From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751865AbaLPQrj (ORCPT ); Tue, 16 Dec 2014 11:47:39 -0500 Received: from terminus.zytor.com ([198.137.202.10]:37249 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751030AbaLPQri (ORCPT ); Tue, 16 Dec 2014 11:47:38 -0500 Message-ID: <54906212.2010102@zytor.com> Date: Tue, 16 Dec 2014 08:47:14 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Juergen Gross , x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, linux-kernel@vger.kernel.org, akataria@vmware.com, jongman.heo@samsung.com Subject: Re: [PATCH] x86: don't rely on VMWare emulating PAT MSR correctly References: <1418723914-9736-1-git-send-email-jgross@suse.com> In-Reply-To: <1418723914-9736-1-git-send-email-jgross@suse.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/16/2014 01:58 AM, Juergen Gross wrote: > VMWare seems not to emulate the PAT MSR correctly: reaeding > MSR_IA32_CR_PAT returns 0 even after writing another value to it. > > Detect this bug and don't use the read value if it is 0. > > Commit bd809af16e3ab1f8d55b3e2928c47c67e2a865d2 ("x86: Enable PAT to > use cache mode translation tables") triggers this VMWare bug when the > kernel is booted as a VMWare guest. > > Reported-by: Jongman Heo > Signed-off-by: Juergen Gross > Tested-by: Jongman Heo I presume cachability control is irrelevant for a VMware guest? I'm wondering if it would be better to just plain ignore the failure rather than disabling PAT. -hpa