Re: [PATCH v6 2/5] iommu: Use bus iommu ops for aux related callback

[Jean-Philippe Brucker]

On Fri, Oct 30, 2020 at 05:55:53AM +0000, Tian, Kevin wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Friday, October 30, 2020 12:58 PM
> > 
> > The aux-domain apis were designed for macro driver where the subdevices
> > are created and used inside a device driver. Use the device's bus iommu
> > ops instead of that in iommu domain for various callbacks.
> 
> IIRC there are only two users on these apis. One is VFIO, and the other
> is on the ARM side (not checked in yet). Jean, can you help confirm 
> whether ARM-side usage still relies on aux apis even with this change?

No, I have something out of tree but no plan to upstream it anymore, and
the SMMUv2 implementation is out as well:

https://lore.kernel.org/linux-iommu/20200713173556.GC3815@xxxxxxxxxxxxxxxxxxxxxxxxx/

> If no, possibly they can be removed completely?

No objection from me. They can be added back later (I still belive adding
PASID to the DMA API would be nice to have once more HW implements it).

Thanks,
Jean