diff options
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
-rw-r--r-- | arch/x86/kvm/cpuid.c | 41 |
1 files changed, 22 insertions, 19 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 596061c1610e..7f1b585f9a67 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -741,6 +741,27 @@ void kvm_set_cpu_caps(void) 0 /* SME */ | F(SEV) | 0 /* VM_PAGE_FLUSH */ | F(SEV_ES) | F(SME_COHERENT)); + kvm_cpu_cap_mask(CPUID_8000_0021_EAX, + F(NO_NESTED_DATA_BP) | F(LFENCE_RDTSC) | 0 /* SmmPgCfgLock */ | + F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */ + ); + + /* + * 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_mask() 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); + kvm_cpu_cap_set(X86_FEATURE_NO_SMM_CTL_MSR); + 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) | @@ -1222,25 +1243,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) break; case 0x80000021: entry->ebx = entry->ecx = entry->edx = 0; - /* - * Pass down these bits: - * EAX 0 NNDBP, Processor ignores nested data breakpoints - * EAX 2 LAS, LFENCE always serializing - * EAX 6 NSCB, Null selector clear base - * - * Other defined bits are for MSRs that KVM does not expose: - * EAX 3 SPCL, SMM page configuration lock - * EAX 13 PCMSR, Prefetch control MSR - * - * KVM doesn't support SMM_CTL. - * EAX 9 SMM_CTL MSR is not supported - */ - entry->eax &= BIT(0) | BIT(2) | BIT(6); - entry->eax |= BIT(9); - if (static_cpu_has(X86_FEATURE_LFENCE_RDTSC)) - entry->eax |= BIT(2); - if (!static_cpu_has_bug(X86_BUG_NULL_SEG)) - entry->eax |= BIT(6); + cpuid_entry_override(entry, CPUID_8000_0021_EAX); break; /*Add support for Centaur's CPUID instruction*/ case 0xC0000000: |