linux-kernel - Re: [PATCH 03/11] KVM: selftests: Mask off OSPKE and OSXSAVE when comparing CPUID entries

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Message-ID: <87ttdsi6lz.fsf@redhat.com>
Date: Fri, 04 Oct 2024 11:02:00 +0200
From: Vitaly Kuznetsov <vkuznets@...hat.com>
To: Sean Christopherson <seanjc@...gle.com>, Sean Christopherson
 <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/11] KVM: selftests: Mask off OSPKE and OSXSAVE when
 comparing CPUID entries

Sean Christopherson <seanjc@...gle.com> writes:

> Mask off OSPKE and OSXSAVE, which are toggled based on corresponding CR4
> enabling bits, when comparing vCPU CPUID against KVM's supported CPUID.
> This will allow setting OSXSAVE by default when creating vCPUs, without
> causing test failures (KVM doesn't enumerate OSXSAVE=1).
>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  tools/testing/selftests/kvm/x86_64/cpuid_test.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/cpuid_test.c b/tools/testing/selftests/kvm/x86_64/cpuid_test.c
> index f7fdcef5fa59..7b3fda6842bc 100644
> --- a/tools/testing/selftests/kvm/x86_64/cpuid_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/cpuid_test.c
> @@ -62,6 +62,12 @@ static struct cpuid_mask get_const_cpuid_mask(const struct kvm_cpuid_entry2 *ent
>  	memset(&mask, 0xff, sizeof(mask));
>  
>  	switch (entry->function) {
> +	case 0x1:
> +		mask.regs[X86_FEATURE_OSXSAVE.reg] &= ~BIT(X86_FEATURE_OSXSAVE.bit);
> +		break;
> +	case 0x7:
> +		mask.regs[X86_FEATURE_OSPKE.reg] &= ~BIT(X86_FEATURE_OSPKE.bit);
> +		break;
>  	case 0xd:
>  		/*
>  		 * CPUID.0xD.{0,1}.EBX enumerate XSAVE size based on the current

Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>

-- 
Vitaly