From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755523Ab1GFBPe (ORCPT ); Tue, 5 Jul 2011 21:15:34 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:63670 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752655Ab1GFBPd (ORCPT ); Tue, 5 Jul 2011 21:15:33 -0400 Message-ID: <4E13B7A1.9010504@cn.fujitsu.com> Date: Wed, 06 Jul 2011 09:17:21 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: Marcelo Tosatti CC: Avi Kivity , LKML , KVM Subject: Re: [PATCH v3 04/19] KVM: MMU: cache mmio info on page fault path References: <4E0C3178.2080603@cn.fujitsu.com> <4E0C31EA.5070403@cn.fujitsu.com> <20110705190457.GA24417@amt.cnet> In-Reply-To: <20110705190457.GA24417@amt.cnet> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-07-06 09:14:44, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-07-06 09:14:46, Serialize complete at 2011-07-06 09:14:46 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 On 07/06/2011 03:04 AM, Marcelo Tosatti wrote: return 0; >> >> /* mmio */ >> - if (is_error_pfn(pfn)) >> - return kvm_handle_bad_page(vcpu->kvm, walker.gfn, pfn); >> + if (is_error_pfn(pfn)) { >> + unsigned access = walker.pte_access; >> + bool dirty = is_dirty_gpte(walker.ptes[walker.level - 1]); >> + >> + if (dirty) >> + access &= ~ACC_WRITE_MASK; >> + >> + return kvm_handle_bad_page(vcpu, mmu_is_nested(vcpu) ? 0 : >> + addr, access, walker.gfn, pfn); >> + } > > Don't get this... if guest pte is dirty you cache without allowing > write access? Why? > Ah, sorry, the logic should be: if pte is not diry, clear write access, will fix it. Thanks, Marcelo!