[PATCH v4 02/23] iommu: Pass in a driver-level user data structure to viommu_alloc op

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Friday, May 9, 2025 11:02 AM
> 
> The new type of vIOMMU for tegra241-cmdqv allows user space VM to use
> one
> of its virtual command queue HW resources exclusively. This requires user
> space to mmap the corresponding MMIO page from kernel space for direct
> HW
> control.
> 
> To forward the mmap info (offset and length), iommufd should add a driver
> specific data structure to the IOMMUFD_CMD_VIOMMU_ALLOC ioctl, for
> driver
> to output the info during the allocation back to user space.
> 
> Similar to the existing ioctls and their IOMMU handlers, add a user_data
> to viommu_alloc op to bridge between iommufd and drivers.
> 
> Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>
> Reviewed-by: Lu Baolu <baolu.lu at linux.intel.com>
> Reviewed-by: Pranjal Shrivastava <praan at google.com>
> Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian at intel.com>