Archipelago » qemu

/*

 * 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"

//#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 uint32_t max_throttle = (32 << 20);

static MigrationState *current_migration;

void qemu_start_incoming_migration(const char *uri)

{

    const char *p;

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

        tcp_start_incoming_migration(p);

#if !defined(WIN32)

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

        exec_start_incoming_migration(p);

#endif

    else

        fprintf(stderr, "unknown migration protocol: %s\n", uri);

}

void do_migrate(Monitor *mon, int detach, const char *uri)

{

    MigrationState *s = NULL;

    const char *p;

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

        s = tcp_start_outgoing_migration(p, max_throttle, detach);

#if !defined(WIN32)

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

        s = exec_start_outgoing_migration(p, max_throttle, detach);

#endif

    else

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

    if (s == NULL)

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

    else {

        if (current_migration)

            current_migration->release(current_migration);

        current_migration = s;

    }

}

void do_migrate_cancel(Monitor *mon)

{

    MigrationState *s = current_migration;

    if (s)

        s->cancel(s);

}

void do_migrate_set_speed(Monitor *mon, const char *value)

{

    double d;

    char *ptr;

    FdMigrationState *s;

    d = strtod(value, &ptr);

    switch (*ptr) {

    case 'G': case 'g':

        d *= 1024;

    case 'M': case 'm':

        d *= 1024;

    case 'K': case 'k':

        d *= 1024;

    default:

        break;

    }

    max_throttle = (uint32_t)d;

    s = migrate_to_fms(current_migration);

    if (s) {

        qemu_file_set_rate_limit(s->file, max_throttle);

    }

}

/* 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;

}

void do_migrate_set_downtime(Monitor *mon, const char *value)

{

    char *ptr;

    double d;

    d = strtod(value, &ptr);

    if (!strcmp(ptr,"ms")) {

        d *= 1000000;

    } else if (!strcmp(ptr,"us")) {

        d *= 1000;

    } else if (!strcmp(ptr,"ns")) {

    } else {

        /* all else considered to be seconds */

        d *= 1000000000;

    }

    max_downtime = (uint64_t)d;

}

void do_info_migrate(Monitor *mon)

{

    MigrationState *s = current_migration;

    if (s) {

        monitor_printf(mon, "Migration status: ");

        switch (s->get_status(s)) {

        case MIG_STATE_ACTIVE:

            monitor_printf(mon, "active\n");

            monitor_printf(mon, "transferred ram: %" PRIu64 " kbytes\n", ram_bytes_transferred() >> 10);

            monitor_printf(mon, "remaining ram: %" PRIu64 " kbytes\n", ram_bytes_remaining() >> 10);

            monitor_printf(mon, "total ram: %" PRIu64 " kbytes\n", ram_bytes_total() >> 10);

            break;

        case MIG_STATE_COMPLETED:

            monitor_printf(mon, "completed\n");

            break;

        case MIG_STATE_ERROR:

            monitor_printf(mon, "failed\n");

            break;

        case MIG_STATE_CANCELLED:

            monitor_printf(mon, "cancelled\n");

            break;

        }

    }

}

/* shared migration helpers */

void migrate_fd_monitor_suspend(FdMigrationState *s)

{

    s->mon_resume = cur_mon;

    if (monitor_suspend(cur_mon) == 0)

        dprintf("suspending monitor\n");

    else

        monitor_printf(cur_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;

    migrate_fd_cleanup(s);

}

void migrate_fd_cleanup(FdMigrationState *s)

{

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

    if (s->file) {

        dprintf("closing file\n");

        qemu_fclose(s->file);

    }

    if (s->fd != -1)

        close(s->fd);

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

    if (s->mon_resume)

        monitor_resume(s->mon_resume);

    s->fd = -1;

}

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);

    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->file);

    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->file) == 1) {

        int state;

        dprintf("done iterating\n");

        vm_stop(0);

        bdrv_flush_all();

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

            vm_start();

            state = MIG_STATE_ERROR;

        } else {

            state = MIG_STATE_COMPLETED;

        }

        migrate_fd_cleanup(s);

        s->state = state;

    }

}

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;

    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;

        migrate_fd_cleanup(s);

    }

    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);

}