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Date: Wed, 29 Feb 2012 11:49:58 +0200
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] kvm: notify host when guest paniced
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To: Wen Congyang <wency@cn.fujitsu.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, kvm list <kvm@vger.kernel.org>, linux-kernel@vger.kernel.org

On 02/29/2012 03:29 AM, Wen Congyang wrote:
> At 02/28/2012 07:23 PM, Avi Kivity Wrote:
> > On 02/27/2012 05:01 AM, Wen Congyang wrote:
> >> We can know the guest is paniced when the guest runs on xen.
> >> But we do not have such feature on kvm. This patch implemnts
> >> this feature, and the implementation is the same as xen:
> >> register panic notifier, and call hypercall when the guest
> >> is paniced.
> > 
> > What's the motivation for this?  "Xen does this" is insufficient.
>
> Another purpose is: management app(for example: libvirt) can do auto
> dump when the guest is crashed. If management app does not do auto
> dump, the guest's user can do dump by hand if he sees the guest is
> paniced.
>
> I am thinking about another status: dumping. This status tells
> the guest's user that the guest is paniced, and the OS's dump function
> is working.
>
> These two status can tell the guest's user whether the guest is pancied,
> and what should he do if the guest is paniced.
>

How about using a virtio-serial channel for this?  You can transfer any
amount of information (including the dump itself).

-- 
error compiling committee.c: too many arguments to function