linux-kernel - Re: [PATCH 3/4] kvm: cpuid: fix xsave area size of XSAVEC

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Date:	Thu, 04 Dec 2014 14:57:13 +0100
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	kvm@...r.kernel.org
Subject: Re: [PATCH 3/4] kvm: cpuid: fix xsave area size of XSAVEC



On 04/12/2014 09:24, Wanpeng Li wrote:
> XSAVEC also use the compacted format for the extended region
> of the XSAVE area. This patch fix it by caculate the size of 
> XSAVEC extended region of XSAVE area as compact format.
> 
> Signed-off-by: Wanpeng Li <wanpeng.li@...ux.intel.com>
> ---
>  arch/x86/kvm/cpuid.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 70f0fa1..e16a0c7 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -92,7 +92,7 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
>  	}
>  
>  	best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
> -	if (best && (best->eax & F(XSAVES)))
> +	if (best && (best->eax & (F(XSAVES) || F(XSAVEC))))

"|" instead of "||" as mentioned by Nadav.

Is the Intel manual implicitly relying on the fact that there is no
processor that has XSAVES but not XSAVEC?

Paolo

>  		best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
>  
>  	/*
> 

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