From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wen Congyang Subject: Re: [PATCH] kvm: notify host when guest paniced Date: Wed, 29 Feb 2012 18:31:24 +0800 Message-ID: <4F4DFE7C.3030501@cn.fujitsu.com> References: <4F4AF1FB.6000903@cn.fujitsu.com> <4F4CB926.6050600@redhat.com> <4F4D7F5E.5040202@cn.fujitsu.com> <4F4DF4C6.90609@redhat.com> <20120229095842.GF5050@redhat.com> <4F4DF86C.5010407@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: qemu-devel , KAMEZAWA Hiroyuki , kvm list , linux-kernel@vger.kernel.org To: Avi Kivity Return-path: In-Reply-To: <4F4DF86C.5010407@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org At 02/29/2012 06:05 PM, Avi Kivity Wrote: > On 02/29/2012 11:58 AM, Daniel P. Berrange wrote: >>> >>> How about using a virtio-serial channel for this? You can transfer any >>> amount of information (including the dump itself). >> >> When the guest OS has crashed, any dumps will be done from the host >> OS using libvirt's core dump mechanism. The guest OS isn't involved >> and is likely too dead to be of any use anyway. Likewise it is >> quite probably too dead to work a virtio-serial channel or any >> similarly complex device. We're really just after the simplest >> possible notification that the guest kernel has paniced. > > If it's alive enough to panic, it's alive enough to kexec its kdump > kernel. After that it can do anything. > > Guest-internal dumps are more useful IMO that host-initiated dumps. In Yes, guest-internal dump is better than host dump. But the user may not start guest-internal dump or guest-internal dump failed. So we need the following feature: 1. If the guest-internal dump does not work, the guest's status is 'crashed'. And then the user does the host dump. 2. If the guest-internal dump is working, the guest's status should be 'dumping'. The user see this status and know the guest has paniced, and the guest-internal dump is working. Thanks Wen Congyang > a cloud, the host-initiated dump is left on the host, outside the reach > of the guest admin, outside the guest image where all the symbols are, > and sometimes not even on the same host if a live migration occurred. > It's more useful in small setups, or if the problem is in the > hypervisor, not the guest. > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757522Ab2B2KaS (ORCPT ); Wed, 29 Feb 2012 05:30:18 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:54241 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751312Ab2B2KaQ (ORCPT ); Wed, 29 Feb 2012 05:30:16 -0500 Message-ID: <4F4DFE7C.3030501@cn.fujitsu.com> Date: Wed, 29 Feb 2012 18:31:24 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Avi Kivity CC: "Daniel P. Berrange" , kvm list , KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org, qemu-devel Subject: Re: [PATCH] kvm: notify host when guest paniced References: <4F4AF1FB.6000903@cn.fujitsu.com> <4F4CB926.6050600@redhat.com> <4F4D7F5E.5040202@cn.fujitsu.com> <4F4DF4C6.90609@redhat.com> <20120229095842.GF5050@redhat.com> <4F4DF86C.5010407@redhat.com> In-Reply-To: <4F4DF86C.5010407@redhat.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-02-29 18:28:24, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-02-29 18:28:26, Serialize complete at 2012-02-29 18:28:26 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At 02/29/2012 06:05 PM, Avi Kivity Wrote: > On 02/29/2012 11:58 AM, Daniel P. Berrange wrote: >>> >>> How about using a virtio-serial channel for this? You can transfer any >>> amount of information (including the dump itself). >> >> When the guest OS has crashed, any dumps will be done from the host >> OS using libvirt's core dump mechanism. The guest OS isn't involved >> and is likely too dead to be of any use anyway. Likewise it is >> quite probably too dead to work a virtio-serial channel or any >> similarly complex device. We're really just after the simplest >> possible notification that the guest kernel has paniced. > > If it's alive enough to panic, it's alive enough to kexec its kdump > kernel. After that it can do anything. > > Guest-internal dumps are more useful IMO that host-initiated dumps. In Yes, guest-internal dump is better than host dump. But the user may not start guest-internal dump or guest-internal dump failed. So we need the following feature: 1. If the guest-internal dump does not work, the guest's status is 'crashed'. And then the user does the host dump. 2. If the guest-internal dump is working, the guest's status should be 'dumping'. The user see this status and know the guest has paniced, and the guest-internal dump is working. Thanks Wen Congyang > a cloud, the host-initiated dump is left on the host, outside the reach > of the guest admin, outside the guest image where all the symbols are, > and sometimes not even on the same host if a live migration occurred. > It's more useful in small setups, or if the problem is in the > hypervisor, not the guest. > From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57851) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S2gnf-0008Km-S8 for qemu-devel@nongnu.org; Wed, 29 Feb 2012 05:30:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S2gnd-00056N-Rs for qemu-devel@nongnu.org; Wed, 29 Feb 2012 05:30:23 -0500 Received: from [222.73.24.84] (port=58586 helo=song.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S2gnd-00056D-Gz for qemu-devel@nongnu.org; Wed, 29 Feb 2012 05:30:21 -0500 Message-ID: <4F4DFE7C.3030501@cn.fujitsu.com> Date: Wed, 29 Feb 2012 18:31:24 +0800 From: Wen Congyang MIME-Version: 1.0 References: <4F4AF1FB.6000903@cn.fujitsu.com> <4F4CB926.6050600@redhat.com> <4F4D7F5E.5040202@cn.fujitsu.com> <4F4DF4C6.90609@redhat.com> <20120229095842.GF5050@redhat.com> <4F4DF86C.5010407@redhat.com> In-Reply-To: <4F4DF86C.5010407@redhat.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [PATCH] kvm: notify host when guest paniced List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: qemu-devel , KAMEZAWA Hiroyuki , kvm list , linux-kernel@vger.kernel.org At 02/29/2012 06:05 PM, Avi Kivity Wrote: > On 02/29/2012 11:58 AM, Daniel P. Berrange wrote: >>> >>> How about using a virtio-serial channel for this? You can transfer any >>> amount of information (including the dump itself). >> >> When the guest OS has crashed, any dumps will be done from the host >> OS using libvirt's core dump mechanism. The guest OS isn't involved >> and is likely too dead to be of any use anyway. Likewise it is >> quite probably too dead to work a virtio-serial channel or any >> similarly complex device. We're really just after the simplest >> possible notification that the guest kernel has paniced. > > If it's alive enough to panic, it's alive enough to kexec its kdump > kernel. After that it can do anything. > > Guest-internal dumps are more useful IMO that host-initiated dumps. In Yes, guest-internal dump is better than host dump. But the user may not start guest-internal dump or guest-internal dump failed. So we need the following feature: 1. If the guest-internal dump does not work, the guest's status is 'crashed'. And then the user does the host dump. 2. If the guest-internal dump is working, the guest's status should be 'dumping'. The user see this status and know the guest has paniced, and the guest-internal dump is working. Thanks Wen Congyang > a cloud, the host-initiated dump is left on the host, outside the reach > of the guest admin, outside the guest image where all the symbols are, > and sometimes not even on the same host if a live migration occurred. > It's more useful in small setups, or if the problem is in the > hypervisor, not the guest. >