From 5e104f24e7ddfa33d5e99b6363c7baf02849f9b7 Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Tue, 17 Jan 2023 12:22:42 +0100
Subject: [PATCH] migration/savevm: Move more savevm handling into
 vmstate_save()

Let's move more code into vmstate_save(), reducing code duplication and
preparing for reuse of vmstate_save() in qemu_savevm_state_setup(). We
have to move vmstate_save() to make the compiler happy.

We'll now also trace from qemu_save_device_state(), triggering the same
tracepoints as previously called from
qemu_savevm_state_complete_precopy_non_iterable() only. Note that
qemu_save_device_state() ignores iterable device state, such as RAM,
and consequently doesn't trigger some other trace points (e.g.,
trace_savevm_state_setup()).

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/savevm.c | 79 ++++++++++++++++++++++------------------------
 1 file changed, 37 insertions(+), 42 deletions(-)

diff --git a/migration/savevm.c b/migration/savevm.c
index e1caa3ea7c..3e3631652e 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -898,17 +898,6 @@ static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se,
     }
 }
 
-static int vmstate_save(QEMUFile *f, SaveStateEntry *se,
-                        JSONWriter *vmdesc)
-{
-    trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
-    if (!se->vmsd) {
-        vmstate_save_old_style(f, se, vmdesc);
-        return 0;
-    }
-    return vmstate_save_state(f, se->vmsd, se->opaque, vmdesc);
-}
-
 /*
  * Write the header for device section (QEMU_VM_SECTION START/END/PART/FULL)
  */
@@ -942,6 +931,43 @@ static void save_section_footer(QEMUFile *f, SaveStateEntry *se)
     }
 }
 
+static int vmstate_save(QEMUFile *f, SaveStateEntry *se, JSONWriter *vmdesc)
+{
+    int ret;
+
+    if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
+        return 0;
+    }
+    if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
+        trace_savevm_section_skip(se->idstr, se->section_id);
+        return 0;
+    }
+
+    trace_savevm_section_start(se->idstr, se->section_id);
+    save_section_header(f, se, QEMU_VM_SECTION_FULL);
+    if (vmdesc) {
+        json_writer_start_object(vmdesc, NULL);
+        json_writer_str(vmdesc, "name", se->idstr);
+        json_writer_int64(vmdesc, "instance_id", se->instance_id);
+    }
+
+    trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)");
+    if (!se->vmsd) {
+        vmstate_save_old_style(f, se, vmdesc);
+    } else {
+        ret = vmstate_save_state(f, se->vmsd, se->opaque, vmdesc);
+        if (ret) {
+            return ret;
+        }
+    }
+
+    trace_savevm_section_end(se->idstr, se->section_id, 0);
+    save_section_footer(f, se);
+    if (vmdesc) {
+        json_writer_end_object(vmdesc);
+    }
+    return 0;
+}
 /**
  * qemu_savevm_command_send: Send a 'QEMU_VM_COMMAND' type element with the
  *                           command and associated data.
@@ -1375,31 +1401,11 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
     json_writer_int64(vmdesc, "page_size", qemu_target_page_size());
     json_writer_start_array(vmdesc, "devices");
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
-
-        if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
-            continue;
-        }
-        if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
-            trace_savevm_section_skip(se->idstr, se->section_id);
-            continue;
-        }
-
-        trace_savevm_section_start(se->idstr, se->section_id);
-
-        json_writer_start_object(vmdesc, NULL);
-        json_writer_str(vmdesc, "name", se->idstr);
-        json_writer_int64(vmdesc, "instance_id", se->instance_id);
-
-        save_section_header(f, se, QEMU_VM_SECTION_FULL);
         ret = vmstate_save(f, se, vmdesc);
         if (ret) {
             qemu_file_set_error(f, ret);
             return ret;
         }
-        trace_savevm_section_end(se->idstr, se->section_id, 0);
-        save_section_footer(f, se);
-
-        json_writer_end_object(vmdesc);
     }
 
     if (inactivate_disks) {
@@ -1618,21 +1624,10 @@ int qemu_save_device_state(QEMUFile *f)
         if (se->is_ram) {
             continue;
         }
-        if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
-            continue;
-        }
-        if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
-            continue;
-        }
-
-        save_section_header(f, se, QEMU_VM_SECTION_FULL);
-
         ret = vmstate_save(f, se, NULL);
         if (ret) {
             return ret;
         }
-
-        save_section_footer(f, se);
     }
 
     qemu_put_byte(f, QEMU_VM_EOF);