linux-kernel - Re: [PATCH 3/3] KVM: MMU: mark page dirty only when page is really written

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Message-ID: <4C5678E3.8090309@redhat.com>
Date:	Mon, 02 Aug 2010 10:50:59 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	KVM list <kvm@...r.kernel.org>
Subject: Re: [PATCH 3/3] KVM: MMU: mark page dirty only when page is really
 written

  On 07/27/2010 06:35 AM, Xiao Guangrong wrote:
> Mark page dirty only when this page is really written, it's more exacter,
> and also can fix dirty page marking in speculation path
>
> Signed-off-by: Xiao Guangrong<xiaoguangrong@...fujitsu.com>
> ---
>   arch/x86/kvm/mmu.c |   47 ++++++++++++++++++++++++++++-------------------
>   1 files changed, 28 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index dd6c192..bcc2173 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -311,24 +311,42 @@ static bool spte_bits_lost(u64 spte)
>   	if (!is_shadow_present_pte(spte))
>   		return false;
>
> -	if (spte&  shadow_accessed_mask)
> +	if (spte&  shadow_accessed_mask&&
> +	      (!is_writable_pte(spte) || spte&  shadow_dirty_mask))
>   		return false;
>

Please add parentheses around bitwise operators to reduce confusion.  
The rest looks good.

-- 
error compiling committee.c: too many arguments to function

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