Re: [PATCH v4 3/7] s390: ap: associate a ap_vfio_queue and a matrix mdev

Pierre Morel
2019-02-27T10:44:30Z

On 27/02/2019 10:32, Cornelia Huck wrote:
> On Fri, 22 Feb 2019 16:29:56 +0100
> Pierre Morel <pmorel@linux.ibm.com> wrote:
>
>> We need to associate the ap_vfio_queue, which will hold the
>> per queue information for interrupt with a matrix mediated device
>> which hold the configuration and the way to the CRYCB.
>>
>> Let's do this when assigning a APID or a APQI to the mediated device
>> and clear the relation when unassigning.
>>
>> Queuing the devices on a list of free devices and testing the
>> matrix_mdev pointer to the associated matrix allow us to know
>> if the queue is associated to the matrix device and associated
>> or not to a mediated device.
>>
>> When resetting an AP queue we must wait until there are no more
>> messages in the message queue before considering the queue is really
>> in a clean state.
>>
>> Let's do it and wait until the status response code indicate the
>> queue is empty after issuing a PAPQ/ZAPQ instruction.
>
> I'm a bit confused about the context where that list moving etc. is
> supposed to take place.

You are confused because... it is confuse.

>
> When are we assigning/deassigning? Is there even supposed to be any
> activity that we need to zap on the queues?

No I mixed two functionalities here. It is not right.

I think I must:

- separate the simplification for the reset may be move the chunks to
the previous patch as it is a simplification coming with the use of the
lists or move them to a separate patch.

- make the commit message less confuse :)

Regards,
Pierre

--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany