Date: Wed, 29 Feb 2012 11:55:57 +0200
From: Gleb Natapov <gleb@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>, kvm list <kvm@vger.kernel.org>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        "Daniel P. Berrange" <berrange@redhat.com>,
        linux-kernel@vger.kernel.org, qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [PATCH] kvm: notify host when guest paniced
Message-ID: <20120229095557.GE24600@redhat.com>
References: <4F4AF1FB.6000903@cn.fujitsu.com>
 <4F4CB926.6050600@redhat.com>
 <4F4D7F5E.5040202@cn.fujitsu.com>
 <4F4DF4C6.90609@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4F4DF4C6.90609@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1673
Lines: 39

On Wed, Feb 29, 2012 at 11:49:58AM +0200, Avi Kivity wrote:
> 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).
> 
Isn't it unreliable after the guest panicked? Having special kdump
kernel that transfers dump to a host via virtio-serial channel though
sounds interesting. May be that's what you mean.

--
			Gleb.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/