From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757191Ab2E3Oue (ORCPT ); Wed, 30 May 2012 10:50:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:39021 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754841Ab2E3Oud (ORCPT ); Wed, 30 May 2012 10:50:33 -0400 Message-ID: <4FC633A7.1050406@zytor.com> Date: Wed, 30 May 2012 07:50:15 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: Andre Przywara , mingo@elte.hu, tglx@linutronix.de, jeremy@goop.org, xen-devel@lists.xensource.com, stable@vger.kernel.org#3.4+, linux-kernel@vger.kernel.org Subject: Re: [Xen-devel] [PATCH] x86/amd: fix crash as Xen Dom0 on AMD Trinity systems References: <1338383402-3838-1-git-send-email-andre.przywara@amd.com> <20120530143937.GF3207@phenom.dumpdata.com> In-Reply-To: <20120530143937.GF3207@phenom.dumpdata.com> X-Enigmail-Version: 1.4.1 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 05/30/2012 07:39 AM, Konrad Rzeszutek Wilk wrote: > On Wed, May 30, 2012 at 03:10:02PM +0200, Andre Przywara wrote: >> Because we are behind a family check before tweaking the topology >> bit, we can use the standard rd/wrmsr variants for the CPUID feature >> register. >> This fixes a crash when using the kernel as a Xen Dom0 on affected >> Trinity systems. The wrmsrl_amd_safe is not properly paravirtualized >> yet (this will be fixed in another patch). > > So with a rdmsrl_amd_safe and wrmsrl_amd_safe being implemented in > the pv_cpu_ops - would this patch even be neccessary? > That is still bogus; a better thing would be to implement the _regs interface. Even better would be to trap and emulate rdmsr/wrmsr! -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.