The Null Selector Clears Base feature was being open-coded for KVM. Add it to its newly added native CPUID leaf 0x80000021 EAX proper. Also drop the bit description comments now it's more self-describing. [ bp: Convert test in check_null_seg_clears_base() too. ] Signed-off-by: Kim Phillips <kim.phillips@xxxxxxx> --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/kernel/cpu/common.c | 4 +--- arch/x86/kvm/cpuid.c | 4 ++-- 3 files changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 4f22d828c753..403a534691cc 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -431,6 +431,7 @@ /* AMD-defined Extended Feature 2 EAX, CPUID level 0x80000021 (EAX), word 20 */ #define X86_FEATURE_NO_NESTED_DATA_BP (20*32+ 0) /* "" No Nested Data Breakpoints */ #define X86_FEATURE_LFENCE_RDTSC (20*32+ 2) /* "" LFENCE always serializing / synchronizes RDTSC */ +#define X86_FEATURE_NULL_SEL_CLR_BASE (20*32+ 6) /* "" Null Selector Clears Base */ /* * BUG word(s) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 094dbcd63f2a..162352d42ce0 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1685,9 +1685,7 @@ void check_null_seg_clears_base(struct cpuinfo_x86 *c) if (!IS_ENABLED(CONFIG_X86_64)) return; - /* Zen3 CPUs advertise Null Selector Clears Base in CPUID. */ - if (c->extended_cpuid_level >= 0x80000021 && - cpuid_eax(0x80000021) & BIT(6)) + if (cpu_has(c, X86_FEATURE_NULL_SEL_CLR_BASE)) return; /* diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 601eeb03ebc9..f1625a58b5ec 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -743,12 +743,12 @@ void kvm_set_cpu_caps(void) kvm_cpu_cap_mask(CPUID_8000_0021_EAX, F(NO_NESTED_DATA_BP) | F(LFENCE_RDTSC) | 0 /* SmmPgCfgLock */ | - BIT(6) /* NULL_SEL_CLR_BASE */ | 0 /* PrefetchCtlMsr */ + F(NULL_SEL_CLR_BASE) | 0 /* PrefetchCtlMsr */ ); 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_caps[CPUID_8000_0021_EAX] |= BIT(6) /* NULL_SEL_CLR_BASE */; + kvm_cpu_cap_set(X86_FEATURE_NULL_SEL_CLR_BASE); kvm_cpu_caps[CPUID_8000_0021_EAX] |= BIT(9) /* NO_SMM_CTL_MSR */; kvm_cpu_cap_mask(CPUID_C000_0001_EDX, -- 2.34.1
