RE: [PATCH v1 08/12] iommufd/viommu: Replace ops->viommu_alloc with ops->viommu_init

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Tuesday, June 10, 2025 1:14 AM
> 
> +	rc = ops->get_viommu_size(cmd->type, idev->dev, &viommu_size);
> +	if (rc)
> +		goto out_put_idev;
> +
> +	/*
> +	 * It is a driver bug for providing a viommu_size smaller than the core
> +	 * vIOMMU structure size
> +	 */
> +	if (WARN_ON_ONCE(viommu_size < sizeof(*viommu))) {
> +		rc = -EINVAL;
> +		goto out_put_idev;
> +	}
> +

It's not about user providing an invalid argument. Sounds cleaner
to return NOSUPPORT in such case.