From: Fabiano Rosas <faro...@suse.de> Add a framework for running migrations back and forth between two guests (aka ping-pong migration). We have seen a couple of bugs that only reproduce when a guest is migrated and the destination machine is used as the source of a new migration.
Add a simple test that does 2 migrations and another test that uses the late-block-activate capability, which is one area where a bug has been found. Note that this does not reuse any of the existing tests (e.g. test_precopy_common), because there is too much ambiguity regarding how to handle the hooks, args->result, stop/continue, etc. Signed-off-by: Fabiano Rosas <faro...@suse.de> Link: https://lore.kernel.org/r/20241125144612.16194-6-faro...@suse.de Signed-off-by: Peter Xu <pet...@redhat.com> --- tests/qtest/migration-test.c | 121 +++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c index 74645f749c..4955b3b9eb 100644 --- a/tests/qtest/migration-test.c +++ b/tests/qtest/migration-test.c @@ -1819,6 +1819,104 @@ finish: test_migrate_end(from, to, args->result == MIG_TEST_SUCCEED); } +static void migrate_dst_becomes_src(QTestState **from, QTestState **to, + QTestMigrationState *src_state, + QTestMigrationState *dst_state) +{ + *from = *to; + + *src_state = (QTestMigrationState) { }; + src_state->serial = dst_state->serial; + qtest_qmp_set_event_callback(*from, migrate_watch_for_events, src_state); + + src_state->stop_seen = dst_state->stop_seen; +} + +static void test_precopy_ping_pong_common(MigrateCommon *args, int n, + bool late_block_activate) +{ + QTestState *from, *to; + bool keep_paused = false; + + g_assert(!args->live); + + g_test_message("Migrating back and forth %d times", n); + + for (int i = 0; i < n; i++) { + g_test_message("%s (%d/%d)", i % 2 ? "pong" : "ping", i + 1, n); + + if (test_migrate_start(&from, &to, args->listen_uri, &args->start)) { + return; + } + + if (late_block_activate) { + migrate_set_capability(from, "late-block-activate", true); + migrate_set_capability(to, "late-block-activate", true); + + /* + * The late-block-activate capability expects that the + * management layer will issue a qmp_continue command on + * the destination once the migration finishes. In order + * to test the capability properly, make sure the test is + * not issuing spurious continue commands. + */ + keep_paused = true; + } + + if (!src_state.stop_seen) { + wait_for_serial(src_state.serial); + } + + /* because of !args->live */ + qtest_qmp_assert_success(from, "{ 'execute' : 'stop'}"); + wait_for_stop(from, &src_state); + + migrate_ensure_converge(from); + migrate_qmp(from, to, args->connect_uri, args->connect_channels, "{}"); + + wait_for_migration_complete(from); + wait_for_migration_complete(to); + + /* note check_guests_ram() requires a stopped guest */ + check_guests_ram(to); + + if (keep_paused) { + /* + * Nothing issued continue on the destination, reflect + * that the guest is paused in the dst_state. + */ + dst_state.stop_seen = true; + } else { + qtest_qmp_assert_success(to, "{ 'execute' : 'cont'}"); + wait_for_serial(dst_state.serial); + dst_state.stop_seen = false; + } + + /* + * Last iteration, let the guest run to make sure there's no + * memory corruption. The test_migrate_end() below will check + * the memory one last time. + */ + if (i == n - 1) { + qtest_qmp_assert_success(to, "{ 'execute' : 'cont'}"); + wait_for_serial(dst_state.serial); + dst_state.stop_seen = false; + break; + } + + /* + * Prepare for migrating back: clear the original source and + * switch source & destination. + */ + migrate_cleanup(from, NULL); + migrate_dst_becomes_src(&from, &to, &src_state, &dst_state); + + args->start.only_target = true; + } + + test_migrate_end(from, to, true); +} + static void file_dirty_offset_region(void) { g_autofree char *path = g_strdup_printf("%s/%s", tmpfs, FILE_TEST_FILENAME); @@ -3772,6 +3870,24 @@ static void test_migrate_dirty_limit(void) test_migrate_end(from, to, true); } +static void test_precopy_ping_pong(void) +{ + MigrateCommon args = { + .listen_uri = "tcp:127.0.0.1:0", + }; + + test_precopy_ping_pong_common(&args, 2, false); +} + +static void test_precopy_ping_pong_late_block(void) +{ + MigrateCommon args = { + .listen_uri = "tcp:127.0.0.1:0", + }; + + test_precopy_ping_pong_common(&args, 2, true); +} + static bool kvm_dirty_ring_supported(void) { #if defined(__linux__) && defined(HOST_X86_64) @@ -4055,6 +4171,11 @@ int main(int argc, char **argv) } } + migration_test_add("/migration/precopy/ping-pong/plain", + test_precopy_ping_pong); + migration_test_add("/migration/precopy/ping-pong/late-block-activate", + test_precopy_ping_pong_late_block); + ret = g_test_run(); g_assert_cmpint(ret, ==, 0); -- 2.47.0
