Re: [PATCH v2 1/2] vfio/type1: Simplify bus_type determination

[Jason Gunthorpe]

On Thu, Jun 23, 2022 at 01:23:05PM +0100, Robin Murphy wrote:

> So yes, technically we could implement an iommu_group_capable() and an
> iommu_group_domain_alloc(), which would still just internally resolve the
> IOMMU ops and instance data from a member device to perform the driver-level
> call, but once again it would be for the benefit of precisely one
> user. 

Benefit one user and come with a fairly complex locking situation to
boot.

Alex, I'd rather think about moving the type 1 code so that the iommu
attach happens during device FD creation (then we have a concrete
non-fake device), not during group FD opening.

That is the model we need for iommufd anyhow.

Jason