From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f169.google.com (mail-lb0-f169.google.com [209.85.217.169]) by kanga.kvack.org (Postfix) with ESMTP id CD3116B0099 for ; Wed, 10 Sep 2014 16:31:49 -0400 (EDT) Received: by mail-lb0-f169.google.com with SMTP id p9so10560691lbv.14 for ; Wed, 10 Sep 2014 13:31:49 -0700 (PDT) Received: from mail-lb0-f174.google.com (mail-lb0-f174.google.com [209.85.217.174]) by mx.google.com with ESMTPS id 1si17763106lal.89.2014.09.10.13.31.48 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 10 Sep 2014 13:31:48 -0700 (PDT) Received: by mail-lb0-f174.google.com with SMTP id n15so11815957lbi.33 for ; Wed, 10 Sep 2014 13:31:48 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <5410B10A.4030207@zytor.com> References: <1410367910-6026-1-git-send-email-toshi.kani@hp.com> <1410367910-6026-3-git-send-email-toshi.kani@hp.com> <1410377428.28990.260.camel@misato.fc.hp.com> <5410B10A.4030207@zytor.com> From: Andy Lutomirski Date: Wed, 10 Sep 2014 13:31:27 -0700 Message-ID: Subject: Re: [PATCH v2 2/6] x86, mm, pat: Change reserve_memtype() to handle WT Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: "H. Peter Anvin" Cc: Toshi Kani , Thomas Gleixner , Ingo Molnar , Andrew Morton , Arnd Bergmann , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Juergen Gross , Stefan Bader , Henrique de Moraes Holschuh , Yigal Korman , Konrad Rzeszutek Wilk On Wed, Sep 10, 2014 at 1:14 PM, H. Peter Anvin wrote: > On 09/10/2014 12:30 PM, Toshi Kani wrote: >> >> When WT is unavailable due to the PAT errata, it does not fail but gets >> redirected to UC-. Similarly, when PAT is disabled, WT gets redirected >> to UC- as well. >> > > But on pre-PAT hardware you can still do WT. > Using MTRRs? /me shudders, although I suppose this would be okay for NV-DIMMs as long as you map the whole thing WT. One of these days I'll finish excising mtrr_add from everything outside arch/x86. I already killed it in all modern graphics drivers :) --Andy > -hpa > -- Andy Lutomirski AMA Capital Management, LLC -- 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