migration: Reference migration state around loadvm_postcopy_handle_run_bh

[mirror_qemu.git] / migration / savevm.c

diff --git a/migration/savevm.c b/migration/savevm.c
index eec5503a422081a5e2fce7238820ec6fc8db1b8b..93387350c7f54634027286a771cb9c5c3876e644 100644 (file)
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -438,7 +438,7 @@ static const VMStateDescription vmstate_target_page_bits = {
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = vmstate_target_page_bits_needed,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_UINT32(target_page_bits, SaveState),
         VMSTATE_END_OF_LIST()
     }
@@ -454,7 +454,7 @@ static const VMStateDescription vmstate_capabilites = {
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = vmstate_capabilites_needed,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_UINT32_V(caps_count, SaveState, 1),
         VMSTATE_VARRAY_UINT32_ALLOC(capabilities, SaveState, caps_count, 1,
                                     vmstate_info_capability,
@@ -499,7 +499,7 @@ static const VMStateDescription vmstate_uuid = {
     .minimum_version_id = 1,
     .needed = vmstate_uuid_needed,
     .post_load = vmstate_uuid_post_load,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_UINT8_ARRAY_V(uuid.data, SaveState, sizeof(QemuUUID), 1),
         VMSTATE_END_OF_LIST()
     }
@@ -512,12 +512,12 @@ static const VMStateDescription vmstate_configuration = {
     .post_load = configuration_post_load,
     .pre_save = configuration_pre_save,
     .post_save = configuration_post_save,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_UINT32(len, SaveState),
         VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, len),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (const VMStateDescription *[]) {
+    .subsections = (const VMStateDescription * const []) {
         &vmstate_target_page_bits,
         &vmstate_capabilites,
         &vmstate_uuid,
@@ -551,11 +551,11 @@ static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field,
 }
 
 static void dump_vmstate_vmss(FILE *out_file,
-                              const VMStateDescription **subsection,
+                              const VMStateDescription *subsection,
                               int indent)
 {
-    if (*subsection != NULL) {
-        dump_vmstate_vmsd(out_file, *subsection, indent, true);
+    if (subsection != NULL) {
+        dump_vmstate_vmsd(out_file, subsection, indent, true);
     }
 }
 
@@ -597,7 +597,7 @@ static void dump_vmstate_vmsd(FILE *out_file,
         fprintf(out_file, "\n%*s]", indent, "");
     }
     if (vmsd->subsections != NULL) {
-        const VMStateDescription **subsection = vmsd->subsections;
+        const VMStateDescription * const *subsection = vmsd->subsections;
         bool first;
 
         fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, "");
@@ -606,7 +606,7 @@ static void dump_vmstate_vmsd(FILE *out_file,
             if (!first) {
                 fprintf(out_file, ",\n");
             }
-            dump_vmstate_vmss(out_file, subsection, indent + 2);
+            dump_vmstate_vmss(out_file, *subsection, indent + 2);
             subsection++;
             first = false;
         }
@@ -831,7 +831,7 @@ void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque)
 static void vmstate_check(const VMStateDescription *vmsd)
 {
     const VMStateField *field = vmsd->fields;
-    const VMStateDescription **subsection = vmsd->subsections;
+    const VMStateDescription * const *subsection = vmsd->subsections;
 
     if (field) {
         while (field->name) {
@@ -2174,6 +2174,7 @@ static void loadvm_postcopy_handle_run_bh(void *opaque)
     qemu_bh_delete(mis->bh);
 
     trace_vmstate_downtime_checkpoint("dst-postcopy-bh-vm-started");
+    object_unref(OBJECT(migration_get_current()));
 }
 
 /* After all discards we can start running and asking for pages */
@@ -2189,6 +2190,7 @@ static int loadvm_postcopy_handle_run(MigrationIncomingState *mis)
 
     postcopy_state_set(POSTCOPY_INCOMING_RUNNING);
     mis->bh = qemu_bh_new(loadvm_postcopy_handle_run_bh, mis);
+    object_ref(OBJECT(migration_get_current()));
     qemu_bh_schedule(mis->bh);
 
     /* We need to finish reading the stream from the package
@@ -3046,10 +3048,9 @@ bool save_snapshot(const char *name, bool overwrite, const char *vmstate,
     QEMUSnapshotInfo sn1, *sn = &sn1;
     int ret = -1, ret2;
     QEMUFile *f;
-    int saved_vm_running;
+    RunState saved_state = runstate_get();
     uint64_t vm_state_size;
     g_autoptr(GDateTime) now = g_date_time_new_now_local();
-    AioContext *aio_context;
 
     GLOBAL_STATE_CODE();
 
@@ -3092,17 +3093,12 @@ bool save_snapshot(const char *name, bool overwrite, const char *vmstate,
     if (bs == NULL) {
         return false;
     }
-    aio_context = bdrv_get_aio_context(bs);
-
-    saved_vm_running = runstate_is_running();
 
     global_state_store();
     vm_stop(RUN_STATE_SAVE_VM);
 
     bdrv_drain_all_begin();
 
-    aio_context_acquire(aio_context);
-
     memset(sn, 0, sizeof(*sn));
 
     /* fill auxiliary fields */
@@ -3139,14 +3135,6 @@ bool save_snapshot(const char *name, bool overwrite, const char *vmstate,
         goto the_end;
     }
 
-    /* The bdrv_all_create_snapshot() call that follows acquires the AioContext
-     * for itself.  BDRV_POLL_WHILE() does not support nested locking because
-     * it only releases the lock once.  Therefore synchronous I/O will deadlock
-     * unless we release the AioContext before bdrv_all_create_snapshot().
-     */
-    aio_context_release(aio_context);
-    aio_context = NULL;
-
     ret = bdrv_all_create_snapshot(sn, bs, vm_state_size,
                                    has_devices, devices, errp);
     if (ret < 0) {
@@ -3157,15 +3145,9 @@ bool save_snapshot(const char *name, bool overwrite, const char *vmstate,
     ret = 0;
 
  the_end:
-    if (aio_context) {
-        aio_context_release(aio_context);
-    }
-
     bdrv_drain_all_end();
 
-    if (saved_vm_running) {
-        vm_start();
-    }
+    vm_resume(saved_state);
     return ret == 0;
 }
 
@@ -3258,7 +3240,6 @@ bool load_snapshot(const char *name, const char *vmstate,
     QEMUSnapshotInfo sn;
     QEMUFile *f;
     int ret;
-    AioContext *aio_context;
     MigrationIncomingState *mis = migration_incoming_get_current();
 
     if (!bdrv_all_can_snapshot(has_devices, devices, errp)) {
@@ -3278,12 +3259,9 @@ bool load_snapshot(const char *name, const char *vmstate,
     if (!bs_vm_state) {
         return false;
     }
-    aio_context = bdrv_get_aio_context(bs_vm_state);
 
     /* Don't even try to load empty VM states */
-    aio_context_acquire(aio_context);
     ret = bdrv_snapshot_find(bs_vm_state, &sn, name);
-    aio_context_release(aio_context);
     if (ret < 0) {
         return false;
     } else if (sn.vm_state_size == 0) {
@@ -3320,10 +3298,8 @@ bool load_snapshot(const char *name, const char *vmstate,
         ret = -EINVAL;
         goto err_drain;
     }
-    aio_context_acquire(aio_context);
     ret = qemu_loadvm_state(f);
     migration_incoming_state_destroy();
-    aio_context_release(aio_context);
 
     bdrv_drain_all_end();
 
@@ -3339,6 +3315,14 @@ err_drain:
     return false;
 }
 
+void load_snapshot_resume(RunState state)
+{
+    vm_resume(state);
+    if (state == RUN_STATE_RUNNING && runstate_get() == RUN_STATE_SUSPENDED) {
+        qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, &error_abort);
+    }
+}
+
 bool delete_snapshot(const char *name, bool has_devices,
                      strList *devices, Error **errp)
 {
@@ -3403,16 +3387,15 @@ static void snapshot_load_job_bh(void *opaque)
 {
     Job *job = opaque;
     SnapshotJob *s = container_of(job, SnapshotJob, common);
-    int orig_vm_running;
+    RunState orig_state = runstate_get();
 
     job_progress_set_remaining(&s->common, 1);
 
-    orig_vm_running = runstate_is_running();
     vm_stop(RUN_STATE_RESTORE_VM);
 
     s->ret = load_snapshot(s->tag, s->vmstate, true, s->devices, s->errp);
-    if (s->ret && orig_vm_running) {
-        vm_start();
+    if (s->ret) {
+        load_snapshot_resume(orig_state);
     }
 
     job_progress_update(&s->common, 1);