Re: [PATCH v5 16/18] iommufd: Add APIs to preserve/unpreserve a vfio cdev

[Nicolin Chen]

On Mon, Sep 21, 2026 at 12:48:32AM +0000, Samiullah Khawaja wrote:
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> @@ -686,6 +687,10 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
>  	int rc;
>  
>  	mutex_lock(&igroup->lock);
> +	if (iommufd_device_is_preserved(idev)) {
> +		rc = -EBUSY;
> +		goto err_unlock;
> +	}

You might need the same check in iommufd_device_do_replace?

> +#ifdef CONFIG_IOMMU_LIVEUPDATE
> +static bool _iommufd_device_has_pasid_attachments(struct iommufd_device *idev)
> +{
> +	struct iommufd_group *igroup = idev->igroup;
> +	unsigned long start = IOMMU_NO_PASID;
> +
> +	if (xa_find_after(&igroup->pasid_attach,
> +			  &start, UINT_MAX, XA_PRESENT))

Nit: it could fit into a single line.

Nicolin