From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756439Ab2HNPCL (ORCPT ); Tue, 14 Aug 2012 11:02:11 -0400 Received: from goliath.siemens.de ([192.35.17.28]:26947 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753063Ab2HNPCJ (ORCPT ); Tue, 14 Aug 2012 11:02:09 -0400 Message-ID: <502A685E.8090002@siemens.com> Date: Tue, 14 Aug 2012 17:01:50 +0200 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Yan Vugenfirer CC: "Daniel P. Berrange" , Marcelo Tosatti , Wen Congyang , kvm list , qemu-devel , "linux-kernel@vger.kernel.org" , Avi Kivity , KAMEZAWA Hiroyuki , Gleb Natapov Subject: Re: [PATCH v8] kvm: notify host when the guest is panicked References: <5021D235.4050800@cn.fujitsu.com> <20120813182132.GB25268@amt.cnet> <20120814085619.GA32708@redhat.com> <502A2B7A.3070801@siemens.com> <86E2467F-0EA3-4A03-BD89-58E41F7DB808@redhat.com> In-Reply-To: <86E2467F-0EA3-4A03-BD89-58E41F7DB808@redhat.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 2012-08-14 16:55, Yan Vugenfirer wrote: > > On Aug 14, 2012, at 1:42 PM, Jan Kiszka wrote: > >> On 2012-08-14 10:56, Daniel P. Berrange wrote: >>> On Mon, Aug 13, 2012 at 03:21:32PM -0300, Marcelo Tosatti wrote: >>>> On Wed, Aug 08, 2012 at 10:43:01AM +0800, Wen Congyang wrote: >>>>> We can know the guest is panicked when the guest runs on xen. >>>>> But we do not have such feature on kvm. >>>>> >>>>> Another purpose of this feature is: management app(for example: >>>>> libvirt) can do auto dump when the guest is panicked. If management >>>>> app does not do auto dump, the guest's user can do dump by hand if >>>>> he sees the guest is panicked. >>>>> >>>>> We have three solutions to implement this feature: >>>>> 1. use vmcall >>>>> 2. use I/O port >>>>> 3. use virtio-serial. >>>>> >>>>> We have decided to avoid touching hypervisor. The reason why I choose >>>>> choose the I/O port is: >>>>> 1. it is easier to implememt >>>>> 2. it does not depend any virtual device >>>>> 3. it can work when starting the kernel >>>> >>>> How about searching for the "Kernel panic - not syncing" string >>>> in the guests serial output? Say libvirtd could take an action upon >>>> that? >>> >>> No, this is not satisfactory. It depends on the guest OS being >>> configured to use the serial port for console output which we >>> cannot mandate, since it may well be required for other purposes. >> > Please don't forget Windows guests, there is no console and no "Kernel Panic" string ;) > > What I used for debugging purposes on Windows guest is to register a bugcheck callback in virtio-net driver and write 1 to VIRTIO_PCI_ISR register. What prevents writing the magic words to a second serial port in the same way via that callback? Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux