Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked

[Jan Kiszka]

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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