Re: [PATCH v2 03/16] iommu: Implement IOMMU domain preservation

[Pranjal Shrivastava <praan@google.com>]

On Mon, May 18, 2026 at 06:55:50PM +0000, Samiullah Khawaja wrote:
> On Mon, May 18, 2026 at 01:13:49PM +0000, Pranjal Shrivastava wrote:
> > On Mon, Apr 27, 2026 at 05:56:20PM +0000, Samiullah Khawaja wrote:
> > > Add IOMMU domain ops that can be implemented by the IOMMU drivers if
[snip]
> > > +	ret = domain->ops->preserve(domain, domain_ser);
> > > +	if (ret) {
> > > +		domain_ser->hdr.deleted = true;
> > 
> > Nit: This will become domain_ser->hdr.flags |= IOMMU_SER_FLAG_DELETED;
> > once we convert the bitfields in PATCH 2 to flags.
> 
> Agreed. I think it is being discussed that bitfields are fine in the
> other thread, but I will switch it to flags for readibility anyway.

Ack. Thanks!

> > 
> > > +		return ret;
> > > +	}
> > > +
> > > +	domain->preserved_state = domain_ser;
> > > +	*ser = domain_ser;
> > > +	return 0;
> > > +}
> > > +EXPORT_SYMBOL_GPL(iommu_domain_preserve);
> > > +
> > 
> > [...]
> > 
> > >  static inline bool iommu_is_dma_domain(struct iommu_domain *domain)
> > > @@ -752,6 +757,11 @@ struct iommu_ops {
> > >   *                           specific mechanisms.
> > >   * @set_pgtable_quirks: Set io page table quirks (IO_PGTABLE_QUIRK_*)
> > >   * @free: Release the domain after use.
> > > + * @preserve: Preserve the iommu domain for liveupdate.
> > > + *            Returns 0 on success, a negative errno on failure.
> > > + * @unpreserve: Unpreserve the iommu domain that was preserved earlier.
> > > + * @restore: Restore the iommu domain after liveupdate.
> > > + *           Returns 0 on success, a negative errno on failure.
> > >   */
> > >  struct iommu_domain_ops {
> > >  	int (*attach_dev)(struct iommu_domain *domain, struct device *dev,
> > > @@ -782,6 +792,9 @@ struct iommu_domain_ops {
> > >  				  unsigned long quirks);
> > > 
> > >  	void (*free)(struct iommu_domain *domain);
> > > +	int (*preserve)(struct iommu_domain *domain, struct iommu_domain_ser *ser);
> > > +	void (*unpreserve)(struct iommu_domain *domain, struct iommu_domain_ser *ser);
> > > +	int (*restore)(struct iommu_domain *domain, struct iommu_domain_ser *ser);
> > 
> > Nit: Should we add restore in the patch we implement it?
> 
> The ops are implemented in iommupt (separate scope) and it is done after
> the iommu pages patch as that is also required for it.

I missed the restore implementation in Patch 6, I thought that'll be
covered in a diff series. Mb. Please ignore this comment.

> > 
> > >  };
> > 
> > With the above nits,
> > 
> > Reviewed-by: Pranjal Shrivastava <praan@google.com>
> 
> Thanks Pranjal.
> > 
> > Thanks,
> > Praan
> 
> Sami

Thanks.
Praan