[Question] Is it must for vfio-mdev parent driver to implement a pci-compliant configuration r/w interface

[Wu Zongyong <wuzongyong@xxxxxxxxxxxxxxxxx>]

Hi,

For vfio, I know there are two method to get region size:
  1. VFIO_DEVICE_GET_REGION_INFO ioctl
  2. write a value of all 1's to the bar register of vfio-device fd
    and then read the value back which is described in pci spec

Now I am curious about is it a must for a vfio-mdev parent driver to
implement the method 2? Or it is just a optional interface.

Thanks,
Wu Zongyong