Re: [PATCH V1 vfio 2/2] vfio: Split migration ops from main device ops

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Jun 27, 2022 at 07:45:04AM +0000, Tian, Kevin wrote:
> > From: Yishai Hadas <yishaih@nvidia.com>
> > Sent: Sunday, June 26, 2022 4:40 PM
> > @@ -1534,8 +1534,8 @@ vfio_ioctl_device_feature_mig_device_state(struct
> > vfio_device *device,
> >  	struct file *filp = NULL;
> >  	int ret;
> > 
> > -	if (!device->ops->migration_set_state ||
> > -	    !device->ops->migration_get_state)
> > +	if (!device->mig_ops->migration_set_state ||
> > +	    !device->mig_ops->migration_get_state)
> >  		return -ENOTTY;
> > 
> 
> device->mig_ops could be NULL.
> 
> I still think that it's cleaner to do above check when registering the device
> while leaving only a simple check on mig_ops here and later. While at it
> you can also include check on VFIO_MIGRATION_STOP_COPY since the uAPI
> claims it must be set in migration_flags. All those checks can be done
> once at registration point.

It makes sense, I also prefer validating ops construction on
registration.

Jason