migration: Add Error** argument to .save_setup() handler

The purpose is to record a potential error in the migration stream if
qemu_savevm_state_setup() fails. Most of the current .save_setup()
handlers can be modified to use the Error argument instead of managing
their own and calling locally error_report().

Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Harsh Prateek Bora <harshpb@linux.ibm.com>
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Thomas Huth <thuth@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Cc: John Snow <jsnow@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/r/20240320064911.545001-8-clg@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>

3 files changed, 11 insertions, 14 deletions

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index e9bc97fee0..823164e81c 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2172,7 +2172,7 @@ static const VMStateDescription vmstate_spapr = {
     }
 };
 
-static int htab_save_setup(QEMUFile *f, void *opaque)
+static int htab_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     SpaprMachineState *spapr = opaque;
 
diff --git a/hw/s390x/s390-stattrib.c b/hw/s390x/s390-stattrib.c
index b743e8a2fe..bc04187b2b 100644
--- a/hw/s390x/s390-stattrib.c
+++ b/hw/s390x/s390-stattrib.c
@@ -168,19 +168,17 @@ static int cmma_load(QEMUFile *f, void *opaque, int version_id)
     return ret;
 }
 
-static int cmma_save_setup(QEMUFile *f, void *opaque)
+static int cmma_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     S390StAttribState *sas = S390_STATTRIB(opaque);
     S390StAttribClass *sac = S390_STATTRIB_GET_CLASS(sas);
-    Error *local_err = NULL;
     int res;
     /*
      * Signal that we want to start a migration, thus needing PGSTE dirty
      * tracking.
      */
-    res = sac->set_migrationmode(sas, true, &local_err);
+    res = sac->set_migrationmode(sas, true, errp);
     if (res) {
-        error_report_err(local_err);
         return res;
     }
     qemu_put_be64(f, STATTR_FLAG_EOS);
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index bf5a29ddc1..5763c0b683 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -376,7 +376,7 @@ static int vfio_save_prepare(void *opaque, Error **errp)
     return 0;
 }
 
-static int vfio_save_setup(QEMUFile *f, void *opaque)
+static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     VFIODevice *vbasedev = opaque;
     VFIOMigration *migration = vbasedev->migration;
@@ -390,8 +390,8 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
                                       stop_copy_size);
     migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
     if (!migration->data_buffer) {
-        error_report("%s: Failed to allocate migration data buffer",
-                     vbasedev->name);
+        error_setg(errp, "%s: Failed to allocate migration data buffer",
+                   vbasedev->name);
         return -ENOMEM;
     }
 
@@ -401,8 +401,8 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
             ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_PRE_COPY,
                                            VFIO_DEVICE_STATE_RUNNING);
             if (ret) {
-                error_report("%s: Failed to set new PRE_COPY state",
-                             vbasedev->name);
+                error_setg(errp, "%s: Failed to set new PRE_COPY state",
+                           vbasedev->name);
                 return ret;
             }
 
@@ -413,8 +413,8 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
             /* vfio_save_complete_precopy() will go to STOP_COPY */
             break;
         default:
-            error_report("%s: Invalid device state %d", vbasedev->name,
-                         migration->device_state);
+            error_setg(errp, "%s: Invalid device state %d", vbasedev->name,
+                       migration->device_state);
             return -EINVAL;
         }
     }
@@ -425,8 +425,7 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
 
     ret = qemu_file_get_error(f);
     if (ret < 0) {
-        error_report("%s: save setup failed : %s", vbasedev->name,
-                     strerror(-ret));
+        error_setg_errno(errp, -ret, "%s: save setup failed", vbasedev->name);
     }
 
     return ret;