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

Jason Wang
2019-10-15T12:13:00Z

On 2019/10/15 下午6:26, Cornelia Huck wrote:
> On Fri, 11 Oct 2019 16:15:51 +0800
> Jason Wang <jasowang@redhat.com> 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@redhat.com>
>> ---
>> 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.