pnv/xive2: Fix TIMA offset for indirect access

pnv/xive2: Fix TIMA offset for indirect access

Direct TIMA operations can be done through 4 pages, each with a
different privilege level dictating what fields can be accessed. On
the other hand, indirect TIMA accesses on P10 are done through a
single page, which is the equivalent of the most privileged page of
direct TIMA accesses.

The offset in the IC bar of an indirect access specifies what hw
thread is targeted (page shift bits) and the offset in the
TIMA being accessed (the page offset bits). When the indirect
access is calling the underlying direct access functions, it is
therefore important to clearly separate the 2, as the direct functions
assume any page shift bits define the privilege ring level. For
indirect accesses, those bits must be 0. This patch fixes the offset
passed to direct TIMA functions.

It didn't matter for SMT1, as the 2 least significant bits of the page
shift are part of the hw thread ID and always 0, so the direct TIMA
functions were accessing the privilege ring 0 page. With SMT4/8, it is
no longer true.

The fix is specific to P10, as indirect TIMA access on P9 was handled
differently.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-ID: <20230703080858.54060-1-fbarrat@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>