Re: [PATCH v3 0/8] Clean up the supported xfeatures

[Sean Christopherson <seanjc@google.com>]

On Fri, Feb 24, 2023, Aaron Lewis wrote:
> Make sure the supported xfeatures, i.e. EDX:EAX of CPUID.(EAX=0DH,ECX=0),
> for MPX, AVX-512, and AMX are in a valid state and follow the rules
> outlined in the SDM vol 1, section 13.3 ENABLING THE XSAVE FEATURE SET
> AND XSAVE-ENABLED FEATURES.  While those rules apply to the enabled
> xfeatures, i.e. XCR0, use them to set the supported xfeatures.  That way
> if they are used by userspace or a guest to set the enabled xfeatures,
> they won't cause a #GP.  
> 
> A test is then added to verify the supported xfeatures are in this
> sanitied state.
> 
> v2 -> v3:
>  - Sanitize the supported XCR0 in XSAVES2 [Sean]
>  - Split AVX-512 into 2 commits [Sean]
>  - Added XFEATURE_MASK_FP to selftests [Sean]
>  - Reworked XCR0 test to split up architectural and kvm rules [Sean]
> 
> Aaron Lewis (8):
>   KVM: x86: Add kvm_permitted_xcr0()
>   KVM: x86: Clear all supported MPX xfeatures if they are not all set
>   KVM: x86: Clear all supported AVX-512 xfeatures if they are not all set
>   KVM: x86: Clear AVX-512 xfeatures if SSE or AVX is clear
>   KVM: x86: Clear all supported AMX xfeatures if they are not all set
>   KVM: selftests: Hoist XGETBV and XSETBV to make them more accessible
>   KVM: selftests: Add XFEATURE masks to common code
>   KVM: selftests: Add XCR0 Test

A few nits on the new selftest, but I can clean those up when posting v4.  I'll
wait to do that until you've had a chance to weigh in on my proposal (see response
to patch 2).

Thanks!