On Tue, Jul 23, 2019 at 2:42 PM Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx> wrote: > > > > On 07/15/2019 02:03 PM, Aaron Lewis wrote: > > Add features X86_FEATURE_FDP_EXCPTN_ONLY and X86_FEATURE_ZERO_FCS_FDS to the > > mask for CPUID.(EAX=07H,ECX=0H):EBX. Doing this will ensure the guest's CPUID > > for these bits match the host, rather than the guest being blindly set to 0. > > > > This is important as these are actually defeature bits, which means that > > a 0 indicates the presence of a feature and a 1 indicates the absence of > > a feature. since these features cannot be emulated, kvm should not > > claim the existence of a feature that isn't present on the host. > > > > Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx> > > Reviewed-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx> > > --- > > arch/x86/kvm/cpuid.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > > index ead681210306..64c3fad068e1 100644 > > --- a/arch/x86/kvm/cpuid.c > > +++ b/arch/x86/kvm/cpuid.c > > @@ -353,7 +353,8 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index) > > F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) | > > F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) | > > F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) | > > - F(SHA_NI) | F(AVX512BW) | F(AVX512VL) | f_intel_pt; > > + F(SHA_NI) | F(AVX512BW) | F(AVX512VL) | f_intel_pt | > > + F(FDP_EXCPTN_ONLY) | F(ZERO_FCS_FDS); > > > > /* cpuid 7.0.ecx*/ > > const u32 kvm_cpuid_7_0_ecx_x86_features = > > Reviewed-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx> ping
