migration: New migrate and migrate-incoming argument 'channels'

MigrateChannelList allows to connect accross multiple interfaces.
Add MigrateChannelList struct as argument to migration QAPIs.

We plan to include multiple channels in future, to connnect
multiple interfaces. Hence, we choose 'MigrateChannelList'
as the new argument over 'MigrateChannel' to make migration
QAPIs future proof.

Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231023182053.8711-10-farosas@suse.de>

qapi/migration.json

@@ -1641,6 +1641,34 @@
     'rdma': 'InetSocketAddress',
     'file': 'FileMigrationArgs' } }
 
+##
+# @MigrationChannelType:
+#
+# The migration channel-type request options.
+#
+# @main: Main outbound migration channel.
+#
+# Since 8.1
+##
+{ 'enum': 'MigrationChannelType',
+  'data': [ 'main' ] }
+
+##
+# @MigrationChannel:
+#
+# Migration stream channel parameters.
+#
+# @channel-type: Channel type for transfering packet information.
+#
+# @addr: Migration endpoint configuration on destination interface.
+#
+# Since 8.1
+##
+{ 'struct': 'MigrationChannel',
+  'data': {
+      'channel-type': 'MigrationChannelType',
+      'addr': 'MigrationAddress' } }
+
 ##
 # @migrate:
 #
@@ -1648,6 +1676,9 @@
 #
 # @uri: the Uniform Resource Identifier of the destination VM
 #
+# @channels: list of migration stream channels with each stream in the
+#     list connected to a destination interface endpoint.
+#
 # @blk: do block migration (full disk copy)
 #
 # @inc: incremental disk copy migration
@@ -1677,13 +1708,57 @@
 # 3. The user Monitor's "detach" argument is invalid in QMP and should
 #    not be used
 #
+# 4. The uri argument should have the Uniform Resource Identifier of
+#    default destination VM. This connection will be bound to default
+#    network.
+#
+# 5. For now, number of migration streams is restricted to one, i.e
+#    number of items in 'channels' list is just 1.
+#
+# 6. The 'uri' and 'channels' arguments are mutually exclusive;
+#    exactly one of the two should be present.
+#
 # Example:
 #
 # -> { "execute": "migrate", "arguments": { "uri": "tcp:0:4446" } }
 # <- { "return": {} }
+# -> { "execute": "migrate",
+#      "arguments": {
+#          "channels": [ { "channel-type": "main",
+#                          "addr": { "transport": "socket",
+#                                    "type": "inet",
+#                                    "host": "10.12.34.9",
+#                                    "port": "1050" } } ] } }
+# <- { "return": {} }
+#
+# -> { "execute": "migrate",
+#      "arguments": {
+#          "channels": [ { "channel-type": "main",
+#                          "addr": { "transport": "exec",
+#                                    "args": [ "/bin/nc", "-p", "6000",
+#                                              "/some/sock" ] } } ] } }
+# <- { "return": {} }
+#
+# -> { "execute": "migrate",
+#      "arguments": {
+#          "channels": [ { "channel-type": "main",
+#                          "addr": { "transport": "rdma",
+#                                    "host": "10.12.34.9",
+#                                    "port": "1050" } } ] } }
+# <- { "return": {} }
+#
+# -> { "execute": "migrate",
+#      "arguments": {
+#          "channels": [ { "channel-type": "main",
+#                          "addr": { "transport": "file",
+#                                    "filename": "/tmp/migfile",
+#                                    "offset": "0x1000" } } ] } }
+# <- { "return": {} }
+#
 ##
 { 'command': 'migrate',
   'data': {'uri': 'str',
+           '*channels': [ 'MigrationChannel' ],
            '*blk': { 'type': 'bool', 'features': [ 'deprecated' ] },
            '*inc': { 'type': 'bool', 'features': [ 'deprecated' ] },
            '*detach': 'bool', '*resume': 'bool' } }
@@ -1697,6 +1772,9 @@
 # @uri: The Uniform Resource Identifier identifying the source or
 #     address to listen on
 #
+# @channels: list of migration stream channels with each stream in the
+#     list connected to a destination interface endpoint.
+#
 # Returns: nothing on success
 #
 # Since: 2.3
@@ -1712,13 +1790,46 @@
 #
 # 3. The uri format is the same as for -incoming
 #
+# 5. For now, number of migration streams is restricted to one, i.e
+#    number of items in 'channels' list is just 1.
+#
+# 4. The 'uri' and 'channels' arguments are mutually exclusive;
+#    exactly one of the two should be present.
+#
 # Example:
 #
 # -> { "execute": "migrate-incoming",
 #      "arguments": { "uri": "tcp::4446" } }
 # <- { "return": {} }
+#
+# -> { "execute": "migrate",
+#      "arguments": {
+#          "channels": [ { "channel-type": "main",
+#                          "addr": { "transport": "socket",
+#                                    "type": "inet",
+#                                    "host": "10.12.34.9",
+#                                    "port": "1050" } } ] } }
+# <- { "return": {} }
+#
+# -> { "execute": "migrate",
+#      "arguments": {
+#          "channels": [ { "channel-type": "main",
+#                          "addr": { "transport": "exec",
+#                                    "args": [ "/bin/nc", "-p", "6000",
+#                                              "/some/sock" ] } } ] } }
+# <- { "return": {} }
+#
+# -> { "execute": "migrate",
+#      "arguments": {
+#          "channels": [ { "channel-type": "main",
+#                          "addr": { "transport": "rdma",
+#                                    "host": "10.12.34.9",
+#                                    "port": "1050" } } ] } }
+# <- { "return": {} }
 ##
-{ 'command': 'migrate-incoming', 'data': {'uri': 'str' } }
+{ 'command': 'migrate-incoming',
+             'data': {'*uri': 'str',
+                      '*channels': [ 'MigrationChannel' ] } }
 
 ##
 # @xen-save-devices-state: