From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758264AbZCBAu1 (ORCPT ); Sun, 1 Mar 2009 19:50:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753777AbZCBAuR (ORCPT ); Sun, 1 Mar 2009 19:50:17 -0500 Received: from terminus.zytor.com ([198.137.202.10]:34441 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750920AbZCBAuQ (ORCPT ); Sun, 1 Mar 2009 19:50:16 -0500 Message-ID: <49AB2C78.9010401@zytor.com> Date: Sun, 01 Mar 2009 16:46:48 -0800 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Andi Kleen , Andrew Morton , Xen-devel , the arch/x86 maintainers , Linux Kernel Mailing List Subject: Re: [PATCH] xen: core dom0 support References: <1235786365-17744-1-git-send-email-jeremy@goop.org> <20090227212812.26d02f34.akpm@linux-foundation.org> <49A8DF28.4050301@goop.org> <87eixi35ew.fsf@basil.nowhere.org> <49AB1B75.2060200@goop.org> <49AB1FB8.607@zytor.com> <49AB2387.8040002@goop.org> <49AB24E0.5020604@zytor.com> <49AB2B7B.2000103@goop.org> In-Reply-To: <49AB2B7B.2000103@goop.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: >> >> What do you define as "full PAT"? If what you mean is that Xen lays >> claims to the PAT MSR and only allows a certain mapping that's hardly >> a problem... other than that it's not an exhaustible resource so I >> guess I really don't understand what you're trying to say here. > > It does not allow guests to set their own PAT MSRs. It can't easily be > multiplexed either, as all CPUs must have the same settings for their > PAT MSRs. I guess it could be handled by allowing domains to set their > own virtual PAT MSRs, and then rewriting the ptes to convert from the > guest PAT settings to Xen's, but I don't know if this is possible in > general (and it poses some problems because the pte modifications would > be guest-visible). > It would make a lot more sense to simply specify a particular set of mappings. Since the only one anyone cares about that isn't in the default set is WC anyway, it's easy to do. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.