On Thu, 2014-05-29 at 00:46 +0200, Alexander Graf wrote:

I don't think so :). In QEMU the PHB emulation would have to notify the 
"container" (IOMMU emulation layer -> PE) that a PE operation happened. 
It's that emulation code's responsibility to broadcast operations across 
its own emulated operations (recover config space access, reconfigure 
BARs, etc) and the VFIO PE operations.

So from a kernel interface point of view, I think leaving out any 
address information is the right way to go. Whether we managed to get 
all QEMU internal interfaces modeled correctly yet has to be seen on the 
next patch set revision :).

For a kernel interface I absolutely agree, all we care about is the group fd.

From a qemu internal, I suppose it makes things easier to operate at the PHB

level for now and we can revisit later if the need arises.

Cheers,
Ben.