From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754802Ab2DSKnF (ORCPT ); Thu, 19 Apr 2012 06:43:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21117 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752692Ab2DSKnB (ORCPT ); Thu, 19 Apr 2012 06:43:01 -0400 Message-ID: <4F8FEC22.400@redhat.com> Date: Thu, 19 Apr 2012 13:42:42 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: HATAYAMA Daisuke CC: zhangyanfei@cn.fujitsu.com, mtosatti@redhat.com, ebiederm@xmission.com, luto@mit.edu, joerg.roedel@amd.com, dzickus@redhat.com, paul.gortmaker@windriver.com, gregkh@suse.de, ludwig.nussel@suse.de, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [PATCH 0/4] Export offsets of VMCS fields as note information for kdump References: <4F8E7A5B.5030904@redhat.com> <4F8E8E3D.8040707@cn.fujitsu.com> <4F8EABF7.805@redhat.com> <20120419.193640.59653378.d.hatayama@jp.fujitsu.com> In-Reply-To: <20120419.193640.59653378.d.hatayama@jp.fujitsu.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/19/2012 01:36 PM, HATAYAMA Daisuke wrote: > From: Avi Kivity > Subject: Re: [PATCH 0/4] Export offsets of VMCS fields as note information for kdump > Date: Wed, 18 Apr 2012 14:56:39 +0300 > > > On 04/18/2012 12:49 PM, zhangyanfei wrote: > >> >> > >> > > >> > What type of resource? Can you give an example? > >> > > >> Sorry. No concrete example for now. > >> > >> We are developing this on a conservative policy and I have put the vmcs processing > >> in a new module in patch set v2 as you required. The new module is auto-loaded when > >> the vmx cpufeature is detected and it depends on module kvm-intel. Loading and unloading > >> this module will have no side effect on the running guests. > >> > >> And one thing I have to stress is that, we can see guest image as crash dump from > >> guest machine's view if we have the vmcsinfo, this itself is useful. > > > > Why is it useful? Without a concrete example, it's hard to justify the > > code bloat. > > > > The reason why we want to retrieve guest machine's memory image as > crash dump is that then we can debug guest machine's status using > symbolic debugger such as gdb and crash utility. > > This is very useful. Please consider the situation where engineers are > forced to look into guest machine's memory image through qemu-kvm's > process core dump using gdb without any symbolic information. It's > very inefficient. I still don't follow. If qemu crashed, the values in guest registers are irrelevant. In what way can the help debug the qemu crash? -- error compiling committee.c: too many arguments to function