From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757295AbYCUNZ0 (ORCPT ); Fri, 21 Mar 2008 09:25:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755232AbYCUNZP (ORCPT ); Fri, 21 Mar 2008 09:25:15 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:51968 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754583AbYCUNZN (ORCPT ); Fri, 21 Mar 2008 09:25:13 -0400 Date: Fri, 21 Mar 2008 14:24:17 +0100 From: Ingo Molnar To: venkatesh.pallipadi@intel.com Cc: ak@muc.de, ebiederm@xmission.com, rdreier@cisco.com, torvalds@linux-foundation.org, gregkh@suse.de, airlied@skynet.ie, davej@redhat.com, tglx@linutronix.de, hpa@zytor.com, akpm@linux-foundation.org, arjan@infradead.org, jesse.barnes@intel.com, linux-kernel@vger.kernel.org Subject: Re: [patch 00/13] x86: PAT support updated - v3 Message-ID: <20080321132417.GJ27245@elte.hu> References: <20080319000012.439150000@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080319000012.439150000@intel.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * venkatesh.pallipadi@intel.com wrote: > Follow up on earlier PAT patch series here: > http://lkml.org/lkml/2008/1/10/312 > > This patch series adds Page Attribute Table (PAT) support on x86. > There have been few changes based on comments for earlier patches and > also issues that was seen while the earlier patchset was in mm. The > main changes include: > > * Unlike earlier patchset, there are no changes to identity mapping of > reserved regions. > * Unlike earlier patches, there are no chanegs to early ioremap. > * We look at MTRR setting and PAT request and track the resultant type > to avoid aliasing. > * UC_MINUS in PAT to provide backward compatibility to /dem/mem mmap users. > > In general, we have tried to make patches more simpler and cleaner. > Hope is to cause less disruption along the way. The changes/cleaups > that went into x86/mm (specifically pageattr.c) has helped us along > the way. > > The patchset is against x86 testing from couple of days back. thanks Venki, i've queued this up so that we can see how well it goes. It now looks a lot less dangerous and more compatible than it did before - but i'm sure there'll be issues nevertheless :-/ > There are two issues that we are leaving out at the moment to make the patch > simple. We will be addressing them with incremental patches soon: > * FB/DRM drivers using pgprot_val and changing protection on their own > without using any proper APIs like ioremap. There are few such usages and > each one will be addressed separately. > * To change attributes from WC to WB in a "perfect way", one has to follow > certain sequence like make page non-present etc. hm, until this is done correctly i guess we should disallow WC to WB transitions? A good number of erratas apply i suspect :-/ Ingo