Re: [PATCH v9 1/6] iommufd: Support a HWPT without an iommu driver for noiommu

[Yi Liu]

On 6/12/26 01:26, Jacob Pan wrote:
> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
>
> Create just a little part of a real iommu driver, enough to
> slot in under the dev_iommu_ops() and allow iommufd to call
> domain_alloc_paging_flags() and fail everything else.
>
> This allows explicitly creating a HWPT under an IOAS.
>
> A new Kconfig option IOMMUFD_NOIOMMU is introduced to differentiate
> from the VFIO group/container based noiommu mode.
>
> Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Reviewed-by: Samiullah Khawaja <skhawaja@xxxxxxxxxx>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Signed-off-by: Jacob Pan <jacob.pan@xxxxxxxxxxxxxxxxxxx>
> ---
> V8:
>    - Guard vIOMMU and vDevice allocation paths for noiommu (Sashiko)
> v7:
>    - Drain no-IOMMU generic-PT freelist (Sashiko)
>    - Import generic-PT IOMMU namespace (Sashiko)
> v6: (Yi)
>    - Sort includes alphabetically (iommu.h after generic_pt/iommu.h)
>    - Fix comment: s/mock page table/SW-only page table/ to avoid confusion
>      with selftest mock
>    - Rewrite noiommu_amdv1_ops comment: explain why AMDV1 format is chosen
>      (multi-page size options), remove references to group-container mode distinction
> v5:
>     - Use the new IOMMUFD_NOIOMMU Kconfig instead of VFIO_NOIOMMU
>     - Use consistent wording referring to VFIO noiommu mode (Kevin)
>     - Copyright date fix (Kevin)
> v4:
>     - Make iommufd_noiommu_ops const
> v3:
>     - Add comment to explain the design difference over the
>       legacy noiommu VFIO code.
> ---
>   drivers/iommu/iommufd/Kconfig           |  12 +++
>   drivers/iommu/iommufd/Makefile          |   1 +
>   drivers/iommu/iommufd/hw_pagetable.c    |  19 ++++-
>   drivers/iommu/iommufd/hwpt_noiommu.c    | 105 ++++++++++++++++++++++++
>   drivers/iommu/iommufd/iommufd_private.h |  12 +++
>   drivers/iommu/iommufd/main.c            |   1 +
>   drivers/iommu/iommufd/viommu.c          |  14 +++-
>   7 files changed, 158 insertions(+), 6 deletions(-)
>   create mode 100644 drivers/iommu/iommufd/hwpt_noiommu.c


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