From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/4] Export offsets of VMCS fields as note information for kdump Date: Thu, 19 Apr 2012 13:42:42 +0300 Message-ID: <4F8FEC22.400@redhat.com> References: <4F8E7A5B.5030904@redhat.com> <4F8E8E3D.8040707@cn.fujitsu.com> <4F8EABF7.805@redhat.com> <20120419.193640.59653378.d.hatayama@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: dzickus-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, luto-3s7WtUTddSA@public.gmane.org, gregkh-l3A5Bk7waGM@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, joerg.roedel-5C7GfCeVMHo@public.gmane.org, mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, paul.gortmaker-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org, zhangyanfei-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org, ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org, ludwig.nussel-l3A5Bk7waGM@public.gmane.org To: HATAYAMA Daisuke Return-path: In-Reply-To: <20120419.193640.59653378.d.hatayama-+CUm20s59erQFUHtdCDX3A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kexec-bounces-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Errors-To: kexec-bounces+glkk-kexec=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: kvm.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