From: Benjamin Herrenschmidt <b...@kernel.crashing.org> It's very easy for the CPU specific has_work() implementation and the logic in ppc_hw_interrupt() to be subtly out of sync.
This can occasionally allow a CPU to wakeup from a PM state and resume executing past the PM instruction when it should resume at the 0x100 vector. This detects if it happens and aborts, making it a lot easier to catch such bugs when testing rather than chasing obscure guest misbehaviour. Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> Signed-off-by: Cédric Le Goater <c...@kaod.org> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au> Message-Id: <20190215161648.9600-8-...@kaod.org> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> --- target/ppc/excp_helper.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c index 37546bb0f0..1a2f469a5f 100644 --- a/target/ppc/excp_helper.c +++ b/target/ppc/excp_helper.c @@ -878,6 +878,22 @@ static void ppc_hw_interrupt(CPUPPCState *env) return; } } + + if (env->resume_as_sreset) { + /* + * This is a bug ! It means that has_work took us out of halt without + * anything to deliver while in a PM state that requires getting + * out via a 0x100 + * + * This means we will incorrectly execute past the power management + * instruction instead of triggering a reset. + * + * It generally means a discrepancy between the wakup conditions in the + * processor has_work implementation and the logic in this function. + */ + cpu_abort(CPU(ppc_env_get_cpu(env)), + "Wakeup from PM state but interrupt Undelivered"); + } } void ppc_cpu_do_system_reset(CPUState *cs) -- 2.20.1