diff options
| author | Alex Mastro <amastro@fb.com> | 2026-06-10 23:44:41 +0300 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2026-06-12 16:10:34 +0300 |
| commit | 298ab7e6f1637cec44163f52e84e2030ec16ed9d (patch) | |
| tree | 75c417105c1d9fc3c2f3c34d451aa4be4ec6ff5e /include/uapi/linux | |
| parent | f2d70dbd3dcefa8e3c380beff9c31f5f033a4221 (diff) | |
| download | linux-298ab7e6f1637cec44163f52e84e2030ec16ed9d.tar.xz | |
iommufd: Clarify IOAS_MAP_FILE dma-buf support
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")
Link: https://patch.msgid.link/r/20260610-tmp-v1-1-b8ccbf557391@fb.com
Signed-off-by: Alex Mastro <amastro@fb.com>
Assisted-by: Codex:gpt-5.5-high
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'include/uapi/linux')
| -rw-r--r-- | include/uapi/linux/iommufd.h | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index e998dfbd6960..0425d452d41e 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -224,13 +224,17 @@ struct iommu_ioas_map { * @size: sizeof(struct iommu_ioas_map_file) * @flags: same as for iommu_ioas_map * @ioas_id: same as for iommu_ioas_map - * @fd: the memfd to map - * @start: byte offset from start of file to map from + * @fd: the memfd or supported dma-buf file to map + * @start: byte offset from start of the file to map from * @length: same as for iommu_ioas_map * @iova: same as for iommu_ioas_map * - * Set an IOVA mapping from a memfd file. All other arguments and semantics - * match those of IOMMU_IOAS_MAP. + * Set an IOVA mapping from a memfd file. On kernels with dma-buf support, + * supported dma-buf files may also be accepted. This is not a generic + * dma-buf import path; currently supported dma-bufs include single-range + * VFIO PCI dma-bufs exported through VFIO_DEVICE_FEATURE_DMA_BUF, and + * other dma-bufs may be rejected. All other arguments and semantics match + * those of IOMMU_IOAS_MAP. */ struct iommu_ioas_map_file { __u32 size; |