On 1/13/21 6:36 PM, Sean Christopherson wrote: > Add a reverse-CPUID entry for the memory encryption word, 0x8000001F.EAX, > and use it to override the supported CPUID flags reported to userspace. > Masking the reported CPUID flags avoids over-reporting KVM support, e.g. > without the mask a SEV-SNP capable CPU may incorrectly advertise SNP > support to userspace. > > Cc: Brijesh Singh <[email protected]> > Cc: Tom Lendacky <[email protected]> > Signed-off-by: Sean Christopherson <[email protected]> > --- > arch/x86/kvm/cpuid.c | 2 ++ > arch/x86/kvm/cpuid.h | 1 + > 2 files changed, 3 insertions(+)
thanks Reviewed-by: Brijesh Singh <[email protected]> > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 13036cf0b912..b7618cdd06b5 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -855,6 +855,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array > *array, u32 function) > case 0x8000001F: > if (!boot_cpu_has(X86_FEATURE_SEV)) > entry->eax = entry->ebx = entry->ecx = entry->edx = 0; > + else > + cpuid_entry_override(entry, CPUID_8000_001F_EAX); > break; > /*Add support for Centaur's CPUID instruction*/ > case 0xC0000000: > diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h > index dc921d76e42e..8b6fc9bde248 100644 > --- a/arch/x86/kvm/cpuid.h > +++ b/arch/x86/kvm/cpuid.h > @@ -63,6 +63,7 @@ static const struct cpuid_reg reverse_cpuid[] = { > [CPUID_8000_0007_EBX] = {0x80000007, 0, CPUID_EBX}, > [CPUID_7_EDX] = { 7, 0, CPUID_EDX}, > [CPUID_7_1_EAX] = { 7, 1, CPUID_EAX}, > + [CPUID_8000_001F_EAX] = {0x8000001f, 1, CPUID_EAX}, > }; > > /*
