Re: [PATCH V3 1/7] mdev: class id support

[Jason Wang]

On 2019/10/15 äå6:26, Cornelia Huck wrote:
> On Fri, 11 Oct 2019 16:15:51 +0800
> Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
> > Mdev bus only supports vfio driver right now, so it doesn't implement
> > match method. But in the future, we may add drivers other than vfio,
> > the first driver could be virtio-mdev. This means we need to add
> > device class id support in bus match method to pair the mdev device
> > and mdev driver correctly.
> >
> > So this patch adds id_table to mdev_driver and class_id for mdev
> > device with the match method for mdev bus.
> >
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > ---
> >   Documentation/driver-api/vfio-mediated-device.rst |  7 ++++++-
> >   drivers/gpu/drm/i915/gvt/kvmgt.c                  |  1 +
> >   drivers/s390/cio/vfio_ccw_ops.c                   |  1 +
> >   drivers/s390/crypto/vfio_ap_ops.c                 |  1 +
> >   drivers/vfio/mdev/mdev_core.c                     | 11 +++++++++++
> >   drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
> >   drivers/vfio/mdev/mdev_private.h                  |  1 +
> >   drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
> >   include/linux/mdev.h                              |  8 ++++++++
> >   include/linux/mod_devicetable.h                   |  8 ++++++++
> >   samples/vfio-mdev/mbochs.c                        |  1 +
> >   samples/vfio-mdev/mdpy.c                          |  1 +
> >   samples/vfio-mdev/mtty.c                          |  1 +
> >   13 files changed, 60 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
> > index 25eb7d5b834b..2035e48da7b2 100644
> > --- a/Documentation/driver-api/vfio-mediated-device.rst
> > +++ b/Documentation/driver-api/vfio-mediated-device.rst
> > @@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
> >         * @probe: called when new device created
> >         * @remove: called when device removed
> >         * @driver: device driver structure
> > +      * @id_table: the ids serviced by this driver
> >         */
> >        struct mdev_driver {
> >   	     const char *name;
> >   	     int  (*probe)  (struct device *dev);
> >   	     void (*remove) (struct device *dev);
> >   	     struct device_driver    driver;
> > +	     const struct mdev_class_id *id_table;
> >        };
> >   
> >   A mediated bus driver for mdev should use this structure in the function calls
> > @@ -165,12 +167,15 @@ register itself with the mdev core driver::
> >   	extern int  mdev_register_device(struct device *dev,
> >   	                                 const struct mdev_parent_ops *ops);
> >   
> > +It is also required to specify the class_id through::
> > +
> > +	extern int mdev_set_class(struct device *dev, u16 id);
> Should the document state explicitly that this should be done in the
> ->create() callback?


Yes, it's better.


> Also, I think that the class_id might be different
> for different mdevs (even if the parent is the same) -- should that be
> mentioned explicitly?


Yes, depends on the mdev_supported_type.

Thanks


> > +
> >   However, the mdev_parent_ops structure is not required in the function call
> >   that a driver should use to unregister itself with the mdev core driver::
> >   
> >   	extern void mdev_unregister_device(struct device *dev);
> >   
> > -
> >   Mediated Device Management Interface Through sysfs
> >   ==================================================
> >   
> (...)
>
> Looks reasonable to me.