Re: [PATCH 2/4] KVM: x86: Advertise AMX CPUIDs in subleaf 0x1E.0x1 to userspace

[Jim Mattson]

On Sat, Jan 24, 2026 at 11:25 PM Zhao Liu <zhao1.liu@xxxxxxxxx> wrote:
>
> > Unless someone feels *very* strongly about the "mirror" terminology, I'm going to
> > use ALIAS instead of MIRROR when applying, to match KVM's existing terminology for
> > the 8000_0001.EDX => 1.EDX aliases.
> >
> > /*
> >  * Intel-defined sub-features, CPUID level 0x0000001E:1 (EAX).  Note, several
> >  * of the bits are aliases to features of the same name that are enumerated via
> >  * various CPUID.0x7 sub-leafs.
> >  */
> > #define X86_FEATURE_AMX_INT8_ALIAS    KVM_X86_FEATURE(CPUID_1E_1_EAX, 0)
> > #define X86_FEATURE_AMX_BF16_ALIAS    KVM_X86_FEATURE(CPUID_1E_1_EAX, 1)
> > #define X86_FEATURE_AMX_COMPLEX_ALIAS KVM_X86_FEATURE(CPUID_1E_1_EAX, 2)
> > #define X86_FEATURE_AMX_FP16_ALIAS    KVM_X86_FEATURE(CPUID_1E_1_EAX, 3)
>
> LGTM, yes, ALIAS sounds better than MIRROR.

Our friendly AI reviewer asks: given that these are aliases, shouldn't
they be hidden from the guest if the features they alias to are hidden
(e.g. clearcpuid=amx_int8).