On Wed, Dec 19, 2018 at 1:02 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 19/12/18 18:39, Jim Mattson wrote: > > Is this an instruction that kvm has to be able to emulate before it > > can enumerate its existence? > > It doesn't have any operands, so no. > > Paolo > > > On Wed, Dec 19, 2018 at 5:51 AM Robert Hoo <robert.hu@xxxxxxxxxxxxxxx> wrote: > >> > >> Signed-off-by: Robert Hoo <robert.hu@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 28c4a50..932b19f 100644 > >> --- a/arch/x86/include/asm/cpufeatures.h > >> +++ b/arch/x86/include/asm/cpufeatures.h > >> @@ -280,6 +280,7 @@ > >> /* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */ > >> #define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */ > >> #define X86_FEATURE_IRPERF (13*32+ 1) /* Instructions Retired Count */ > >> +#define X86_FEATURE_WBNOINVD (13*32+ 9) /* Writeback and Don't invalid cache */ > >> #define X86_FEATURE_XSAVEERPTR (13*32+ 2) /* Always save/restore FP error pointers */ > >> #define X86_FEATURE_AMD_IBPB (13*32+12) /* "" Indirect Branch Prediction Barrier */ > >> #define X86_FEATURE_AMD_IBRS (13*32+14) /* "" Indirect Branch Restricted Speculation */ > >> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > >> index cc6dd65..763e115 100644 > >> --- a/arch/x86/kvm/cpuid.c > >> +++ b/arch/x86/kvm/cpuid.c > >> @@ -380,7 +380,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > >> > >> /* cpuid 0x80000008.ebx */ > >> const u32 kvm_cpuid_8000_0008_ebx_x86_features = > >> - F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) | > >> + F(WBNOINVD) | F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) | > >> F(AMD_SSB_NO) | F(AMD_STIBP); > >> > >> /* cpuid 0xC0000001.edx */ > >> -- > >> 1.8.3.1 > >> What is the point of enumerating support for WBNOINVD if kvm is going to implement it as WBINVD?
