RE: [PATCH v1 7/8] iommufd/device: Use iommu_group_replace_domain()

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Thursday, February 2, 2023 3:05 PM
>
> @@ -246,6 +249,18 @@ static int iommufd_device_do_attach(struct
> iommufd_device *idev,
>  		}
>  	}
> 
> +	if (cur_hwpt) {
> +		/* Replace the cur_hwpt */
> +		mutex_lock(&cur_hwpt->devices_lock);
> +		if (cur_hwpt->ioas != hwpt->ioas)
> +			iopt_remove_reserved_iova(&cur_hwpt->ioas->iopt,
> +						  idev->dev);
> +		list_del(&cur_hwpt->hwpt_item);

emmm shouldn't this be done only when the device is the last
one attached to the hwpt? and if it's the last one you should
also iopt_table_remove_domain() together with list_del, i.e.
similar housekeeping as done in iommufd_device_detach().