migration: Add blocker information

Modify query-migrate so that it has a flag indicating if outbound
migration is blocked, and if it is a list of reasons.

Signed-off-by: Dr. David Alan Gilbert <[email protected]>
Message-Id: <20210202135522[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Reviewed-by: Peter Xu <[email protected]>
Signed-off-by: Dr. David Alan Gilbert <[email protected]>

diff --git a/migration/migration.c b/migration/migration.c
index 38efaeee94149eeecdc8a50c066b9e87d75e448d..a5ddf43559eb29e65444b5d5e0f54eb74ae718b5 100644 (file)
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -174,6 +174,8 @@ INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
 static MigrationState *current_migration;
 static MigrationIncomingState *current_incoming;
 
+static GSList *migration_blockers;
+
 static bool migration_object_check(MigrationState *ms, Error **errp);
 static int migration_maybe_pause(MigrationState *s,
                                  int *current_active_state,
@@ -1074,6 +1076,27 @@ static void fill_source_migration_info(MigrationInfo *info)
 {
     MigrationState *s = migrate_get_current();
 
+    info->blocked = migration_is_blocked(NULL);
+    info->has_blocked_reasons = info->blocked;
+    info->blocked_reasons = NULL;
+    if (info->blocked) {
+        GSList *cur_blocker = migration_blockers;
+
+        /*
+         * There are two types of reasons a migration might be blocked;
+         * a) devices marked in VMState as non-migratable, and
+         * b) Explicit migration blockers
+         * We need to add both of them here.
+         */
+        qemu_savevm_non_migratable_list(&info->blocked_reasons);
+
+        while (cur_blocker) {
+            QAPI_LIST_PREPEND(info->blocked_reasons,
+                              g_strdup(error_get_pretty(cur_blocker->data)));
+            cur_blocker = g_slist_next(cur_blocker);
+        }
+    }
+
     switch (s->state) {
     case MIGRATION_STATUS_NONE:
         /* no migration has happened ever */
@@ -2025,8 +2048,6 @@ void migrate_init(MigrationState *s)
     s->threshold_size = 0;
 }
 
-static GSList *migration_blockers;
-
 int migrate_add_blocker(Error *reason, Error **errp)
 {
     if (only_migratable) {

diff --git a/migration/savevm.c b/migration/savevm.c
index d5bf53388fe3a736b0b98664f1d95ccb85f536ce..1178c6ca90b41a7a5f7a08516d008d07983b4485 100644 (file)
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1154,6 +1154,19 @@ bool qemu_savevm_state_blocked(Error **errp)
     return false;
 }
 
+void qemu_savevm_non_migratable_list(strList **reasons)
+{
+    SaveStateEntry *se;
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (se->vmsd && se->vmsd->unmigratable) {
+            QAPI_LIST_PREPEND(*reasons,
+                              g_strdup_printf("non-migratable device: %s",
+                                              se->idstr));
+        }
+    }
+}
+
 void qemu_savevm_state_header(QEMUFile *f)
 {
     trace_savevm_state_header();

diff --git a/migration/savevm.h b/migration/savevm.h
index aaee2528ed0101abe5e9917be92b161bbe204a51..6461342cb43877cb0aaf4247c0cd539d937aa37b 100644 (file)
--- a/migration/savevm.h
+++ b/migration/savevm.h
@@ -30,6 +30,7 @@
 #define QEMU_VM_SECTION_FOOTER       0x7e
 
 bool qemu_savevm_state_blocked(Error **errp);
+void qemu_savevm_non_migratable_list(strList **reasons);
 void qemu_savevm_state_setup(QEMUFile *f);
 bool qemu_savevm_state_guest_unplug_pending(void);
 int qemu_savevm_state_resume_prepare(MigrationState *s);

diff --git a/qapi/migration.json b/qapi/migration.json
index 797f9edbc2b0057f5a6be5f5f8479d1781ea7684..076d2d5634a65e36db8367f50c9e600e3271a6aa 100644 (file)
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -224,6 +224,10 @@
 #        only returned if VFIO device is present, migration is supported by all
 #        VFIO devices and status is 'active' or 'completed' (since 5.2)
 #
+# @blocked: True if outgoing migration is blocked (since 6.0)
+#
+# @blocked-reasons: A list of reasons an outgoing migration is blocked (since 6.0)
+#
 # Since: 0.14
 ##
 { 'struct': 'MigrationInfo',
@@ -237,6 +241,8 @@
            '*setup-time': 'int',
            '*cpu-throttle-percentage': 'int',
            '*error-desc': 'str',
+           'blocked': 'bool',
+           '*blocked-reasons': ['str'],
            '*postcopy-blocktime' : 'uint32',
            '*postcopy-vcpu-blocktime': ['uint32'],
            '*compression': 'CompressionStats',