Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935021Ab2JaICR (ORCPT ); Wed, 31 Oct 2012 04:02:17 -0400 Received: from nat28.tlf.novell.com ([130.57.49.28]:60266 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933836Ab2JaICI convert rfc822-to-8bit (ORCPT ); Wed, 31 Oct 2012 04:02:08 -0400 Message-Id: <5090E93302000078000A59C8@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Wed, 31 Oct 2012 08:02:43 +0000 From: "Jan Beulich" To: "Olaf Hering" Cc: "Jeremy Fitzhardinge" , "xen-devel" , "Konrad Rzeszutek Wilk" , Subject: Re: [Xen-devel] [PATCH v4] xen PVonHVM: move shared_info to reserved memory area References: <1351612057-21822-1-git-send-email-olaf@aepfle.de> <50900B1D02000078000A586C@nat28.tlf.novell.com> <20121030163006.GA26404@aepfle.de> <5090124C02000078000A58AC@nat28.tlf.novell.com> <20121030170321.GA1251@aepfle.de> In-Reply-To: <20121030170321.GA1251@aepfle.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1231 Lines: 29 >>> On 30.10.12 at 18:03, Olaf Hering wrote: > On Tue, Oct 30, Jan Beulich wrote: > >> And iirc you're doing this relocation because otherwise the newly >> booting kernel image may get overwritten at an (from its >> perspective) arbitrary location. What I'm trying to point out is >> that the shared info structure is not the only thing (potentially) >> inside the kernel image that might get overwritten - the relocated >> (by the old kernel) vCPU info may as well. Plus I think the new >> kernel has no way of relocating it a second time (including back >> into the shared info structure) with how the hypervisor works at >> present. > > Thanks, I have not looked at this, nor was I aware of it until now. > I will see what needs to be done. > > Is this also an issue with the xenlinux based PVonHVM code? No - this code doesn't make use of that feature (yet, we've got a feature request that would involve doing so), as it only ever touches vCPU 0's info. Jan -- 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/