From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f182.google.com (mail-pd0-f182.google.com [209.85.192.182]) by kanga.kvack.org (Postfix) with ESMTP id 1A7BC6B0036 for ; Fri, 5 Sep 2014 11:07:55 -0400 (EDT) Received: by mail-pd0-f182.google.com with SMTP id fp1so15974622pdb.27 for ; Fri, 05 Sep 2014 08:07:54 -0700 (PDT) Received: from mail.zytor.com (terminus.zytor.com. [2001:1868:205::10]) by mx.google.com with ESMTPS id k5si4752771pdn.89.2014.09.05.08.07.52 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 05 Sep 2014 08:07:52 -0700 (PDT) Message-ID: <5409D197.2060900@zytor.com> Date: Fri, 05 Sep 2014 08:07:03 -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> <5408C9C4.1010705@zytor.com> <20140904231923.GA15320@khazad-dum.debian.net> <1409876991.28990.172.camel@misato.fc.hp.com> <1409925614.28990.184.camel@misato.fc.hp.com> In-Reply-To: <1409925614.28990.184.camel@misato.fc.hp.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Toshi Kani , Andy Lutomirski Cc: Henrique de Moraes Holschuh , Thomas Gleixner , Ingo Molnar , akpm@linuxfoundation.org, Arnd Bergmann , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Juergen Gross , Stefan Bader , Konrad Rzeszutek Wilk On 09/05/2014 07:00 AM, Toshi Kani wrote: > > That's a fine idea, but as Ingo also suggested, I am going to disable > this feature on all Pentium 4 models. That should give us a safety > margin. Using slot 4 has a benefit that it keeps the PAT setup > consistent with Xen. > Slot 4 is also the maximally problematic one, because it is the one that might be incorrectly invoked for the page tables themselves. -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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756214AbaIEPIO (ORCPT ); Fri, 5 Sep 2014 11:08:14 -0400 Received: from terminus.zytor.com ([198.137.202.10]:47874 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752006AbaIEPIM (ORCPT ); Fri, 5 Sep 2014 11:08:12 -0400 Message-ID: <5409D197.2060900@zytor.com> Date: Fri, 05 Sep 2014 08:07:03 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.7.0 MIME-Version: 1.0 To: Toshi Kani , Andy Lutomirski CC: Henrique de Moraes Holschuh , Thomas Gleixner , Ingo Molnar , akpm@linuxfoundation.org, Arnd Bergmann , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Juergen Gross , Stefan Bader , Konrad Rzeszutek Wilk 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> <5408C9C4.1010705@zytor.com> <20140904231923.GA15320@khazad-dum.debian.net> <1409876991.28990.172.camel@misato.fc.hp.com> <1409925614.28990.184.camel@misato.fc.hp.com> In-Reply-To: <1409925614.28990.184.camel@misato.fc.hp.com> 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 On 09/05/2014 07:00 AM, Toshi Kani wrote: > > That's a fine idea, but as Ingo also suggested, I am going to disable > this feature on all Pentium 4 models. That should give us a safety > margin. Using slot 4 has a benefit that it keeps the PAT setup > consistent with Xen. > Slot 4 is also the maximally problematic one, because it is the one that might be incorrectly invoked for the page tables themselves. -hpa