From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752615Ab2L0EDL (ORCPT ); Wed, 26 Dec 2012 23:03:11 -0500 Received: from terminus.zytor.com ([198.137.202.10]:52388 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751743Ab2L0EDJ (ORCPT ); Wed, 26 Dec 2012 23:03:09 -0500 Message-ID: <50DBC856.6030208@zytor.com> Date: Wed, 26 Dec 2012 20:02:30 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Daniel Kiper CC: andrew.cooper3@citrix.com, ebiederm@xmission.com, jbeulich@suse.com, konrad.wilk@oracle.com, maxim.uvarov@oracle.com, mingo@redhat.com, tglx@linutronix.de, vgoyal@redhat.com, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, xen-devel@lists.xensource.com Subject: Re: [PATCH v3 00/11] xen: Initial kexec/kdump implementation References: <1356574740-6806-1-git-send-email-daniel.kiper@oracle.com> In-Reply-To: <1356574740-6806-1-git-send-email-daniel.kiper@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/26/2012 06:18 PM, Daniel Kiper wrote: > Hi, > > This set of patches contains initial kexec/kdump implementation for Xen v3. > Currently only dom0 is supported, however, almost all infrustructure > required for domU support is ready. > > Jan Beulich suggested to merge Xen x86 assembler code with baremetal x86 code. > This could simplify and reduce a bit size of kernel code. However, this solution > requires some changes in baremetal x86 code. First of all code which establishes > transition page table should be moved back from machine_kexec_$(BITS).c to > relocate_kernel_$(BITS).S. Another important thing which should be changed in that > case is format of page_list array. Xen kexec hypercall requires to alternate physical > addresses with virtual ones. These and other required stuff have not been done in that > version because I am not sure that solution will be accepted by kexec/kdump maintainers. > I hope that this email spark discussion about that topic. > I want a detailed list of the constraints that this assumes and therefore imposes on the native implementation as a result of this. We have had way too many patches where Xen PV hacks effectively nailgun arbitrary, and sometimes poor, design decisions in place and now we can't fix them. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.