migration.c - qemu - Git at Google

 /*
  * QEMU live migration
  *
  * Copyright IBM, Corp. 2008
  *
  * Authors:
  *  Anthony Liguori   <aliguori@us.ibm.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2.  See
  * the COPYING file in the top-level directory.
  *
  * Contributions after 2012-01-13 are licensed under the terms of the
  * GNU GPL, version 2 or (at your option) any later version.
  */

 #include "qemu-common.h"
 #include "migration.h"
 #include "monitor.h"
 #include "buffered_file.h"
 #include "sysemu.h"
 #include "block.h"
 #include "qemu_socket.h"
 #include "block-migration.h"
 #include "qmp-commands.h"

 //#define DEBUG_MIGRATION

 #ifdef DEBUG_MIGRATION
 #define DPRINTF(fmt, ...) \
     do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
 #else
 #define DPRINTF(fmt, ...) \
     do { } while (0)
 #endif

 enum {
     MIG_STATE_ERROR,
     MIG_STATE_SETUP,
     MIG_STATE_CANCELLED,
     MIG_STATE_ACTIVE,
     MIG_STATE_COMPLETED,
 };

 #define MAX_THROTTLE  (32 << 20)      /* Migration speed throttling */

 static NotifierList migration_state_notifiers =
     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);

 /* When we add fault tolerance, we could have several
    migrations at once.  For now we don't need to add
    dynamic creation of migration */

 static MigrationState *migrate_get_current(void)
 {
     static MigrationState current_migration = {
         .state = MIG_STATE_SETUP,
         .bandwidth_limit = MAX_THROTTLE,
     };

     return &current_migration;
 }

 int qemu_start_incoming_migration(const char *uri, Error **errp)
 {
     const char *p;
     int ret;

     if (strstart(uri, "tcp:", &p))
         ret = tcp_start_incoming_migration(p, errp);
 #if !defined(WIN32)
     else if (strstart(uri, "exec:", &p))
         ret =  exec_start_incoming_migration(p);
     else if (strstart(uri, "unix:", &p))
         ret = unix_start_incoming_migration(p);
     else if (strstart(uri, "fd:", &p))
         ret = fd_start_incoming_migration(p);
 #endif
     else {
         fprintf(stderr, "unknown migration protocol: %s\n", uri);
         ret = -EPROTONOSUPPORT;
     }
     return ret;
 }

 void process_incoming_migration(QEMUFile *f)
 {
     if (qemu_loadvm_state(f) < 0) {
         fprintf(stderr, "load of migration failed\n");
         exit(0);
     }
     qemu_announce_self();
     DPRINTF("successfully loaded vm state\n");

     bdrv_clear_incoming_migration_all();
     /* Make sure all file formats flush their mutable metadata */
     bdrv_invalidate_cache_all();

     if (autostart) {
         vm_start();
     } else {
         runstate_set(RUN_STATE_PRELAUNCH);
     }
 }

 /* amount of nanoseconds we are willing to wait for migration to be down.
  * the choice of nanoseconds is because it is the maximum resolution that
  * get_clock() can achieve. It is an internal measure. All user-visible
  * units must be in seconds */
 static uint64_t max_downtime = 30000000;

 uint64_t migrate_max_downtime(void)
 {
     return max_downtime;
 }

 MigrationInfo *qmp_query_migrate(Error **errp)
 {
     MigrationInfo *info = g_malloc0(sizeof(*info));
     MigrationState *s = migrate_get_current();

     switch (s->state) {
     case MIG_STATE_SETUP:
         /* no migration has happened ever */
         break;
     case MIG_STATE_ACTIVE:
         info->has_status = true;
         info->status = g_strdup("active");

         info->has_ram = true;
         info->ram = g_malloc0(sizeof(*info->ram));
         info->ram->transferred = ram_bytes_transferred();
         info->ram->remaining = ram_bytes_remaining();
         info->ram->total = ram_bytes_total();
         info->ram->total_time = qemu_get_clock_ms(rt_clock)
             - s->total_time;

         if (blk_mig_active()) {
             info->has_disk = true;
             info->disk = g_malloc0(sizeof(*info->disk));
             info->disk->transferred = blk_mig_bytes_transferred();
             info->disk->remaining = blk_mig_bytes_remaining();
             info->disk->total = blk_mig_bytes_total();
         }
         break;
     case MIG_STATE_COMPLETED:
         info->has_status = true;
         info->status = g_strdup("completed");

         info->has_ram = true;
         info->ram = g_malloc0(sizeof(*info->ram));
         info->ram->transferred = ram_bytes_transferred();
         info->ram->remaining = 0;
         info->ram->total = ram_bytes_total();
         info->ram->total_time = s->total_time;
         break;
     case MIG_STATE_ERROR:
         info->has_status = true;
         info->status = g_strdup("failed");
         break;
     case MIG_STATE_CANCELLED:
         info->has_status = true;
         info->status = g_strdup("cancelled");
         break;
     }

     return info;
 }

 /* shared migration helpers */

 static int migrate_fd_cleanup(MigrationState *s)
 {
     int ret = 0;

     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);

     if (s->file) {
         DPRINTF("closing file\n");
         ret = qemu_fclose(s->file);
         s->file = NULL;
     }

     if (s->fd != -1) {
         close(s->fd);
         s->fd = -1;
     }

     return ret;
 }

 void migrate_fd_error(MigrationState *s)
 {
     DPRINTF("setting error state\n");
     s->state = MIG_STATE_ERROR;
     notifier_list_notify(&migration_state_notifiers, s);
     migrate_fd_cleanup(s);
 }

 static void migrate_fd_completed(MigrationState *s)
 {
     DPRINTF("setting completed state\n");
     if (migrate_fd_cleanup(s) < 0) {
         s->state = MIG_STATE_ERROR;
     } else {
         s->state = MIG_STATE_COMPLETED;
         runstate_set(RUN_STATE_POSTMIGRATE);
     }
     notifier_list_notify(&migration_state_notifiers, s);
 }

 static void migrate_fd_put_notify(void *opaque)
 {
     MigrationState *s = opaque;

     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
     qemu_file_put_notify(s->file);
     if (s->file && qemu_file_get_error(s->file)) {
         migrate_fd_error(s);
     }
 }

 static ssize_t migrate_fd_put_buffer(void *opaque, const void *data,
                                      size_t size)
 {
     MigrationState *s = opaque;
     ssize_t ret;

     if (s->state != MIG_STATE_ACTIVE) {
         return -EIO;
     }

     do {
         ret = s->write(s, data, size);
     } while (ret == -1 && ((s->get_error(s)) == EINTR));

     if (ret == -1)
         ret = -(s->get_error(s));

     if (ret == -EAGAIN) {
         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
     }

     return ret;
 }

 static void migrate_fd_put_ready(void *opaque)
 {
     MigrationState *s = opaque;
     int ret;

     if (s->state != MIG_STATE_ACTIVE) {
         DPRINTF("put_ready returning because of non-active state\n");
         return;
     }

     DPRINTF("iterate\n");
     ret = qemu_savevm_state_iterate(s->file);
     if (ret < 0) {
         migrate_fd_error(s);
     } else if (ret == 1) {
         int old_vm_running = runstate_is_running();

         DPRINTF("done iterating\n");
         qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
         vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);

         if (qemu_savevm_state_complete(s->file) < 0) {
             migrate_fd_error(s);
         } else {
             migrate_fd_completed(s);
         }
         s->total_time = qemu_get_clock_ms(rt_clock) - s->total_time;
         if (s->state != MIG_STATE_COMPLETED) {
             if (old_vm_running) {
                 vm_start();
             }
         }
     }
 }

 static void migrate_fd_cancel(MigrationState *s)
 {
     if (s->state != MIG_STATE_ACTIVE)
         return;

     DPRINTF("cancelling migration\n");

     s->state = MIG_STATE_CANCELLED;
     notifier_list_notify(&migration_state_notifiers, s);
     qemu_savevm_state_cancel(s->file);

     migrate_fd_cleanup(s);
 }

 static void migrate_fd_wait_for_unfreeze(void *opaque)
 {
     MigrationState *s = opaque;
     int ret;

     DPRINTF("wait for unfreeze\n");
     if (s->state != MIG_STATE_ACTIVE)
         return;

     do {
         fd_set wfds;

         FD_ZERO(&wfds);
         FD_SET(s->fd, &wfds);

         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
     } while (ret == -1 && (s->get_error(s)) == EINTR);

     if (ret == -1) {
         qemu_file_set_error(s->file, -s->get_error(s));
     }
 }

 static int migrate_fd_close(void *opaque)
 {
     MigrationState *s = opaque;

     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
     return s->close(s);
 }

 void add_migration_state_change_notifier(Notifier *notify)
 {
     notifier_list_add(&migration_state_notifiers, notify);
 }

 void remove_migration_state_change_notifier(Notifier *notify)
 {
     notifier_remove(notify);
 }

 bool migration_is_active(MigrationState *s)
 {
     return s->state == MIG_STATE_ACTIVE;
 }

 bool migration_has_finished(MigrationState *s)
 {
     return s->state == MIG_STATE_COMPLETED;
 }

 bool migration_has_failed(MigrationState *s)
 {
     return (s->state == MIG_STATE_CANCELLED ||
             s->state == MIG_STATE_ERROR);
 }

 void migrate_fd_connect(MigrationState *s)
 {
     int ret;

     s->state = MIG_STATE_ACTIVE;
     s->file = qemu_fopen_ops_buffered(s,
                                       s->bandwidth_limit,
                                       migrate_fd_put_buffer,
                                       migrate_fd_put_ready,
                                       migrate_fd_wait_for_unfreeze,
                                       migrate_fd_close);

     DPRINTF("beginning savevm\n");
     ret = qemu_savevm_state_begin(s->file, &s->params);
     if (ret < 0) {
         DPRINTF("failed, %d\n", ret);
         migrate_fd_error(s);
         return;
     }
     migrate_fd_put_ready(s);
 }

 static MigrationState *migrate_init(const MigrationParams *params)
 {
     MigrationState *s = migrate_get_current();
     int64_t bandwidth_limit = s->bandwidth_limit;

     memset(s, 0, sizeof(*s));
     s->bandwidth_limit = bandwidth_limit;
     s->params = *params;

     s->bandwidth_limit = bandwidth_limit;
     s->state = MIG_STATE_SETUP;
     s->total_time = qemu_get_clock_ms(rt_clock);

     return s;
 }

 static GSList *migration_blockers;

 void migrate_add_blocker(Error *reason)
 {
     migration_blockers = g_slist_prepend(migration_blockers, reason);
 }

 void migrate_del_blocker(Error *reason)
 {
     migration_blockers = g_slist_remove(migration_blockers, reason);
 }

 void qmp_migrate(const char *uri, bool has_blk, bool blk,
                  bool has_inc, bool inc, bool has_detach, bool detach,
                  Error **errp)
 {
     MigrationState *s = migrate_get_current();
     MigrationParams params;
     const char *p;
     int ret;

     params.blk = blk;
     params.shared = inc;

     if (s->state == MIG_STATE_ACTIVE) {
         error_set(errp, QERR_MIGRATION_ACTIVE);
         return;
     }

     if (qemu_savevm_state_blocked(errp)) {
         return;
     }

     if (migration_blockers) {
         *errp = error_copy(migration_blockers->data);
         return;
     }

     s = migrate_init(&params);

     if (strstart(uri, "tcp:", &p)) {
         ret = tcp_start_outgoing_migration(s, p, errp);
 #if !defined(WIN32)
     } else if (strstart(uri, "exec:", &p)) {
         ret = exec_start_outgoing_migration(s, p);
     } else if (strstart(uri, "unix:", &p)) {
         ret = unix_start_outgoing_migration(s, p);
     } else if (strstart(uri, "fd:", &p)) {
         ret = fd_start_outgoing_migration(s, p);
 #endif
     } else {
         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol");
         return;
     }

     if (ret < 0) {
         if (!error_is_set(errp)) {
             DPRINTF("migration failed: %s\n", strerror(-ret));
             /* FIXME: we should return meaningful errors */
             error_set(errp, QERR_UNDEFINED_ERROR);
         }
         return;
     }

     notifier_list_notify(&migration_state_notifiers, s);
 }

 void qmp_migrate_cancel(Error **errp)
 {
     migrate_fd_cancel(migrate_get_current());
 }

 void qmp_migrate_set_speed(int64_t value, Error **errp)
 {
     MigrationState *s;

     if (value < 0) {
         value = 0;
     }

     s = migrate_get_current();
     s->bandwidth_limit = value;
     qemu_file_set_rate_limit(s->file, s->bandwidth_limit);
 }

 void qmp_migrate_set_downtime(double value, Error **errp)
 {
     value *= 1e9;
     value = MAX(0, MIN(UINT64_MAX, value));
     max_downtime = (uint64_t)value;
 }
	/*
	* QEMU live migration
	*
	* Copyright IBM, Corp. 2008
	*
	* Authors:
	* Anthony Liguori <aliguori@us.ibm.com>
	*
	* This work is licensed under the terms of the GNU GPL, version 2. See
	* the COPYING file in the top-level directory.
	*
	* Contributions after 2012-01-13 are licensed under the terms of the
	* GNU GPL, version 2 or (at your option) any later version.
	*/

	#include "qemu-common.h"
	#include "migration.h"
	#include "monitor.h"
	#include "buffered_file.h"
	#include "sysemu.h"
	#include "block.h"
	#include "qemu_socket.h"
	#include "block-migration.h"
	#include "qmp-commands.h"

	//#define DEBUG_MIGRATION

	#ifdef DEBUG_MIGRATION
	#define DPRINTF(fmt, ...) \
	do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
	#else
	#define DPRINTF(fmt, ...) \
	do { } while (0)
	#endif

	enum {
	MIG_STATE_ERROR,
	MIG_STATE_SETUP,
	MIG_STATE_CANCELLED,
	MIG_STATE_ACTIVE,
	MIG_STATE_COMPLETED,
	};

	#define MAX_THROTTLE (32 << 20) /* Migration speed throttling */

	static NotifierList migration_state_notifiers =
	NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);

	/* When we add fault tolerance, we could have several
	migrations at once. For now we don't need to add
	dynamic creation of migration */

	static MigrationState *migrate_get_current(void)
	{
	static MigrationState current_migration = {
	.state = MIG_STATE_SETUP,
	.bandwidth_limit = MAX_THROTTLE,
	};

	return &current_migration;
	}

	int qemu_start_incoming_migration(const char uri, Error *errp)
	{
	const char *p;
	int ret;

	if (strstart(uri, "tcp:", &p))
	ret = tcp_start_incoming_migration(p, errp);
	#if !defined(WIN32)
	else if (strstart(uri, "exec:", &p))
	ret = exec_start_incoming_migration(p);
	else if (strstart(uri, "unix:", &p))
	ret = unix_start_incoming_migration(p);
	else if (strstart(uri, "fd:", &p))
	ret = fd_start_incoming_migration(p);
	#endif
	else {
	fprintf(stderr, "unknown migration protocol: %s\n", uri);
	ret = -EPROTONOSUPPORT;
	}
	return ret;
	}

	void process_incoming_migration(QEMUFile *f)
	{
	if (qemu_loadvm_state(f) < 0) {
	fprintf(stderr, "load of migration failed\n");
	exit(0);
	}
	qemu_announce_self();
	DPRINTF("successfully loaded vm state\n");

	bdrv_clear_incoming_migration_all();
	/* Make sure all file formats flush their mutable metadata */
	bdrv_invalidate_cache_all();

	if (autostart) {
	vm_start();
	} else {
	runstate_set(RUN_STATE_PRELAUNCH);
	}
	}

	/* amount of nanoseconds we are willing to wait for migration to be down.
	* the choice of nanoseconds is because it is the maximum resolution that
	* get_clock() can achieve. It is an internal measure. All user-visible
	* units must be in seconds */
	static uint64_t max_downtime = 30000000;

	uint64_t migrate_max_downtime(void)
	{
	return max_downtime;
	}

	MigrationInfo qmp_query_migrate(Error *errp)
	{
	MigrationInfo info = g_malloc0(sizeof(info));
	MigrationState *s = migrate_get_current();

	switch (s->state) {
	case MIG_STATE_SETUP:
	/* no migration has happened ever */
	break;
	case MIG_STATE_ACTIVE:
	info->has_status = true;
	info->status = g_strdup("active");

	info->has_ram = true;
	info->ram = g_malloc0(sizeof(*info->ram));
	info->ram->transferred = ram_bytes_transferred();
	info->ram->remaining = ram_bytes_remaining();
	info->ram->total = ram_bytes_total();
	info->ram->total_time = qemu_get_clock_ms(rt_clock)
	- s->total_time;

	if (blk_mig_active()) {
	info->has_disk = true;
	info->disk = g_malloc0(sizeof(*info->disk));
	info->disk->transferred = blk_mig_bytes_transferred();
	info->disk->remaining = blk_mig_bytes_remaining();
	info->disk->total = blk_mig_bytes_total();
	}
	break;
	case MIG_STATE_COMPLETED:
	info->has_status = true;
	info->status = g_strdup("completed");

	info->has_ram = true;
	info->ram = g_malloc0(sizeof(*info->ram));
	info->ram->transferred = ram_bytes_transferred();
	info->ram->remaining = 0;
	info->ram->total = ram_bytes_total();
	info->ram->total_time = s->total_time;
	break;
	case MIG_STATE_ERROR:
	info->has_status = true;
	info->status = g_strdup("failed");
	break;
	case MIG_STATE_CANCELLED:
	info->has_status = true;
	info->status = g_strdup("cancelled");
	break;
	}

	return info;
	}

	/* shared migration helpers */

	static int migrate_fd_cleanup(MigrationState *s)
	{
	int ret = 0;

	qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);

	if (s->file) {
	DPRINTF("closing file\n");
	ret = qemu_fclose(s->file);
	s->file = NULL;
	}

	if (s->fd != -1) {
	close(s->fd);
	s->fd = -1;
	}

	return ret;
	}

	void migrate_fd_error(MigrationState *s)
	{
	DPRINTF("setting error state\n");
	s->state = MIG_STATE_ERROR;
	notifier_list_notify(&migration_state_notifiers, s);
	migrate_fd_cleanup(s);
	}

	static void migrate_fd_completed(MigrationState *s)
	{
	DPRINTF("setting completed state\n");
	if (migrate_fd_cleanup(s) < 0) {
	s->state = MIG_STATE_ERROR;
	} else {
	s->state = MIG_STATE_COMPLETED;
	runstate_set(RUN_STATE_POSTMIGRATE);
	}
	notifier_list_notify(&migration_state_notifiers, s);
	}

	static void migrate_fd_put_notify(void *opaque)
	{
	MigrationState *s = opaque;

	qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
	qemu_file_put_notify(s->file);
	if (s->file && qemu_file_get_error(s->file)) {
	migrate_fd_error(s);
	}
	}

	static ssize_t migrate_fd_put_buffer(void opaque, const void data,
	size_t size)
	{
	MigrationState *s = opaque;
	ssize_t ret;

	if (s->state != MIG_STATE_ACTIVE) {
	return -EIO;
	}

	do {
	ret = s->write(s, data, size);
	} while (ret == -1 && ((s->get_error(s)) == EINTR));

	if (ret == -1)
	ret = -(s->get_error(s));

	if (ret == -EAGAIN) {
	qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
	}

	return ret;
	}

	static void migrate_fd_put_ready(void *opaque)
	{
	MigrationState *s = opaque;
	int ret;

	if (s->state != MIG_STATE_ACTIVE) {
	DPRINTF("put_ready returning because of non-active state\n");
	return;
	}

	DPRINTF("iterate\n");
	ret = qemu_savevm_state_iterate(s->file);
	if (ret < 0) {
	migrate_fd_error(s);
	} else if (ret == 1) {
	int old_vm_running = runstate_is_running();

	DPRINTF("done iterating\n");
	qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
	vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);

	if (qemu_savevm_state_complete(s->file) < 0) {
	migrate_fd_error(s);
	} else {
	migrate_fd_completed(s);
	}
	s->total_time = qemu_get_clock_ms(rt_clock) - s->total_time;
	if (s->state != MIG_STATE_COMPLETED) {
	if (old_vm_running) {
	vm_start();
	}
	}
	}
	}

	static void migrate_fd_cancel(MigrationState *s)
	{
	if (s->state != MIG_STATE_ACTIVE)
	return;

	DPRINTF("cancelling migration\n");

	s->state = MIG_STATE_CANCELLED;
	notifier_list_notify(&migration_state_notifiers, s);
	qemu_savevm_state_cancel(s->file);

	migrate_fd_cleanup(s);
	}

	static void migrate_fd_wait_for_unfreeze(void *opaque)
	{
	MigrationState *s = opaque;
	int ret;

	DPRINTF("wait for unfreeze\n");
	if (s->state != MIG_STATE_ACTIVE)
	return;

	do {
	fd_set wfds;

	FD_ZERO(&wfds);
	FD_SET(s->fd, &wfds);

	ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
	} while (ret == -1 && (s->get_error(s)) == EINTR);

	if (ret == -1) {
	qemu_file_set_error(s->file, -s->get_error(s));
	}
	}

	static int migrate_fd_close(void *opaque)
	{
	MigrationState *s = opaque;

	qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
	return s->close(s);
	}

	void add_migration_state_change_notifier(Notifier *notify)
	{
	notifier_list_add(&migration_state_notifiers, notify);
	}

	void remove_migration_state_change_notifier(Notifier *notify)
	{
	notifier_remove(notify);
	}

	bool migration_is_active(MigrationState *s)
	{
	return s->state == MIG_STATE_ACTIVE;
	}

	bool migration_has_finished(MigrationState *s)
	{
	return s->state == MIG_STATE_COMPLETED;
	}

	bool migration_has_failed(MigrationState *s)
	{
	return (s->state == MIG_STATE_CANCELLED \|\|
	s->state == MIG_STATE_ERROR);
	}

	void migrate_fd_connect(MigrationState *s)
	{
	int ret;

	s->state = MIG_STATE_ACTIVE;
	s->file = qemu_fopen_ops_buffered(s,
	s->bandwidth_limit,
	migrate_fd_put_buffer,
	migrate_fd_put_ready,
	migrate_fd_wait_for_unfreeze,
	migrate_fd_close);

	DPRINTF("beginning savevm\n");
	ret = qemu_savevm_state_begin(s->file, &s->params);
	if (ret < 0) {
	DPRINTF("failed, %d\n", ret);
	migrate_fd_error(s);
	return;
	}
	migrate_fd_put_ready(s);
	}

	static MigrationState migrate_init(const MigrationParams params)
	{
	MigrationState *s = migrate_get_current();
	int64_t bandwidth_limit = s->bandwidth_limit;

	memset(s, 0, sizeof(*s));
	s->bandwidth_limit = bandwidth_limit;
	s->params = *params;

	s->bandwidth_limit = bandwidth_limit;
	s->state = MIG_STATE_SETUP;
	s->total_time = qemu_get_clock_ms(rt_clock);

	return s;
	}

	static GSList *migration_blockers;

	void migrate_add_blocker(Error *reason)
	{
	migration_blockers = g_slist_prepend(migration_blockers, reason);
	}

	void migrate_del_blocker(Error *reason)
	{
	migration_blockers = g_slist_remove(migration_blockers, reason);
	}

	void qmp_migrate(const char *uri, bool has_blk, bool blk,
	bool has_inc, bool inc, bool has_detach, bool detach,
	Error **errp)
	{
	MigrationState *s = migrate_get_current();
	MigrationParams params;
	const char *p;
	int ret;

	params.blk = blk;
	params.shared = inc;

	if (s->state == MIG_STATE_ACTIVE) {
	error_set(errp, QERR_MIGRATION_ACTIVE);
	return;
	}

	if (qemu_savevm_state_blocked(errp)) {
	return;
	}

	if (migration_blockers) {
	*errp = error_copy(migration_blockers->data);
	return;
	}

	s = migrate_init(&params);

	if (strstart(uri, "tcp:", &p)) {
	ret = tcp_start_outgoing_migration(s, p, errp);
	#if !defined(WIN32)
	} else if (strstart(uri, "exec:", &p)) {
	ret = exec_start_outgoing_migration(s, p);
	} else if (strstart(uri, "unix:", &p)) {
	ret = unix_start_outgoing_migration(s, p);
	} else if (strstart(uri, "fd:", &p)) {
	ret = fd_start_outgoing_migration(s, p);
	#endif
	} else {
	error_set(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol");
	return;
	}

	if (ret < 0) {
	if (!error_is_set(errp)) {
	DPRINTF("migration failed: %s\n", strerror(-ret));
	/* FIXME: we should return meaningful errors */
	error_set(errp, QERR_UNDEFINED_ERROR);
	}
	return;
	}

	notifier_list_notify(&migration_state_notifiers, s);
	}

	void qmp_migrate_cancel(Error **errp)
	{
	migrate_fd_cancel(migrate_get_current());
	}

	void qmp_migrate_set_speed(int64_t value, Error **errp)
	{
	MigrationState *s;

	if (value < 0) {
	value = 0;
	}

	s = migrate_get_current();
	s->bandwidth_limit = value;
	qemu_file_set_rate_limit(s->file, s->bandwidth_limit);
	}

	void qmp_migrate_set_downtime(double value, Error **errp)
	{
	value *= 1e9;
	value = MAX(0, MIN(UINT64_MAX, value));
	max_downtime = (uint64_t)value;
	}