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>

1 files changed, 8 insertions, 7 deletions

diff --git a/migration/ram.c b/migration/ram.c
index 44d7073730..6ea5a06e00 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3066,22 +3066,23 @@ static bool mapped_ram_read_header(QEMUFile *file, MappedRamHeader *header,
  *
  * @f: QEMUFile where to send the data
  * @opaque: RAMState pointer
+ * @errp: pointer to Error*, to store an error if it happens.
  */
-static int ram_save_setup(QEMUFile *f, void *opaque)
+static int ram_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     RAMState **rsp = opaque;
     RAMBlock *block;
     int ret, max_hg_page_size;
 
     if (compress_threads_save_setup()) {
-        error_report("%s: failed to start compress threads", __func__);
+        error_setg(errp, "%s: failed to start compress threads", __func__);
         return -1;
     }
 
     /* migration has already setup the bitmap, reuse it. */
     if (!migration_in_colo_state()) {
         if (ram_init_all(rsp) != 0) {
-            error_report("%s: failed to setup RAM for migration", __func__);
+            error_setg(errp, "%s: failed to setup RAM for migration", __func__);
             compress_threads_save_cleanup();
             return -1;
         }
@@ -3118,14 +3119,14 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
 
     ret = rdma_registration_start(f, RAM_CONTROL_SETUP);
     if (ret < 0) {
-        error_report("%s: failed to start RDMA registration", __func__);
+        error_setg(errp, "%s: failed to start RDMA registration", __func__);
         qemu_file_set_error(f, ret);
         return ret;
     }
 
     ret = rdma_registration_stop(f, RAM_CONTROL_SETUP);
     if (ret < 0) {
-        error_report("%s: failed to stop RDMA registration", __func__);
+        error_setg(errp, "%s: failed to stop RDMA registration", __func__);
         qemu_file_set_error(f, ret);
         return ret;
     }
@@ -3142,7 +3143,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     ret = multifd_send_sync_main();
     bql_lock();
     if (ret < 0) {
-        error_report("%s: multifd synchronization failed", __func__);
+        error_setg(errp, "%s: multifd synchronization failed", __func__);
         return ret;
     }
 
@@ -3154,7 +3155,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
     ret = qemu_fflush(f);
     if (ret < 0) {
-        error_report("%s failed : %s", __func__, strerror(-ret));
+        error_setg_errno(errp, -ret, "%s failed", __func__);
     }
     return ret;
 }