From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH][v2 3/3] VMX: x86: Only reset MMU when necessary
Date: Wed, 12 May 2010 11:47:36 +0300
Message-ID: <4BEA6B28.9060404@redhat.com>
References: <1273653642-23132-1-git-send-email-sheng@linux.intel.com> <1273653642-23132-4-git-send-email-sheng@linux.intel.com>
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Cc: Marcelo Tosatti <mtosatti@redhat.com>, kvm@vger.kernel.org
To: Sheng Yang <sheng@linux.intel.com>
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On 05/12/2010 11:40 AM, Sheng Yang wrote:
> Only modifying some bits of CR0/CR4 needs paging mode switch.
>
> Modify EFER.NXE bit would result in reserved bit updates.
>
> Signed-off-by: Sheng Yang<sheng@linux.intel.com>
> ---
>   arch/x86/kvm/x86.c |   16 ++++++++++++++--
>   1 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 764f89b..f442da2 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -416,6 +416,10 @@ out:
>
>   static int __kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
>   {
> +	unsigned long old_cr0 = kvm_read_cr0(vcpu);
> +	unsigned long update_bits = X86_CR0_PG | X86_CR0_WP |
> +				    X86_CR0_CD | X86_CR0_NW;
> +
>    

CR0_WP...

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