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/*

 * 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.

 *

 */

#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 "qemu-objects.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

/* Migration speed throttling */

static int64_t max_throttle = (32 << 20);

static MigrationState *current_migration;

static NotifierList migration_state_notifiers =

    NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);

int qemu_start_incoming_migration(const char *uri)

{

    const char *p;

    int ret;

    if (strstart(uri, "tcp:", &p))

        ret = tcp_start_incoming_migration(p);

#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");

    incoming_expected = false;

    if (autostart)

        vm_start();

}

int do_migrate(Monitor *mon, const QDict *qdict, QObject **ret_data)

{

    MigrationState *s = NULL;

    const char *p;

    int detach = qdict_get_try_bool(qdict, "detach", 0);

    int blk = qdict_get_try_bool(qdict, "blk", 0);

    int inc = qdict_get_try_bool(qdict, "inc", 0);

    const char *uri = qdict_get_str(qdict, "uri");

    if (current_migration &&

        current_migration->get_status(current_migration) == MIG_STATE_ACTIVE) {

        monitor_printf(mon, "migration already in progress\n");

        return -1;

    }

    if (qemu_savevm_state_blocked(mon)) {

        return -1;

    }

    if (strstart(uri, "tcp:", &p)) {

        s = tcp_start_outgoing_migration(mon, p, max_throttle, detach,

                                         blk, inc);

#if !defined(WIN32)

    } else if (strstart(uri, "exec:", &p)) {

        s = exec_start_outgoing_migration(mon, p, max_throttle, detach,

                                          blk, inc);

    } else if (strstart(uri, "unix:", &p)) {

        s = unix_start_outgoing_migration(mon, p, max_throttle, detach,

                                          blk, inc);

    } else if (strstart(uri, "fd:", &p)) {

        s = fd_start_outgoing_migration(mon, p, max_throttle, detach, 

                                        blk, inc);

#endif

    } else {

        monitor_printf(mon, "unknown migration protocol: %s\n", uri);

        return -1;

    }

    if (s == NULL) {

        monitor_printf(mon, "migration failed\n");

        return -1;

    }

    if (current_migration) {

        current_migration->release(current_migration);

    }

    current_migration = s;

    notifier_list_notify(&migration_state_notifiers);

    return 0;

}

int do_migrate_cancel(Monitor *mon, const QDict *qdict, QObject **ret_data)

{

    MigrationState *s = current_migration;

    if (s)

        s->cancel(s);

    return 0;

}

int do_migrate_set_speed(Monitor *mon, const QDict *qdict, QObject **ret_data)

{

    int64_t d;

    FdMigrationState *s;

    d = qdict_get_int(qdict, "value");

    if (d < 0) {

        d = 0;

    }

    max_throttle = d;

    s = migrate_to_fms(current_migration);

    if (s && s->file) {

        qemu_file_set_rate_limit(s->file, max_throttle);

    }

    return 0;

}

/* 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;

}

int do_migrate_set_downtime(Monitor *mon, const QDict *qdict,

                            QObject **ret_data)

{

    double d;

    d = qdict_get_double(qdict, "value") * 1e9;

    d = MAX(0, MIN(UINT64_MAX, d));

    max_downtime = (uint64_t)d;

    return 0;

}

static void migrate_print_status(Monitor *mon, const char *name,

                                 const QDict *status_dict)

{

    QDict *qdict;

    qdict = qobject_to_qdict(qdict_get(status_dict, name));

    monitor_printf(mon, "transferred %s: %" PRIu64 " kbytes\n", name,

                        qdict_get_int(qdict, "transferred") >> 10);

    monitor_printf(mon, "remaining %s: %" PRIu64 " kbytes\n", name,

                        qdict_get_int(qdict, "remaining") >> 10);

    monitor_printf(mon, "total %s: %" PRIu64 " kbytes\n", name,

                        qdict_get_int(qdict, "total") >> 10);

}

void do_info_migrate_print(Monitor *mon, const QObject *data)

{

    QDict *qdict;

    qdict = qobject_to_qdict(data);

    monitor_printf(mon, "Migration status: %s\n",

                   qdict_get_str(qdict, "status"));

    if (qdict_haskey(qdict, "ram")) {

        migrate_print_status(mon, "ram", qdict);

    }

    if (qdict_haskey(qdict, "disk")) {

        migrate_print_status(mon, "disk", qdict);

    }

}

static void migrate_put_status(QDict *qdict, const char *name,

                               uint64_t trans, uint64_t rem, uint64_t total)

{

    QObject *obj;

    obj = qobject_from_jsonf("{ 'transferred': %" PRId64 ", "

                               "'remaining': %" PRId64 ", "

                               "'total': %" PRId64 " }", trans, rem, total);

    qdict_put_obj(qdict, name, obj);

}

void do_info_migrate(Monitor *mon, QObject **ret_data)

{

    QDict *qdict;

    MigrationState *s = current_migration;

    if (s) {

        switch (s->get_status(s)) {

        case MIG_STATE_ACTIVE:

            qdict = qdict_new();

            qdict_put(qdict, "status", qstring_from_str("active"));

            migrate_put_status(qdict, "ram", ram_bytes_transferred(),

                               ram_bytes_remaining(), ram_bytes_total());

            if (blk_mig_active()) {

                migrate_put_status(qdict, "disk", blk_mig_bytes_transferred(),

                                   blk_mig_bytes_remaining(),

                                   blk_mig_bytes_total());

            }

            *ret_data = QOBJECT(qdict);

            break;

        case MIG_STATE_COMPLETED:

            *ret_data = qobject_from_jsonf("{ 'status': 'completed' }");

            break;

        case MIG_STATE_ERROR:

            *ret_data = qobject_from_jsonf("{ 'status': 'failed' }");

            break;

        case MIG_STATE_CANCELLED:

            *ret_data = qobject_from_jsonf("{ 'status': 'cancelled' }");

            break;

        }

    }

}

/* shared migration helpers */

void migrate_fd_monitor_suspend(FdMigrationState *s, Monitor *mon)

{

    s->mon = mon;

    if (monitor_suspend(mon) == 0) {

        DPRINTF("suspending monitor\n");

    } else {

        monitor_printf(mon, "terminal does not allow synchronous "

                       "migration, continuing detached\n");

    }

}

void migrate_fd_error(FdMigrationState *s)

{

    DPRINTF("setting error state\n");

    s->state = MIG_STATE_ERROR;

    notifier_list_notify(&migration_state_notifiers);

    migrate_fd_cleanup(s);

}

int migrate_fd_cleanup(FdMigrationState *s)

{

    int ret = 0;

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

    if (s->file) {

        DPRINTF("closing file\n");

        if (qemu_fclose(s->file) != 0) {

            ret = -1;

        }

        s->file = NULL;

    }

    if (s->fd != -1)

        close(s->fd);

    /* Don't resume monitor until we've flushed all of the buffers */

    if (s->mon) {

        monitor_resume(s->mon);

    }

    s->fd = -1;

    return ret;

}

void migrate_fd_put_notify(void *opaque)

{

    FdMigrationState *s = opaque;

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

    qemu_file_put_notify(s->file);

}

ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)

{

    FdMigrationState *s = opaque;

    ssize_t ret;

    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);

    } else if (ret < 0) {

        if (s->mon) {

            monitor_resume(s->mon);

        }

        s->state = MIG_STATE_ERROR;

        notifier_list_notify(&migration_state_notifiers);

    }

    return ret;

}

void migrate_fd_connect(FdMigrationState *s)

{

    int ret;

    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->mon, s->file, s->mig_state.blk,

                                  s->mig_state.shared);

    if (ret < 0) {

        DPRINTF("failed, %d\n", ret);

        migrate_fd_error(s);

        return;

    }

    migrate_fd_put_ready(s);

}

void migrate_fd_put_ready(void *opaque)

{

    FdMigrationState *s = opaque;

    if (s->state != MIG_STATE_ACTIVE) {

        DPRINTF("put_ready returning because of non-active state\n");

        return;

    }

    DPRINTF("iterate\n");

    if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {

        int state;

        int old_vm_running = vm_running;

        DPRINTF("done iterating\n");

        vm_stop(VMSTOP_MIGRATE);

        if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {

            if (old_vm_running) {

                vm_start();

            }

            state = MIG_STATE_ERROR;

        } else {

            state = MIG_STATE_COMPLETED;

        }

        if (migrate_fd_cleanup(s) < 0) {

            if (old_vm_running) {

                vm_start();

            }

            state = MIG_STATE_ERROR;

        }

        s->state = state;

        notifier_list_notify(&migration_state_notifiers);

    }

}

int migrate_fd_get_status(MigrationState *mig_state)

{

    FdMigrationState *s = migrate_to_fms(mig_state);

    return s->state;

}

void migrate_fd_cancel(MigrationState *mig_state)

{

    FdMigrationState *s = migrate_to_fms(mig_state);

    if (s->state != MIG_STATE_ACTIVE)

        return;

    DPRINTF("cancelling migration\n");

    s->state = MIG_STATE_CANCELLED;

    notifier_list_notify(&migration_state_notifiers);

    qemu_savevm_state_cancel(s->mon, s->file);

    migrate_fd_cleanup(s);

}

void migrate_fd_release(MigrationState *mig_state)

{

    FdMigrationState *s = migrate_to_fms(mig_state);

    DPRINTF("releasing state\n");

    if (s->state == MIG_STATE_ACTIVE) {

        s->state = MIG_STATE_CANCELLED;

        notifier_list_notify(&migration_state_notifiers);

        migrate_fd_cleanup(s);

    }

    qemu_free(s);

}

void migrate_fd_wait_for_unfreeze(void *opaque)

{

    FdMigrationState *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);

}

int migrate_fd_close(void *opaque)

{

    FdMigrationState *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_list_remove(&migration_state_notifiers, notify);

}

int get_migration_state(void)

{

    if (current_migration) {

        return migrate_fd_get_status(current_migration);

    } else {

        return MIG_STATE_ERROR;

    }

}