Re: [PATCH v9 5/6] vfio: Enable cdev noiommu mode under iommufd

[Yi Liu]

On 6/12/26 01:26, Jacob Pan wrote:
> Now that devices under noiommu mode can bind with IOMMUFD and perform
> IOAS operations, lift restrictions on cdev from VFIO side.
> Use cases are documented in Documentation/driver-api/vfio.rst
>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Signed-off-by: Jacob Pan <jacob.pan@xxxxxxxxxxxxxxxxxxx>
> ---
> v9:
>    - Leave device->device.devt unset for no-IOMMU dev so cdev_device_add()
>      registers only the struct device and does not expose an unsupported
>      cdev. (Alex, Sashiko)
>    - Hold registration while checking cdev no-IOMMU access (Sashiko)
> v8:
>    - Fix warning message (Kevin)
> v7:
>    - Avoid treating emulated device as noiommu device (Sashiko)
>    - Keep platforms w/ GENERIC_ATOMIC64 to use VFIO group noiommu as
>      before (Sashiko)
>    - Restore order of group & cdev init for noiommu (Yi)
>    - Consolidate noiommu helper for cdev & group (Yi)
> v6:
>    - Revert back to unified VFIO_NOIOMMU Kconfig for both cdev and group.
>      Use Kconfig dependency to restrict usages and avoid null group
>      checks. (Alex & Yi)
>    - Add CAP_SYS_RAWIO checks for cdev open to maintain security parity
>      with the group noiommu path. (Alex)
> v5:
>     - Add Kconfig VFIO_CDEV_NOIOMMU to select IOMMUFD_NOIOMMU
>       and its dependencies
>     - Add comment to explain vfio_noiommu conditional definition (Alex)
>     - Removed early return for group noiommu in bind/unbind
>     - Use consistent wording referring to VFIO noiommu mode (Kevin)
>     - Update unsafe_noiommu Kconfig help text (Kevin)
>     - Change dev_warn to dev_info for noiommu enabling msg (Kevin)
> v4:
>     - Remove early return in iommufd_bind for noiommu (Alex)
> v3:
>     - Consolidate into fewer patches
> v2:
>     - removed unnecessary device->noiommu set in
>       iommufd_vfio_compat_ioas_get_id()
> ---
>   drivers/vfio/Kconfig       |  7 ++++---
>   drivers/vfio/device_cdev.c |  9 +++++++++
>   drivers/vfio/iommufd.c     | 12 ++++++++----
>   drivers/vfio/vfio.h        | 23 +++++++++--------------
>   drivers/vfio/vfio_main.c   | 26 +++++++++++++++++++++++++-
>   include/linux/vfio.h       |  1 +
>   6 files changed, 56 insertions(+), 22 deletions(-)

LGTM.

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