RE: [virtio-comment] Re: [PATCH 0/2] Selective queue enabling

[Parav Pandit <parav@nvidia.com>]

> From: Eugenio Perez Martin <eperezma@redhat.com>
> Sent: Tuesday, June 13, 2023 6:13 AM

> > - enable all queues before DRIVER_OK
> > - reset all data queues before DRIVER_OK
> > - DRIVER_OK
> > - CVQ commands
> > - re-enable data queues
> >
> >
> > No?
> >
> 
> If it is valid to write to queue_reset before DRIVER_OK, then sure. I asked for
> that in the past at https://lists.oasis-open.org/archives/virtio-
> dev/202305/msg00329.html
> .

Before DRIVER_OK stage, queue_enable is already available so why to use queue reset?
They have duplicate functionality, hence there is no motivation to support queue_reset before DRIVER_OK stage?

It is not explicitly mentioned in the spec that one can setup the queue using queue reset instead of queue enable.
As Jason mentioned it is implementation specific, one device supports it and one doesn't.
Hence, it will break on those devices which doesnt support it.

Therefore, I would like to add it to the spec.
"queue_reset register MUST be accessed by the driver only after device has reached the DRIVER_OK stage."

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