diff options
| author | Kim Phillips <kim.phillips@amd.com> | 2023-01-24 10:33:16 -0600 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-01-25 16:25:46 +0100 |
| commit | 5b909d4ae59aedc711b7a432da021be0e82c95a0 (patch) | |
| tree | 6058d658298f09fd039686e827fe510010692021 /arch/x86 | |
| parent | 84168ae786f8a15a7eb0f79d34f20b8d261ce2f5 (diff) | |
x86/cpu, kvm: Add the Null Selector Clears Base feature
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@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-6-kim.phillips@amd.com
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 4 | ||||
| -rw-r--r-- | 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 901128ed4c7a..6bed80cf0dc5 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -430,6 +430,7 @@ /* 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 e6f32347ac87..e6bf9b17ac21 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 12455dc5afe5..dde8d6bb22a0 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -743,7 +743,7 @@ 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 */ ); /* @@ -759,7 +759,7 @@ void kvm_set_cpu_caps(void) 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, |