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

[Jason Gunthorpe]

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..

Jason