Re: [PATCH v9 4/6] iommufd: Add an ioctl to query PA from IOVA for noiommu mode

[Yi Liu]

On 6/12/26 01:26, Jacob Pan wrote:
> To support no-IOMMU mode where userspace drivers perform unsafe DMA
> using physical addresses, introduce a new API to retrieve the
> physical address of a user-allocated DMA buffer that has been mapped to
> an IOVA via IOMMU_IOAS_MAP. The mapping is backed by SW-only I/O page
> tables maintained by the GENERIC_PT framework.
>
> Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Co-developed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Signed-off-by: Jacob Pan <jacob.pan@xxxxxxxxxxxxxxxxxxx>
> ---
> v9
>     - Make no-IOMMU GET_PA length a real upper bound and reject zero length,
>      avoiding an unbounded scan while holding IOAS locks. This matches the
>      bounded-range semantics expected by the incoming
>      iommu_iova_to_phys_length() helper.
> v8:
>     - Fix comment on start IOVA range (Kevin)
> v7:
>     - Fix commit message (Yi)
>     - Avoid duplicated tmp_length settting (yi)
>     - Handle race with dma-buf revoke pages (Sashiko)
> v6:
>     - Limit search length (Baolu, Jason)
> v5:
>     - Fix next_iova exceeds iopt_area_last_iova (Alex)
>     - Rename IOCTL more specific to NOIOMMU, i.e.
> 	 IOMMUFD_CMD_IOAS_NOIOMMU_GET_PA (Kevin)
>     - Add header stubs for iopt_get_phys()
> v4:
>     - Fix ioctl return type (Yi Liu)
> ---
>   drivers/iommu/iommufd/io_pagetable.c    | 78 +++++++++++++++++++++++++
>   drivers/iommu/iommufd/ioas.c            | 36 ++++++++++++
>   drivers/iommu/iommufd/iommufd_private.h | 18 ++++++
>   drivers/iommu/iommufd/main.c            |  3 +
>   include/uapi/linux/iommufd.h            | 28 +++++++++
>   5 files changed, 163 insertions(+)

Reviewed-by: Yi Liu <yi.l.liu@xxxxxxxxx>