On Fri, Sep 30, 2022 at 2:04 PM Dong, Eddie <eddie.dong@xxxxxxxxx> wrote:
>
>
>
> > -----Original Message-----
> > From: Jim Mattson <jmattson@xxxxxxxxxx>
> > Sent: Thursday, September 29, 2022 3:52 PM
> > To: kvm@xxxxxxxxxxxxxxx; pbonzini@xxxxxxxxxx; Christopherson,, Sean
> > <seanjc@xxxxxxxxxx>
> > Cc: Jim Mattson <jmattson@xxxxxxxxxx>
> > Subject: [PATCH 1/6] KVM: x86: Mask off reserved bits in CPUID.80000001H
> >
> > KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM
> > actually supports. CPUID.80000001:EBX[27:16] are reserved bits and should
> > be masked off.
> >
> > Fixes: 0771671749b5 ("KVM: Enhance guest cpuid management")
> > Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
> > ---
> > arch/x86/kvm/cpuid.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index
> > 4c1c2c06e96b..ea4e213bcbfb 100644
> > --- a/arch/x86/kvm/cpuid.c
> > +++ b/arch/x86/kvm/cpuid.c
> > @@ -1119,6 +1119,7 @@ static inline int __do_cpuid_func(struct
> > kvm_cpuid_array *array, u32 function)
> > entry->eax = max(entry->eax, 0x80000021);
> > break;
> > case 0x80000001:
> > + entry->ebx &= ~GENMASK(27, 16);
>
> ebx of leaf 0x80000001 is reserved, at least from SDM of Intel processor. Do I miss something?
This is an AMD defined leaf, so the APM is authoritative.
> > cpuid_entry_override(entry, CPUID_8000_0001_EDX);
> > cpuid_entry_override(entry, CPUID_8000_0001_ECX);
> > break;
> > --
> > 2.38.0.rc1.362.ged0d419d3c-goog
>
