Excerpts from Frederic Barrat's message of 2016-02-07 00:28:50 +1100:

Cxl kernel API was defining the process problem state area during
context initialization, making it possible to map the problem state
area before attaching the context. This won't work on a powerVM
guest. So do the logical thing, like in userspace: attach first, then
map the problem state area.
Remove calls to cxl_assign_psn_space during init. The function is
already called on the attach paths.

Looks good.

It might be a reasonable idea to make cxl_psa_map fail outright if it is
called on a context that has not been attached yet like we do in the
user api, but I trust kernel devs to get this right more than userspace
so I'm not too worried :)

Cheers,
-Ian