[Qemu-devel] [PULL 02/18] COLO: migrate COLO related info to secondary node

[Amit Shah <amit.shah@redhat.com>]

From: zhanghailiang <zhang.zhanghailiang@huawei.com>

We can determine whether or not VM in destination should go into COLO mode
by referring to the info that was migrated.

We skip this section if COLO is not enabled (i.e.
migrate_set_capability colo off), so that, It doesn't break compatibility
with migration no matter whether users configure the --enable-colo/disable-colo
on the source/destination side or not;

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Amit Shah <amit@amitshah.net>
---
 include/migration/colo.h |  2 ++
 migration/Makefile.objs  |  1 +
 migration/colo-comm.c    | 51 ++++++++++++++++++++++++++++++++++++++++++++++++
 vl.c                     |  3 +++
 4 files changed, 57 insertions(+)
 create mode 100644 migration/colo-comm.c

diff --git a/include/migration/colo.h b/include/migration/colo.h
index 59a632a..1c899a0 100644
--- a/include/migration/colo.h
+++ b/include/migration/colo.h
@@ -14,7 +14,9 @@
 #define QEMU_COLO_H
 
 #include "qemu-common.h"
+#include "migration/migration.h"
 
 bool colo_supported(void);
+void colo_info_init(void);
 
 #endif
diff --git a/migration/Makefile.objs b/migration/Makefile.objs
index cff96f0..4bbe9ab 100644
--- a/migration/Makefile.objs
+++ b/migration/Makefile.objs
@@ -1,6 +1,7 @@
 common-obj-y += migration.o socket.o fd.o exec.o
 common-obj-y += tls.o
 common-obj-$(CONFIG_COLO) += colo.o
+common-obj-y += colo-comm.o
 common-obj-y += vmstate.o
 common-obj-y += qemu-file.o
 common-obj-y += qemu-file-channel.o
diff --git a/migration/colo-comm.c b/migration/colo-comm.c
new file mode 100644
index 0000000..a2d5185
--- /dev/null
+++ b/migration/colo-comm.c
@@ -0,0 +1,51 @@
+/*
+ * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
+ * (a.k.a. Fault Tolerance or Continuous Replication)
+ *
+ * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2016 FUJITSU LIMITED
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include <migration/colo.h>
+#include "trace.h"
+
+typedef struct {
+     bool colo_requested;
+} COLOInfo;
+
+static COLOInfo colo_info;
+
+static void colo_info_pre_save(void *opaque)
+{
+    COLOInfo *s = opaque;
+
+    s->colo_requested = migrate_colo_enabled();
+}
+
+static bool colo_info_need(void *opaque)
+{
+   return migrate_colo_enabled();
+}
+
+static const VMStateDescription colo_state = {
+    .name = "COLOState",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .pre_save = colo_info_pre_save,
+    .needed = colo_info_need,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(colo_requested, COLOInfo),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+void colo_info_init(void)
+{
+    vmstate_register(NULL, 0, &colo_state, &colo_info);
+}
diff --git a/vl.c b/vl.c
index 74dfe4e..a1cee4f 100644
--- a/vl.c
+++ b/vl.c
@@ -90,6 +90,7 @@ int main(int argc, char **argv)
 #include "audio/audio.h"
 #include "migration/migration.h"
 #include "sysemu/cpus.h"
+#include "migration/colo.h"
 #include "sysemu/kvm.h"
 #include "qapi/qmp/qjson.h"
 #include "qemu/option.h"
@@ -4426,6 +4427,8 @@ int main(int argc, char **argv, char **envp)
 #endif
     }
 
+    colo_info_init();
+
     if (net_init_clients() < 0) {
         exit(1);
     }
-- 
2.7.4