Re: [PATCH v5 06/18] iommu: Implement device and IOMMU HW preservation

[Nicolin Chen]

On Mon, Sep 21, 2026 at 12:48:22AM +0000, Samiullah Khawaja wrote:
> @@ -827,6 +838,8 @@ struct iommu_domain_ops {
>   * @singleton_group: Used internally for drivers that have only one group
>   * @max_pasids: number of supported PASIDs
>   * @ready: set once iommu_device_register() has completed successfully
> + * @outgoing_preserved_state: preserved iommu state of outgoing kernel for
> + * liveupdate.
>   */
>  struct iommu_device {
>  	struct list_head list;
> @@ -836,6 +849,10 @@ struct iommu_device {
>  	struct iommu_group *singleton_group;
>  	u32 max_pasids;
>  	bool ready;
> +
> +#ifdef CONFIG_IOMMU_LIVEUPDATE
> +	struct iommu_hw_ser *outgoing_preserved_state;
> +#endif

It'd be nicer to align the naming.

There are:
	struct iommu_hw_ser *outgoing_preserved_state;
	..
	struct iommu_device_ser *device_ser;
	..
	struct iommu_domain_ser *preserved_state

Maybe use "_ser" for all?

>  
>  /**
> @@ -890,6 +907,9 @@ struct dev_iommu {
>  	u32				pci_32bit_workaround:1;
>  	u32				require_direct:1;
>  	u32				shadow_on_flush:1;
> +#ifdef CONFIG_IOMMU_LIVEUPDATE
> +	struct iommu_device_ser		*device_ser;
> +#endif

Missing its kdoc update.


> @@ -1206,6 +1226,28 @@ static inline void *dev_iommu_priv_get(struct device *dev)
>  
>  void dev_iommu_priv_set(struct device *dev, void *priv);
>  
> +/**
> + * typedef iommu_dev_iter_fn - Callback for iterating IOMMU attached devices
> + * @dev: Attached device
> + * @iommu: IOMMU instance
> + * @arg: Private argument passed to iterator
> + *
> + * Return: 0 on success, or negative error code.
> + */
> +typedef int (*iommu_dev_iter_fn)(struct device *dev,
> +				 struct iommu_device *iommu, void *arg);
> +
> +/**
> + * struct iommu_dev_iter - Iterator for devices attached to an IOMMU
> + */
> +struct iommu_dev_iter {
> +	struct iommu_device *iommu;
> +	iommu_dev_iter_fn fn;
> +	void *arg;
> +};
> +
> +int iommu_for_each_dev(struct iommu_dev_iter *iter);

It isn't very necessarily to expose iommu_dev_iter.

iommu_for_each_dev could be simpler:

int iommu_for_each_dev(struct iommu_device *iommu, iommu_dev_iter_fn fn,
		       void *arg);

Also, arg seems unused?

Nicolin