[Intel-gfx] [PATCH V2 6/8] mdev: introduce virtio device and its device ops

[Parav Pandit]

Hi Alex,


> -----Original Message-----
> From: Alex Williamson <alex.williamson at redhat.com>
> Sent: Tuesday, September 24, 2019 6:07 PM
> To: Jason Wang <jasowang at redhat.com>
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> Subject: Re: [PATCH V2 6/8] mdev: introduce virtio device and its device ops
> 
> On Tue, 24 Sep 2019 21:53:30 +0800
> Jason Wang <jasowang at redhat.com> wrote:
> 
> > This patch implements basic support for mdev driver that supports
> > virtio transport for kernel virtio driver.
> >
> > Signed-off-by: Jason Wang <jasowang at redhat.com>
> > ---
> >  include/linux/mdev.h        |   2 +
> >  include/linux/virtio_mdev.h | 145
> > ++++++++++++++++++++++++++++++++++++
> >  2 files changed, 147 insertions(+)
> >  create mode 100644 include/linux/virtio_mdev.h
> >
> > diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
> > 3414307311f1..73ac27b3b868 100644
> > --- a/include/linux/mdev.h
> > +++ b/include/linux/mdev.h
> > @@ -126,6 +126,8 @@ struct mdev_device *mdev_from_dev(struct device
> > *dev);
> >
> >  enum {
> >  	MDEV_ID_VFIO = 1,
> > +	MDEV_ID_VIRTIO = 2,
> > +	MDEV_ID_VHOST = 3,
> 
> MDEV_ID_VHOST isn't used yet here.  Also, given the strong interdependence
> between the class_id and the ops structure, we might wand to define them in
> the same place.  Thanks,
> 

When mlx5_core creates mdevs (parent->ops->create() and it wants to bind to mlx5 mdev driver (which does mdev_register_driver()), 
mlx5 core driver will publish MDEV_ID_MLX5_NET defined in central place as include/linux/mdev.h without any ops structure.
Because such ops are not relevant. It uses usual, standard ops probe() remove() on the mdev (similar to a regular PCI device).
So for VHOST case ops may be closely related to ID, but not for other type of ID.

Just want to make sure, that scope of ID covers this case.