[Qemu-devel] [RFC PATCH v2 04/23] COLO migration: add a migration capability 'colo'

[Yang Hongyang]

Add a migration capability 'colo'. If this capability is on,
The migration will never end, and the VM will be continuously
checkpointed.

Signed-off-by: Yang Hongyang <address@hidden>
---
 migration.c      | 8 ++++++++
 qapi-schema.json | 5 ++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/migration.c b/migration.c
index 8d675b3..5d28237 100644
--- a/migration.c
+++ b/migration.c
@@ -25,6 +25,7 @@
 #include "qemu/thread.h"
 #include "qmp-commands.h"
 #include "trace.h"
+#include "migration/migration-colo.h"
 
 enum {
     MIG_STATE_ERROR = -1,
@@ -277,6 +278,13 @@ void 
qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
     }
 
     for (cap = params; cap; cap = cap->next) {
+        if (cap->value->capability == MIGRATION_CAPABILITY_COLO &&
+            cap->value->state && !colo_supported()) {
+            error_setg(errp, "COLO is not currently supported, please rerun"
+                             " configure with --enable-colo option in order to"
+                             " support COLO feature");
+            continue;
+        }
         s->enabled_capabilities[cap->value->capability] = cap->value->state;
     }
 }
diff --git a/qapi-schema.json b/qapi-schema.json
index 689b548..8d58ef7 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -491,10 +491,13 @@
 # @auto-converge: If enabled, QEMU will automatically throttle down the guest
 #          to speed up convergence of RAM migration. (since 1.6)
 #
+# @colo: If enabled, the migration will never end, and the VM will instead be
+#          continuously checkpointed. (since 2.2)
+#
 # Since: 1.2
 ##
 { 'enum': 'MigrationCapability',
-  'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks'] }
+  'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks', 'colo'] }
 
 ##
 # @MigrationCapabilityStatus
-- 
1.9.1