From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753934AbZAZTyY (ORCPT ); Mon, 26 Jan 2009 14:54:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753283AbZAZTyP (ORCPT ); Mon, 26 Jan 2009 14:54:15 -0500 Received: from gw.goop.org ([64.81.55.164]:41002 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753053AbZAZTyO (ORCPT ); Mon, 26 Jan 2009 14:54:14 -0500 Message-ID: <497E14E3.2080509@goop.org> Date: Mon, 26 Jan 2009 11:54:11 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Jan Beulich CC: Ingo Molnar , Xen-devel , Linux Kernel Mailing List , Nick Piggin Subject: Re: [Xen-devel] [PATCH 2/2] x86: add pte_set_flags/clear_flags forpteflag manipulation References: <4978F216.5040803@goop.org> <49798A5E.76E4.0078.0@novell.com> <497A3117.2070809@goop.org> <497D798C.76E4.0078.0@novell.com> In-Reply-To: <497D798C.76E4.0078.0@novell.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jan Beulich wrote: > Whether a pte is live doesn't matter here: If you change P on Xen, the > frame number representation *must* change from/to PFN to/from MFN. > In no case (other than iomem pages) is it allowed to flip just this bit. Yes, true. Same with _PAGE_SPECIAL, which is actually flipped by code here. I guess a warning here might be useful, but really the calling code needs to be properly disciplined; after all setting P on a swap entry is no fun either. J