[Qemu-devel] [PATCH v2 1/3] Add -incoming pause

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

-incoming pause causes qemu to wait for an incoming migration
to be specified later.  The monitor can be used to set migration
capabilities that may affect the incoming connection process.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
---
 migration/migration.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index b3adbc6..77263a5 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -49,6 +49,8 @@ enum {
 static NotifierList migration_state_notifiers =
     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
 
+static bool paused_incoming;
+
 /* When we add fault tolerance, we could have several
    migrations at once.  For now we don't need to add
    dynamic creation of migration */
@@ -65,25 +67,40 @@ MigrationState *migrate_get_current(void)
     return &current_migration;
 }
 
+/*
+ * Called on -incoming with a pause: uri.
+ * The migration can be started later after any parameters have been
+ * changed.
+ */
+static void paused_incoming_migration(Error **errp)
+{
+    if (paused_incoming) {
+        error_setg(errp, "Pausing an already paused incoming migration");
+    }
+    paused_incoming = true;
+}
+
 void qemu_start_incoming_migration(const char *uri, Error **errp)
 {
     const char *p;
 
-    if (strstart(uri, "tcp:", &p))
+    if (!strcmp(uri, "pause")) {
+        paused_incoming_migration(errp);
+    } else if (strstart(uri, "tcp:", &p)) {
         tcp_start_incoming_migration(p, errp);
 #ifdef CONFIG_RDMA
-    else if (strstart(uri, "rdma:", &p))
+    } else if (strstart(uri, "rdma:", &p)) {
         rdma_start_incoming_migration(p, errp);
 #endif
 #if !defined(WIN32)
-    else if (strstart(uri, "exec:", &p))
+    } else if (strstart(uri, "exec:", &p)) {
         exec_start_incoming_migration(p, errp);
-    else if (strstart(uri, "unix:", &p))
+    } else if (strstart(uri, "unix:", &p)) {
         unix_start_incoming_migration(p, errp);
-    else if (strstart(uri, "fd:", &p))
+    } else if (strstart(uri, "fd:", &p)) {
         fd_start_incoming_migration(p, errp);
 #endif
-    else {
+    } else {
         error_setg(errp, "unknown migration protocol: %s", uri);
     }
 }
-- 
2.1.0