linux-kernel - Re: [PATCH] kvm: x86: Cleanup vcpu->arch.guest_xstate

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Date:   Wed, 29 Apr 2020 10:35:43 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Xiaoyao Li <xiaoyao.li@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kvm: x86: Cleanup vcpu->arch.guest_xstate_size

Xiaoyao Li <xiaoyao.li@...el.com> writes:

> vcpu->arch.guest_xstate_size lost its only user since commit df1daba7d1cb
> ("KVM: x86: support XSAVES usage in the host"), so clean it up.
>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
> ---
>  arch/x86/include/asm/kvm_host.h | 1 -
>  arch/x86/kvm/cpuid.c            | 8 ++------
>  arch/x86/kvm/x86.c              | 2 --
>  3 files changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 7cd68d1d0627..34a05ca3c904 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -654,7 +654,6 @@ struct kvm_vcpu_arch {
>  
>  	u64 xcr0;
>  	u64 guest_supported_xcr0;
> -	u32 guest_xstate_size;
>  
>  	struct kvm_pio_request pio;
>  	void *pio_data;
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 6828be99b908..f3eb4f171d3d 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -84,15 +84,11 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
>  				   kvm_read_cr4_bits(vcpu, X86_CR4_PKE));
>  
>  	best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
> -	if (!best) {
> +	if (!best)
>  		vcpu->arch.guest_supported_xcr0 = 0;
> -		vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
> -	} else {
> +	else
>  		vcpu->arch.guest_supported_xcr0 =
>  			(best->eax | ((u64)best->edx << 32)) & supported_xcr0;
> -		vcpu->arch.guest_xstate_size = best->ebx =
> -			xstate_required_size(vcpu->arch.xcr0, false);
> -	}
>  
>  	best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
>  	if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 856b6fc2c2ba..7cd51a3acc43 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9358,8 +9358,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>  	}
>  	fx_init(vcpu);
>  
> -	vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
> -
>  	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
>  
>  	vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;

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

-- 
Vitaly