vfio: Have the core code decode the VFIO_DEVICE_FEATURE ioctl

Invoke a new device op 'device_feature' to handle just the data array
portion of the command. This lifts the ioctl validation to the core code
and makes it simpler for either the core code, or layered drivers, to
implement their own feature values.

Provide vfio_check_feature() to consolidate checking the flags/etc against
what the driver supports.

Link: https://lore.kernel.org/all/[email protected]
Signed-off-by: Jason Gunthorpe <[email protected]>
Tested-by: Shameer Kolothum <[email protected]>
Reviewed-by: Alex Williamson <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Signed-off-by: Yishai Hadas <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>

0 files changed, 0 insertions, 0 deletions