[COLO-Frame,v11,02/39] migration: Introduce capability 'x-colo' to migration

diff --git a/include/migration/colo.h b/include/migration/colo.h
new file mode 100644
index 0000000..c60a590
--- /dev/null
+++ b/include/migration/colo.h
@@ -0,0 +1,20 @@ 
+/*
+ * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
+ * (a.k.a. Fault Tolerance or Continuous Replication)
+ *
+ * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2015 FUJITSU LIMITED
+ * Copyright (c) 2015 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.
+ */
+
+#ifndef QEMU_COLO_H
+#define QEMU_COLO_H
+
+#include "qemu-common.h"
+
+bool colo_supported(void);
+
+#endif
diff --git a/include/migration/migration.h b/include/migration/migration.h
index fd018b7..1f004e4 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -268,6 +268,7 @@  int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen);
 
 int migrate_use_xbzrle(void);
 int64_t migrate_xbzrle_cache_size(void);
+bool migrate_colo_enabled(void);
 
 int64_t xbzrle_cache_resize(int64_t new_size);
 
diff --git a/migration/Makefile.objs b/migration/Makefile.objs
index 0cac6d7..65ecc35 100644
--- a/migration/Makefile.objs
+++ b/migration/Makefile.objs
@@ -1,4 +1,5 @@ 
 common-obj-y += migration.o tcp.o
+common-obj-$(CONFIG_COLO) += colo.o
 common-obj-y += vmstate.o
 common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o
 common-obj-y += xbzrle.o postcopy-ram.o
diff --git a/migration/colo.c b/migration/colo.c
new file mode 100644
index 0000000..2c40d2e
--- /dev/null
+++ b/migration/colo.c
@@ -0,0 +1,18 @@ 
+/*
+ * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
+ * (a.k.a. Fault Tolerance or Continuous Replication)
+ *
+ * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2015 FUJITSU LIMITED
+ * Copyright (c) 2015 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 "migration/colo.h"
+
+bool colo_supported(void)
+{
+    return true;
+}
diff --git a/migration/migration.c b/migration/migration.c
index 1a42aee..efacf52 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -33,6 +33,7 @@ 
 #include "qom/cpu.h"
 #include "exec/memory.h"
 #include "exec/address-spaces.h"
+#include "migration/colo.h"
 
 #define MAX_THROTTLE  (32 << 20)      /* Migration transfer speed throttling */
 
@@ -480,6 +481,9 @@  MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
 
     caps = NULL; /* silence compiler warning */
     for (i = 0; i < MIGRATION_CAPABILITY_MAX; i++) {
+        if (i == MIGRATION_CAPABILITY_X_COLO && !colo_supported()) {
+            continue;
+        }
         if (head == NULL) {
             head = g_malloc0(sizeof(*caps));
             caps = head;
@@ -679,6 +683,13 @@  void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
     }
 
     for (cap = params; cap; cap = cap->next) {
+        if (cap->value->capability == MIGRATION_CAPABILITY_X_COLO &&
+            !colo_supported()) {
+            error_setg(errp, "COLO is not currently supported, please"
+                             " configure with --enable-colo option in order to"
+                             " support COLO feature");
+            continue;
+        }
         s->enabled_capabilities[cap->value->capability] = cap->value->state;
     }
 
@@ -1581,6 +1592,12 @@  fail:
     migrate_set_state(s, current_active_state, MIGRATION_STATUS_FAILED);
 }
 
+bool migrate_colo_enabled(void)
+{
+    MigrationState *s = migrate_get_current();
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO];
+}
+
 /*
  * Master migration thread on the source VM.
  * It drives the migration and pumps the data down the outgoing channel.
diff --git a/qapi-schema.json b/qapi-schema.json
index 8b1a423..d20c0ec 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -546,11 +546,15 @@ 
 #          been migrated, pulling the remaining pages along as needed. NOTE: If
 #          the migration fails during postcopy the VM will fail.  (since 2.5)
 #
+# @x-colo: If enabled, migration will never end, and the state of the VM on the
+#        primary side will be migrated continuously to the VM on secondary
+#        side. (since 2.6)
+#
 # Since: 1.2
 ##
 { 'enum': 'MigrationCapability',
   'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
-           'compress', 'events', 'x-postcopy-ram'] }
+           'compress', 'events', 'x-postcopy-ram', 'x-colo'] }
 
 ##
 # @MigrationCapabilityStatus
diff --git a/qmp-commands.hx b/qmp-commands.hx
index e209688..92042d8 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -3625,6 +3625,7 @@  Query current migration capabilities
          - "rdma-pin-all" : RDMA Pin Page state (json-bool)
          - "auto-converge" : Auto Converge state (json-bool)
          - "zero-blocks" : Zero Blocks state (json-bool)
+         - "x-colo" : COarse-Grain LOck Stepping for Non-stop Service (json-bool)
 
 Arguments:
 
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index d7898a0..12eb4c6 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -38,3 +38,4 @@  stub-obj-y += qmp_pc_dimm_device_list.o
 stub-obj-y += target-monitor-defs.o
 stub-obj-y += target-get-monitor-def.o
 stub-obj-y += vhost.o
+stub-obj-y += migration-colo.o
diff --git a/stubs/migration-colo.c b/stubs/migration-colo.c
new file mode 100644
index 0000000..3d817df
--- /dev/null
+++ b/stubs/migration-colo.c
@@ -0,0 +1,18 @@ 
+/*
+ * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
+ * (a.k.a. Fault Tolerance or Continuous Replication)
+ *
+ * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2015 FUJITSU LIMITED
+ * Copyright (c) 2015 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 "migration/colo.h"
+
+bool colo_supported(void)
+{
+    return false;
+}