Re: [PATCH v12 05/10] pci: add admin vq registers to virtio over pci

[Max Gurtovoy <mgurtovoy@nvidia.com>]

On 25/04/2023 1:14, Parav Pandit wrote:
> On 4/24/2023 6:06 PM, Max Gurtovoy wrote:
>
> > > +If VIRTIO_F_ADMIN_VQ has been negotiated, and if the driver
> > > +configures any administration virtqueues, the driver MUST
> > > +configure the administration virtqueues using the index
> > > +in the range \field{admin_queue_index} to
> > > +\field{admin_queue_index} + \field{admin_queue_num} - 1 inclusive.
> > > +The driver MAY configure less administration virtqueues than
> > > +supported by the device.
> >
> > we need to say something about other virtq's indexes.
> > For example, if aq index = 0 then for the vblk device the request 
> > queues would start from index = 1.
> >
> > can we address this ?
>
> It may slightly complicate the device implementation when device 
> dynamically changes the VQ indices based on the negotiation of the 
> feature bit.
> Also the drivers with and without need a different VQ index handling.
>
> I am thinking that aq index should not overlap with the vq index in 
> range exposed by num_queues field.
>
> This also aligns to the exclusion of aq count from num_queues field.

The namespace of the aq and other vq index is the same.
And the configuration is done using the same queue_select and other 
registers.
Thus, we need to address the above comment otherwise all the device 
virtqueues chapters are wrong.