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

[Samiullah Khawaja]

On Tue, Oct 06, 2026 at 08:21:15PM -0700, Nicolin Chen wrote:
> 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?

That is a fair point. I will update this.
> >  /**
> > @@ -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.

Will 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?

Agreed. I will update it to this:

int iommu_for_each_dev(struct iommu_device *iommu, iommu_dev_iter_fn fn);
> Nicolin

Thanks,
Sami