RE: [PATCH v2] iommufd/device: Enforce reserved IOVA also when attached to hwpt_nested

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Tuesday, August 6, 2024 1:02 PM
> 
> +iommufd_group_do_replace_reserved_iova(struct iommufd_group *igroup,
> +				       struct iommufd_hw_pagetable *hwpt)
>  {
> -	struct iommufd_hw_pagetable *old_hwpt = igroup->hwpt;
> +	struct iommufd_hwpt_paging *hwpt_paging =
> to_hwpt_paging(hwpt);
>  	struct iommufd_device *cur;
>  	int rc;
> 
>  	lockdep_assert_held(&igroup->lock);
> 
> -	if (!hwpt_is_paging(old_hwpt) ||
> -	    hwpt_paging->ioas != to_hwpt_paging(old_hwpt)->ioas) {
> +	if (!hwpt_paging)
> +		return 0;
> +
> +	if (hwpt_to_ioas(hwpt) &&

this check is always true when hwpt_paging is valid.

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>