From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id D19696B0036 for ; Thu, 4 Sep 2014 16:21:55 -0400 (EDT) Received: by mail-pa0-f54.google.com with SMTP id fb1so20741729pad.13 for ; Thu, 04 Sep 2014 13:21:54 -0700 (PDT) Received: from mail.zytor.com (terminus.zytor.com. [2001:1868:205::10]) by mx.google.com with ESMTPS id bi17si5418433pdb.236.2014.09.04.13.21.53 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Sep 2014 13:21:53 -0700 (PDT) Message-ID: <5408C9C4.1010705@zytor.com> Date: Thu, 04 Sep 2014 13:21:24 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH 1/5] x86, mm, pat: Set WT to PA4 slot of PAT MSR References: <1409855739-8985-1-git-send-email-toshi.kani@hp.com> <1409855739-8985-2-git-send-email-toshi.kani@hp.com> <20140904201123.GA9116@khazad-dum.debian.net> In-Reply-To: <20140904201123.GA9116@khazad-dum.debian.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Henrique de Moraes Holschuh , Toshi Kani Cc: tglx@linutronix.de, mingo@redhat.com, akpm@linuxfoundation.org, arnd@arndb.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net, konrad.wilk@oracle.com On 09/04/2014 01:11 PM, Henrique de Moraes Holschuh wrote: > > I am worried of uncharted territory, here. I'd actually advocate for not > enabling the upper four PAT entries on IA-32 at all, unless Windows 9X / XP > is using them as well. Is this a real concern, or am I being overly > cautious? > It is extremely unlikely that we'd have PAT issues in 32-bit mode and not in 64-bit mode on the same CPU. As far as I know, the current blacklist rule is very conservative due to lack of testing more than anything else. -hpa -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org