Re: [RFC 2/8] iommu: Add a helper to check if any iommu device is registered

[Jacob Pan]

Hi Jason,

On Wed, 3 Dec 2025 09:11:29 -0400
Jason Gunthorpe <jgg@xxxxxxxxxx> wrote:

> On Tue, Dec 02, 2025 at 04:06:35PM -0800, Jacob Pan wrote:
> > However, as you pointed out there seems to be no standard ordering
> > for iommu device registration across platforms. e.g. VT-d hooks up
> > with x86_init, smmuv3 does that in platform driver probe. This
> > patchset puts dummy driver under early_initcall which is after both
> > but not a guarantee for all platforms. Any suggestions?  
> 
> I think we need to do something more like the sefltest does and
> manually bind a driver to a device so this init time ordering
> shouldn't matter.
I have moved this dummy iommu driver init under iommufd_init(), which
aligns well since it runs after all physical IOMMU drivers have
registered. This dummy driver is intended for iommufd after all. But I
don't see a need to bind to a platform device as the selttest does.