[Intel-gfx] [PATCH v2 00/11] Connect VFIO to IOMMUFD

[Matthew Rosato]

On 11/7/22 7:52 PM, Jason Gunthorpe wrote:
> This series provides an alternative container layer for VFIO implemented
> using iommufd. This is optional, if CONFIG_IOMMUFD is not set then it will
> not be compiled in.
> 
> At this point iommufd can be injected by passing in a iommfd FD to
> VFIO_GROUP_SET_CONTAINER which will use the VFIO compat layer in iommufd
> to obtain the compat IOAS and then connect up all the VFIO drivers as
> appropriate.
> 
> This is temporary stopping point, a following series will provide a way to
> directly open a VFIO device FD and directly connect it to IOMMUFD using
> native ioctls that can expose the IOMMUFD features like hwpt, future
> vPASID and dynamic attachment.
> 
> This series, in compat mode, has passed all the qemu tests we have
> available, including the test suites for the Intel GVT mdev. Aside from
> the temporary limitation with P2P memory this is belived to be fully
> compatible with VFIO.

AFAICT there is no equivalent means to specify vfio_iommu_type1.dma_entry_limit when using iommufd; looks like we'll just always get the default 65535.  Was this because you envision the limit being not applicable for iommufd (limits will be enforced via either means and eventually we won't want to ) or was it an oversight?

Thanks,
Matt