From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755010AbYIQWL7 (ORCPT ); Wed, 17 Sep 2008 18:11:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753450AbYIQWLv (ORCPT ); Wed, 17 Sep 2008 18:11:51 -0400 Received: from mx2.redhat.com ([66.187.237.31]:47439 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753082AbYIQWLv (ORCPT ); Wed, 17 Sep 2008 18:11:51 -0400 Message-ID: <48D17E75.80807@redhat.com> Date: Wed, 17 Sep 2008 15:02:29 -0700 From: Avi Kivity User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Nick Piggin , Hugh Dickens , Linux Memory Management List , Linux Kernel Mailing List , Avi Kivity , Andrew Morton , Rik van Riel Subject: Re: Populating multiple ptes at fault time References: <48D142B2.3040607@goop.org> In-Reply-To: <48D142B2.3040607@goop.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: > Minor faults are easier; if the page already exists in memory, we should > just create mappings to it. If neighbouring pages are also already > present, then we can can cheaply create mappings for them too. > > One problem is the accessed bit. If it's unset, the shadow code cannot make the pte present (since it has to trap in order to set the accessed bit); if it's set, we're lying to the vm. This doesn't affect Xen, only kvm. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.