Re: [Qemu-devel] [PATCH] Reset system before loadvm

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2011-06-14 12:50, Avi Kivity wrote:
> On 06/14/2011 09:19 AM, Jan Kiszka wrote:
>> On 2011-06-12 19:13, Avi Kivity wrote:
>> >  On 06/11/2011 12:05 PM, Jan Kiszka wrote:
>> >>  From: Jan Kiszka<jan.kiszka@siemens.com>
>> >>
>> >>  In case we load the vmstate during incoming migration, we start
>> from a
>> >>  clean, default machine state as we went through system reset
>> before. But
>> >>  if we load from a snapshot, the machine can be in any state. That can
>> >>  cause troubles if loading an older image which does not carry all
>> state
>> >>  information the executing QEMU requires. Almost no device takes
>> care of
>> >>  this scenario.
>> >>
>> >>  However, fixing this is trivial. We just need to issue a system reset
>> >>  during loadvm as well.
>>
> 
>> >>  +    qemu_system_reset();
>> >>        ret = qemu_loadvm_state(f);
>> >>
>> >>        qemu_fclose(f);
>> >
>> >  Should we suppress the reset event sent out on the monitor?  After
>> all,
>> >  it's the result of an internal implementation choice, not something
>> the
>> >  user or the guest did.
>>
>> We already issue this pattern during -loadvm or -incoming - or is the
>> monitor not yet connected at this point?
> 
> I believe it is not.  But regardless, we shouldn't add more incorrect
> behaviour.

It depends on how the reset event is defined in QMP. As I see it, there
is nothing stated about reset reasons or sources. So emitting
information about the actually happening reset can't be incorrect. Just
like emitting the information about the VM stop/start around loadvm.

Jan

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