Re: [Qemu-devel] [SeaBIOS] [PATCH v16] Add pvpanic device driver

[Paolo Bonzini]

Il 30/03/2013 14:20, Kevin O'Connor ha scritto:
> On Fri, Mar 29, 2013 at 02:49:12PM +0100, Paolo Bonzini wrote:
>> Il 29/03/2013 14:33, Kevin O'Connor ha scritto:
>>> On Fri, Mar 29, 2013 at 04:18:44PM +0800, Hu Tao wrote:
>>>> pvpanic device is used to notify host(qemu) when guest panic happens.
>>>
>>> Thanks.  However, we're planning a move of ACPI tables from SeaBIOS to
>>> QEMU.  I think this should wait until after the move.
>>
>> The device should be in QEMU 1.5, and the SSDT probably will still be in
>> SeaBIOS by then (and might even be the last to move, since it's quite
>> complex and dynamic).  I don't think it is fair to block this patch on
>> those grounds...
> 
> What is the user visible impact of not having a panic device?

Management cannot restart or dump the guest after a panic, and cannot
log that a panic happened (as opposed to a random watchdog event).

> My main concern is that the patch creates a new fw_cfg channel between
> qemu and seabios thats sole purpose is to alter the OS visible ACPI
> tables.  These types of QEMU->SeaBIOS interfaces are fragile and are
> (in sum) quite complex.

Yes, this is true.

Paolo