From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:57580) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gyUkh-0004ss-MW for qemu-devel@nongnu.org; Mon, 25 Feb 2019 23:54:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gyUkd-000247-ER for qemu-devel@nongnu.org; Mon, 25 Feb 2019 23:53:57 -0500 From: David Gibson Date: Tue, 26 Feb 2019 15:52:21 +1100 Message-Id: <20190226045304.25618-8-david@gibson.dropbear.id.au> In-Reply-To: <20190226045304.25618-1-david@gibson.dropbear.id.au> References: <20190226045304.25618-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 07/50] target/ppc: Detect erroneous condition in interrupt delivery List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: peter.maydell@linaro.org Cc: gkurz@kaod.org, clg@kaod.org, lvivier@redhat.com, qemu-devel@nongnu.org, qemu-ppc@nongnu.org, Benjamin Herrenschmidt , David Gibson From: Benjamin Herrenschmidt 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 Signed-off-by: C=C3=A9dric Le Goater Reviewed-by: David Gibson Message-Id: <20190215161648.9600-8-clg@kaod.org> Signed-off-by: David Gibson --- 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 wi= thout + * anything to deliver while in a PM state that requires getting + * out via a 0x100 + * + * This means we will incorrectly execute past the power managem= ent + * 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 funct= ion. + */ + cpu_abort(CPU(ppc_env_get_cpu(env)), + "Wakeup from PM state but interrupt Undelivered"); + } } =20 void ppc_cpu_do_system_reset(CPUState *cs) --=20 2.20.1