Re: [PATCH v2 03/19] iommu: Pass in a viommu pointer to domain_alloc_user op

Nicolin Chen
2024-09-05T17:20:39Z

On Thu, Sep 05, 2024 at 12:54:54PM -0300, Jason Gunthorpe wrote:
> On Tue, Aug 27, 2024 at 09:59:40AM -0700, Nicolin Chen wrote:
> > With a viommu object wrapping a potentially shareable S2 domain, a nested
> > domain should be allocated by associating to a viommu instead. Driver can
> > store this viommu pointer somewhere, so as to later use it calling viommu
> > helpers for virtual device ID lookup and viommu invalidation.
> >
> > For drivers without a viommu support, keep the parent domain input, which
> > should be just viommu->hwpt->common.domain otherwise.
>
> I've been thinking of add an op for nested allocation since every
> driver immediately jumps to a special function for nested allocation
> anyhow without sharing any code.
>
> Adding a new parameter that is nested only seems like a good point to
> try to do that..

Yea, it makes sense to have a domain_alloc_nested, for hwpt_nested
exclusively. Then domain_alloc_user would be for hwpt_paging only.

Thanks
Nicolin