tree 789d3ed07b8aa9b649d05e5792cbc23da74ae319
parent 3d65b958c5463a1c06cac51b6474097ecdbb576e
author Peter Maydell <peter.maydell@linaro.org> 1704811424 +0000
committer Peter Maydell <peter.maydell@linaro.org> 1704811424 +0000

hw/intc/arm_gicv3_cpuif: handle LPIs in in the list registers

The hypervisor can deliver (virtual) LPIs to a guest by setting up a
list register to have an intid which is an LPI.  The GIC has to treat
these a little differently to standard interrupt IDs, because LPIs
have no Active state, and so the guest will only EOI them, it will
not also deactivate them.  So icv_eoir_write() must do two things:

 * if the LPI ID is not in any list register, we drop the
   priority but do not increment the EOI count
 * if the LPI ID is in a list register, we immediately deactivate
   it, regardless of the split-drop-and-deactivate control

This can be seen in the VirtualWriteEOIR0() and VirtualWriteEOIR1()
pseudocode in the GICv3 architecture specification.

Without this fix, potentially a hypervisor guest might stall because
LPIs get stuck in a bogus Active+Pending state.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Miguel Luis <miguel.luis@oracle.com>