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 "qemu_socket.h"

#include "migration.h"

#include "qemu-char.h"

#include "sysemu.h"

#include "console.h"

#include "buffered_file.h"

#include "block.h"

//#define DEBUG_MIGRATION_TCP

typedef struct FdMigrationState

{

    MigrationState mig_state;

    QEMUFile *file;

    int64_t bandwidth_limit;

    int fd;

    int detach;

    int state;

} FdMigrationState;

#ifdef DEBUG_MIGRATION_TCP

#define dprintf(fmt, ...) \

    do { printf("migration-tcp: " fmt, ## __VA_ARGS__); } while (0)

#else

#define dprintf(fmt, ...) \

    do { } while (0)

#endif

static void tcp_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->detach == 2) {

        monitor_resume();

        s->detach = 0;

    }

    s->fd = -1;

}

static void tcp_error(FdMigrationState *s)

{

    dprintf("setting error state\n");

    s->state = MIG_STATE_ERROR;

    tcp_cleanup(s);

}

static void fd_put_notify(void *opaque)

{

    FdMigrationState *s = opaque;

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

    qemu_file_put_notify(s->file);

}

static ssize_t fd_put_buffer(void *opaque, const void *data, size_t size)

{

    FdMigrationState *s = opaque;

    ssize_t ret;

    do {

        ret = send(s->fd, data, size, 0);

    } while (ret == -1 && (socket_error() == EINTR || socket_error() == EWOULDBLOCK));

    if (ret == -1)

        ret = -socket_error();

    if (ret == -EAGAIN)

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

    return ret;

}

static int fd_close(void *opaque)

{

    FdMigrationState *s = opaque;

    dprintf("fd_close\n");

    if (s->fd != -1) {

        close(s->fd);

        s->fd = -1;

    }

    return 0;

}

static void 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 && socket_error() == EINTR);

}

static void 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) {

        dprintf("done iterating\n");

        vm_stop(0);

        bdrv_flush_all();

        qemu_savevm_state_complete(s->file);

        s->state = MIG_STATE_COMPLETED;

        tcp_cleanup(s);

    }

}

static void tcp_connect_migrate(FdMigrationState *s)

{

    int ret;

    s->file = qemu_fopen_ops_buffered(s,

                                      s->bandwidth_limit,

                                      fd_put_buffer,

                                      fd_put_ready,

                                      fd_wait_for_unfreeze,

                                      fd_close);

    dprintf("beginning savevm\n");

    ret = qemu_savevm_state_begin(s->file);

    if (ret < 0) {

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

        tcp_error(s);

        return;

    }

    fd_put_ready(s);

}

static void tcp_wait_for_connect(void *opaque)

{

    FdMigrationState *s = opaque;

    int val, ret;

    socklen_t valsize = sizeof(val);

    dprintf("connect completed\n");

    do {

        ret = getsockopt(s->fd, SOL_SOCKET, SO_ERROR, &val, &valsize);

    } while (ret == -1 && socket_error() == EINTR);

    if (ret < 0) {

        tcp_error(s);

        return;

    }

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

    if (val == 0)

        tcp_connect_migrate(s);

    else {

        dprintf("error connecting %d\n", val);

        tcp_error(s);

    }

}

static FdMigrationState *to_fms(MigrationState *mig_state)

{

    return container_of(mig_state, FdMigrationState, mig_state);

}

static int tcp_get_status(MigrationState *mig_state)

{

    FdMigrationState *s = to_fms(mig_state);

    return s->state;

}

static void tcp_cancel(MigrationState *mig_state)

{

    FdMigrationState *s = to_fms(mig_state);

    if (s->state != MIG_STATE_ACTIVE)

        return;

    dprintf("cancelling migration\n");

    s->state = MIG_STATE_CANCELLED;

    tcp_cleanup(s);

}

static void tcp_release(MigrationState *mig_state)

{

    FdMigrationState *s = to_fms(mig_state);

    dprintf("releasing state\n");

    if (s->state == MIG_STATE_ACTIVE) {

        s->state = MIG_STATE_CANCELLED;

        tcp_cleanup(s);

    }

    free(s);

}

MigrationState *tcp_start_outgoing_migration(const char *host_port,

                                             int64_t bandwidth_limit,

                                             int async)

{

    struct sockaddr_in addr;

    FdMigrationState *s;

    int ret;

    if (parse_host_port(&addr, host_port) < 0)

        return NULL;

    s = qemu_mallocz(sizeof(*s));

    if (s == NULL)

        return NULL;

    s->mig_state.cancel = tcp_cancel;

    s->mig_state.get_status = tcp_get_status;

    s->mig_state.release = tcp_release;

    s->state = MIG_STATE_ACTIVE;

    s->detach = !async;

    s->bandwidth_limit = bandwidth_limit;

    s->fd = socket(PF_INET, SOCK_STREAM, 0);

    if (s->fd == -1) {

        qemu_free(s);

        return NULL;

    }

    socket_set_nonblock(s->fd);

    if (s->detach == 1) {

        dprintf("detaching from monitor\n");

        monitor_suspend();

        s->detach = 2;

    }

    do {

        ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));

        if (ret == -1)

            ret = -socket_error();

        if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)

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

    } while (ret == -EINTR);

    if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {

        dprintf("connect failed\n");

        close(s->fd);

        qemu_free(s);

        return NULL;

    } else if (ret >= 0)

        tcp_connect_migrate(s);

    return &s->mig_state;

}

static void tcp_accept_incoming_migration(void *opaque)

{

    struct sockaddr_in addr;

    socklen_t addrlen = sizeof(addr);

    int s = (unsigned long)opaque;

    QEMUFile *f;

    int c, ret;

    do {

        c = accept(s, (struct sockaddr *)&addr, &addrlen);

    } while (c == -1 && socket_error() == EINTR);

    dprintf("accepted migration\n");

    if (c == -1) {

        fprintf(stderr, "could not accept migration connection\n");

        return;

    }

    f = qemu_fopen_socket(c);

    if (f == NULL) {

        fprintf(stderr, "could not qemu_fopen socket\n");

        goto out;

    }

    vm_stop(0); /* just in case */

    ret = qemu_loadvm_state(f);

    if (ret < 0) {

        fprintf(stderr, "load of migration failed\n");

        goto out_fopen;

    }

    qemu_announce_self();

    dprintf("successfully loaded vm state\n");

    /* we've successfully migrated, close the server socket */

    qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);

    close(s);

    vm_start();

out_fopen:

    qemu_fclose(f);

out:

    close(c);

}

int tcp_start_incoming_migration(const char *host_port)

{

    struct sockaddr_in addr;

    int val;

    int s;

    if (parse_host_port(&addr, host_port) < 0) {

        fprintf(stderr, "invalid host/port combination: %s\n", host_port);

        return -EINVAL;

    }

    s = socket(PF_INET, SOCK_STREAM, 0);

    if (s == -1)

        return -socket_error();

    val = 1;

    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));

    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)

        goto err;

    if (listen(s, 1) == -1)

        goto err;

    qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,

                         (void *)(unsigned long)s);

    return 0;

err:

    close(s);

    return -socket_error();

}