; } else { cpuid_entry_override(entry, CPUID_8000_001F_EAX); /* Clear NumVMPL since KVM does not support VMPL. */ entry->ebx &= ~GENMASK(31, 12); /* * Enumerate '0' for "PA bits reduction", the adjusted * MAXPHYADDR is enumerated directly (see 0x80000008). */ entry->ebx &= ~GENMASK(11, 6); } break; /*Add support for Centaur's CPUID instruction*/ case 0xC0000000: /*Just support up to 0xC0000004 now*/ entry->eax = min(entry->eax, 0xC0000004); break; case 0xC0000001: cpuid_entry_override(entry, CPUID_C000_0001_EDX); break; case 3: /* Processor serial number */ case 5: /* MONITOR/MWAIT */ case 0xC0000002: case 0xC0000003: case 0xC0000004: default: entry->eax = entry->ebx = entry->ecx = entry->edx = 0; break; } r = 0; out: put_cpu(); return r; } static int do_cpuid_func(struct kvm_cpuid_array *array, u32 func, unsigned int type) { if (type == KVM_GET_EMULATED_CPUID) return __do_cpuid_func_emulated(array, func); return __do_cpuid_func(array, func); } #define CENTAUR_CPUID_SIGNATURE 0xC0000000 static int get_cpuid_func(struct kvm_cpuid_array *array, u32 func, unsigned int type) { u32 limit; int r; if (func == CENTAUR_CPUID_SIGNATURE && boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR) return 0; r = do_cpuid_func(array, func, type); if (r) return r; limit = array->entries[array->nent - 1].eax; for (func = func + 1; func <= limit; ++func) { r = do_cpuid_func(array, func, type); if (r) break; } return r; } static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries, __u32 num_entries, unsigned int ioctl_type) { int i; __u32 pad[3]; if (ioctl_type != KVM_GET_EMULATED_CPUID) return false; /* * We want to make sure that ->padding is being passed clean from * userspace in case we want to use it for something in the future. * * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we * have to give ourselves satisfied only with the emulated side. /me * sheds a tear. */ for (i = 0; i < num_entries; i++) { if (copy_from_user(pad, entries[i].padding, sizeof(pad))) return true; if (pad[0] || pad[1] || pad[2]) return true; } return false; } int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid, struct kvm_cpuid_entry2 __user *entries, unsigned int type) { static const u32 funcs[] = { 0, 0x80000000, CENTAUR_CPUID_SIGNATURE, KVM_CPUID_SIGNATURE, }; struct kvm_cpuid_array array = { .nent = 0, }; int r, i; if (cpuid->nent < 1) return -E2BIG; if (cpuid->nent > KVM_MAX_CPUID_ENTRIES) cpuid->nent = KVM_MAX_CPUID_ENTRIES; if (sanity_check_entries(entries, cpuid->nent, type)) return -EINVAL; array.entries = vzalloc(array_size(sizeof(struct kvm_cpuid_entry2), cpuid->nent)); if (!array.entries) return -ENOMEM; array.maxnent = cpuid->nent; for (i = 0; i < ARRAY_SIZE(funcs); i++) { r = get_cpuid_func(&array, funcs[i], type); if (r) goto out_free; } cpuid->nent = array.nent; if (copy_to_user(entries, array.entries, array.nent * sizeof(struct kvm_cpuid_entry2))) r = -EFAULT; out_free: vfree(array.entries); return r; } struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu, u32 function, u32 index) { return cpuid_entry2_find(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent, function, index); } EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry); /* * Intel CPUID semantics treats any query for an out-of-range leaf as if the * highest basic leaf (i.e. CPUID.0H:EAX) were requested. AMD CPUID semantics * returns all zeroes for any undefined leaf, whether or not the leaf is in * range. Centaur/VIA follows Intel semantics. * * A leaf is considered out-of-range if its function is higher than the maximum * supported leaf of its associated class or if its associated class does not * exist. * * There are three primary classes to be considered, with their respective * ranges described as " - [, - ] inclusive. A primary * class exists if a guest CPUID entry for its leaf exists. For a given * class, CPUID..EAX contains the max supported leaf for the class. * * - Basic: 0x00000000 - 0x3fffffff, 0x50000000 - 0x7fffffff * - Hypervisor: 0x40000000 - 0x4fffffff * - Extended: 0x80000000 - 0xbfffffff * - Centaur: 0xc0000000 - 0xcfffffff * * The Hypervisor class is further subdivided into sub-classes that each act as * their own independent class associated with a 0x100 byte range. E.g. if Qemu * is advertising support for both HyperV and KVM, the resulting Hypervisor * CPUID sub-classes are: * * - HyperV: 0x40000000 - 0x400000ff * - KVM: 0x40000100 - 0x400001ff */ static struct kvm_cpuid_entry2 * get_out_of_range_cpuid_entry(struct kvm_vcpu *vcpu, u32 *fn_ptr, u32 index) { struct kvm_cpuid_entry2 *basic, *class; u32 function = *fn_ptr; basic = kvm_find_cpuid_entry(vcpu, 0, 0); if (!basic) return NULL; if (is_guest_vendor_amd(basic->ebx, basic->ecx, basic->edx) || is_guest_vendor_hygon(basic->ebx, basic->ecx, basic->edx)) return NULL; if (function >= 0x40000000 && function <= 0x4fffffff) class = kvm_find_cpuid_entry(vcpu, function & 0xffffff00, 0); else if (function >= 0xc0000000) class = kvm_find_cpuid_entry(vcpu, 0xc0000000, 0); else class = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0); if (class && function <= class->eax) return NULL; /* * Leaf specific adjustments are also applied when redirecting to the * max basic entry, e.g. if the max basic leaf is 0xb but there is no * entry for CPUID.0xb.index (see below), then the output value for EDX * needs to be pulled from CPUID.0xb.1. */ *fn_ptr = basic->eax; /* * The class does not exist or the requested function is out of range; * the effective CPUID entry is the max basic leaf. Note, the index of * the original requested leaf is observed! */ return kvm_find_cpuid_entry(vcpu, basic->eax, index); } bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx, bool exact_only) { u32 orig_function = *eax, function = *eax, index = *ecx; struct kvm_cpuid_entry2 *entry; bool exact, used_max_basic = false; entry = kvm_find_cpuid_entry(vcpu, function, index); exact = !!entry; if (!entry && !exact_only) { entry = get_out_of_range_cpuid_entry(vcpu, &function, index); used_max_basic = !!entry; } if (entry) { *eax = entry->eax; *ebx = entry->ebx; *ecx = entry->ecx; *edx = entry->edx; if (function == 7 && index == 0) { u64 data; if (!__kvm_get_msr(vcpu, MSR_IA32_TSX_CTRL, &data, true) && (data & TSX_CTRL_CPUID_CLEAR)) *ebx &= ~(F(RTM) | F(HLE)); } } else { *eax = *ebx = *ecx = *edx = 0; /* * When leaf 0BH or 1FH is defined, CL is pass-through * and EDX is always the x2APIC ID, even for undefined * subleaves. Index 1 will exist iff the leaf is * implemented, so we pass through CL iff leaf 1 * exists. EDX can be copied from any existing index. */ if (function == 0xb || function == 0x1f) { entry = kvm_find_cpuid_entry(vcpu, function, 1); if (entry) { *ecx = index & 0xff; *edx = entry->edx; } } } trace_kvm_cpuid(orig_function, index, *eax, *ebx, *ecx, *edx, exact, used_max_basic); return exact; } EXPORT_SYMBOL_GPL(kvm_cpuid); int kvm_emulate_cpuid(struct kvm_vcpu *vcpu) { u32 eax, ebx, ecx, edx; if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0)) return 1; eax = kvm_rax_read(vcpu); ecx = kvm_rcx_read(vcpu); kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, false); kvm_rax_write(vcpu, eax); kvm_rbx_write(vcpu, ebx); kvm_rcx_write(vcpu, ecx); kvm_rdx_write(vcpu, edx); return kvm_skip_emulated_instruction(vcpu); } EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);