Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754488Ab0F2JRb (ORCPT ); Tue, 29 Jun 2010 05:17:31 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:58947 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752354Ab0F2JRa (ORCPT ); Tue, 29 Jun 2010 05:17:30 -0400 Message-ID: <4C29B948.8070304@cn.fujitsu.com> Date: Tue, 29 Jun 2010 17:13:44 +0800 From: Xiao Guangrong User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , LKML , KVM list Subject: Re: [PATCH v2 3/10] KVM: MMU: fix direct sp's access corruptted References: <4C2498EC.2010006@cn.fujitsu.com> <4C249BAD.6000609@cn.fujitsu.com> <4C287081.40300@redhat.com> <4C287332.5080803@cn.fujitsu.com> <4C2883D3.2050606@redhat.com> <4C2949A5.1070303@cn.fujitsu.com> <4C299B7E.5020303@redhat.com> <4C29A25C.7040900@cn.fujitsu.com> <4C29B390.80602@redhat.com> <4C29B700.8040502@cn.fujitsu.com> <4C29B93C.9010101@redhat.com> In-Reply-To: <4C29B93C.9010101@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1173 Lines: 41 Avi Kivity wrote: > On 06/29/2010 12:04 PM, Xiao Guangrong wrote: >> >>> Simply replace (*spte& SPTE_NO_DIRTY) with a condition that checks >>> whether sp->access is consistent with gw->pt(e)_access. >>> >>> >> If the guest mapping is writable and it !dirty, we mark SPTE_NO_DIRTY >> flag in >> the spte, when the next #PF occurs, we just need check this flag and >> see whether >> gpte's D bit is set, if it's true, we zap this spte and map to the >> correct sp. >> > > My point is, SPTE_NO_DIRTY is equivalent to an sp->role.access check > (the access check is a bit slower, but that shouldn't matter). > I see. > >>> Can you write a test case for qemu-kvm.git/kvm/test that demonstrates >>> the problem and the fix? It will help ensure we don't regress in this >>> area. >>> >>> >> OK, but allow me do it later :-) >> >> > > Sure, but please do it soon. Sure, i will do it as soon as possible. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/