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>
82a65e3188