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Date: Wed, 14 Mar 2012 18:58:47 +0800
From: Wen Congyang <wency@cn.fujitsu.com>
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Subject: Re: [Qemu-devel] [PATCH 0/2 v3] kvm: notify host when guest panicked
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To: Avi Kivity <avi@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>, kvm list <kvm@vger.kernel.org>, Jan Kiszka <jan.kiszka@siemens.com>, qemu-devel <qemu-devel@nongnu.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Amit Shah <amit.shah@redhat.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

At 03/14/2012 06:52 PM, Avi Kivity Wrote:
> On 03/14/2012 12:52 PM, Wen Congyang wrote:
>>>
>>>> If so, is this channel visible to guest userspace? If the channle is visible to guest
>>>> userspace, the program running in userspace may write the same message to the channel.
>>>
>>> Access control is via permissions.  You can have udev scripts assign
>>> whatever uid and gid to the port of your interest.  By default, all
>>> ports are only accessible to the root user.
>>
>> We should also prevent root user writing message to this channel if it is
>> used for panicked notification.
>>
> 
> Why?  root can easily cause a panic.
> 

root user can write the same message to virtio-serial while the guest is running...

Thanks
Wen Congyang