From patchwork Tue Feb 16 10:35:35 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Avi Kivity X-Patchwork-Id: 79585 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 o1GAbnhE017437 for ; Tue, 16 Feb 2010 10:37:49 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932846Ab0BPKfy (ORCPT ); Tue, 16 Feb 2010 05:35:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35308 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932833Ab0BPKfl (ORCPT ); Tue, 16 Feb 2010 05:35:41 -0500 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o1GAZflh011603 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 16 Feb 2010 05:35:41 -0500 Received: from cleopatra.tlv.redhat.com (cleopatra.tlv.redhat.com [10.35.255.11]) by int-mx05.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o1GAZcQF020429; Tue, 16 Feb 2010 05:35:40 -0500 Received: from localhost.localdomain (file.tlv.redhat.com [10.35.255.8]) by cleopatra.tlv.redhat.com (Postfix) with ESMTP id 37502250AF5; Tue, 16 Feb 2010 12:35:37 +0200 (IST) From: Avi Kivity To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH 37/38] KVM: VMX: emulate accessed bit for EPT Date: Tue, 16 Feb 2010 12:35:35 +0200 Message-Id: <1266316536-28936-38-git-send-email-avi@redhat.com> In-Reply-To: <1266316536-28936-1-git-send-email-avi@redhat.com> References: <1266316536-28936-1-git-send-email-avi@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.18 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]); Tue, 16 Feb 2010 10:37:49 +0000 (UTC) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 913ef4b..b8da671 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -838,9 +838,15 @@ 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) {