Re: [PATCH 3/5] vDPA: introduce vDPA bus

On 2020/1/17 下午10:12, Rob Miller wrote:

    >> + * @get_vendor_id:          Get id for the vendor that
    provides this device
    >> + *                          @vdev: vdpa device
    >> + *                          Returns u32: virtio vendor id
    > what's the idea behind this? userspace normally doesn't interact
    with
    > this ... debugging?


    This allows some vendor specific driver on top of vDPA bus. If
    this is
    not interested, I can drop this.

RJM>] wouldn't  usage of get_device_id & get_vendor_id, beyond 
reporting, tend to possibly leading to vendor specific code in the 
framework instead of leaving the framework agnostic and leave the 
vendor specific stuff to the vendor's vDPA device driver?

For virtio device id, I think it is needed for kernel/userspace to know 
which driver to load (e.g loading virtio-net for networking devic).

For virtio vendor id, it was needed by kernel virtio driver, and virtio 
bus can match driver based on virtio vendor id. So it doesn't prevent 
3rd vendor specific driver for virtio device.

Maybe we can report VIRTIO_DEV_ANY_ID as vendor id to forbid vendor 
specific stuffs.

Thanks