RE: [RFC 03/20] vfio: Add vfio_[un]register_device()

[Tian, Kevin]

> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Wednesday, September 22, 2021 12:01 AM
> 
> >  One open about how to organize the device nodes under
> /dev/vfio/devices/.
> > This RFC adopts a simple policy by keeping a flat layout with mixed
> devname
> > from all kinds of devices. The prerequisite of this model is that devnames
> > from different bus types are unique formats:
> 
> This isn't reliable, the devname should just be vfio0, vfio1, etc
> 
> The userspace can learn the correct major/minor by inspecting the
> sysfs.
> 
> This whole concept should disappear into the prior patch that adds the
> struct device in the first place, and I think most of the code here
> can be deleted once the struct device is used properly.
> 

Can you help elaborate above flow? This is one area where we need
more guidance.

When Qemu accepts an option "-device vfio-pci,host=DDDD:BB:DD.F",
how does Qemu identify which vifo0/1/... is associated with the specified 
DDDD:BB:DD.F? 

Thanks
Kevin