Re: [PATCH] iommufd: Clarify IOAS_MAP_FILE dma-buf support

[Jason Gunthorpe]

On Wed, Jun 10, 2026 at 01:44:41PM -0700, Alex Mastro wrote:
> IOMMU_IOAS_MAP_FILE is documented as mapping a memfd, but the
> implementation first tries to resolve the fd as a dma-buf and has a
> special path for supported dma-buf exporters. In particular, VFIO PCI
> dma-bufs exported through VFIO_DEVICE_FEATURE_DMA_BUF can be mapped when
> they describe a single DMA range.
> 
> Update the UAPI comment so userspace understands that certain kinds of
> dma-buf are supported in addition to memfd.
> 
> Fixes: 44ebaa1744fd ("iommufd: Accept a DMABUF through IOMMU_IOAS_MAP_FILE")
> Signed-off-by: Alex Mastro <amastro@xxxxxx>
> Assisted-by: Codex:gpt-5.5-high
> ---
>  include/uapi/linux/iommufd.h | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)

Applied thanks

Jason