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>

1 files changed, 3 insertions, 1 deletions

diff --git a/hw/intc/arm_gicv3_its_common.c b/hw/intc/arm_gicv3_its_common.c
index 68b20fccd1..f2cce597a9 100644
--- a/hw/intc/arm_gicv3_its_common.c
+++ b/hw/intc/arm_gicv3_its_common.c
@@ -23,7 +23,7 @@
 #include "hw/intc/arm_gicv3_its_common.h"
 #include "qemu/log.h"
 
-static void gicv3_its_pre_save(void *opaque)
+static int gicv3_its_pre_save(void *opaque)
 {
     GICv3ITSState *s = (GICv3ITSState *)opaque;
     GICv3ITSCommonClass *c = ARM_GICV3_ITS_COMMON_GET_CLASS(s);
@@ -31,6 +31,8 @@ static void gicv3_its_pre_save(void *opaque)
     if (c->pre_save) {
         c->pre_save(s);
     }
+
+    return 0;
 }
 
 static int gicv3_its_post_load(void *opaque, int version_id)