CMPccXADD is a new set of instructions in the latest Intel platform Sierra Forest. It includes a semaphore operation that can compare and add the operands if condition is met, which can improve database performance. The bit definition: CPUID.(EAX=7,ECX=1):EAX[bit 7] This patch enables this CPUID in the kernel feature bits and expose it to guest OS. Signed-off-by: Jiaxi Chen <jiaxi.chen@xxxxxxxxxxxxxxx> --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/kvm/cpuid.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index ef4775c6db01..445626cb5779 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -308,6 +308,7 @@ /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */ #define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */ #define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */ +#define X86_FEATURE_CMPCCXADD (12*32+ 7) /* CMPccXADD instructions */ /* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */ #define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */ diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 7065462378e2..3f745f6fdc43 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -657,7 +657,7 @@ void kvm_set_cpu_caps(void) kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD); kvm_cpu_cap_mask(CPUID_7_1_EAX, - F(AVX_VNNI) | F(AVX512_BF16) + F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) ); kvm_cpu_cap_mask(CPUID_D_1_EAX, -- 2.27.0
