Of the MSI-X PBA pending bits, the PCI Local Bus Specification says:
Software should never write, and should only read
Pending Bits. If software writes to Pending Bits, the
result is undefined.
Log a GUEST_ERROR message if the PBA is written to by software.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: Dmitry Fleytman <dmitry.fleytman@gmail.com>
Cc: Akihiko Odaki <akihiko.odaki@daynix.com>
Cc: Sriram Yagnaraman <sriram.yagnaraman@ericsson.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>