From: Peter Xu <peterx@redhat.com>
Date: Tue, 27 Jan 2026 18:52:54 +0000 (-0500)
Subject: migration/colo/xen: Use generic helpers in qemu_save_device_state()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=32ed27e5b920695c82c5a397d3837a00a5b5b46a;p=thirdparty%2Fqemu.git

migration/colo/xen: Use generic helpers in qemu_save_device_state()

Use qemu_savevm_state_non_iterable*() helpers for saving device states,
rather than walking the vmstate handlers on its own.

Non-iterables can be either early_setup devices, or otherwise.

Note that QEMU only has one early_setup device currently, which is
virtio-mem, and I highly doubt if it is used in either COLO or Xen users..
However this step is still better needed to provide full coverage of all
non-iterable vmstates.

When at it, allow it to report errors.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Paul Durrant <paul@xen.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Tested-by: Lukas Straub <lukasstraub2@web.de>
Link: https://lore.kernel.org/qemu-devel/20260127185254.3954634-25-peterx@redhat.com
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---

diff --git a/migration/colo.c b/migration/colo.c
index db804b25a9..f7a5bd3619 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -454,7 +454,7 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
     }
 
     /* Note: device state is saved into buffer */
-    ret = qemu_save_device_state(fb);
+    ret = qemu_save_device_state(fb, &local_err);
 
     bql_unlock();
     if (ret < 0) {
diff --git a/migration/savevm.c b/migration/savevm.c
index b29272db3b..3a16c467b2 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1887,26 +1887,24 @@ static bool qemu_savevm_se_iterable(SaveStateEntry *se)
     return se->ops && se->ops->save_setup;
 }
 
-int qemu_save_device_state(QEMUFile *f)
+int qemu_save_device_state(QEMUFile *f, Error **errp)
 {
-    Error *local_err = NULL;
-    SaveStateEntry *se;
-
-    cpu_synchronize_all_states();
+    int ret;
 
-    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
-        int ret;
+    /* Both COLO and Xen never use vmdesc, hence NULL. */
+    ret = qemu_savevm_state_non_iterable_early(f, NULL, errp);
+    if (ret) {
+        return ret;
+    }
 
-        ret = vmstate_save(f, se, NULL, &local_err);
-        if (ret) {
-            error_report_err(local_err);
-            return ret;
-        }
+    ret = qemu_savevm_state_non_iterable(f, errp);
+    if (ret) {
+        return ret;
     }
 
     qemu_savevm_state_end(f);
 
-    return qemu_file_get_error(f);
+    return 0;
 }
 
 static SaveStateEntry *find_se(const char *idstr, uint32_t instance_id)
@@ -3346,9 +3344,11 @@ void qmp_xen_save_devices_state(const char *filename, bool has_live, bool live,
     f = qemu_file_new_output(QIO_CHANNEL(ioc));
     object_unref(OBJECT(ioc));
     qemu_savevm_send_header(f);
-    ret = qemu_save_device_state(f);
+    ret = qemu_save_device_state(f, errp);
     if (ret < 0 || qemu_fclose(f) < 0) {
-        error_setg(errp, "saving Xen device state failed");
+        if (*errp == NULL) {
+            error_setg(errp, "saving Xen device state failed");
+        }
     } else {
         /* libxl calls the QMP command "stop" before calling
          * "xen-save-devices-state" and in case of migration failure, libxl
diff --git a/migration/savevm.h b/migration/savevm.h
index 6a589b2990..2ba0881f3b 100644
--- a/migration/savevm.h
+++ b/migration/savevm.h
@@ -66,8 +66,7 @@ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
                                            uint64_t *start_list,
                                            uint64_t *length_list);
 void qemu_savevm_send_colo_enable(QEMUFile *f);
-int qemu_save_device_state(QEMUFile *f);
-
+int qemu_save_device_state(QEMUFile *f, Error **errp);
 int qemu_loadvm_state(QEMUFile *f, Error **errp);
 void qemu_loadvm_state_cleanup(MigrationIncomingState *mis);
 int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis,