From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH][v2 3/3] KVM: x86: Use FPU API
Date: Mon, 17 May 2010 12:37:29 +0300
Message-ID: <4BF10E59.1090200@redhat.com>
References: <1274087308-26676-1-git-send-email-sheng@linux.intel.com> <1274087308-26676-4-git-send-email-sheng@linux.intel.com>
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Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
To: Sheng Yang <sheng@linux.intel.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <1274087308-26676-4-git-send-email-sheng@linux.intel.com>
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List-Id: kvm.vger.kernel.org

On 05/17/2010 12:08 PM, Sheng Yang wrote:
> Convert KVM to use generic FPU API.
>
>   void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
>   {
>   	if (vcpu->guest_fpu_loaded)
> @@ -5156,7 +5134,7 @@ void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
>
>   	vcpu->guest_fpu_loaded = 1;
>   	unlazy_fpu(current);
> -	kvm_fx_restore(&vcpu->arch.guest_fx_image);
> +	fpu_restore_checking(&vcpu->arch.guest_fpu);
>   	trace_kvm_fpu(1);
>   }
>    

Do we need to do something on error here?

I think an error can only occur if userspace sets bad fpu state, so 
maybe do the check in the ioctl.

In any case, unrelated to this patch.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.