Re: [PATCH v2 5/6] migration: Modified 'migrate-incoming' QAPI and HMP side changes on the destination interface.

[Daniel P . Berrangé]

On Wed, Feb 08, 2023 at 09:35:59AM +0000, Het Gala wrote:
> 'migrate-incoming' QAPI design have been modified into well-defined
> MigrateChannel struct to prevent multiple encoding of uri strings on
> the destination side.'uri' parameter is kept for backward compatibility.
> 
> Suggested-by: Daniel P. Berrange <berrange@redhat.com>
> Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
> Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
> Signed-off-by: Het Gala <het.gala@nutanix.com>
> ---
>  migration/migration-hmp-cmds.c |  8 +++++++-
>  migration/migration.c          |  3 ++-
>  qapi/migration.json            | 22 ++++++++++++++++++++--
>  softmmu/vl.c                   |  2 +-
>  4 files changed, 30 insertions(+), 5 deletions(-)
> 
> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
> index a9f65ded7a..ae3c5ea5b2 100644
> --- a/migration/migration-hmp-cmds.c
> +++ b/migration/migration-hmp-cmds.c
> @@ -500,8 +500,14 @@ void hmp_migrate_incoming(Monitor *mon, const QDict 
> *qdict)
>      Error *err = NULL;
>      const char *uri = qdict_get_str(qdict, "uri");
>  
> -    qmp_migrate_incoming(uri, &err);
> +    MigrateChannel *channel = g_new0(MigrateChannel, 1);
> +    if (!migrate_channel_from_qdict(&channel, qdict, &err)) {
> +        error_setg(&err, "error in retrieving channel from qdict");
> +        return;
> +    }
>  
> +    qmp_migrate_incoming(uri, channel, &err);
> +    qapi_free_MigrateChannel(channel);
>      hmp_handle_error(mon, err);
>  }
>  
> diff --git a/migration/migration.c b/migration/migration.c
> index accbf72a18..e22ce2dd15 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2314,7 +2314,8 @@ void migrate_del_blocker(Error *reason)
>      migration_blockers = g_slist_remove(migration_blockers, reason);
>  }
>  
> -void qmp_migrate_incoming(const char *uri, Error **errp)
> +void qmp_migrate_incoming(const char *uri, MigrateChannel *channel,
> +                          Error **errp)
>  {
>      Error *local_err = NULL;
>      static bool once = true;
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 79acfcfe4e..3a88912f4d 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -1623,7 +1623,11 @@
>  # with -incoming defer
>  #
>  # @uri: The Uniform Resource Identifier identifying the source or
> -#       address to listen on
> +#       the address to listen on
> +#
> +# @channel: Struct containing migration channel type, along with
> +#           all the details of the destination interface required
> +#           for the address to listen on for migration stream.
>  #
>  # Returns: nothing on success
>  #
> @@ -1640,14 +1644,28 @@
>  #
>  # 3. The uri format is the same as for -incoming
>  #
> +# 4. The 'uri' and 'channel' arguments are mutually exclusive but, atleast
> +#    one of the two arguments should be present.
> +#
>  # Example:
>  #
>  # -> { "execute": "migrate-incoming",
>  #      "arguments": { "uri": "tcp::4446" } }
>  # <- { "return": {} }
>  #
> +# -> { "execute": "migrate-incoming",
> +#      "arguments": {
> +#          "channel": { "channeltype": "main",
> +#                        "addr": { "transport": "socket",
> +#                                  "socket-type": { "type": "inet",
> +#                                                   "host": "10.12.34.9",
> +#                                                   "port": "1050" } } } } }
> +# <- { "return": {} }
> +#
>  ##
> -{ 'command': 'migrate-incoming', 'data': {'uri': 'str' } }
> +{ 'command': 'migrate-incoming',
> +             'data': {'*uri': 'str',
> +                      '*channel': 'MigrateChannel'} }

Same question of whether we need to future proof now by making this

  '*channels': ['MigrateChannel']

?

Otherwise we'll have to add this 'channels' field later, and
end up with 'channel' and 'channels' and 'uri'


With regards,
Daniel
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