[Intel-gfx] [PATCH v5 16/19] vfio: Add VFIO_DEVICE_BIND_IOMMUFD

[Tian, Kevin]

> From: Liu, Yi L <yi.l.liu at intel.com>
> Sent: Friday, March 3, 2023 2:58 PM
> 
> > What should we return here anyhow if an access was created?
> 
> iommufd_access->obj.id. should be fine. Is it?
> 

Thinking more I'm not sure whether it's a good idea to fill the
dev_id field with an access object id and then later confuse
the user to get an -ENOENT error when trying to allocate a
hwpt with an access object id.

How can user differentiate it from the real error case where
invalid iommufd object is used?

It sounds clearer to return dev_id only when there is a true
device object being created by the bind_iommufd cmd. Then
the user can use it to decide whether  to further attempt
dev_id related cmds.