On 12/7/20 5:22 PM, Jim Mattson wrote: > On Mon, Dec 7, 2020 at 2:38 PM Babu Moger <babu.moger@xxxxxxx> wrote: >> >> Newer AMD processors have a feature to virtualize the use of the SPEC_CTRL >> MSR. This feature is identified via CPUID 0x8000000A_EDX[20]. When present, >> the SPEC_CTRL MSR is automatically virtualized and no longer requires >> hypervisor intervention. >> >> Signed-off-by: Babu Moger <babu.moger@xxxxxxx> >> --- >> arch/x86/include/asm/cpufeatures.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h >> index dad350d42ecf..d649ac5ed7c7 100644 >> --- a/arch/x86/include/asm/cpufeatures.h >> +++ b/arch/x86/include/asm/cpufeatures.h >> @@ -335,6 +335,7 @@ >> #define X86_FEATURE_AVIC (15*32+13) /* Virtual Interrupt Controller */ >> #define X86_FEATURE_V_VMSAVE_VMLOAD (15*32+15) /* Virtual VMSAVE VMLOAD */ >> #define X86_FEATURE_VGIF (15*32+16) /* Virtual GIF */ >> +#define X86_FEATURE_V_SPEC_CTRL (15*32+20) /* Virtual SPEC_CTRL */ > > Shouldn't this bit be reported by KVM_GET_SUPPORTED_CPUID when it's > enumerated on the host? Jim, I am not sure if this needs to be reported by KVM_GET_SUPPORTED_CPUID. I dont see V_VMSAVE_VMLOAD or VGIF being reported via KVM_GET_SUPPORTED_CPUID. Do you see the need for that? >> /* Intel-defined CPU features, CPUID level 0x00000007:0 (ECX), word 16 */ >> #define X86_FEATURE_AVX512VBMI (16*32+ 1) /* AVX512 Vector Bit Manipulation instructions*/ >>
