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/target/arm/machine.c b/target/arm/machine.c
index e5fe083da4..29df7ac87d 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -394,7 +394,7 @@ static const VMStateInfo vmstate_powered_off = {
     .put = put_power,
 };
 
-static void cpu_pre_save(void *opaque)
+static int cpu_pre_save(void *opaque)
 {
     ARMCPU *cpu = opaque;
 
@@ -415,6 +415,8 @@ static void cpu_pre_save(void *opaque)
            cpu->cpreg_array_len * sizeof(uint64_t));
     memcpy(cpu->cpreg_vmstate_values, cpu->cpreg_values,
            cpu->cpreg_array_len * sizeof(uint64_t));
+
+    return 0;
 }
 
 static int cpu_post_load(void *opaque, int version_id)