Re: [Qemu-devel] [PATCH v3 06/33] add the vmstate description for device reset state

[Damien Hedde <damien.hedde@greensocs.com>]

On 8/7/19 4:54 PM, Peter Maydell wrote:
> On Mon, 29 Jul 2019 at 15:58, Damien Hedde <damien.hedde@greensocs.com> wrote:
>>
>> It contains the resetting counter and cold flag status.
>>
>> At this point, migration of bus reset related state (counter and cold/warm
>> flag) is handled by parent device. This done using the post_load
>> function in the vmsd subsection.
>>
>> This is last point allow to add an initial support of migration with part of
>> qdev/qbus tree in reset state under the following condition:
>> + time-lasting reset are asserted on Device only
>>
>> Note that if this condition is not respected, migration will succeed and
>> no failure will occurs. The only impact is that the resetting counter
>> of a bus may lower afer a migration.
>>
>> Signed-off-by: Damien Hedde <damien.hedde@greensocs.com>
> 
> 
>> +const struct VMStateDescription device_vmstate_reset = {
>> +    .name = "device_reset",
>> +    .version_id = 0,
>> +    .minimum_version_id = 0,
>> +    .needed = device_vmstate_reset_needed,
>> +    .post_load = device_vmstate_reset_post_load,
>> +    .fields = (VMStateField[]) {
>> +        VMSTATE_UINT32(resetting, DeviceState),
>> +        VMSTATE_BOOL(reset_is_cold, DeviceState),
>> +        VMSTATE_END_OF_LIST()
>> +    },
>> +};
>> -
> 
> Forgot to ask -- why don't we migrate the hold_needed flags?

The flag is only used to keep the info between executing the init
and hold phases. We can't interrupt the code in between since this
mess is during resettable_assert_reset method which is atomic.
I can add a comment to explain that.

> 
> thanks
> -- PMM
>