From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757199AbbCCS1z (ORCPT ); Tue, 3 Mar 2015 13:27:55 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:44021 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757088AbbCCS1x convert rfc822-to-8bit (ORCPT ); Tue, 3 Mar 2015 13:27:53 -0500 User-Agent: K-9 Mail for Android In-Reply-To: <20150303181542.GZ8749@wotan.suse.de> References: <1424707260-4302-1-git-send-email-boris.ostrovsky@oracle.com> <54EB5EC7.2020300@citrix.com> <54F5C4D6.9010907@oracle.com> <20150303181542.GZ8749@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Subject: Re: [Xen-devel] [PATCH] x86/xen: Initialize cr4 shadow for 64-bit PV(H) guests From: Konrad Rzeszutek Wilk Date: Tue, 03 Mar 2015 13:27:39 -0500 To: "Luis R. Rodriguez" , Boris Ostrovsky CC: David Vrabel , xen-devel@lists.xenproject.org, "linux-kernel@vger.kernel.org" , Andy Lutomirski , Andrey Ryabinin Message-ID: <9AC75058-026E-4CFA-9F3E-D9AEABC84CE3@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On March 3, 2015 1:15:42 PM EST, "Luis R. Rodriguez" wrote: >On Tue, Mar 03, 2015 at 09:27:34AM -0500, Boris Ostrovsky wrote: >> On 03/03/2015 12:35 AM, Luis R. Rodriguez wrote: >>> On Mon, Feb 23, 2015 at 9:09 AM, David Vrabel > wrote: >>>> On 23/02/15 16:01, Boris Ostrovsky wrote: >>>>> Commit 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4") >>>>> introduced CR4 shadows. >>>>> >>>>> These shadows are initialized in early boot code. The commit >missed >>>>> initialization for 64-bit PV(H) guests that this patch adds. >>>> Applied to stable/for-linus-4.0, thanks. >>>> >>>> Boris, can you kick of a set of tests on this branch, please? >>> Do we know worst case what should blow up without this commit ? >> >> PVH guest will crash. > >Oh wow that is serious. And this is a reactive measure to a change >upstream, >it might be hard but it'd be nice if we can have a proactive >architecture >to address this. Don't mind me though, I realize this seems hard, just >thinking out loud right now. Did you find it through code inspection or >a test? Boris runs every night on different hardware an regression test against the latest Linux kernel. > > Luis L