Merge tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu into staging

Migration pull request

- Fabiano's fixed-ram patches (1-5 only)
- Peter's cleanups on multifd tls IOC referencing
- Steve's cpr patches for vfio (migration patches only)
- Fabiano's fix on mbps stats racing with COMPLETE state
- Fabiano's fix on return path thread hang

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# gpg: Good signature from "Peter Xu <xzpeter@gmail.com>" [marginal]
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* tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu: (25 commits)
  migration: Use migrate_has_error() in close_return_path_on_source()
  migration: Join the return path thread before releasing to_dst_file
  migration: Fix qmp_query_migrate mbps value
  migration: options incompatible with cpr
  migration: update cpr-reboot description
  migration: stop vm for cpr
  migration: notifier error checking
  migration: refactor migrate_fd_connect failures
  migration: per-mode notifiers
  migration: MigrationNotifyFunc
  migration: remove postcopy_after_devices
  migration: MigrationEvent for notifiers
  migration: convert to NotifierWithReturn
  migration: remove error from notifier data
  notify: pass error to notifier with return
  migration/multifd: Drop unnecessary helper to destroy IOC
  migration/multifd: Cleanup outgoing_args in state destroy
  migration/multifd: Make multifd_channel_connect() return void
  migration/multifd: Drop registered_yank
  migration/multifd: Cleanup TLS iochannel referencing
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

include/hw/vfio/vfio-common.h

@@ -62,7 +62,7 @@ typedef struct VFIORegion {
 typedef struct VFIOMigration {
     struct VFIODevice *vbasedev;
     VMChangeStateEntry *vm_state;
-    Notifier migration_state;
+    NotifierWithReturn migration_state;
     uint32_t device_state;
     int data_fd;
     void *data_buffer;

include/hw/virtio/virtio-net.h

@@ -221,7 +221,7 @@ struct VirtIONet {
     DeviceListener primary_listener;
     QDict *primary_opts;
     bool primary_opts_from_json;
-    Notifier migration_state;
+    NotifierWithReturn migration_state;
     VirtioNetRssData rss_data;
     struct NetRxPkt *rx_pkt;
     struct EBPFRSSContext ebpf_rss;

include/migration/misc.h

@@ -31,7 +31,6 @@ typedef enum PrecopyNotifyReason {
 
 typedef struct PrecopyNotifyData {
     enum PrecopyNotifyReason reason;
-    Error **errp;
 } PrecopyNotifyData;
 
 void precopy_infrastructure_init(void);
@@ -61,15 +60,51 @@ void migration_object_init(void);
 void migration_shutdown(void);
 bool migration_is_idle(void);
 bool migration_is_active(MigrationState *);
-void migration_add_notifier(Notifier *notify,
-                            void (*func)(Notifier *notifier, void *data));
-void migration_remove_notifier(Notifier *notify);
-void migration_call_notifiers(MigrationState *s);
+bool migrate_mode_is_cpr(MigrationState *);
+
+typedef enum MigrationEventType {
+    MIG_EVENT_PRECOPY_SETUP,
+    MIG_EVENT_PRECOPY_DONE,
+    MIG_EVENT_PRECOPY_FAILED,
+    MIG_EVENT_MAX
+} MigrationEventType;
+
+typedef struct MigrationEvent {
+    MigrationEventType type;
+} MigrationEvent;
+
+/*
+ * A MigrationNotifyFunc may return an error code and an Error object,
+ * but only when @e->type is MIG_EVENT_PRECOPY_SETUP.  The code is an int
+ * to allow for different failure modes and recovery actions.
+ */
+typedef int (*MigrationNotifyFunc)(NotifierWithReturn *notify,
+                                   MigrationEvent *e, Error **errp);
+
+/*
+ * Register the notifier @notify to be called when a migration event occurs
+ * for MIG_MODE_NORMAL, as specified by the MigrationEvent passed to @func.
+ * Notifiers may receive events in any of the following orders:
+ *    - MIG_EVENT_PRECOPY_SETUP -> MIG_EVENT_PRECOPY_DONE
+ *    - MIG_EVENT_PRECOPY_SETUP -> MIG_EVENT_PRECOPY_FAILED
+ *    - MIG_EVENT_PRECOPY_FAILED
+ */
+void migration_add_notifier(NotifierWithReturn *notify,
+                            MigrationNotifyFunc func);
+
+/*
+ * Same as migration_add_notifier, but applies to be specified @mode.
+ */
+void migration_add_notifier_mode(NotifierWithReturn *notify,
+                                 MigrationNotifyFunc func, MigMode mode);
+
+void migration_remove_notifier(NotifierWithReturn *notify);
+int migration_call_notifiers(MigrationState *s, MigrationEventType type,
+                             Error **errp);
 bool migration_in_setup(MigrationState *);
 bool migration_has_finished(MigrationState *);
 bool migration_has_failed(MigrationState *);
 /* ...and after the device transmission */
-bool migration_in_postcopy_after_devices(MigrationState *);
 /* True if incoming migration entered POSTCOPY_INCOMING_DISCARD */
 bool migration_in_incoming_postcopy(void);
 /* True if incoming migration entered POSTCOPY_INCOMING_ADVISE */

include/qemu/notify.h

@@ -45,12 +45,16 @@ bool notifier_list_empty(NotifierList *list);
 /* Same as Notifier but allows .notify() to return errors */
 typedef struct NotifierWithReturn NotifierWithReturn;
 
+/* Return int to allow for different failure modes and recovery actions */
+typedef int (*NotifierWithReturnFunc)(NotifierWithReturn *notifier, void *data,
+                                      Error **errp);
+
 struct NotifierWithReturn {
     /**
      * Return 0 on success (next notifier will be invoked), otherwise
      * notifier_with_return_list_notify() will stop and return the value.
      */
-    int (*notify)(NotifierWithReturn *notifier, void *data);
+    NotifierWithReturnFunc notify;
     QLIST_ENTRY(NotifierWithReturn) node;
 };
 
@@ -69,6 +73,6 @@ void notifier_with_return_list_add(NotifierWithReturnList *list,
 void notifier_with_return_remove(NotifierWithReturn *notifier);
 
 int notifier_with_return_list_notify(NotifierWithReturnList *list,
-                                     void *data);
+                                     void *data, Error **errp);
 
 #endif