On Sat, Aug 12, 2023 at 09:36:33AM +0800, Baolu Lu wrote:
> > @@ -290,6 +295,7 @@ struct iommu_ops {
> > unsigned long pgsize_bitmap;
> > struct module *owner;
> > struct iommu_domain *identity_domain;
> > + struct iommu_domain *default_domain;
>
> I am imaging whether we can merge above two pointers into a single one.
> It is either an IDENTITY or PLATFORM domain and the core will choose it
> as the default domain of a group if iommu_group_alloc_default_domain()
> fails to allocate one through the iommu dev_ops.
I think that would be the wrong direction..
identity_domain is a pointer that is always, ALWAYS an identity
domain. It is the shortcut for drivers (and all drivers should do
this) that implement a global static identity domain.
default_domain is a shortcut to avoid implementing the entire flow
around def_domain_type/domain_alloc for special cases. For this patch
the specialc ase is the IOMMU_DOMAIN_PLATFORM.
We'll probably also get a blocking_domain pointer here too.
All of this is removing the type multiplexor in alloc_domain so we can
so alloc_domain_paging()
> Probably we could give it a more meaningful name? For example,
> supplemental_domain or rescue_domain?
But that isn't what it is for, default_domain is the operational
domain for attached drivers..
Jason
