From patchwork Wed Feb 3 21:11:03 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rik van Riel X-Patchwork-Id: 76814 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o13LBK5k004918 for ; Wed, 3 Feb 2010 21:11:20 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932912Ab0BCVLS (ORCPT ); Wed, 3 Feb 2010 16:11:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44610 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932908Ab0BCVLR (ORCPT ); Wed, 3 Feb 2010 16:11:17 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o13LB9I2008272 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 3 Feb 2010 16:11:09 -0500 Received: from annuminas.surriel.com (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o13LB7Zu012759; Wed, 3 Feb 2010 16:11:08 -0500 Date: Wed, 3 Feb 2010 16:11:03 -0500 From: Rik van Riel To: jdike@addtoit.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, avi@redhat.com, aarcange@redhat.com, mtosatti@redhat.com Subject: [PATCH] emulate accessed bit for EPT Message-ID: <20100203161103.11e2b572@annuminas.surriel.com> Organization: Red Hat, Inc. Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Wed, 03 Feb 2010 21:11:21 +0000 (UTC) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 89a49fb..6101615 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -856,9 +856,15 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp, u64 *spte; int young = 0; - /* always return old for EPT */ + /* + * Emulate the accessed bit for EPT, by checking if this page has + * an EPT mapping, and clearing it if it does. On the next access, + * a new EPT mapping will be established. + * This has some overhead, but not as much as the cost of swapping + * out actively used pages or breaking up actively used hugepages. + */ if (!shadow_accessed_mask) - return 0; + return kvm_unmap_rmapp(kvm, rmapp, data); spte = rmap_next(kvm, rmapp, NULL); while (spte) {