From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753472Ab2IHKSO (ORCPT ); Sat, 8 Sep 2012 06:18:14 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:50526 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753322Ab2IHKSK (ORCPT ); Sat, 8 Sep 2012 06:18:10 -0400 Message-ID: <504B1B58.4030103@redhat.com> Date: Sat, 08 Sep 2012 12:18:00 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: "Justin M. Forbes" , Jan Beulich , Stefan Bader , Matt Wilson , xen-devel@lists.xen.org, Linux Kernel Mailing List Subject: Re: [Xen-devel] [PATCH/RFC] Fix xsave bug on older Xen hypervisors References: <1347018043-21252-1-git-send-email-stefan.bader@canonical.com> <504A05B00200007800099C7B@nat28.tlf.novell.com> <5049F4E9.9050306@canonical.com> <504A1A950200007800099D4C@nat28.tlf.novell.com> <20120907142251.GA20096@linuxtx.org> <20120907145433.GA5378@phenom.dumpdata.com> In-Reply-To: <20120907145433.GA5378@phenom.dumpdata.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 07/09/2012 16:54, Konrad Rzeszutek Wilk ha scritto: >>> But iirc that bad patch is a Linux side one (i.e. you're trying to fix >>> something upstream that isn't upstream)? >>> >> Right, so the patch that this improves upon, and that Fedora and Ubuntu are >> currently carrying is not upstream because: >> >> a) It's crap, it cripples upstream xen users, but doesn't impact RHEL xen >> users because xsave was never supported there. >> >> b) The hypervisor was patched to make it unnecessary quite some time ago, >> and we hoped EC2 would eventually pick up that correct patch and we could >> drop the crap kernel patch. >> >> Unfortunately this has not happened. We are at a point where EC2 really is >> a quirk that has to be worked around. Distros do not want to maintain >> a separate EC2 build of the kernel, so the easiest way is to cripple >> current upstream xen users. This quirk is unfortunately the best possible >> solution. Having it upstream also makes it possible for any user to build >> an upstream kernel that will run on EC2 without having to dig a random >> patch out of a vendor kernel. > > Sure. Jan is asking though for actual confirmation that the upstream kernel > does indeed go belly up without a workaround. > And whether this patch (which I would did since Canonical is carrying it) does > fix the issue. > > I am still a newbie on the Amazon EC2 upload your kernel thing (hint, would > appreciate somebody taking this patch and trying it out). You can just pick an old version of the CentOS kernel package, for example 2.6.18-128.el5 or 2.6.18-164.el5 (respectively CentOS/RHEL 5.3 and 5.4). Paolo