> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Saturday, February 25, 2023 8:28 AM
> +
> +int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
> +{
> + struct iommu_hwpt_alloc *cmd = ucmd->cmd;
> + struct iommufd_hw_pagetable *hwpt;
> + struct iommufd_device *idev;
> + struct iommufd_ioas *ioas;
> + int rc;
> +
> + if (cmd->flags)
> + return -EOPNOTSUPP;
miss a check on the __reserved field.
> +/**
> + * struct iommu_hwpt_alloc - ioctl(IOMMU_HWPT_ALLOC)
> + * @size: sizeof(struct iommu_hwpt_alloc)
> + * @flags: Must be 0
> + * @dev_id: The device to allocate this HWPT for
> + * @pt_id: The IOAS to connect this HWPT to
> + * @out_hwpt_id: The ID of the new HWPT
> + * @__reserved: Must be 0
> + *
> + * Explicitly allocate a hardware page table object. This is the same object
> + * type that is returned by iommufd_device_attach() and represents the
> + * underlying iommu driver's iommu_domain kernel object.
> + *
> + * A normal HWPT will be created with the mappings from the given IOAS.
> + */
'normal' is a confusing word in this context.
