Re: [PATCH v4 16/16] iommu/amd: Add support for nested domain attach/detach

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Oct 21, 2025 at 01:43:24AM +0000, Suravee Suthikulpanit wrote:
> +static int nested_attach_device(struct iommu_domain *dom, struct device *dev)
> +{
> +	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
> +	struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data);
> +	int ret = 0;
> +
> +	if (WARN_ON(dom->type != IOMMU_DOMAIN_NESTED))
> +		return -EINVAL;
> +
> +	mutex_lock(&dev_data->mutex);
> +
> +	/* Update device table entry */
> +	set_dte_nested(iommu, dom, dev_data);
> +	amd_iommu_device_flush_dte(dev_data);
> +	amd_iommu_completion_wait(iommu);

The structure is still upside down and it should probably be fixed
rather than duplicate this code (and missing the clone_aliases!)

dev_update_dte() should take in the struct dev_table_entry *:

static void dev_update_dte(struct iommu_dev_data *dev_data,
			   struct dev_table_entry *dte)
{
	struct amd_iommu *iommu = get_amd_iommu_from_dev(dev_data->dev);

	amd_iommu_update_dte256(iommu, dev_data, dte);
	clone_aliases(iommu, dev_data->dev);
	device_flush_dte(dev_data);
	iommu_completion_wait(iommu);
}

And this function should be exported and called instead of open coding
it above.

Rework set_dte_entry() to return new instead of calling
update_dte256().

Jason