From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: [PATCH 6/9] KVM: MMU: Add missing dirty bit Date: Fri, 05 Jan 2007 07:55:45 -0000 Message-ID: <20070105075545.83E2F250048@il.qumranet.com> References: <459E02E7.5020407@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: akpm-3NddpPZAyC0@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org In-Reply-To: <459E02E7.5020407-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org If we emulate a write, we fail to set the dirty bit on the guest pte, leading the guest to believe the page is clean, and thus lose data. Bad. Fix by setting the guest pte dirty bit under such conditions. Signed-off-by: Avi Kivity Index: linux-2.6/drivers/kvm/paging_tmpl.h =================================================================== --- linux-2.6.orig/drivers/kvm/paging_tmpl.h +++ linux-2.6/drivers/kvm/paging_tmpl.h @@ -317,6 +317,7 @@ static int FNAME(fix_write_pf)(struct kv } else if (kvm_mmu_lookup_page(vcpu, gfn)) { pgprintk("%s: found shadow page for %lx, marking ro\n", __FUNCTION__, gfn); + *guest_ent |= PT_DIRTY_MASK; *write_pt = 1; return 0; } ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV