Message-ID: <4CEF0F48.8000202@cn.fujitsu.com>
Date: Fri, 26 Nov 2010 09:37:12 +0800
From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
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To: Avi Kivity <avi@redhat.com>
CC: Marcelo Tosatti <mtosatti@redhat.com>, KVM <kvm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/6] KVM: MMU: fix forgot flush tlbs on sync_page path
References: <4CE63CF4.80502@cn.fujitsu.com>
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Hi Avi, Marcelo,

What do you think of this patchset? Could you give me some comments please?

Thanks!

On 11/19/2010 05:01 PM, Xiao Guangrong wrote:
> We should flush all tlbs after drop spte on sync_page path since:
> 
> Quote from Avi:
> | sync_page
> | drop_spte
> | kvm_mmu_notifier_invalidate_page
> | kvm_unmap_rmapp
> | spte doesn't exist -> no flush
> | page is freed
> | guest can write into freed page? 
> 
> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
> ---
>  arch/x86/kvm/paging_tmpl.h |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 590bf12..ca0e5e8 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -786,6 +786,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
>  			else
>  				nonpresent = shadow_notrap_nonpresent_pte;
>  			drop_spte(vcpu->kvm, &sp->spt[i], nonpresent);
> +			kvm_flush_remote_tlbs(vcpu->kvm);
>  			continue;
>  		}
>  

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