Re: [PATCH v4] iommu/amd: Add support for hw_info for iommu capability query

[Jason Gunthorpe]

On Thu, Sep 04, 2025 at 07:31:12PM +0000, Suravee Suthikulpanit wrote:
> AMD IOMMU Extended Feature (EFR) and Extended Feature 2 (EFR2) registers
> specify features supported by each IOMMU hardware instance.
> The IOMMU driver checks each feature-specific bits before enabling
> each feature at run time.
> 
> For IOMMUFD, the hypervisor passes the raw value of amd_iommu_efr and
> amd_iommu_efr2 to VMM via iommufd IOMMU_DEVICE_GET_HW_INFO ioctl.
> 
> Reviewed-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> ---
> Change in v4:
>  * Add CONFIG_AMD_IOMMU_IOMMUFD
>  * Update comment regarding EFR/EFR2 from struct iommu_hw_info_amd.
> 
> Change in v3:
>  * Remove extern
>  * Fix link to IOMMU spec
>  * Update kdoc
> 
> Change in v2:
>  * Do not mask the EFR/EFR2 and simply return the value reported by hardware
>  * Move amd_iommufd_hw_info() to drivers/iommu/amd/iommufd.c
>  * Also support IOMMU_HW_INFO_TYPE_DEFAULT
> 
>  drivers/iommu/amd/Kconfig    | 10 ++++++++++
>  drivers/iommu/amd/Makefile   |  1 +
>  drivers/iommu/amd/iommu.c    |  2 ++
>  drivers/iommu/amd/iommufd.c  | 31 +++++++++++++++++++++++++++++++
>  drivers/iommu/amd/iommufd.h  | 15 +++++++++++++++
>  include/uapi/linux/iommufd.h | 28 ++++++++++++++++++++++++++++
>  6 files changed, 87 insertions(+)
>  create mode 100644 drivers/iommu/amd/iommufd.c
>  create mode 100644 drivers/iommu/amd/iommufd.h

There was a kbuild issue so this needs to be resent, but

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Jason