hw/intc/arm_gicv3_its: Implement INV command properly

hw/intc/arm_gicv3_its: Implement INV command properly

We were previously implementing INV (like INVALL) to just blow away
cached highest-priority-pending-LPI information on all connected
redistributors.  For GICv4.0, this isn't going to be sufficient,
because the LPI we are invalidating cached information for might be
either physical or virtual, and the required action is different for
those two cases.  So we need to do the full process of looking up the
ITE from the devid and eventid.  This also means we can do the error
checks that the spec lists for this command.

Split out INV handling into a process_inv() function like our other
command-processing functions.  For the moment, stick to handling only
physical LPIs; we will add the vLPI parts later.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220408141550.1271295-19-peter.maydell@linaro.org