migration: pre_save return int

Modify the pre_save method on VMStateDescription to return an int
rather than void so that it potentially can fail.

Changed zillions of devices to make them return 0; the only
case I've made it return non-0 is hw/intc/s390_flic_kvm.c that already
had an error_report/return case.

Note: If you add an error exit in your pre_save you must emit
an error_report to say why.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170925112917.21340-2-dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

6 files changed, 18 insertions, 6 deletions

diff --git a/hw/timer/cadence_ttc.c b/hw/timer/cadence_ttc.c
index 03f5b9c..5e65fdb 100644
--- a/hw/timer/cadence_ttc.c
+++ b/hw/timer/cadence_ttc.c
@@ -421,9 +421,11 @@ static void cadence_ttc_init(Object *obj)
     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->iomem);
 }
 
-static void cadence_timer_pre_save(void *opaque)
+static int cadence_timer_pre_save(void *opaque)
 {
     cadence_timer_sync((CadenceTimerState *)opaque);
+
+    return 0;
 }
 
 static int cadence_timer_post_load(void *opaque, int version_id)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index a2c18b3..577371b 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -216,12 +216,14 @@ static void update_irq(struct HPETTimer *timer, int set)
     }
 }
 
-static void hpet_pre_save(void *opaque)
+static int hpet_pre_save(void *opaque)
 {
     HPETState *s = opaque;
 
     /* save current counter value */
     s->hpet_counter = hpet_get_ticks(s);
+
+    return 0;
 }
 
 static int hpet_pre_load(void *opaque)
diff --git a/hw/timer/i8254_common.c b/hw/timer/i8254_common.c
index ee064aa..b623c96 100644
--- a/hw/timer/i8254_common.c
+++ b/hw/timer/i8254_common.c
@@ -237,7 +237,7 @@ static int pit_load_old(QEMUFile *f, void *opaque, int version_id)
     return 0;
 }
 
-static void pit_dispatch_pre_save(void *opaque)
+static int pit_dispatch_pre_save(void *opaque)
 {
     PITCommonState *s = opaque;
     PITCommonClass *c = PIT_COMMON_GET_CLASS(s);
@@ -245,6 +245,8 @@ static void pit_dispatch_pre_save(void *opaque)
     if (c->pre_save) {
         c->pre_save(s);
     }
+
+    return 0;
 }
 
 static int pit_dispatch_post_load(void *opaque, int version_id)
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index 82843ed..7764be2 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -795,11 +795,13 @@ static void rtc_set_date_from_host(ISADevice *dev)
     rtc_set_cmos(s, &tm);
 }
 
-static void rtc_pre_save(void *opaque)
+static int rtc_pre_save(void *opaque)
 {
     RTCState *s = opaque;
 
     rtc_update_time(s);
+
+    return 0;
 }
 
 static int rtc_post_load(void *opaque, int version_id)
diff --git a/hw/timer/pl031.c b/hw/timer/pl031.c
index dbbeb9b..d3aacce 100644
--- a/hw/timer/pl031.c
+++ b/hw/timer/pl031.c
@@ -211,7 +211,7 @@ static void pl031_init(Object *obj)
     s->timer = timer_new_ns(rtc_clock, pl031_interrupt, s);
 }
 
-static void pl031_pre_save(void *opaque)
+static int pl031_pre_save(void *opaque)
 {
     PL031State *s = opaque;
 
@@ -219,6 +219,8 @@ static void pl031_pre_save(void *opaque)
      * store the base time relative to the QEMU_CLOCK_VIRTUAL for backwards-compatibility.  */
     int64_t delta = qemu_clock_get_ns(rtc_clock) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
     s->tick_offset_vmstate = s->tick_offset + delta / NANOSECONDS_PER_SECOND;
+
+    return 0;
 }
 
 static int pl031_post_load(void *opaque, int version_id)
diff --git a/hw/timer/twl92230.c b/hw/timer/twl92230.c
index c0aa8ae..eb58c37 100644
--- a/hw/timer/twl92230.c
+++ b/hw/timer/twl92230.c
@@ -791,11 +791,13 @@ static const VMStateDescription vmstate_menelaus_tm = {
     }
 };
 
-static void menelaus_pre_save(void *opaque)
+static int menelaus_pre_save(void *opaque)
 {
     MenelausState *s = opaque;
     /* Should be <= 1000 */
     s->rtc_next_vmstate =  s->rtc.next - qemu_clock_get_ms(rtc_clock);
+
+    return 0;
 }
 
 static int menelaus_post_load(void *opaque, int version_id)