Message-ID: <502A2B7A.3070801@siemens.com>
Date: Tue, 14 Aug 2012 12:42:02 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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To: "Daniel P. Berrange" <berrange@redhat.com>
CC: Marcelo Tosatti <mtosatti@redhat.com>, Wen Congyang <wency@cn.fujitsu.com>,
        kvm list <kvm@vger.kernel.org>, qemu-devel <qemu-devel@nongnu.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Avi Kivity <avi@redhat.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Gleb Natapov <gleb@redhat.com>
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>
In-Reply-To: <20120814085619.GA32708@redhat.com>
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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.

Well, we have more than a single serial port, even when leaving
virtio-serial aside...

Jan

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Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
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