Re: [PATCH 12/14] iommufd: Add APIs to preserve/unpreserve a vfio cdev

[Vipin Sharma]

On Tue, Feb 03, 2026 at 10:09:46PM +0000, Samiullah Khawaja wrote:
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> +#ifdef CONFIG_IOMMU_LIVEUPDATE
> +int iommufd_device_preserve(struct liveupdate_session *s,
> +			    struct iommufd_device *idev,
> +			    u64 *tokenp)
> +{
> +	struct iommufd_group *igroup = idev->igroup;
> +	struct iommufd_hwpt_paging *hwpt_paging;
> +	struct iommufd_hw_pagetable *hwpt;
> +	struct iommufd_attach *attach;
> +	int ret;
> +
> +	mutex_lock(&igroup->lock);
> +	attach = xa_load(&igroup->pasid_attach, IOMMU_NO_PASID);
> +	if (!attach) {
> +		ret = -ENOENT;
> +		goto out;
> +	}

Should VFIO in its can_preserve() add this check?

> +void iommufd_device_unpreserve(struct liveupdate_session *s,
> +			       struct iommufd_device *idev,
> +			       u64 token)

Where is token used in this function?