Message ID | 20190128094625.4428-16-clg@kaod.org (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | ppc: support for the baremetal XIVE interrupt controller (POWER9) | expand |
On Mon, Jan 28, 2019 at 10:46:21AM +0100, Cédric Le Goater wrote: > From: Benjamin Herrenschmidt <benh@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 <benh@kernel.crashing.org> > Signed-off-by: Cédric Le Goater <clg@kaod.org> Reviewed-by: David Gibson <david@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 37546bb0f0fe..1a2f469a5fa2 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)
diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c index 37546bb0f0fe..1a2f469a5fa2 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)