On Wed, Dec 01 2021 at 11:11, Jason Gunthorpe wrote: > On Wed, Dec 01, 2021 at 03:52:02PM +0100, Thomas Gleixner wrote: >> So we really can go and create a MSI irqdomain and stick the pointer >> into stdev->dev.irqdomain. The parent domain of this irqdomain is >> >> stdev->pdev.dev.irqdomain->parent > > It can work (pending some solution to the iommu stuff), but IMHO it is > strange/hacky to put HW objects like irqdomain on what is a character > struct device with a set major/minor in dev->devt and associated > struct cdev. > > Conceptually it makes no sense to me, cdevs are software constructs, > they should never go into HW areas.. I picked that because it _is_ already used to establish the connection to the switchtec_class NTB driver which is beyond the usual cdev muck. Thanks, tglx