On Fri, Mar 10, 2023 at 02:15:32AM +0000, Tian, Kevin wrote: > > From: Liu, Yi L <[email protected]> > > Sent: Wednesday, March 8, 2023 9:14 PM > > > > After making the no-DMA drivers (samples/vfio-mdev) providing iommufd > > callbacks, __vfio_register_dev() should check the presence of the iommufd > > callbacks if CONFIG_IOMMUFD is enabled. > > > > Signed-off-by: Yi Liu <[email protected]> > > --- > > drivers/vfio/vfio_main.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > > index 43bd6b76e2b6..89497c933490 100644 > > --- a/drivers/vfio/vfio_main.c > > +++ b/drivers/vfio/vfio_main.c > > @@ -255,8 +255,9 @@ static int __vfio_register_dev(struct vfio_device > > *device, > > { > > int ret; > > > > - if (WARN_ON(device->ops->bind_iommufd && > > - (!device->ops->unbind_iommufd || > > + if (WARN_ON(IS_ENABLED(CONFIG_IOMMUFD) && > > + (!device->ops->bind_iommufd || > > + !device->ops->unbind_iommufd || > > !device->ops->attach_ioas))) > > return -EINVAL; > > > > I don't think IS_ENABLED() check is necessary. those ops are > defined in the driver side w/o a conditional CONFIG_IOMMUFD. > > We should warn out lacking of those ops to the driver developer > as early as possible, instead of postponing it until someone > starts to build kernel with CONFIG_IOMMUFD.
The ops are NULL if !CONFIG_IOMMUFD. The previous code was OK because it checked for non-null bind before demanding the others be non-null. Jason
