Re: [PATCH v3 1/6] KVM: MMU: fix forgot flush tlbs on sync_page path

Xiao Guangrong
2010-11-26T01:32:33Z

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;
> }
>