From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754829Ab3ADOej (ORCPT ); Fri, 4 Jan 2013 09:34:39 -0500 Received: from smtp.eu.citrix.com ([46.33.159.39]:16448 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754613Ab3ADOeg (ORCPT ); Fri, 4 Jan 2013 09:34:36 -0500 X-IronPort-AV: E=Sophos;i="4.84,409,1355097600"; d="scan'208";a="457628" Message-ID: <1357310073.14291.42.camel@zakaz.uk.xensource.com> Subject: Re: [Xen-devel] [PATCH v3 00/11] xen: Initial kexec/kdump implementation From: Ian Campbell To: Daniel Kiper CC: Andrew Cooper , "xen-devel@lists.xensource.com" , "konrad.wilk@oracle.com" , "maxim.uvarov@oracle.com" , "x86@kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "mingo@redhat.com" , "Eric W. Biederman" , "jbeulich@suse.com" , "H. Peter Anvin" , "tglx@linutronix.de" , "vgoyal@redhat.com" Date: Fri, 4 Jan 2013 14:34:33 +0000 In-Reply-To: <20130104142257.GC3346@host-192-168-1-59.local.net-space.pl> References: <1356574740-6806-1-git-send-email-daniel.kiper@oracle.com> <50DBC856.6030208@zytor.com> <791b4922-078f-4adc-b3f3-0651f2266147@email.android.com> <50DC58C4.3000307@citrix.com> <874nj7qsor.fsf@xmission.com> <50E41973.9050705@citrix.com> <20130104142257.GC3346@host-192-168-1-59.local.net-space.pl> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2013-01-04 at 14:22 +0000, Daniel Kiper wrote: > On Wed, Jan 02, 2013 at 11:26:43AM +0000, Andrew Cooper wrote: > > On 27/12/12 18:02, Eric W. Biederman wrote: > > >Andrew Cooper writes: > > > > > >>On 27/12/2012 07:53, Eric W. Biederman wrote: > > >>>The syscall ABI still has the wrong semantics. > > >>> > > >>>Aka totally unmaintainable and umergeable. > > >>> > > >>>The concept of domU support is also strange. What does domU support even mean, when the dom0 support is loading a kernel to pick up Xen when Xen falls over. > > >>There are two requirements pulling at this patch series, but I agree > > >>that we need to clarify them. > > >It probably make sense to split them apart a little even. > > > > > > > > > > Thinking about this split, there might be a way to simply it even more. > > > > /sbin/kexec can load the "Xen" crash kernel itself by issuing > > hypercalls using /dev/xen/privcmd. This would remove the need for > > the dom0 kernel to distinguish between loading a crash kernel for > > itself and loading a kernel for Xen. > > > > Or is this just a silly idea complicating the matter? > > This is impossible with current Xen kexec/kdump interface. > It should be changed to do that. However, I suppose that > Xen community would not be interested in such changes. The current HYPERVISOR_kexec interface is pretty fricken bad (it basically hardcodes the Linux Circa-2.6.18 internal interface!). I'd be all for a new HYPERVISOR_kexec (with the old gaining a _compat suffix) which implements something more generic that isn't tied to a particular dom0 kernel implementation (be it differing versions of Linux or e.g. *BSD). If that enables /sbin/kexec to load the kernel directly then so much the better, assuming the /sbin/kexec maintainers are happy with that approach. Ian.