Message-ID: <4F4E0299.9080800@redhat.com>
Date: Wed, 29 Feb 2012 12:48:57 +0200
From: Avi Kivity <avi@redhat.com>
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To: Gleb Natapov <gleb@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
References: <4F4AF1FB.6000903@cn.fujitsu.com> <4F4CB926.6050600@redhat.com> <4F4D7F5E.5040202@cn.fujitsu.com> <4F4DF4C6.90609@redhat.com> <20120229095557.GE24600@redhat.com> <4F4DF749.7060507@redhat.com> <20120229100550.GF24600@redhat.com> <4F4DF913.5030809@redhat.com> <20120229104449.GG24600@redhat.com>
In-Reply-To: <20120229104449.GG24600@redhat.com>
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On 02/29/2012 12:44 PM, Gleb Natapov wrote:
> > > > 
> > > Yes, crash can be so severe that it is not even detected by a kernel
> > > itself, so not OOPS message even printed. But in most cases if kernel is
> > > functional enough to print OOPS it is functional enough to call single
> > > hypercall instruction.
> > 
> > Why not print the oops to virtio-serial?  Or even just a regular serial
> > port?  That's what bare metal does.
> > 
> The more interface is complex the more chances it will fail during
> panic. Regular serial is likely more reliable than virtio-serial.
> Hypercall is likely more reliable than uart. On serial user can
> fake panic notification. 

The serial device is under control of the kernel, so the user can only
access it if the kernel so allows.

> Can this be problematic?

>From the point of view of the guest, yes, it can generate support calls
in fill up the admin's dump quota.  From the point of view of the host,
there's no difference between the guest's admin and a random user.

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

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