diff options
Diffstat (limited to 'arch/x86/kvm/cpuid.h')
| -rw-r--r-- | arch/x86/kvm/cpuid.h | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h new file mode 100644 index 000000000..8d863f455 --- /dev/null +++ b/arch/x86/kvm/cpuid.h @@ -0,0 +1,307 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef ARCH_X86_KVM_CPUID_H +#define ARCH_X86_KVM_CPUID_H + +#include "reverse_cpuid.h" +#include <asm/cpu.h> +#include <asm/processor.h> +#include <uapi/asm/kvm_para.h> + +#include "smm.h" + +extern u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly; +extern bool kvm_is_configuring_cpu_caps __read_mostly; + +void kvm_initialize_cpu_caps(void); + +static inline void kvm_finalize_cpu_caps(void) +{ + WARN_ON_ONCE(!kvm_is_configuring_cpu_caps); + kvm_is_configuring_cpu_caps = false; +} + +void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu); +struct kvm_cpuid_entry2 *kvm_find_cpuid_entry2(struct kvm_cpuid_entry2 *entries, + int nent, u32 function, u64 index); +/* + * Magic value used by KVM when querying userspace-provided CPUID entries and + * doesn't care about the CPIUD index because the index of the function in + * question is not significant. Note, this magic value must have at least one + * bit set in bits[63:32] and must be consumed as a u64 by kvm_find_cpuid_entry2() + * to avoid false positives when processing guest CPUID input. + * + * KVM_CPUID_INDEX_NOT_SIGNIFICANT should never be used directly outside of + * kvm_find_cpuid_entry2() and kvm_find_cpuid_entry(). + */ +#define KVM_CPUID_INDEX_NOT_SIGNIFICANT -1ull + +static inline struct kvm_cpuid_entry2 *kvm_find_cpuid_entry_index(struct kvm_vcpu *vcpu, + u32 function, u32 index) +{ + return kvm_find_cpuid_entry2(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent, + function, index); +} + +static inline struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu, + u32 function) +{ + return kvm_find_cpuid_entry2(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent, + function, KVM_CPUID_INDEX_NOT_SIGNIFICANT); +} + +int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid, + struct kvm_cpuid_entry2 __user *entries, + unsigned int type); +int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, + struct kvm_cpuid *cpuid, + struct kvm_cpuid_entry __user *entries); +int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, + struct kvm_cpuid2 *cpuid, + struct kvm_cpuid_entry2 __user *entries); +int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, + struct kvm_cpuid2 *cpuid, + struct kvm_cpuid_entry2 __user *entries); +bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, + u32 *ecx, u32 *edx, bool exact_only); + +void __init kvm_init_xstate_sizes(void); +u32 xstate_required_size(u64 xstate_bv, bool compacted); + +int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu); +int cpuid_query_maxguestphyaddr(struct kvm_vcpu *vcpu); +u64 kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu *vcpu); + +static inline int cpuid_maxphyaddr(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.maxphyaddr; +} + +static inline bool kvm_vcpu_is_legal_gpa(struct kvm_vcpu *vcpu, gpa_t gpa) +{ + return !(gpa & vcpu->arch.reserved_gpa_bits); +} + +static inline bool kvm_vcpu_is_legal_aligned_gpa(struct kvm_vcpu *vcpu, + gpa_t gpa, gpa_t alignment) +{ + return IS_ALIGNED(gpa, alignment) && kvm_vcpu_is_legal_gpa(vcpu, gpa); +} + +static inline bool page_address_valid(struct kvm_vcpu *vcpu, gpa_t gpa) +{ + return kvm_vcpu_is_legal_aligned_gpa(vcpu, gpa, PAGE_SIZE); +} + +static __always_inline void cpuid_entry_override(struct kvm_cpuid_entry2 *entry, + unsigned int leaf) +{ + u32 *reg = cpuid_entry_get_reg(entry, leaf * 32); + + BUILD_BUG_ON(leaf >= ARRAY_SIZE(kvm_cpu_caps)); + *reg = kvm_cpu_caps[leaf]; +} + +static __always_inline bool guest_cpuid_has(struct kvm_vcpu *vcpu, + unsigned int x86_feature) +{ + const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature); + struct kvm_cpuid_entry2 *entry; + u32 *reg; + + /* + * XSAVES is a special snowflake. Due to lack of a dedicated intercept + * on SVM, KVM must assume that XSAVES (and thus XRSTORS) is usable by + * the guest if the host supports XSAVES and *XSAVE* is exposed to the + * guest. Because the guest can execute XSAVES and XRSTORS, i.e. can + * indirectly consume XSS, KVM must ensure XSS is zeroed when running + * the guest, i.e. must set XSAVES in vCPU capabilities. But to reject + * direct XSS reads and writes (to minimize the virtualization hole and + * honor userspace's CPUID), KVM needs to check the raw guest CPUID, + * not KVM's view of guest capabilities. + * + * For all other features, guest capabilities are accurate. Expand + * this allowlist with extreme vigilance. + */ + BUILD_BUG_ON(x86_feature != X86_FEATURE_XSAVES); + + entry = kvm_find_cpuid_entry_index(vcpu, cpuid.function, cpuid.index); + if (!entry) + return false; + + reg = __cpuid_entry_get_reg(entry, cpuid.reg); + if (!reg) + return false; + + return *reg & __feature_bit(x86_feature); +} + +static inline bool guest_cpuid_is_amd_compatible(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.is_amd_compatible; +} + +static inline bool guest_cpuid_is_intel_compatible(struct kvm_vcpu *vcpu) +{ + return !guest_cpuid_is_amd_compatible(vcpu); +} + +static inline int guest_cpuid_family(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, 0x1); + if (!best) + return -1; + + return x86_family(best->eax); +} + +static inline int guest_cpuid_model(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, 0x1); + if (!best) + return -1; + + return x86_model(best->eax); +} + +static inline bool cpuid_model_is_consistent(struct kvm_vcpu *vcpu) +{ + return boot_cpu_data.x86_model == guest_cpuid_model(vcpu); +} + +static inline int guest_cpuid_stepping(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, 0x1); + if (!best) + return -1; + + return x86_stepping(best->eax); +} + +static inline bool cpuid_fault_enabled(struct kvm_vcpu *vcpu) +{ + return (vcpu->arch.msr_misc_features_enables & + MSR_MISC_FEATURES_ENABLES_CPUID_FAULT) || + (vcpu->arch.msr_hwcr & MSR_K7_HWCR_CPUID_USER_DIS); +} + +static inline bool kvm_is_cpuid_allowed(struct kvm_vcpu *vcpu) +{ + return !cpuid_fault_enabled(vcpu) || is_smm(vcpu) || + !kvm_x86_call(get_cpl)(vcpu); +} + +static __always_inline void kvm_cpu_cap_clear(unsigned int x86_feature) +{ + unsigned int x86_leaf = __feature_leaf(x86_feature); + + WARN_ON_ONCE(!kvm_is_configuring_cpu_caps); + kvm_cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature); +} + +static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature) +{ + unsigned int x86_leaf = __feature_leaf(x86_feature); + + WARN_ON_ONCE(!kvm_is_configuring_cpu_caps); + kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature); +} + +static __always_inline u32 kvm_cpu_cap_get(unsigned int x86_feature) +{ + unsigned int x86_leaf = __feature_leaf(x86_feature); + + return kvm_cpu_caps[x86_leaf] & __feature_bit(x86_feature); +} + +static __always_inline bool kvm_cpu_cap_has(unsigned int x86_feature) +{ + return !!kvm_cpu_cap_get(x86_feature); +} + +static __always_inline void kvm_cpu_cap_check_and_set(unsigned int x86_feature) +{ + if (boot_cpu_has(x86_feature)) + kvm_cpu_cap_set(x86_feature); +} + +static __always_inline bool guest_pv_has(struct kvm_vcpu *vcpu, + unsigned int kvm_feature) +{ + if (!vcpu->arch.pv_cpuid.enforce) + return true; + + return vcpu->arch.pv_cpuid.features & (1u << kvm_feature); +} + +static __always_inline void guest_cpu_cap_set(struct kvm_vcpu *vcpu, + unsigned int x86_feature) +{ + unsigned int x86_leaf = __feature_leaf(x86_feature); + + vcpu->arch.cpu_caps[x86_leaf] |= __feature_bit(x86_feature); +} + +static __always_inline void guest_cpu_cap_clear(struct kvm_vcpu *vcpu, + unsigned int x86_feature) +{ + unsigned int x86_leaf = __feature_leaf(x86_feature); + + vcpu->arch.cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature); +} + +static __always_inline void guest_cpu_cap_change(struct kvm_vcpu *vcpu, + unsigned int x86_feature, + bool guest_has_cap) +{ + if (guest_has_cap) + guest_cpu_cap_set(vcpu, x86_feature); + else + guest_cpu_cap_clear(vcpu, x86_feature); +} + +static __always_inline bool guest_cpu_cap_has(struct kvm_vcpu *vcpu, + unsigned int x86_feature) +{ + unsigned int x86_leaf = __feature_leaf(x86_feature); + + /* + * Except for MWAIT, querying dynamic feature bits is disallowed, so + * that KVM can defer runtime updates until the next CPUID emulation. + */ + BUILD_BUG_ON(x86_feature == X86_FEATURE_APIC || + x86_feature == X86_FEATURE_OSXSAVE || + x86_feature == X86_FEATURE_OSPKE); + + return vcpu->arch.cpu_caps[x86_leaf] & __feature_bit(x86_feature); +} + +static inline bool kvm_vcpu_is_legal_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) +{ + if (guest_cpu_cap_has(vcpu, X86_FEATURE_LAM)) + cr3 &= ~(X86_CR3_LAM_U48 | X86_CR3_LAM_U57); + + return kvm_vcpu_is_legal_gpa(vcpu, cr3); +} + +static inline bool guest_has_spec_ctrl_msr(struct kvm_vcpu *vcpu) +{ + return (guest_cpu_cap_has(vcpu, X86_FEATURE_SPEC_CTRL) || + guest_cpu_cap_has(vcpu, X86_FEATURE_AMD_STIBP) || + guest_cpu_cap_has(vcpu, X86_FEATURE_AMD_IBRS) || + guest_cpu_cap_has(vcpu, X86_FEATURE_AMD_SSBD)); +} + +static inline bool guest_has_pred_cmd_msr(struct kvm_vcpu *vcpu) +{ + return (guest_cpu_cap_has(vcpu, X86_FEATURE_SPEC_CTRL) || + guest_cpu_cap_has(vcpu, X86_FEATURE_AMD_IBPB) || + guest_cpu_cap_has(vcpu, X86_FEATURE_SBPB)); +} + +#endif |