[PATCH v2 07/21] migration: Add Error** argument to .load_setup() handler

["Cédric Le Goater" <clg@redhat.com>]

This will be useful to report errors at a higher level, mostly in VFIO
today.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 include/migration/register.h |  3 ++-
 hw/vfio/migration.c          |  2 +-
 migration/ram.c              |  3 ++-
 migration/savevm.c           | 10 ++++++----
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/include/migration/register.h b/include/migration/register.h
index 96eae9dba2970552c379c732393e3ab6ef578a58..2cfc167f717de8e08c1ca8accdc3011c03eb1554 100644
--- a/include/migration/register.h
+++ b/include/migration/register.h
@@ -231,10 +231,11 @@ typedef struct SaveVMHandlers {
      *
      * @f: QEMUFile where to receive the data
      * @opaque: data pointer passed to register_savevm_live()
+     * @errp: pointer to Error*, to store an error if it happens.
      *
      * Returns zero to indicate success and negative for error
      */
-    int (*load_setup)(QEMUFile *f, void *opaque);
+    int (*load_setup)(QEMUFile *f, void *opaque, Error **errp);
 
     /**
      * @load_cleanup
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 8bcb4bc73cd5ba5338e3ffa4d907d0e6bfbb9485..2dfbe671f6f45aa530c7341177bb532d8292cecd 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -580,7 +580,7 @@ static void vfio_save_state(QEMUFile *f, void *opaque)
     }
 }
 
-static int vfio_load_setup(QEMUFile *f, void *opaque)
+static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     VFIODevice *vbasedev = opaque;
 
diff --git a/migration/ram.c b/migration/ram.c
index 745482899e18c86b73261b683c1bec04039a76d2..d648134133fc22cd91c7b2064198a90287ee733d 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3498,8 +3498,9 @@ void colo_release_ram_cache(void)
  *
  * @f: QEMUFile where to receive the data
  * @opaque: RAMState pointer
+ * @errp: pointer to Error*, to store an error if it happens.
  */
-static int ram_load_setup(QEMUFile *f, void *opaque)
+static int ram_load_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     xbzrle_load_setup();
     ramblock_recv_map_init();
diff --git a/migration/savevm.c b/migration/savevm.c
index b5b3b51bad94dc4c04ae22cd687ba111299339aa..a4ef41d3ff5b471a1cd4166c2dc5813e44ea3a5a 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2741,7 +2741,7 @@ static void qemu_loadvm_state_switchover_ack_needed(MigrationIncomingState *mis)
     trace_loadvm_state_switchover_ack_needed(mis->switchover_ack_pending_num);
 }
 
-static int qemu_loadvm_state_setup(QEMUFile *f)
+static int qemu_loadvm_state_setup(QEMUFile *f, Error **errp)
 {
     SaveStateEntry *se;
     int ret;
@@ -2757,10 +2757,11 @@ static int qemu_loadvm_state_setup(QEMUFile *f)
             }
         }
 
-        ret = se->ops->load_setup(f, se->opaque);
+        ret = se->ops->load_setup(f, se->opaque, errp);
         if (ret < 0) {
+            error_prepend(errp, "Load state of device %s failed: ",
+                          se->idstr);
             qemu_file_set_error(f, ret);
-            error_report("Load state of device %s failed", se->idstr);
             return ret;
         }
     }
@@ -2941,7 +2942,8 @@ int qemu_loadvm_state(QEMUFile *f)
         return ret;
     }
 
-    if (qemu_loadvm_state_setup(f) != 0) {
+    if (qemu_loadvm_state_setup(f, &local_err) != 0) {
+        error_report_err(local_err);
         return -EINVAL;
     }
 
-- 
2.43.2