From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753966AbZEYJJT (ORCPT ); Mon, 25 May 2009 05:09:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752129AbZEYJJJ (ORCPT ); Mon, 25 May 2009 05:09:09 -0400 Received: from one.firstfloor.org ([213.235.205.2]:48004 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752042AbZEYJJI (ORCPT ); Mon, 25 May 2009 05:09:08 -0400 Date: Mon, 25 May 2009 11:15:30 +0200 From: Andi Kleen To: Tomasz Chmielewski Cc: LKML , mingo@elte.hu, Alan , Gerd Hoffmann , jeremy@goop.org, Andi Kleen , "H. Peter Anvin" , JBeulich@novell.com, jbarnes@virtuousgeek.org Subject: Re: [Xen-devel] Re: [GIT PULL] xen /proc/mtrr implementation Message-ID: <20090525091530.GW846@one.firstfloor.org> References: <4A1A59DD.7030101@wpkg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A1A59DD.7030101@wpkg.org> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Are these ones (below) good CPU to worry about? That's slightly > off-topic as they are KVM guests, but still, the guest kernel seems to > disable PAT (unless I'm mistaken). To my knowledge the only CPUs with broken PAT are some very old Pentium Pros dating from back the time when PAT was new and noone used it. On those it should be disabled or the high bits not used. The kernel is overall too conservative with its white list. Today a lot of other common operating systems use PAT extensively, so in general it works on the hardware level. -Andi -- ak@linux.intel.com -- Speaking for myself only.