[PATCH] mos6522: update counters when timer interrupts are off

From: Laurent Vivier <laurent@vivier.eu>
To: qemu-devel@nongnu.org
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>,
	Laurent Vivier <laurent@vivier.eu>,
	qemu-ppc@nongnu.org,
	Andrew Randrianasulu <randrianasulu@gmail.com>,
	David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH] mos6522: update counters when timer interrupts are off
Date: Mon, 25 Nov 2019 15:14:14 +0100	[thread overview]
Message-ID: <20191125141414.5015-1-laurent@vivier.eu> (raw)

Even if the interrupts are off, counters must be updated because
they are running anyway and kernel can try to read them
(it's the case with g3beige kernel).

Reported-by: Andrew Randrianasulu <randrianasulu@gmail.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 hw/misc/mos6522.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/misc/mos6522.c b/hw/misc/mos6522.c
index aa3bfe1afd..cecf0be59e 100644
--- a/hw/misc/mos6522.c
+++ b/hw/misc/mos6522.c
@@ -113,6 +113,10 @@ static int64_t get_next_irq_time(MOS6522State *s, MOS6522Timer *ti,
     int64_t d, next_time;
     unsigned int counter;
 
+    if (ti->frequency == 0) {
+        return INT64_MAX;
+    }
+
     /* current counter value */
     d = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time,
                  ti->frequency, NANOSECONDS_PER_SECOND);
@@ -149,10 +153,10 @@ static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti,
     if (!ti->timer) {
         return;
     }
+    ti->next_irq_time = get_next_irq_time(s, ti, current_time);
     if ((s->ier & T1_INT) == 0 || (s->acr & T1MODE) != T1MODE_CONT) {
         timer_del(ti->timer);
     } else {
-        ti->next_irq_time = get_next_irq_time(s, ti, current_time);
         timer_mod(ti->timer, ti->next_irq_time);
     }
 }
@@ -163,10 +167,10 @@ static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti,
     if (!ti->timer) {
         return;
     }
+    ti->next_irq_time = get_next_irq_time(s, ti, current_time);
     if ((s->ier & T2_INT) == 0) {
         timer_del(ti->timer);
     } else {
-        ti->next_irq_time = get_next_irq_time(s, ti, current_time);
         timer_mod(ti->timer, ti->next_irq_time);
     }
 }
-- 
2.21.0


