Re: [PATCH V5 22/23] migration-test: cpr-transfer

[Peter Xu]

On Tue, Dec 24, 2024 at 08:17:07AM -0800, Steve Sistare wrote:
> Add a migration test for cpr-transfer mode.  Defer the connection to the
> target monitor, else the test hangs because in cpr-transfer mode QEMU does
> not listen for monitor connections until we send the migrate command to
> source QEMU.
> 
> To test -incoming defer, send a migrate incoming command to the target,
> after sending the migrate command to the source, as required by
> cpr-transfer mode.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  tests/qtest/migration/cpr-tests.c | 60 
> +++++++++++++++++++++++++++++++++++++++
>  tests/qtest/migration/framework.c | 19 +++++++++++++
>  tests/qtest/migration/framework.h |  3 ++
>  3 files changed, 82 insertions(+)
> 
> diff --git a/tests/qtest/migration/cpr-tests.c 
> b/tests/qtest/migration/cpr-tests.c
> index 44ce89a..b221980 100644
> --- a/tests/qtest/migration/cpr-tests.c
> +++ b/tests/qtest/migration/cpr-tests.c
> @@ -44,6 +44,62 @@ static void test_mode_reboot(void)
>      test_file_common(&args, true);
>  }
>  
> +static void *test_mode_transfer_start(QTestState *from, QTestState *to)
> +{
> +    migrate_set_parameter_str(from, "mode", "cpr-transfer");
> +    return NULL;
> +}
> +
> +/*
> + * cpr-transfer mode cannot use the target monitor prior to starting the
> + * migration, and cannot connect synchronously to the monitor, so defer
> + * the target connection.
> + */
> +static void test_mode_transfer_common(bool incoming_defer)
> +{
> +    g_autofree char *cpr_path = g_strdup_printf("%s/cpr.sock", tmpfs);
> +    g_autofree char *mig_path = g_strdup_printf("%s/migsocket", tmpfs);
> +    g_autofree char *uri = g_strdup_printf("unix:%s", mig_path);
> +
> +    const char *opts = "-machine aux-ram-share=on -nodefaults";
> +    g_autofree const char *cpr_channel = g_strdup_printf(
> +        "cpr,addr.transport=socket,addr.type=unix,addr.path=%s",
> +        cpr_path);
> +    g_autofree char *opts_target = g_strdup_printf("-incoming %s %s",
> +                                                   cpr_channel, opts);
> +
> +    g_autofree char *connect_channels = g_strdup_printf(
> +        "[ { 'channel-type': 'main',"
> +        "    'addr': { 'transport': 'socket',"
> +        "              'type': 'unix',"
> +        "              'path': '%s' } } ]",
> +        mig_path);

So this test already uses json-format channels, IMHO we probably don't need
MigrateCommon.cpr_channel anymore?  We could put them all here. Then..

> +
> +    MigrateCommon args = {
> +        .start.opts_source = opts,
> +        .start.opts_target = opts_target,
> +        .start.defer_target_connect = true,
> +        .start.memory_backend = "-object 
> memory-backend-memfd,id=pc.ram,size=%s"
> +                                " -machine memory-backend=pc.ram",
> +        .listen_uri = incoming_defer ? "defer" : uri,
> +        .connect_channels = connect_channels,
> +        .cpr_channel = cpr_channel,
> +        .start_hook = test_mode_transfer_start,
> +    };
> +
> +    test_precopy_common(&args);
> +}
> +
> +static void test_mode_transfer(void)
> +{
> +    test_mode_transfer_common(NULL);
> +}
> +
> +static void test_mode_transfer_defer(void)
> +{
> +    test_mode_transfer_common(true);
> +}
> +
>  void migration_test_add_cpr(MigrationTestEnv *env)
>  {
>      tmpfs = env->tmpfs;
> @@ -55,4 +111,8 @@ void migration_test_add_cpr(MigrationTestEnv *env)
>      if (getenv("QEMU_TEST_FLAKY_TESTS")) {
>          migration_test_add("/migration/mode/reboot", test_mode_reboot);
>      }
> +
> +    migration_test_add("/migration/mode/transfer", test_mode_transfer);
> +    migration_test_add("/migration/mode/transfer/defer",
> +                       test_mode_transfer_defer);
>  }
> diff --git a/tests/qtest/migration/framework.c 
> b/tests/qtest/migration/framework.c
> index c6ea3e1..f6175de 100644
> --- a/tests/qtest/migration/framework.c
> +++ b/tests/qtest/migration/framework.c
> @@ -411,6 +411,7 @@ void migrate_end(QTestState *from, QTestState *to, bool 
> test_dest)
>      qtest_quit(to);
>  
>      cleanup("migsocket");
> +    cleanup("cpr.sock");
>      cleanup("src_serial");
>      cleanup("dest_serial");
>      cleanup(FILE_TEST_FILENAME);
> @@ -692,8 +693,11 @@ void test_precopy_common(MigrateCommon *args)
>  {
>      QTestState *from, *to;
>      void *data_hook = NULL;
> +    QObject *in_channels = NULL;
>      QObject *out_channels = NULL;
>  
> +    g_assert(!args->cpr_channel || args->connect_channels);
> +
>      if (migrate_start(&from, &to, args->listen_uri, &args->start)) {
>          return;
>      }
> @@ -725,8 +729,20 @@ void test_precopy_common(MigrateCommon *args)
>          }
>      }
>  
> +    /*
> +     * The cpr channel must be included in outgoing channels, but not in
> +     * migrate-incoming channels.
> +     */
>      if (args->connect_channels) {
> +        in_channels = qobject_from_json(args->connect_channels, 
> &error_abort);
>          out_channels = qobject_from_json(args->connect_channels, 
> &error_abort);
> +
> +        if (args->cpr_channel) {
> +            QList *channels_list = qobject_to(QList, out_channels);
> +            QObject *obj = migrate_str_to_channel(args->cpr_channel);
> +
> +            qlist_append(channels_list, obj);
> +        }

... here IIUC we don't need this trick to manipulate the qlist anymore?

Looks like if with that (convert the current cpr_connect string to JSON
format, attach it with connect_channels), then we also don't need the
pre-requisite patch to make connect_channels manipulate-able. Not sure.

>      }
>  
>      if (args->result == MIG_TEST_QMP_ERROR) {
> @@ -739,6 +755,9 @@ void test_precopy_common(MigrateCommon *args)
>      if (args->start.defer_target_connect) {
>          qtest_connect(to);
>          qtest_qmp_handshake(to);
> +        if (!strcmp(args->listen_uri, "defer")) {
> +            migrate_incoming_qmp(to, args->connect_uri, in_channels, "{}");
> +        }
>      }
>  
>      if (args->result != MIG_TEST_SUCCEED) {
> diff --git a/tests/qtest/migration/framework.h 
> b/tests/qtest/migration/framework.h
> index 1341368..4678e2a 100644
> --- a/tests/qtest/migration/framework.h
> +++ b/tests/qtest/migration/framework.h
> @@ -152,6 +152,9 @@ typedef struct {
>       */
>      const char *connect_channels;
>  
> +    /* Optional: the cpr migration channel, in JSON or dotted keys format */
> +    const char *cpr_channel;
> +
>      /* Optional: callback to run at start to set migration parameters */
>      TestMigrateStartHook start_hook;
>      /* Optional: callback to run at finish to cleanup */
> -- 
> 1.8.3.1
> 

-- 
Peter Xu