Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753925Ab2E3PMk (ORCPT ); Wed, 30 May 2012 11:12:40 -0400 Received: from mail.skyhub.de ([78.46.96.112]:41122 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751961Ab2E3PMi (ORCPT ); Wed, 30 May 2012 11:12:38 -0400 Date: Wed, 30 May 2012 17:12:36 +0200 From: Borislav Petkov To: Konrad Rzeszutek Wilk Cc: "H. Peter Anvin" , Jan Beulich , Andre Przywara , Jacob Shin , mingo@elte.hu, jeremy@goop.org, tglx@linutronix.de, xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org Subject: Re: [Xen-devel] [PATCH] x86/amd: fix crash as Xen Dom0 on AMD Trinity systems Message-ID: <20120530151235.GB15635@x1.osrc.amd.com> Mail-Followup-To: Borislav Petkov , Konrad Rzeszutek Wilk , "H. Peter Anvin" , Jan Beulich , Andre Przywara , Jacob Shin , mingo@elte.hu, jeremy@goop.org, tglx@linutronix.de, xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org References: <1338383402-3838-1-git-send-email-andre.przywara@amd.com> <4FC63DAF0200007800086DC5@nat28.tlf.novell.com> <4FC62888.9010407@amd.com> <4FC649790200007800086E51@nat28.tlf.novell.com> <4FC631F0.9080109@zytor.com> <20120530144929.GH3207@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120530144929.GH3207@phenom.dumpdata.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1532 Lines: 37 On Wed, May 30, 2012 at 10:49:29AM -0400, Konrad Rzeszutek Wilk wrote: > On Wed, May 30, 2012 at 07:42:56AM -0700, H. Peter Anvin wrote: > > On 05/30/2012 07:23 AM, Jan Beulich wrote: > > > > > > I see - the Xen code blindly overwrites pv_cpu_ops, despite not > > > having initialized all members. That's an obvious oversight of the > > > patch that introduced the _regs variants. > > > > > > Plus having secondary instances of things like rdmsrl_amd_safe() > > > in asm/paravirt.h seems pretty strange an approach (which was > > > why initially I didn't spot how a crash could happen there) - only > > > the lowest level functions should get re-implemented here. > > > > > > > This kinds of things are part of why Xen makes me want to cry regularly. > > It looks like an oversight by Borislav (177fed1ee8d727c39601ce9fc2299b4cb25a718e > and 132ec92f) and Yinghai (b05f78f5c713eda2c34e495d92495ee4f1c3b5e1) where > they added these wrappers way back in 2009! This is exactly why xen has nothing to do in arch/x86/. It is not an oversight - I simply didn't test it on xen because I don't care about it. Remember our last discussion about mcelog? This current case should be a perfect example for why xen shouldn't be sprinkling code all over the place. -- Regards/Gruss, Boris. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/