tests/qtest: precopy migration with suspend

Add a test case to verify that the suspended state is handled correctly
during live migration precopy.  The test suspends the src, migrates, then
wakes the dest.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-12-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>

tests/qtest/migration-helpers.c

@@ -32,6 +32,9 @@ bool migrate_watch_for_events(QTestState *who, const char *name,
     if (g_str_equal(name, "STOP")) {
         state->stop_seen = true;
         return true;
+    } else if (g_str_equal(name, "SUSPEND")) {
+        state->suspend_seen = true;
+        return true;
     } else if (g_str_equal(name, "RESUME")) {
         state->resume_seen = true;
         return true;

tests/qtest/migration-helpers.h

@@ -18,6 +18,8 @@
 typedef struct QTestMigrationState {
     bool stop_seen;
     bool resume_seen;
+    bool suspend_seen;
+    bool suspend_me;
 } QTestMigrationState;
 
 bool migrate_watch_for_events(QTestState *who, const char *name,

tests/qtest/migration-test.c

@@ -178,7 +178,7 @@ static void bootfile_delete(void)
 /*
  * Wait for some output in the serial output file,
  * we get an 'A' followed by an endless string of 'B's
- * but on the destination we won't have the A.
+ * but on the destination we won't have the A (unless we enabled suspend/resume)
  */
 static void wait_for_serial(const char *side)
 {
@@ -245,6 +245,13 @@ static void wait_for_resume(QTestState *who, QTestMigrationState *state)
     }
 }
 
+static void wait_for_suspend(QTestState *who, QTestMigrationState *state)
+{
+    if (state->suspend_me && !state->suspend_seen) {
+        qtest_qmp_eventwait(who, "SUSPEND");
+    }
+}
+
 /*
  * It's tricky to use qemu's migration event capability with qtest,
  * events suddenly appearing confuse the qmp()/hmp() responses.
@@ -299,7 +306,7 @@ static void wait_for_migration_pass(QTestState *who)
 {
     uint64_t pass, prev_pass = 0, changes = 0;
 
-    while (changes < 2 && !src_state.stop_seen) {
+    while (changes < 2 && !src_state.stop_seen && !src_state.suspend_seen) {
         usleep(1000);
         pass = get_migration_pass(who);
         changes += (pass != prev_pass);
@@ -584,6 +591,12 @@ static void migrate_wait_for_dirty_mem(QTestState *from,
         usleep(1000 * 10);
     } while (qtest_readq(to, marker_address) != MAGIC_MARKER);
 
+
+    /* If suspended, src only iterates once, and watch_byte may never change */
+    if (src_state.suspend_me) {
+        return;
+    }
+
     /*
      * Now ensure that already transferred bytes are
      * dirty again from the guest workload. Note the
@@ -771,6 +784,7 @@ static int test_migrate_start(QTestState **from, QTestState **to,
     dst_state = (QTestMigrationState) { };
     src_state = (QTestMigrationState) { };
     bootfile_create(tmpfs, args->suspend_me);
+    src_state.suspend_me = args->suspend_me;
 
     if (strcmp(arch, "i386") == 0 || strcmp(arch, "x86_64") == 0) {
         memory_size = "150M";
@@ -1717,6 +1731,7 @@ static void test_precopy_common(MigrateCommon *args)
     /* Wait for the first serial output from the source */
     if (args->result == MIG_TEST_SUCCEED) {
         wait_for_serial("src_serial");
+        wait_for_suspend(from, &src_state);
     }
 
     if (args->live) {
@@ -1793,6 +1808,11 @@ static void test_precopy_common(MigrateCommon *args)
 
         wait_for_resume(to, &dst_state);
 
+        if (args->start.suspend_me) {
+            /* wakeup succeeds only if guest is suspended */
+            qtest_qmp_assert_success(to, "{'execute': 'system_wakeup'}");
+        }
+
         wait_for_serial("dest_serial");
     }
 
@@ -1879,6 +1899,34 @@ static void test_precopy_unix_plain(void)
     test_precopy_common(&args);
 }
 
+static void test_precopy_unix_suspend_live(void)
+{
+    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
+    MigrateCommon args = {
+        .listen_uri = uri,
+        .connect_uri = uri,
+        /*
+         * despite being live, the test is fast because the src
+         * suspends immediately.
+         */
+        .live = true,
+        .start.suspend_me = true,
+    };
+
+    test_precopy_common(&args);
+}
+
+static void test_precopy_unix_suspend_notlive(void)
+{
+    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
+    MigrateCommon args = {
+        .listen_uri = uri,
+        .connect_uri = uri,
+        .start.suspend_me = true,
+    };
+
+    test_precopy_common(&args);
+}
 
 static void test_precopy_unix_dirty_ring(void)
 {
@@ -3279,7 +3327,7 @@ static bool kvm_dirty_ring_supported(void)
 int main(int argc, char **argv)
 {
     bool has_kvm, has_tcg;
-    bool has_uffd;
+    bool has_uffd, is_x86;
     const char *arch;
     g_autoptr(GError) err = NULL;
     const char *qemu_src = getenv(QEMU_ENV_SRC);
@@ -3309,6 +3357,7 @@ int main(int argc, char **argv)
 
     has_uffd = ufd_version_check();
     arch = qtest_get_arch();
+    is_x86 = !strcmp(arch, "i386") || !strcmp(arch, "x86_64");
 
     /*
      * On ppc64, the test only works with kvm-hv, but not with kvm-pr and TCG
@@ -3339,6 +3388,13 @@ int main(int argc, char **argv)
 
     module_call_init(MODULE_INIT_QOM);
 
+    if (is_x86) {
+        qtest_add_func("/migration/precopy/unix/suspend/live",
+                       test_precopy_unix_suspend_live);
+        qtest_add_func("/migration/precopy/unix/suspend/notlive",
+                       test_precopy_unix_suspend_notlive);
+    }
+
     if (has_uffd) {
         qtest_add_func("/migration/postcopy/plain", test_postcopy);
         qtest_add_func("/migration/postcopy/recovery/plain",