From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755634Ab2IGPFZ (ORCPT ); Fri, 7 Sep 2012 11:05:25 -0400 Received: from rcsinet15.oracle.com ([148.87.113.117]:30371 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752158Ab2IGPFV (ORCPT ); Fri, 7 Sep 2012 11:05:21 -0400 Date: Fri, 7 Sep 2012 10:54:33 -0400 From: Konrad Rzeszutek Wilk To: "Justin M. Forbes" Cc: 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 Message-ID: <20120907145433.GA5378@phenom.dumpdata.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120907142251.GA20096@linuxtx.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > 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).