Re: [PATCH 2/9] iommufd: Add DMABUF to iopt_pages

[Nicolin Chen]

On Fri, Nov 07, 2025 at 12:49:34PM -0400, Jason Gunthorpe wrote:
> 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.
> 
> Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
 
Reviewed-by: Nicolin Chen <nicol...@nvidia.com>