Re: [PATCH V4 05/18] iommu/ioasid: Redefine IOASID set and allocation APIs

From: Jason Gunthorpe
Date: Fri Apr 16 2021 - 10:35:00 EST

On Fri, Apr 16, 2021 at 04:26:19PM +0200, Auger Eric wrote:

> This was largely done during several confs including plumber, KVM forum,
> for several years. Also API docs were shared on the ML. I don't remember
> any voice was raised at those moments.

I don't think anyone objects to the high level ideas, but
implementation does matter. I don't think anyone presented "hey we
will tunnel an uAPI through VFIO to the IOMMU subsystem" - did they?

Look at the fairly simple IMS situation, for example. This was
presented at plumbers too, and the slides were great - but the
implementation was too hacky. It required a major rework of the x86
interrupt handling before it was OK.