Re: [PATCH V1 11/11] migration-test: test cpr-exec

[Peter Xu <peterx@redhat.com>]

On Fri, Sep 19, 2025 at 07:12:33AM -0700, Steve Sistare wrote:
> Add a test for the cpr-exec migration mode.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>

Looks good, only some nitpicks or pure questions below.

> ---
>  tests/qtest/migration/cpr-tests.c | 120 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 120 insertions(+)
> 
> diff --git a/tests/qtest/migration/cpr-tests.c b/tests/qtest/migration/cpr-tests.c
> index 5e764a6..f33af76 100644
> --- a/tests/qtest/migration/cpr-tests.c
> +++ b/tests/qtest/migration/cpr-tests.c
> @@ -110,6 +110,125 @@ static void test_mode_transfer_defer(void)
>      test_mode_transfer_common(true);
>  }
>  
> +static void set_cpr_exec_args(QTestState *who, MigrateCommon *args)
> +{
> +    g_autofree char *qtest_from_args = NULL;
> +    g_autofree char *from_args = NULL;
> +    g_autofree char *to_args = NULL;
> +    g_autofree char *exec_args = NULL;
> +    g_auto(GStrv) argv = NULL;
> +    char *from_str, *src, *dst;
> +
> +    args->start.hide_stderr = false;    /* omit redirection word from args */

It's default off, right?  Could I request for some more explanations?

Could we also set it in test_mode_exec() directly if needed?

> +    migrate_args(&from_args, &to_args, args->listen_uri, &args->start);
> +    qtest_from_args = qtest_qemu_args(from_args);
> +
> +    /* De-dup spaces so argv does not contain empty strings */
> +    from_str = src = dst = g_strstrip(qtest_from_args);
> +    do {
> +        if (*src != ' ' || src[-1] != ' ') {
> +            *dst++ = *src;
> +        }
> +    } while (*src++);

Pure ask.. when will empty string be present?

> +
> +    exec_args = g_strconcat(qtest_qemu_binary(QEMU_ENV_SRC),

Should this be QEMU_ENV_DST?

OTOH, we can use migration_get_env()->qemu_dst to reduce referencing global
vars.

> +                            " -incoming defer ", from_str, NULL);
> +    argv = g_strsplit(exec_args, " ", -1);
> +    migrate_set_parameter_strv(who, "cpr-exec-command", argv);
> +}
> +
> +static void wait_for_migration_event(QTestState *who, const char *waitfor)
> +{
> +    QDict *rsp, *data;
> +    char *status;
> +    bool done = false;
> +
> +    while (!done) {
> +        rsp = qtest_qmp_eventwait_ref(who, "MIGRATION");
> +        g_assert(qdict_haskey(rsp, "data"));
> +        data = qdict_get_qdict(rsp, "data");
> +        g_assert(qdict_haskey(data, "status"));
> +        status = g_strdup(qdict_get_str(data, "status"));
> +        g_assert(strcmp(status, "failed"));
> +        done = !strcmp(status, waitfor);
> +        qobject_unref(rsp);
> +    }
> +}
> +
> +static void test_cpr_exec(MigrateCommon *args)
> +{
> +    QTestState *from, *to;
> +    void *data_hook = NULL;
> +    g_autofree char *connect_uri = g_strdup(args->connect_uri);
> +    g_autofree char *filename = g_strdup_printf("%s/%s", tmpfs,
> +                                                FILE_TEST_FILENAME);
> +
> +

Newline can be dropped.

> +    if (migrate_start(&from, NULL, args->listen_uri, &args->start)) {
> +        return;
> +    }
> +
> +    /* Source and dest never run concurrently */
> +    g_assert_false(args->live);
> +
> +    if (args->start_hook) {
> +        data_hook = args->start_hook(from, NULL);
> +    }
> +
> +    wait_for_serial("src_serial");
> +    set_cpr_exec_args(from, args);
> +    migrate_set_capability(from, "events", true);
> +    migrate_qmp(from, NULL, connect_uri, NULL, "{}");
> +    wait_for_migration_event(from, "completed");
> +
> +    to = qtest_init_after_exec(from);
> +
> +    qtest_qmp_assert_success(to, "{ 'execute': 'migrate-incoming',"
> +                             "  'arguments': { "
> +                             "      'channels': [ { 'channel-type': 'main',"
> +                             "      'addr': { 'transport': 'file',"
> +                             "                'filename': %s,"
> +                             "                'offset': 0  } } ] } }",
> +                             filename);
> +    wait_for_migration_complete(to);
> +
> +    wait_for_resume(to, get_dst());
> +    /* Device on target is still named src_serial because args do not change */
> +    wait_for_serial("src_serial");
> +
> +    if (args->end_hook) {
> +        args->end_hook(from, to, data_hook);
> +    }
> +
> +    migrate_end(from, to, args->result == MIG_TEST_SUCCEED);
> +}
> +
> +static void *test_mode_exec_start(QTestState *from, QTestState *to)
> +{
> +    assert(!to);
> +    migrate_set_parameter_str(from, "mode", "cpr-exec");
> +    return NULL;
> +}
> +
> +static void test_mode_exec(void)
> +{
> +    g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
> +                                           FILE_TEST_FILENAME);
> +    g_autofree char *listen_uri = g_strdup_printf("defer");
> +
> +    MigrateCommon args = {
> +        .start.only_source = true,
> +        .start.opts_source = "-machine aux-ram-share=on -nodefaults",
> +        .start.memory_backend = "-object memory-backend-memfd,id=pc.ram,size=%s"
> +                                " -machine memory-backend=pc.ram",
> +        .connect_uri = uri,
> +        .listen_uri = listen_uri,
> +        .start_hook = test_mode_exec_start,
> +    };
> +
> +    test_cpr_exec(&args);
> +}
> +
>  void migration_test_add_cpr(MigrationTestEnv *env)
>  {
>      tmpfs = env->tmpfs;
> @@ -132,5 +251,6 @@ void migration_test_add_cpr(MigrationTestEnv *env)
>          migration_test_add("/migration/mode/transfer", test_mode_transfer);
>          migration_test_add("/migration/mode/transfer/defer",
>                             test_mode_transfer_defer);
> +        migration_test_add("/migration/mode/exec", test_mode_exec);
>      }
>  }
> -- 
> 1.8.3.1
> 

-- 
Peter Xu