iommufd: Add DMABUF to iopt_pages

Add IOPT_ADDRESS_DMABUF to the iopt_pages and the basic infrastructure to
create an iopt_pages from a struct dma_buf *.

DMABUF pages are not supported for accesses, and for now can only be used
with the VFIO DMABUF exporter.

The overall flow will be similar to memfd where the user can pass in a
DMABUF file descriptor to IOMMU_IOAS_MAP_FILE and create an area and
pages. Like other areas it can be copied and otherwise manipulated, though
there is little point in doing so.

There is no pinned page accounting done for DMABUF maps.

The DMABUF attachment exists so long as the dmabuf is mapped into an IOAS,
even if the IOAS is not mapped to any domains.

Link: https://patch.msgid.link/r/2-v2-b2c110338e3f+5c2-iommufd_dmabuf_jgg@nvidia.com
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

0 files changed, 0 insertions, 0 deletions