[PATCH v3 5/7] x86/cpu, kvm: Define a scattered AMD Automatic IBRS feature bit

Kim Phillips
2022-11-30T00:00:08Z

It's a part of the CPUID 0x80000021 leaf, and this allows us to
group this and other CPUID 0x80000021 EAX feature bits to being
propagated via kvm_set_cpu_caps instead of open-coding them in
__do_cpuid_func().

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/scattered.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 5ddde18c1ae8..961eb49532b7 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -309,6 +309,7 @@
#define X86_FEATURE_MSR_TSX_CTRL (11*32+20) /* "" MSR IA32_TSX_CTRL (Intel) implemented */
#define X86_FEATURE_NO_NESTED_DATA_BP (11*32+21) /* "" AMD No Nested Data Breakpoints */
#define X86_FEATURE_NULL_SEL_CLR_BASE (11*32+22) /* "" AMD Null Selector Clears Base */
+#define X86_FEATURE_AUTOIBRS (11*32+23) /* AMD Automatic IBRS */

/* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
#define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index caa03466cd9e..7ae7203cd410 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -48,6 +48,7 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_NO_NESTED_DATA_BP,CPUID_EAX, 0, 0x80000021, 0 },
{ X86_FEATURE_LFENCE_RDTSC, CPUID_EAX, 2, 0x80000021, 0 },
{ X86_FEATURE_NULL_SEL_CLR_BASE,CPUID_EAX, 6, 0x80000021, 0 },
+ { X86_FEATURE_AUTOIBRS, CPUID_EAX, 8, 0x80000021, 0 },
{ X86_FEATURE_PERFMON_V2, CPUID_EAX, 0, 0x80000022, 0 },
{ X86_FEATURE_AMD_LBR_V2, CPUID_EAX, 1, 0x80000022, 0 },
{ 0, 0, 0, 0, 0 }
--
2.34.1