At present the code handling IBM's Enhanced Error Handling (EEH) interface
on VFIO devices operates by bypassing the usual VFIO logic with
vfio_container_ioctl(). That's a poorly designed interface with unclear
semantics about exactly what can be operated on.
In particular it operates on a single vfio container internally (hence the
name), but takes an address space and group id, from which it deduces the
container in a rather roundabout way. groupids are something that code
outside vfio shouldn't even be aware of.
This patch creates new interfaces for EEH operations. Internally we
have vfio_eeh_container_op() which takes a VFIOContainer object
directly. For external use we have vfio_eeh_as_ok() which determines
if an AddressSpace is usable for EEH (at present this means it has a
single container and at most a single group attached), and
vfio_eeh_as_op() which will perform an operation on an AddressSpace in
the unambiguous case, and otherwise returns an error.
This interface still isn't great, but it's enough of an improvement to
allow a number of cleanups in other places.
Signed-off-by: David Gibson <address@hidden>