From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756454Ab0KLK0H (ORCPT ); Fri, 12 Nov 2010 05:26:07 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:58915 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752444Ab0KLK0E (ORCPT ); Fri, 12 Nov 2010 05:26:04 -0500 Message-ID: <4CDD173E.8010706@cn.fujitsu.com> Date: Fri, 12 Nov 2010 18:30:22 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.11) Gecko/20100713 Thunderbird/3.0.6 MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , LKML , KVM Subject: [PATCH 1/4] KVM: MMU: don't drop spte if overwrite it from W to RO X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-11-12 18:26:30, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-11-12 18:26:30, Serialize complete at 2010-11-12 18:26:30 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We just need flush tlb if overwrite a writable spte with a read-only one Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 19 +++++++++---------- 1 files changed, 9 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 4b6d54c..1a93ab4 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2044,6 +2044,15 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, if (pte_access & ACC_WRITE_MASK) mark_page_dirty(vcpu->kvm, gfn); + /* + * If we overwrite a writable spte with a read-only one, + * flush remote TLBs. Otherwise rmap_write_protect will + * find a read-only spte, even though the writable spte + * might be cached on a CPU's TLB. + */ + else if (is_writable_pte(*sptep)) + ret = 1; + set_pte: update_spte(sptep, spte); done: @@ -2084,16 +2093,6 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, spte_to_pfn(*sptep), pfn); drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte); kvm_flush_remote_tlbs(vcpu->kvm); - /* - * If we overwrite a writable spte with a read-only one, - * drop it and flush remote TLBs. Otherwise rmap_write_protect - * will find a read-only spte, even though the writable spte - * might be cached on a CPU's TLB. - */ - } else if (is_writable_pte(*sptep) && - (!(pte_access & ACC_WRITE_MASK) || !dirty)) { - drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte); - kvm_flush_remote_tlbs(vcpu->kvm); } else was_rmapped = 1; } -- 1.7.0.4