diff options
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 49 |
1 files changed, 30 insertions, 19 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index d0df4f9ad4a7..465e2c1a63e3 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -686,6 +686,7 @@ do { \ const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32); \ const u32 __maybe_unused kvm_cpu_cap_init_in_progress = leaf; \ u32 kvm_cpu_cap_passthrough = 0; \ + u32 kvm_cpu_cap_synthesized = 0; \ u32 kvm_cpu_cap_emulated = 0; \ \ if (leaf < NCAPINTS) \ @@ -694,7 +695,8 @@ do { \ kvm_cpu_caps[leaf] = (mask); \ \ kvm_cpu_caps[leaf] |= kvm_cpu_cap_passthrough; \ - kvm_cpu_caps[leaf] &= raw_cpuid_get(cpuid); \ + kvm_cpu_caps[leaf] &= (raw_cpuid_get(cpuid) | \ + kvm_cpu_cap_synthesized); \ kvm_cpu_caps[leaf] |= kvm_cpu_cap_emulated; \ } while (0) @@ -742,6 +744,17 @@ do { \ }) /* + * Synthesized Feature - For features that are synthesized into boot_cpu_data, + * i.e. may not be present in the raw CPUID, but can still be advertised to + * userspace. Primarily used for mitigation related feature flags. + */ +#define SYNTHESIZED_F(name) \ +({ \ + kvm_cpu_cap_synthesized |= F(name); \ + F(name); \ +}) + +/* * Passthrough Feature - For features that KVM supports based purely on raw * hardware CPUID, i.e. that KVM virtualizes even if the host kernel doesn't * use the feature. Simply force set the feature in KVM's capabilities, raw @@ -1105,35 +1118,32 @@ void kvm_set_cpu_caps(void) kvm_cpu_cap_init(CPUID_8000_0021_EAX, F(NO_NESTED_DATA_BP) | - F(LFENCE_RDTSC) | + /* + * Synthesize "LFENCE is serializing" into the AMD-defined entry + * in KVM's supported CPUID, i.e. if the feature is reported as + * supported by the kernel. LFENCE_RDTSC was a Linux-defined + * synthetic feature long before AMD joined the bandwagon, e.g. + * LFENCE is serializing on most CPUs that support SSE2. On + * CPUs that don't support AMD's leaf, ANDing with the raw host + * CPUID will drop the flags, and reporting support in AMD's + * leaf can make it easier for userspace to detect the feature. + */ + SYNTHESIZED_F(LFENCE_RDTSC) | 0 /* SmmPgCfgLock */ | F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | EMULATED_F(NO_SMM_CTL_MSR) | 0 /* PrefetchCtlMsr */ | - F(WRMSR_XX_BASE_NS) + F(WRMSR_XX_BASE_NS) | + SYNTHESIZED_F(SBPB) | + SYNTHESIZED_F(IBPB_BRTYPE) | + SYNTHESIZED_F(SRSO_NO) ); - kvm_cpu_cap_check_and_set(X86_FEATURE_SBPB); - kvm_cpu_cap_check_and_set(X86_FEATURE_IBPB_BRTYPE); - kvm_cpu_cap_check_and_set(X86_FEATURE_SRSO_NO); - kvm_cpu_cap_init(CPUID_8000_0022_EAX, F(PERFMON_V2) ); - /* - * Synthesize "LFENCE is serializing" into the AMD-defined entry in - * KVM's supported CPUID if the feature is reported as supported by the - * kernel. LFENCE_RDTSC was a Linux-defined synthetic feature long - * before AMD joined the bandwagon, e.g. LFENCE is serializing on most - * CPUs that support SSE2. On CPUs that don't support AMD's leaf, - * kvm_cpu_cap_init() will unfortunately drop the flag due to ANDing - * the mask with the raw host CPUID, and reporting support in AMD's - * leaf can make it easier for userspace to detect the feature. - */ - if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC)) - kvm_cpu_cap_set(X86_FEATURE_LFENCE_RDTSC); if (!static_cpu_has_bug(X86_BUG_NULL_SEG)) kvm_cpu_cap_set(X86_FEATURE_NULL_SEL_CLR_BASE); @@ -1171,6 +1181,7 @@ EXPORT_SYMBOL_GPL(kvm_set_cpu_caps); #undef SF #undef X86_64_F #undef EMULATED_F +#undef SYNTHESIZED_F #undef PASSTHROUGH_F #undef ALIASED_1_EDX_F |