Re: [PATCH v11 00/18] iommufd support pasid attach/replace

[Nicolin Chen <nicolinc@nvidia.com>]

On Fri, Mar 21, 2025 at 10:19:22AM -0700, Yi Liu wrote:
> PASID (Process Address Space ID) is a PCIe extension that tags the DMA
> transactions from a physical device. Most modern IOMMU hardware supports
> PASID-granular address translation. This allows a PASID-capable device
> to be attached to multiple hardware page tables (hwpts, also known as
> domains), with each attachment tagged by a PASID.
> 
> This series builds on previous series [1]. It begins by adding a missing
> IOMMU API to replace the domain for a PASID. Utilizing the IOMMU PASID
> attach/replace/detach APIs, this series introduces iommufd APIs for device
> drivers to attach, replace, or detach PASIDs to/from hwpts at the request
> of userspace. It also enforces PASID compatibility with domain requirements,
> allocates PASID-compatible hwpts in iommufd, and includes self-tests to
> validate the iommufd APIs.
> 
> The complete code is available at the following link [2]. Please note that
> the existing iommufd self-test was broken, and a temporary fix patch is at
> the top of the branch [2]. If you wish to run the iommufd self-test, please
> apply that fix. We apologize for any inconvenience.
> 
> The series is based on Jason's for-next branch.
> 
> https://web.git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd.git/commit/?h=for-next&id=e009e088d88e8402539f9595b10c0014125a70c1
> 
> [1] https://lore.kernel.org/linux-iommu/20250226011849.5102-1-yi.l.liu@intel.com/
> [2] https://github.com/yiliu1765/iommufd/tree/iommufd_pasid
> [3] https://lore.kernel.org/linux-iommu/20250306034842.5950-1-yi.l.liu@intel.com/
> 
> Change log:
> 
> v11:
>  - Handle is always valid for the replace API, hence drop some meaningless check (Nic/Baolu)
>  - Avoid inline helpers in .c file patch 02 an 06 of v10 (Baolu)
>  - Use xa_load() instead of xa_cmpxch() in iommufd_device_do_replace() (Jason/Nic)
>  - Fix a memleak in patch 11 0f v10, it's due to an order broken (Nic/Jason)
>  - Make the auto_hwpts always be non-pasid-compat to avoid confusion between
>    the RID and PASID path
>  - Add pasid-num-bit as 0 for non-pasid-capable mock device (Nic)
>  - Misc tweaks to the patch 17 and 18 (Nic)
>  - More r-b tags

I am running some sanity with this v11 using the iommufd_pasid
branch, and will give Tested-by in the next a couple of hours
so long as everything works fine.

I sent a couple of replies today but I think they are trivial
and can be cleaned up later if we really want to.

Thanks
Nicolin