migration: Add yank feature

Register yank functions on sockets to shut them down.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <484c6a14cc2506bebedd5a237259b91363ff8f88.1609167865.git.lukasstraub2@web.de>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

migration/channel.c

@@ -18,6 +18,8 @@
 #include "trace.h"
 #include "qapi/error.h"
 #include "io/channel-tls.h"
+#include "io/channel-socket.h"
+#include "qemu/yank.h"
 
 /**
  * @migration_channel_process_incoming - Create new incoming migration channel
@@ -35,6 +37,11 @@ void migration_channel_process_incoming(QIOChannel *ioc)
     trace_migration_set_incoming_channel(
         ioc, object_get_typename(OBJECT(ioc)));
 
+    if (object_dynamic_cast(OBJECT(ioc), TYPE_QIO_CHANNEL_SOCKET)) {
+        yank_register_function(MIGRATION_YANK_INSTANCE, yank_generic_iochannel,
+                               QIO_CHANNEL(ioc));
+    }
+
     if (s->parameters.tls_creds &&
         *s->parameters.tls_creds &&
         !object_dynamic_cast(OBJECT(ioc),
@@ -67,6 +74,12 @@ void migration_channel_connect(MigrationState *s,
         ioc, object_get_typename(OBJECT(ioc)), hostname, error);
 
     if (!error) {
+        if (object_dynamic_cast(OBJECT(ioc), TYPE_QIO_CHANNEL_SOCKET)) {
+            yank_register_function(MIGRATION_YANK_INSTANCE,
+                                   yank_generic_iochannel,
+                                   QIO_CHANNEL(ioc));
+        }
+
         if (s->parameters.tls_creds &&
             *s->parameters.tls_creds &&
             !object_dynamic_cast(OBJECT(ioc),

migration/migration.c

@@ -57,6 +57,7 @@
 #include "net/announce.h"
 #include "qemu/queue.h"
 #include "multifd.h"
+#include "qemu/yank.h"
 
 #ifdef CONFIG_VFIO
 #include "hw/vfio/vfio-common.h"
@@ -255,6 +256,8 @@ void migration_incoming_state_destroy(void)
         qapi_free_SocketAddressList(mis->socket_address_list);
         mis->socket_address_list = NULL;
     }
+
+    yank_unregister_instance(MIGRATION_YANK_INSTANCE);
 }
 
 static void migrate_generate_event(int new_state)
@@ -416,6 +419,10 @@ static void qemu_start_incoming_migration(const char *uri, Error **errp)
 {
     const char *p = NULL;
 
+    if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
+        return;
+    }
+
     qapi_event_send_migration(MIGRATION_STATUS_SETUP);
     if (strstart(uri, "tcp:", &p) ||
         strstart(uri, "unix:", NULL) ||
@@ -430,6 +437,7 @@ static void qemu_start_incoming_migration(const char *uri, Error **errp)
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_incoming_migration(p, errp);
     } else {
+        yank_unregister_instance(MIGRATION_YANK_INSTANCE);
         error_setg(errp, "unknown migration protocol: %s", uri);
     }
 }
@@ -1731,6 +1739,7 @@ static void migrate_fd_cleanup(MigrationState *s)
     }
     notifier_list_notify(&migration_state_notifiers, s);
     block_cleanup_parameters(s);
+    yank_unregister_instance(MIGRATION_YANK_INSTANCE);
 }
 
 static void migrate_fd_cleanup_schedule(MigrationState *s)
@@ -2005,6 +2014,7 @@ void qmp_migrate_recover(const char *uri, Error **errp)
      * only re-setup the migration stream and poke existing migration
      * to continue using that newly established channel.
      */
+    yank_unregister_instance(MIGRATION_YANK_INSTANCE);
     qemu_start_incoming_migration(uri, errp);
 }
 
@@ -2148,6 +2158,12 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
         return;
     }
 
+    if (!(has_resume && resume)) {
+        if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
+            return;
+        }
+    }
+
     if (strstart(uri, "tcp:", &p) ||
         strstart(uri, "unix:", NULL) ||
         strstart(uri, "vsock:", NULL)) {
@@ -2161,6 +2177,9 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_outgoing_migration(s, p, &local_err);
     } else {
+        if (!(has_resume && resume)) {
+            yank_unregister_instance(MIGRATION_YANK_INSTANCE);
+        }
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
                    "a valid migration protocol");
         migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
@@ -2170,6 +2189,9 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
     }
 
     if (local_err) {
+        if (!(has_resume && resume)) {
+            yank_unregister_instance(MIGRATION_YANK_INSTANCE);
+        }
         migrate_fd_error(s, local_err);
         error_propagate(errp, local_err);
         return;

migration/multifd.c

@@ -25,6 +25,9 @@
 #include "trace.h"
 #include "multifd.h"
 
+#include "qemu/yank.h"
+#include "io/channel-socket.h"
+
 /* Multiple fd's */
 
 #define MULTIFD_MAGIC 0x11223344U
@@ -974,6 +977,13 @@ int multifd_load_cleanup(Error **errp)
     for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
+        if (object_dynamic_cast(OBJECT(p->c), TYPE_QIO_CHANNEL_SOCKET)
+            && OBJECT(p->c)->ref == 1) {
+            yank_unregister_function(MIGRATION_YANK_INSTANCE,
+                                     yank_generic_iochannel,
+                                     QIO_CHANNEL(p->c));
+        }
+
         object_unref(OBJECT(p->c));
         p->c = NULL;
         qemu_mutex_destroy(&p->mutex);

migration/qemu-file-channel.c

@@ -27,6 +27,7 @@
 #include "qemu-file.h"
 #include "io/channel-socket.h"
 #include "qemu/iov.h"
+#include "qemu/yank.h"
 
 
 static ssize_t channel_writev_buffer(void *opaque,
@@ -104,6 +105,12 @@ static int channel_close(void *opaque, Error **errp)
     int ret;
     QIOChannel *ioc = QIO_CHANNEL(opaque);
     ret = qio_channel_close(ioc, errp);
+    if (object_dynamic_cast(OBJECT(ioc), TYPE_QIO_CHANNEL_SOCKET)
+        && OBJECT(ioc)->ref == 1) {
+        yank_unregister_function(MIGRATION_YANK_INSTANCE,
+                                 yank_generic_iochannel,
+                                 QIO_CHANNEL(ioc));
+    }
     object_unref(OBJECT(ioc));
     return ret;
 }

migration/savevm.c

@@ -62,6 +62,7 @@
 #include "migration/colo.h"
 #include "qemu/bitmap.h"
 #include "net/announce.h"
+#include "qemu/yank.h"
 
 const unsigned int postcopy_ram_discard_version;
 
@@ -3006,6 +3007,10 @@ int load_snapshot(const char *name, Error **errp)
     qemu_system_reset(SHUTDOWN_CAUSE_NONE);
     mis->from_src_file = f;
 
+    if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
+        ret = -EINVAL;
+        goto err_drain;
+    }
     aio_context_acquire(aio_context);
     ret = qemu_loadvm_state(f);
     migration_incoming_state_destroy();