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qemu-e2k/migration.c
Chris Lalancette 4951f65bd3 Migration via unix sockets. 
Implement migration via unix sockets.  While you can fake this using
exec and netcat, this involves forking another process and is
generally not very nice.  By doing this directly in qemu, we can avoid
the copy through the external nc command.  This is useful for
implementations (such as libvirt) that want to do "secure" migration;
we pipe the data on the sending side into the unix socket, libvirt
picks it up, encrypts it, and transports it, and then on the remote
side libvirt decrypts it, dumps it to another unix socket, and
feeds it into qemu.

The implementation is straightforward and looks very similar to
migration-exec.c and migration-tcp.c

Signed-off-by: Chris Lalancette <clalance@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-08-24 08:01:42 -05:00

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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"
//#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);
else if (strstart(uri, "unix:", &p))
unix_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);
else if (strstart(uri, "unix:", &p))
s = unix_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;
int old_vm_running = vm_running;
dprintf("done iterating\n");
vm_stop(0);
qemu_aio_flush();
bdrv_flush_all();
if ((qemu_savevm_state_complete(s->file)) < 0) {
if (old_vm_running) {
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);
}
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