From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753015AbXCPH2W (ORCPT ); Fri, 16 Mar 2007 03:28:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753017AbXCPH2W (ORCPT ); Fri, 16 Mar 2007 03:28:22 -0400 Received: from 207.47.60.147.static.nextweb.net ([207.47.60.147]:31779 "EHLO rpc.xensource.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753011AbXCPH2V (ORCPT ); Fri, 16 Mar 2007 03:28:21 -0400 Subject: Re: [Fastboot] [PATCH 1/1] Allow i386 crash kernels to handle x86_64 dumps From: Ian Campbell To: Magnus Damm Cc: Horms , Vivek Goyal , fastboot@lists.osdl.org, linux-kernel@vger.kernel.org In-Reply-To: References: <1173891609.8591.41.camel@localhost.localdomain> <20070315014635.GC28396@verge.net.au> <20070315045536.GA6766@in.ibm.com> <20070315050754.GB22329@verge.net.au> <20070315054726.GC6766@in.ibm.com> <1173961378.8591.63.camel@localhost.localdomain> <20070315132616.GH6766@in.ibm.com> <20070315234807.GB10861@verge.net.au> Content-Type: text/plain Date: Fri, 16 Mar 2007 07:28:17 +0000 Message-Id: <1174030097.28658.37.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 16 Mar 2007 07:28:21.0034 (UTC) FILETIME=[AC8588A0:01C7679C] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2007-03-16 at 11:40 +0900, Magnus Damm wrote: > Right. And maybe it's a good idea to make sure that this feature is > actually supported by kexec-tools before adding code to the kernel? I sent patches to the fastboot list at the same time I sent these ones to support differences in the underlying hypervisor architecture in the tools. They haven't appeared in the archives yet so I fear they have gone astray. I'll resend when I get to the office in a bit. The tools already have support for introducing a SHIM when kexecing between different architectures (at least in the 64->32 direction if I understand kexec-tools-testing/purgatory/arch/i386/compat_x86_64.S and k-t-t.../kexec/arch/i386/compat_x86_64.S correctly). This is really just an extension of that. > My gut feeling about this is that you are begging for trouble. The > kexec/kdump solution is fragile just by itself, and trying to go > between architectures is just going to be painful. It works fine under Xen and I think going from 64Xen+32Kernel->32Kernel makes more sense than going from 64Xen+32Kernel->64Kernel. As I said originally I'm not so convinced it makes sense in the native case but I see no reason to outlaw it (people get to keep both pieces etc...) Ian.