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qemu/migration/migration.c
Kevin Wolf 4417ab7adf block: New BdrvChildRole.activate() for blk_resume_after_migration() 
Instead of manually calling blk_resume_after_migration() in migration
code after doing bdrv_invalidate_cache_all(), integrate the BlockBackend
activation with cache invalidation into a single function. This is
achieved with a new callback in BdrvChildRole that is called by
bdrv_invalidate_cache_all().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-05-11 12:08:24 +02:00

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64 KiB
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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.
*
* 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/osdep.h"
#include "qemu/cutils.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "migration/migration.h"
#include "migration/qemu-file.h"
#include "sysemu/sysemu.h"
#include "block/block.h"
#include "qapi/qmp/qerror.h"
#include "qapi/util.h"
#include "qemu/sockets.h"
#include "qemu/rcu.h"
#include "migration/block.h"
#include "postcopy-ram.h"
#include "qemu/thread.h"
#include "qmp-commands.h"
#include "trace.h"
#include "qapi-event.h"
#include "qom/cpu.h"
#include "exec/memory.h"
#include "exec/address-spaces.h"
#include "io/channel-buffer.h"
#include "io/channel-tls.h"
#include "migration/colo.h"
#define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */
/* Amount of time to allocate to each "chunk" of bandwidth-throttled
* data. */
#define BUFFER_DELAY 100
#define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
/* Time in milliseconds we are allowed to stop the source,
* for sending the last part */
#define DEFAULT_MIGRATE_SET_DOWNTIME 300
/* Maximum migrate downtime set to 2000 seconds */
#define MAX_MIGRATE_DOWNTIME_SECONDS 2000
#define MAX_MIGRATE_DOWNTIME (MAX_MIGRATE_DOWNTIME_SECONDS * 1000)
/* Default compression thread count */
#define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
/* Default decompression thread count, usually decompression is at
* least 4 times as fast as compression.*/
#define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
/*0: means nocompress, 1: best speed, ... 9: best compress ratio */
#define DEFAULT_MIGRATE_COMPRESS_LEVEL 1
/* Define default autoconverge cpu throttle migration parameters */
#define DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL 20
#define DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT 10
/* Migration XBZRLE default cache size */
#define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
/* The delay time (in ms) between two COLO checkpoints
* Note: Please change this default value to 10000 when we support hybrid mode.
*/
#define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY 200
static NotifierList migration_state_notifiers =
NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
static bool deferred_incoming;
/*
* Current state of incoming postcopy; note this is not part of
* MigrationIncomingState since it's state is used during cleanup
* at the end as MIS is being freed.
*/
static PostcopyState incoming_postcopy_state;
/* When we add fault tolerance, we could have several
migrations at once. For now we don't need to add
dynamic creation of migration */
/* For outgoing */
MigrationState *migrate_get_current(void)
{
static bool once;
static MigrationState current_migration = {
.state = MIGRATION_STATUS_NONE,
.xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
.mbps = -1,
.parameters = {
.compress_level = DEFAULT_MIGRATE_COMPRESS_LEVEL,
.compress_threads = DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
.decompress_threads = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
.cpu_throttle_initial = DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL,
.cpu_throttle_increment = DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT,
.max_bandwidth = MAX_THROTTLE,
.downtime_limit = DEFAULT_MIGRATE_SET_DOWNTIME,
.x_checkpoint_delay = DEFAULT_MIGRATE_X_CHECKPOINT_DELAY,
},
};
if (!once) {
current_migration.parameters.tls_creds = g_strdup("");
current_migration.parameters.tls_hostname = g_strdup("");
once = true;
}
return &current_migration;
}
MigrationIncomingState *migration_incoming_get_current(void)
{
static bool once;
static MigrationIncomingState mis_current;
if (!once) {
mis_current.state = MIGRATION_STATUS_NONE;
memset(&mis_current, 0, sizeof(MigrationIncomingState));
QLIST_INIT(&mis_current.loadvm_handlers);
qemu_mutex_init(&mis_current.rp_mutex);
qemu_event_init(&mis_current.main_thread_load_event, false);
once = true;
}
return &mis_current;
}
void migration_incoming_state_destroy(void)
{
struct MigrationIncomingState *mis = migration_incoming_get_current();
qemu_event_destroy(&mis->main_thread_load_event);
loadvm_free_handlers(mis);
}
typedef struct {
bool optional;
uint32_t size;
uint8_t runstate[100];
RunState state;
bool received;
} GlobalState;
static GlobalState global_state;
int global_state_store(void)
{
if (!runstate_store((char *)global_state.runstate,
sizeof(global_state.runstate))) {
error_report("runstate name too big: %s", global_state.runstate);
trace_migrate_state_too_big();
return -EINVAL;
}
return 0;
}
void global_state_store_running(void)
{
const char *state = RunState_lookup[RUN_STATE_RUNNING];
strncpy((char *)global_state.runstate,
state, sizeof(global_state.runstate));
}
static bool global_state_received(void)
{
return global_state.received;
}
static RunState global_state_get_runstate(void)
{
return global_state.state;
}
void global_state_set_optional(void)
{
global_state.optional = true;
}
static bool global_state_needed(void *opaque)
{
GlobalState *s = opaque;
char *runstate = (char *)s->runstate;
/* If it is not optional, it is mandatory */
if (s->optional == false) {
return true;
}
/* If state is running or paused, it is not needed */
if (strcmp(runstate, "running") == 0 ||
strcmp(runstate, "paused") == 0) {
return false;
}
/* for any other state it is needed */
return true;
}
static int global_state_post_load(void *opaque, int version_id)
{
GlobalState *s = opaque;
Error *local_err = NULL;
int r;
char *runstate = (char *)s->runstate;
s->received = true;
trace_migrate_global_state_post_load(runstate);
r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE__MAX,
-1, &local_err);
if (r == -1) {
if (local_err) {
error_report_err(local_err);
}
return -EINVAL;
}
s->state = r;
return 0;
}
static void global_state_pre_save(void *opaque)
{
GlobalState *s = opaque;
trace_migrate_global_state_pre_save((char *)s->runstate);
s->size = strlen((char *)s->runstate) + 1;
}
static const VMStateDescription vmstate_globalstate = {
.name = "globalstate",
.version_id = 1,
.minimum_version_id = 1,
.post_load = global_state_post_load,
.pre_save = global_state_pre_save,
.needed = global_state_needed,
.fields = (VMStateField[]) {
VMSTATE_UINT32(size, GlobalState),
VMSTATE_BUFFER(runstate, GlobalState),
VMSTATE_END_OF_LIST()
},
};
void register_global_state(void)
{
/* We would use it independently that we receive it */
strcpy((char *)&global_state.runstate, "");
global_state.received = false;
vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
}
static void migrate_generate_event(int new_state)
{
if (migrate_use_events()) {
qapi_event_send_migration(new_state, &error_abort);
}
}
/*
* Called on -incoming with a defer: uri.
* The migration can be started later after any parameters have been
* changed.
*/
static void deferred_incoming_migration(Error **errp)
{
if (deferred_incoming) {
error_setg(errp, "Incoming migration already deferred");
}
deferred_incoming = true;
}
/* Request a range of pages from the source VM at the given
* start address.
* rbname: Name of the RAMBlock to request the page in, if NULL it's the same
* as the last request (a name must have been given previously)
* Start: Address offset within the RB
* Len: Length in bytes required - must be a multiple of pagesize
*/
void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname,
ram_addr_t start, size_t len)
{
uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname up to 256 */
size_t msglen = 12; /* start + len */
*(uint64_t *)bufc = cpu_to_be64((uint64_t)start);
*(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len);
if (rbname) {
int rbname_len = strlen(rbname);
assert(rbname_len < 256);
bufc[msglen++] = rbname_len;
memcpy(bufc + msglen, rbname, rbname_len);
msglen += rbname_len;
migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES_ID, msglen, bufc);
} else {
migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES, msglen, bufc);
}
}
void qemu_start_incoming_migration(const char *uri, Error **errp)
{
const char *p;
qapi_event_send_migration(MIGRATION_STATUS_SETUP, &error_abort);
if (!strcmp(uri, "defer")) {
deferred_incoming_migration(errp);
} else if (strstart(uri, "tcp:", &p)) {
tcp_start_incoming_migration(p, errp);
#ifdef CONFIG_RDMA
} else if (strstart(uri, "rdma:", &p)) {
rdma_start_incoming_migration(p, errp);
#endif
} else if (strstart(uri, "exec:", &p)) {
exec_start_incoming_migration(p, errp);
} else if (strstart(uri, "unix:", &p)) {
unix_start_incoming_migration(p, errp);
} else if (strstart(uri, "fd:", &p)) {
fd_start_incoming_migration(p, errp);
} else {
error_setg(errp, "unknown migration protocol: %s", uri);
}
}
static void process_incoming_migration_bh(void *opaque)
{
Error *local_err = NULL;
MigrationIncomingState *mis = opaque;
/* Make sure all file formats flush their mutable metadata.
* If we get an error here, just don't restart the VM yet. */
bdrv_invalidate_cache_all(&local_err);
if (local_err) {
error_report_err(local_err);
local_err = NULL;
autostart = false;
}
/*
* This must happen after all error conditions are dealt with and
* we're sure the VM is going to be running on this host.
*/
qemu_announce_self();
/* If global state section was not received or we are in running
state, we need to obey autostart. Any other state is set with
runstate_set. */
if (!global_state_received() ||
global_state_get_runstate() == RUN_STATE_RUNNING) {
if (autostart) {
vm_start();
} else {
runstate_set(RUN_STATE_PAUSED);
}
} else {
runstate_set(global_state_get_runstate());
}
migrate_decompress_threads_join();
/*
* This must happen after any state changes since as soon as an external
* observer sees this event they might start to prod at the VM assuming
* it's ready to use.
*/
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_COMPLETED);
qemu_bh_delete(mis->bh);
migration_incoming_state_destroy();
}
static void process_incoming_migration_co(void *opaque)
{
QEMUFile *f = opaque;
MigrationIncomingState *mis = migration_incoming_get_current();
PostcopyState ps;
int ret;
mis->from_src_file = f;
mis->largest_page_size = qemu_ram_pagesize_largest();
postcopy_state_set(POSTCOPY_INCOMING_NONE);
migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
MIGRATION_STATUS_ACTIVE);
ret = qemu_loadvm_state(f);
ps = postcopy_state_get();
trace_process_incoming_migration_co_end(ret, ps);
if (ps != POSTCOPY_INCOMING_NONE) {
if (ps == POSTCOPY_INCOMING_ADVISE) {
/*
* Where a migration had postcopy enabled (and thus went to advise)
* but managed to complete within the precopy period, we can use
* the normal exit.
*/
postcopy_ram_incoming_cleanup(mis);
} else if (ret >= 0) {
/*
* Postcopy was started, cleanup should happen at the end of the
* postcopy thread.
*/
trace_process_incoming_migration_co_postcopy_end_main();
return;
}
/* Else if something went wrong then just fall out of the normal exit */
}
/* we get COLO info, and know if we are in COLO mode */
if (!ret && migration_incoming_enable_colo()) {
mis->migration_incoming_co = qemu_coroutine_self();
qemu_thread_create(&mis->colo_incoming_thread, "COLO incoming",
colo_process_incoming_thread, mis, QEMU_THREAD_JOINABLE);
mis->have_colo_incoming_thread = true;
qemu_coroutine_yield();
/* Wait checkpoint incoming thread exit before free resource */
qemu_thread_join(&mis->colo_incoming_thread);
}
if (ret < 0) {
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_FAILED);
error_report("load of migration failed: %s", strerror(-ret));
migrate_decompress_threads_join();
exit(EXIT_FAILURE);
}
qemu_fclose(f);
free_xbzrle_decoded_buf();
mis->bh = qemu_bh_new(process_incoming_migration_bh, mis);
qemu_bh_schedule(mis->bh);
}
void migration_fd_process_incoming(QEMUFile *f)
{
Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, f);
migrate_decompress_threads_create();
qemu_file_set_blocking(f, false);
qemu_coroutine_enter(co);
}
void migration_channel_process_incoming(MigrationState *s,
QIOChannel *ioc)
{
trace_migration_set_incoming_channel(
ioc, object_get_typename(OBJECT(ioc)));
if (s->parameters.tls_creds &&
*s->parameters.tls_creds &&
!object_dynamic_cast(OBJECT(ioc),
TYPE_QIO_CHANNEL_TLS)) {
Error *local_err = NULL;
migration_tls_channel_process_incoming(s, ioc, &local_err);
if (local_err) {
error_report_err(local_err);
}
} else {
QEMUFile *f = qemu_fopen_channel_input(ioc);
migration_fd_process_incoming(f);
}
}
void migration_channel_connect(MigrationState *s,
QIOChannel *ioc,
const char *hostname)
{
trace_migration_set_outgoing_channel(
ioc, object_get_typename(OBJECT(ioc)), hostname);
if (s->parameters.tls_creds &&
*s->parameters.tls_creds &&
!object_dynamic_cast(OBJECT(ioc),
TYPE_QIO_CHANNEL_TLS)) {
Error *local_err = NULL;
migration_tls_channel_connect(s, ioc, hostname, &local_err);
if (local_err) {
migrate_fd_error(s, local_err);
error_free(local_err);
}
} else {
QEMUFile *f = qemu_fopen_channel_output(ioc);
s->to_dst_file = f;
migrate_fd_connect(s);
}
}
/*
* Send a message on the return channel back to the source
* of the migration.
*/
void migrate_send_rp_message(MigrationIncomingState *mis,
enum mig_rp_message_type message_type,
uint16_t len, void *data)
{
trace_migrate_send_rp_message((int)message_type, len);
qemu_mutex_lock(&mis->rp_mutex);
qemu_put_be16(mis->to_src_file, (unsigned int)message_type);
qemu_put_be16(mis->to_src_file, len);
qemu_put_buffer(mis->to_src_file, data, len);
qemu_fflush(mis->to_src_file);
qemu_mutex_unlock(&mis->rp_mutex);
}
/*
* Send a 'SHUT' message on the return channel with the given value
* to indicate that we've finished with the RP. Non-0 value indicates
* error.
*/
void migrate_send_rp_shut(MigrationIncomingState *mis,
uint32_t value)
{
uint32_t buf;
buf = cpu_to_be32(value);
migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf);
}
/*
* Send a 'PONG' message on the return channel with the given value
* (normally in response to a 'PING')
*/
void migrate_send_rp_pong(MigrationIncomingState *mis,
uint32_t value)
{
uint32_t buf;
buf = cpu_to_be32(value);
migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
}
MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
{
MigrationCapabilityStatusList *head = NULL;
MigrationCapabilityStatusList *caps;
MigrationState *s = migrate_get_current();
int i;
caps = NULL; /* silence compiler warning */
for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
if (i == MIGRATION_CAPABILITY_X_COLO && !colo_supported()) {
continue;
}
if (head == NULL) {
head = g_malloc0(sizeof(*caps));
caps = head;
} else {
caps->next = g_malloc0(sizeof(*caps));
caps = caps->next;
}
caps->value =
g_malloc(sizeof(*caps->value));
caps->value->capability = i;
caps->value->state = s->enabled_capabilities[i];
}
return head;
}
MigrationParameters *qmp_query_migrate_parameters(Error **errp)
{
MigrationParameters *params;
MigrationState *s = migrate_get_current();
params = g_malloc0(sizeof(*params));
params->has_compress_level = true;
params->compress_level = s->parameters.compress_level;
params->has_compress_threads = true;
params->compress_threads = s->parameters.compress_threads;
params->has_decompress_threads = true;
params->decompress_threads = s->parameters.decompress_threads;
params->has_cpu_throttle_initial = true;
params->cpu_throttle_initial = s->parameters.cpu_throttle_initial;
params->has_cpu_throttle_increment = true;
params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
params->has_tls_creds = !!s->parameters.tls_creds;
params->tls_creds = g_strdup(s->parameters.tls_creds);
params->has_tls_hostname = !!s->parameters.tls_hostname;
params->tls_hostname = g_strdup(s->parameters.tls_hostname);
params->has_max_bandwidth = true;
params->max_bandwidth = s->parameters.max_bandwidth;
params->has_downtime_limit = true;
params->downtime_limit = s->parameters.downtime_limit;
params->has_x_checkpoint_delay = true;
params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
return params;
}
/*
* Return true if we're already in the middle of a migration
* (i.e. any of the active or setup states)
*/
static bool migration_is_setup_or_active(int state)
{
switch (state) {
case MIGRATION_STATUS_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_ACTIVE:
case MIGRATION_STATUS_SETUP:
return true;
default:
return false;
}
}
static void get_xbzrle_cache_stats(MigrationInfo *info)
{
if (migrate_use_xbzrle()) {
info->has_xbzrle_cache = true;
info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
info->xbzrle_cache->bytes = xbzrle_mig_bytes_transferred();
info->xbzrle_cache->pages = xbzrle_mig_pages_transferred();
info->xbzrle_cache->cache_miss = xbzrle_mig_pages_cache_miss();
info->xbzrle_cache->cache_miss_rate = xbzrle_mig_cache_miss_rate();
info->xbzrle_cache->overflow = xbzrle_mig_pages_overflow();
}
}
static void populate_ram_info(MigrationInfo *info, MigrationState *s)
{
info->has_ram = true;
info->ram = g_malloc0(sizeof(*info->ram));
info->ram->transferred = ram_bytes_transferred();
info->ram->total = ram_bytes_total();
info->ram->duplicate = dup_mig_pages_transferred();
/* legacy value. It is not used anymore */
info->ram->skipped = 0;
info->ram->normal = norm_mig_pages_transferred();
info->ram->normal_bytes = norm_mig_pages_transferred() *
qemu_target_page_size();
info->ram->mbps = s->mbps;
info->ram->dirty_sync_count = ram_dirty_sync_count();
info->ram->postcopy_requests = ram_postcopy_requests();
info->ram->page_size = qemu_target_page_size();
if (s->state != MIGRATION_STATUS_COMPLETED) {
info->ram->remaining = ram_bytes_remaining();
info->ram->dirty_pages_rate = ram_dirty_pages_rate();
}
}
MigrationInfo *qmp_query_migrate(Error **errp)
{
MigrationInfo *info = g_malloc0(sizeof(*info));
MigrationState *s = migrate_get_current();
switch (s->state) {
case MIGRATION_STATUS_NONE:
/* no migration has happened ever */
break;
case MIGRATION_STATUS_SETUP:
info->has_status = true;
info->has_total_time = false;
break;
case MIGRATION_STATUS_ACTIVE:
case MIGRATION_STATUS_CANCELLING:
info->has_status = true;
info->has_total_time = true;
info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
- s->total_time;
info->has_expected_downtime = true;
info->expected_downtime = s->expected_downtime;
info->has_setup_time = true;
info->setup_time = s->setup_time;
populate_ram_info(info, s);
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();
}
if (cpu_throttle_active()) {
info->has_cpu_throttle_percentage = true;
info->cpu_throttle_percentage = cpu_throttle_get_percentage();
}
get_xbzrle_cache_stats(info);
break;
case MIGRATION_STATUS_POSTCOPY_ACTIVE:
/* Mostly the same as active; TODO add some postcopy stats */
info->has_status = true;
info->has_total_time = true;
info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
- s->total_time;
info->has_expected_downtime = true;
info->expected_downtime = s->expected_downtime;
info->has_setup_time = true;
info->setup_time = s->setup_time;
populate_ram_info(info, s);
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();
}
get_xbzrle_cache_stats(info);
break;
case MIGRATION_STATUS_COLO:
info->has_status = true;
/* TODO: display COLO specific information (checkpoint info etc.) */
break;
case MIGRATION_STATUS_COMPLETED:
get_xbzrle_cache_stats(info);
info->has_status = true;
info->has_total_time = true;
info->total_time = s->total_time;
info->has_downtime = true;
info->downtime = s->downtime;
info->has_setup_time = true;
info->setup_time = s->setup_time;
populate_ram_info(info, s);
break;
case MIGRATION_STATUS_FAILED:
info->has_status = true;
if (s->error) {
info->has_error_desc = true;
info->error_desc = g_strdup(error_get_pretty(s->error));
}
break;
case MIGRATION_STATUS_CANCELLED:
info->has_status = true;
break;
}
info->status = s->state;
return info;
}
void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
Error **errp)
{
MigrationState *s = migrate_get_current();
MigrationCapabilityStatusList *cap;
bool old_postcopy_cap = migrate_postcopy_ram();
if (migration_is_setup_or_active(s->state)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return;
}
for (cap = params; cap; cap = cap->next) {
if (cap->value->capability == MIGRATION_CAPABILITY_X_COLO) {
if (!colo_supported()) {
error_setg(errp, "COLO is not currently supported, please"
" configure with --enable-colo option in order to"
" support COLO feature");
continue;
}
}
s->enabled_capabilities[cap->value->capability] = cap->value->state;
}
if (migrate_postcopy_ram()) {
if (migrate_use_compression()) {
/* The decompression threads asynchronously write into RAM
* rather than use the atomic copies needed to avoid
* userfaulting. It should be possible to fix the decompression
* threads for compatibility in future.
*/
error_report("Postcopy is not currently compatible with "
"compression");
s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] =
false;
}
/* This check is reasonably expensive, so only when it's being
* set the first time, also it's only the destination that needs
* special support.
*/
if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) &&
!postcopy_ram_supported_by_host()) {
/* postcopy_ram_supported_by_host will have emitted a more
* detailed message
*/
error_report("Postcopy is not supported");
s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM] =
false;
}
}
}
void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
{
MigrationState *s = migrate_get_current();
if (params->has_compress_level &&
(params->compress_level < 0 || params->compress_level > 9)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level",
"is invalid, it should be in the range of 0 to 9");
return;
}
if (params->has_compress_threads &&
(params->compress_threads < 1 || params->compress_threads > 255)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"compress_threads",
"is invalid, it should be in the range of 1 to 255");
return;
}
if (params->has_decompress_threads &&
(params->decompress_threads < 1 || params->decompress_threads > 255)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"decompress_threads",
"is invalid, it should be in the range of 1 to 255");
return;
}
if (params->has_cpu_throttle_initial &&
(params->cpu_throttle_initial < 1 ||
params->cpu_throttle_initial > 99)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"cpu_throttle_initial",
"an integer in the range of 1 to 99");
return;
}
if (params->has_cpu_throttle_increment &&
(params->cpu_throttle_increment < 1 ||
params->cpu_throttle_increment > 99)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"cpu_throttle_increment",
"an integer in the range of 1 to 99");
return;
}
if (params->has_max_bandwidth &&
(params->max_bandwidth < 0 || params->max_bandwidth > SIZE_MAX)) {
error_setg(errp, "Parameter 'max_bandwidth' expects an integer in the"
" range of 0 to %zu bytes/second", SIZE_MAX);
return;
}
if (params->has_downtime_limit &&
(params->downtime_limit < 0 ||
params->downtime_limit > MAX_MIGRATE_DOWNTIME)) {
error_setg(errp, "Parameter 'downtime_limit' expects an integer in "
"the range of 0 to %d milliseconds",
MAX_MIGRATE_DOWNTIME);
return;
}
if (params->has_x_checkpoint_delay && (params->x_checkpoint_delay < 0)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"x_checkpoint_delay",
"is invalid, it should be positive");
}
if (params->has_compress_level) {
s->parameters.compress_level = params->compress_level;
}
if (params->has_compress_threads) {
s->parameters.compress_threads = params->compress_threads;
}
if (params->has_decompress_threads) {
s->parameters.decompress_threads = params->decompress_threads;
}
if (params->has_cpu_throttle_initial) {
s->parameters.cpu_throttle_initial = params->cpu_throttle_initial;
}
if (params->has_cpu_throttle_increment) {
s->parameters.cpu_throttle_increment = params->cpu_throttle_increment;
}
if (params->has_tls_creds) {
g_free(s->parameters.tls_creds);
s->parameters.tls_creds = g_strdup(params->tls_creds);
}
if (params->has_tls_hostname) {
g_free(s->parameters.tls_hostname);
s->parameters.tls_hostname = g_strdup(params->tls_hostname);
}
if (params->has_max_bandwidth) {
s->parameters.max_bandwidth = params->max_bandwidth;
if (s->to_dst_file) {
qemu_file_set_rate_limit(s->to_dst_file,
s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
}
}
if (params->has_downtime_limit) {
s->parameters.downtime_limit = params->downtime_limit;
}
if (params->has_x_checkpoint_delay) {
s->parameters.x_checkpoint_delay = params->x_checkpoint_delay;
if (migration_in_colo_state()) {
colo_checkpoint_notify(s);
}
}
}
void qmp_migrate_start_postcopy(Error **errp)
{
MigrationState *s = migrate_get_current();
if (!migrate_postcopy_ram()) {
error_setg(errp, "Enable postcopy with migrate_set_capability before"
" the start of migration");
return;
}
if (s->state == MIGRATION_STATUS_NONE) {
error_setg(errp, "Postcopy must be started after migration has been"
" started");
return;
}
/*
* we don't error if migration has finished since that would be racy
* with issuing this command.
*/
atomic_set(&s->start_postcopy, true);
}
/* shared migration helpers */
void migrate_set_state(int *state, int old_state, int new_state)
{
if (atomic_cmpxchg(state, old_state, new_state) == old_state) {
trace_migrate_set_state(new_state);
migrate_generate_event(new_state);
}
}
static void migrate_fd_cleanup(void *opaque)
{
MigrationState *s = opaque;
qemu_bh_delete(s->cleanup_bh);
s->cleanup_bh = NULL;
migration_page_queue_free();
if (s->to_dst_file) {
trace_migrate_fd_cleanup();
qemu_mutex_unlock_iothread();
if (s->migration_thread_running) {
qemu_thread_join(&s->thread);
s->migration_thread_running = false;
}
qemu_mutex_lock_iothread();
migrate_compress_threads_join();
qemu_fclose(s->to_dst_file);
s->to_dst_file = NULL;
}
assert((s->state != MIGRATION_STATUS_ACTIVE) &&
(s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE));
if (s->state == MIGRATION_STATUS_CANCELLING) {
migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING,
MIGRATION_STATUS_CANCELLED);
}
notifier_list_notify(&migration_state_notifiers, s);
}
void migrate_fd_error(MigrationState *s, const Error *error)
{
trace_migrate_fd_error(error_get_pretty(error));
assert(s->to_dst_file == NULL);
migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_FAILED);
if (!s->error) {
s->error = error_copy(error);
}
notifier_list_notify(&migration_state_notifiers, s);
}
static void migrate_fd_cancel(MigrationState *s)
{
int old_state ;
QEMUFile *f = migrate_get_current()->to_dst_file;
trace_migrate_fd_cancel();
if (s->rp_state.from_dst_file) {
/* shutdown the rp socket, so causing the rp thread to shutdown */
qemu_file_shutdown(s->rp_state.from_dst_file);
}
do {
old_state = s->state;
if (!migration_is_setup_or_active(old_state)) {
break;
}
migrate_set_state(&s->state, old_state, MIGRATION_STATUS_CANCELLING);
} while (s->state != MIGRATION_STATUS_CANCELLING);
/*
* If we're unlucky the migration code might be stuck somewhere in a
* send/write while the network has failed and is waiting to timeout;
* if we've got shutdown(2) available then we can force it to quit.
* The outgoing qemu file gets closed in migrate_fd_cleanup that is
* called in a bh, so there is no race against this cancel.
*/
if (s->state == MIGRATION_STATUS_CANCELLING && f) {
qemu_file_shutdown(f);
}
if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) {
Error *local_err = NULL;
bdrv_invalidate_cache_all(&local_err);
if (local_err) {
error_report_err(local_err);
} else {
s->block_inactive = false;
}
}
}
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_in_setup(MigrationState *s)
{
return s->state == MIGRATION_STATUS_SETUP;
}
bool migration_has_finished(MigrationState *s)
{
return s->state == MIGRATION_STATUS_COMPLETED;
}
bool migration_has_failed(MigrationState *s)
{
return (s->state == MIGRATION_STATUS_CANCELLED ||
s->state == MIGRATION_STATUS_FAILED);
}
bool migration_in_postcopy(void)
{
MigrationState *s = migrate_get_current();
return (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
}
bool migration_in_postcopy_after_devices(MigrationState *s)
{
return migration_in_postcopy() && s->postcopy_after_devices;
}
bool migration_is_idle(void)
{
MigrationState *s = migrate_get_current();
switch (s->state) {
case MIGRATION_STATUS_NONE:
case MIGRATION_STATUS_CANCELLED:
case MIGRATION_STATUS_COMPLETED:
case MIGRATION_STATUS_FAILED:
return true;
case MIGRATION_STATUS_SETUP:
case MIGRATION_STATUS_CANCELLING:
case MIGRATION_STATUS_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_ACTIVE:
case MIGRATION_STATUS_COLO:
return false;
case MIGRATION_STATUS__MAX:
g_assert_not_reached();
}
return false;
}
MigrationState *migrate_init(const MigrationParams *params)
{
MigrationState *s = migrate_get_current();
/*
* Reinitialise all migration state, except
* parameters/capabilities that the user set, and
* locks.
*/
s->bytes_xfer = 0;
s->xfer_limit = 0;
s->cleanup_bh = 0;
s->to_dst_file = NULL;
s->state = MIGRATION_STATUS_NONE;
s->params = *params;
s->rp_state.from_dst_file = NULL;
s->rp_state.error = false;
s->mbps = 0.0;
s->downtime = 0;
s->expected_downtime = 0;
s->setup_time = 0;
s->start_postcopy = false;
s->postcopy_after_devices = false;
s->migration_thread_running = false;
error_free(s->error);
s->error = NULL;
migrate_set_state(&s->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP);
s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
return s;
}
static GSList *migration_blockers;
int migrate_add_blocker(Error *reason, Error **errp)
{
if (only_migratable) {
error_propagate(errp, error_copy(reason));
error_prepend(errp, "disallowing migration blocker "
"(--only_migratable) for: ");
return -EACCES;
}
if (migration_is_idle()) {
migration_blockers = g_slist_prepend(migration_blockers, reason);
return 0;
}
error_propagate(errp, error_copy(reason));
error_prepend(errp, "disallowing migration blocker (migration in "
"progress) for: ");
return -EBUSY;
}
void migrate_del_blocker(Error *reason)
{
migration_blockers = g_slist_remove(migration_blockers, reason);
}
int check_migratable(Object *obj, Error **err)
{
DeviceClass *dc = DEVICE_GET_CLASS(obj);
if (only_migratable && dc->vmsd) {
if (dc->vmsd->unmigratable) {
error_setg(err, "Device %s is not migratable, but "
"--only-migratable was specified",
object_get_typename(obj));
return -1;
}
}
return 0;
}
void qmp_migrate_incoming(const char *uri, Error **errp)
{
Error *local_err = NULL;
static bool once = true;
if (!deferred_incoming) {
error_setg(errp, "For use with '-incoming defer'");
return;
}
if (!once) {
error_setg(errp, "The incoming migration has already been started");
}
qemu_start_incoming_migration(uri, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
once = false;
}
bool migration_is_blocked(Error **errp)
{
if (qemu_savevm_state_blocked(errp)) {
return true;
}
if (migration_blockers) {
*errp = error_copy(migration_blockers->data);
return true;
}
return false;
}
void qmp_migrate(const char *uri, bool has_blk, bool blk,
bool has_inc, bool inc, bool has_detach, bool detach,
Error **errp)
{
Error *local_err = NULL;
MigrationState *s = migrate_get_current();
MigrationParams params;
const char *p;
params.blk = has_blk && blk;
params.shared = has_inc && inc;
if (migration_is_setup_or_active(s->state) ||
s->state == MIGRATION_STATUS_CANCELLING ||
s->state == MIGRATION_STATUS_COLO) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return;
}
if (runstate_check(RUN_STATE_INMIGRATE)) {
error_setg(errp, "Guest is waiting for an incoming migration");
return;
}
if (migration_is_blocked(errp)) {
return;
}
s = migrate_init(&params);
if (strstart(uri, "tcp:", &p)) {
tcp_start_outgoing_migration(s, p, &local_err);
#ifdef CONFIG_RDMA
} else if (strstart(uri, "rdma:", &p)) {
rdma_start_outgoing_migration(s, p, &local_err);
#endif
} else if (strstart(uri, "exec:", &p)) {
exec_start_outgoing_migration(s, p, &local_err);
} else if (strstart(uri, "unix:", &p)) {
unix_start_outgoing_migration(s, p, &local_err);
} else if (strstart(uri, "fd:", &p)) {
fd_start_outgoing_migration(s, p, &local_err);
} else {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
"a valid migration protocol");
migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_FAILED);
return;
}
if (local_err) {
migrate_fd_error(s, local_err);
error_propagate(errp, local_err);
return;
}
}
void qmp_migrate_cancel(Error **errp)
{
migrate_fd_cancel(migrate_get_current());
}
void qmp_migrate_set_cache_size(int64_t value, Error **errp)
{
MigrationState *s = migrate_get_current();
int64_t new_size;
/* Check for truncation */
if (value != (size_t)value) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
"exceeding address space");
return;
}
/* Cache should not be larger than guest ram size */
if (value > ram_bytes_total()) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
"exceeds guest ram size ");
return;
}
new_size = xbzrle_cache_resize(value);
if (new_size < 0) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
"is smaller than page size");
return;
}
s->xbzrle_cache_size = new_size;
}
int64_t qmp_query_migrate_cache_size(Error **errp)
{
return migrate_xbzrle_cache_size();
}
void qmp_migrate_set_speed(int64_t value, Error **errp)
{
MigrationParameters p = {
.has_max_bandwidth = true,
.max_bandwidth = value,
};
qmp_migrate_set_parameters(&p, errp);
}
void qmp_migrate_set_downtime(double value, Error **errp)
{
if (value < 0 || value > MAX_MIGRATE_DOWNTIME_SECONDS) {
error_setg(errp, "Parameter 'downtime_limit' expects an integer in "
"the range of 0 to %d seconds",
MAX_MIGRATE_DOWNTIME_SECONDS);
return;
}
value *= 1000; /* Convert to milliseconds */
value = MAX(0, MIN(INT64_MAX, value));
MigrationParameters p = {
.has_downtime_limit = true,
.downtime_limit = value,
};
qmp_migrate_set_parameters(&p, errp);
}
bool migrate_release_ram(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_RELEASE_RAM];
}
bool migrate_postcopy_ram(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM];
}
bool migrate_auto_converge(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
}
bool migrate_zero_blocks(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
}
bool migrate_use_compression(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS];
}
int migrate_compress_level(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.compress_level;
}
int migrate_compress_threads(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.compress_threads;
}
int migrate_decompress_threads(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.decompress_threads;
}
bool migrate_use_events(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS];
}
int migrate_use_xbzrle(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
}
int64_t migrate_xbzrle_cache_size(void)
{
MigrationState *s;
s = migrate_get_current();
return s->xbzrle_cache_size;
}
/* migration thread support */
/*
* Something bad happened to the RP stream, mark an error
* The caller shall print or trace something to indicate why
*/
static void mark_source_rp_bad(MigrationState *s)
{
s->rp_state.error = true;
}
static struct rp_cmd_args {
ssize_t len; /* -1 = variable */
const char *name;
} rp_cmd_args[] = {
[MIG_RP_MSG_INVALID] = { .len = -1, .name = "INVALID" },
[MIG_RP_MSG_SHUT] = { .len = 4, .name = "SHUT" },
[MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" },
[MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" },
[MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" },
[MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" },
};
/*
* Process a request for pages received on the return path,
* We're allowed to send more than requested (e.g. to round to our page size)
* and we don't need to send pages that have already been sent.
*/
static void migrate_handle_rp_req_pages(MigrationState *ms, const char* rbname,
ram_addr_t start, size_t len)
{
long our_host_ps = getpagesize();
trace_migrate_handle_rp_req_pages(rbname, start, len);
/*
* Since we currently insist on matching page sizes, just sanity check
* we're being asked for whole host pages.
*/
if (start & (our_host_ps-1) ||
(len & (our_host_ps-1))) {
error_report("%s: Misaligned page request, start: " RAM_ADDR_FMT
" len: %zd", __func__, start, len);
mark_source_rp_bad(ms);
return;
}
if (ram_save_queue_pages(rbname, start, len)) {
mark_source_rp_bad(ms);
}
}
/*
* Handles messages sent on the return path towards the source VM
*
*/
static void *source_return_path_thread(void *opaque)
{
MigrationState *ms = opaque;
QEMUFile *rp = ms->rp_state.from_dst_file;
uint16_t header_len, header_type;
uint8_t buf[512];
uint32_t tmp32, sibling_error;
ram_addr_t start = 0; /* =0 to silence warning */
size_t len = 0, expected_len;
int res;
trace_source_return_path_thread_entry();
while (!ms->rp_state.error && !qemu_file_get_error(rp) &&
migration_is_setup_or_active(ms->state)) {
trace_source_return_path_thread_loop_top();
header_type = qemu_get_be16(rp);
header_len = qemu_get_be16(rp);
if (header_type >= MIG_RP_MSG_MAX ||
header_type == MIG_RP_MSG_INVALID) {
error_report("RP: Received invalid message 0x%04x length 0x%04x",
header_type, header_len);
mark_source_rp_bad(ms);
goto out;
}
if ((rp_cmd_args[header_type].len != -1 &&
header_len != rp_cmd_args[header_type].len) ||
header_len > sizeof(buf)) {
error_report("RP: Received '%s' message (0x%04x) with"
"incorrect length %d expecting %zu",
rp_cmd_args[header_type].name, header_type, header_len,
(size_t)rp_cmd_args[header_type].len);
mark_source_rp_bad(ms);
goto out;
}
/* We know we've got a valid header by this point */
res = qemu_get_buffer(rp, buf, header_len);
if (res != header_len) {
error_report("RP: Failed reading data for message 0x%04x"
" read %d expected %d",
header_type, res, header_len);
mark_source_rp_bad(ms);
goto out;
}
/* OK, we have the message and the data */
switch (header_type) {
case MIG_RP_MSG_SHUT:
sibling_error = ldl_be_p(buf);
trace_source_return_path_thread_shut(sibling_error);
if (sibling_error) {
error_report("RP: Sibling indicated error %d", sibling_error);
mark_source_rp_bad(ms);
}
/*
* We'll let the main thread deal with closing the RP
* we could do a shutdown(2) on it, but we're the only user
* anyway, so there's nothing gained.
*/
goto out;
case MIG_RP_MSG_PONG:
tmp32 = ldl_be_p(buf);
trace_source_return_path_thread_pong(tmp32);
break;
case MIG_RP_MSG_REQ_PAGES:
start = ldq_be_p(buf);
len = ldl_be_p(buf + 8);
migrate_handle_rp_req_pages(ms, NULL, start, len);
break;
case MIG_RP_MSG_REQ_PAGES_ID:
expected_len = 12 + 1; /* header + termination */
if (header_len >= expected_len) {
start = ldq_be_p(buf);
len = ldl_be_p(buf + 8);
/* Now we expect an idstr */
tmp32 = buf[12]; /* Length of the following idstr */
buf[13 + tmp32] = '\0';
expected_len += tmp32;
}
if (header_len != expected_len) {
error_report("RP: Req_Page_id with length %d expecting %zd",
header_len, expected_len);
mark_source_rp_bad(ms);
goto out;
}
migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len);
break;
default:
break;
}
}
if (qemu_file_get_error(rp)) {
trace_source_return_path_thread_bad_end();
mark_source_rp_bad(ms);
}
trace_source_return_path_thread_end();
out:
ms->rp_state.from_dst_file = NULL;
qemu_fclose(rp);
return NULL;
}
static int open_return_path_on_source(MigrationState *ms)
{
ms->rp_state.from_dst_file = qemu_file_get_return_path(ms->to_dst_file);
if (!ms->rp_state.from_dst_file) {
return -1;
}
trace_open_return_path_on_source();
qemu_thread_create(&ms->rp_state.rp_thread, "return path",
source_return_path_thread, ms, QEMU_THREAD_JOINABLE);
trace_open_return_path_on_source_continue();
return 0;
}
/* Returns 0 if the RP was ok, otherwise there was an error on the RP */
static int await_return_path_close_on_source(MigrationState *ms)
{
/*
* If this is a normal exit then the destination will send a SHUT and the
* rp_thread will exit, however if there's an error we need to cause
* it to exit.
*/
if (qemu_file_get_error(ms->to_dst_file) && ms->rp_state.from_dst_file) {
/*
* shutdown(2), if we have it, will cause it to unblock if it's stuck
* waiting for the destination.
*/
qemu_file_shutdown(ms->rp_state.from_dst_file);
mark_source_rp_bad(ms);
}
trace_await_return_path_close_on_source_joining();
qemu_thread_join(&ms->rp_state.rp_thread);
trace_await_return_path_close_on_source_close();
return ms->rp_state.error;
}
/*
* Switch from normal iteration to postcopy
* Returns non-0 on error
*/
static int postcopy_start(MigrationState *ms, bool *old_vm_running)
{
int ret;
QIOChannelBuffer *bioc;
QEMUFile *fb;
int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
bool restart_block = false;
migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
trace_postcopy_start();
qemu_mutex_lock_iothread();
trace_postcopy_start_set_run();
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
*old_vm_running = runstate_is_running();
global_state_store();
ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
if (ret < 0) {
goto fail;
}
ret = bdrv_inactivate_all();
if (ret < 0) {
goto fail;
}
restart_block = true;
/*
* Cause any non-postcopiable, but iterative devices to
* send out their final data.
*/
qemu_savevm_state_complete_precopy(ms->to_dst_file, true);
/*
* in Finish migrate and with the io-lock held everything should
* be quiet, but we've potentially still got dirty pages and we
* need to tell the destination to throw any pages it's already received
* that are dirty
*/
if (ram_postcopy_send_discard_bitmap(ms)) {
error_report("postcopy send discard bitmap failed");
goto fail;
}
/*
* send rest of state - note things that are doing postcopy
* will notice we're in POSTCOPY_ACTIVE and not actually
* wrap their state up here
*/
qemu_file_set_rate_limit(ms->to_dst_file, INT64_MAX);
/* Ping just for debugging, helps line traces up */
qemu_savevm_send_ping(ms->to_dst_file, 2);
/*
* While loading the device state we may trigger page transfer
* requests and the fd must be free to process those, and thus
* the destination must read the whole device state off the fd before
* it starts processing it. Unfortunately the ad-hoc migration format
* doesn't allow the destination to know the size to read without fully
* parsing it through each devices load-state code (especially the open
* coded devices that use get/put).
* So we wrap the device state up in a package with a length at the start;
* to do this we use a qemu_buf to hold the whole of the device state.
*/
bioc = qio_channel_buffer_new(4096);
qio_channel_set_name(QIO_CHANNEL(bioc), "migration-postcopy-buffer");
fb = qemu_fopen_channel_output(QIO_CHANNEL(bioc));
object_unref(OBJECT(bioc));
/*
* Make sure the receiver can get incoming pages before we send the rest
* of the state
*/
qemu_savevm_send_postcopy_listen(fb);
qemu_savevm_state_complete_precopy(fb, false);
qemu_savevm_send_ping(fb, 3);
qemu_savevm_send_postcopy_run(fb);
/* <><> end of stuff going into the package */
/* Last point of recovery; as soon as we send the package the destination
* can open devices and potentially start running.
* Lets just check again we've not got any errors.
*/
ret = qemu_file_get_error(ms->to_dst_file);
if (ret) {
error_report("postcopy_start: Migration stream errored (pre package)");
goto fail_closefb;
}
restart_block = false;
/* Now send that blob */
if (qemu_savevm_send_packaged(ms->to_dst_file, bioc->data, bioc->usage)) {
goto fail_closefb;
}
qemu_fclose(fb);
/* Send a notify to give a chance for anything that needs to happen
* at the transition to postcopy and after the device state; in particular
* spice needs to trigger a transition now
*/
ms->postcopy_after_devices = true;
notifier_list_notify(&migration_state_notifiers, ms);
ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop;
qemu_mutex_unlock_iothread();
/*
* Although this ping is just for debug, it could potentially be
* used for getting a better measurement of downtime at the source.
*/
qemu_savevm_send_ping(ms->to_dst_file, 4);
if (migrate_release_ram()) {
ram_postcopy_migrated_memory_release(ms);
}
ret = qemu_file_get_error(ms->to_dst_file);
if (ret) {
error_report("postcopy_start: Migration stream errored");
migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_FAILED);
}
return ret;
fail_closefb:
qemu_fclose(fb);
fail:
migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_FAILED);
if (restart_block) {
/* A failure happened early enough that we know the destination hasn't
* accessed block devices, so we're safe to recover.
*/
Error *local_err = NULL;
bdrv_invalidate_cache_all(&local_err);
if (local_err) {
error_report_err(local_err);
}
}
qemu_mutex_unlock_iothread();
return -1;
}
/**
* migration_completion: Used by migration_thread when there's not much left.
* The caller 'breaks' the loop when this returns.
*
* @s: Current migration state
* @current_active_state: The migration state we expect to be in
* @*old_vm_running: Pointer to old_vm_running flag
* @*start_time: Pointer to time to update
*/
static void migration_completion(MigrationState *s, int current_active_state,
bool *old_vm_running,
int64_t *start_time)
{
int ret;
if (s->state == MIGRATION_STATUS_ACTIVE) {
qemu_mutex_lock_iothread();
*start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
*old_vm_running = runstate_is_running();
ret = global_state_store();
if (!ret) {
ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
/*
* Don't mark the image with BDRV_O_INACTIVE flag if
* we will go into COLO stage later.
*/
if (ret >= 0 && !migrate_colo_enabled()) {
ret = bdrv_inactivate_all();
}
if (ret >= 0) {
qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
qemu_savevm_state_complete_precopy(s->to_dst_file, false);
s->block_inactive = true;
}
}
qemu_mutex_unlock_iothread();
if (ret < 0) {
goto fail;
}
} else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
trace_migration_completion_postcopy_end();
qemu_savevm_state_complete_postcopy(s->to_dst_file);
trace_migration_completion_postcopy_end_after_complete();
}
/*
* If rp was opened we must clean up the thread before
* cleaning everything else up (since if there are no failures
* it will wait for the destination to send it's status in
* a SHUT command).
* Postcopy opens rp if enabled (even if it's not avtivated)
*/
if (migrate_postcopy_ram()) {
int rp_error;
trace_migration_completion_postcopy_end_before_rp();
rp_error = await_return_path_close_on_source(s);
trace_migration_completion_postcopy_end_after_rp(rp_error);
if (rp_error) {
goto fail_invalidate;
}
}
if (qemu_file_get_error(s->to_dst_file)) {
trace_migration_completion_file_err();
goto fail_invalidate;
}
if (!migrate_colo_enabled()) {
migrate_set_state(&s->state, current_active_state,
MIGRATION_STATUS_COMPLETED);
}
return;
fail_invalidate:
/* If not doing postcopy, vm_start() will be called: let's regain
* control on images.
*/
if (s->state == MIGRATION_STATUS_ACTIVE) {
Error *local_err = NULL;
qemu_mutex_lock_iothread();
bdrv_invalidate_cache_all(&local_err);
if (local_err) {
error_report_err(local_err);
} else {
s->block_inactive = false;
}
qemu_mutex_unlock_iothread();
}
fail:
migrate_set_state(&s->state, current_active_state,
MIGRATION_STATUS_FAILED);
}
bool migrate_colo_enabled(void)
{
MigrationState *s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO];
}
/*
* Master migration thread on the source VM.
* It drives the migration and pumps the data down the outgoing channel.
*/
static void *migration_thread(void *opaque)
{
MigrationState *s = opaque;
/* Used by the bandwidth calcs, updated later */
int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
int64_t initial_bytes = 0;
/*
* The final stage happens when the remaining data is smaller than
* this threshold; it's calculated from the requested downtime and
* measured bandwidth
*/
int64_t threshold_size = 0;
int64_t start_time = initial_time;
int64_t end_time;
bool old_vm_running = false;
bool entered_postcopy = false;
/* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */
enum MigrationStatus current_active_state = MIGRATION_STATUS_ACTIVE;
bool enable_colo = migrate_colo_enabled();
rcu_register_thread();
qemu_savevm_state_header(s->to_dst_file);
if (migrate_postcopy_ram()) {
/* Now tell the dest that it should open its end so it can reply */
qemu_savevm_send_open_return_path(s->to_dst_file);
/* And do a ping that will make stuff easier to debug */
qemu_savevm_send_ping(s->to_dst_file, 1);
/*
* Tell the destination that we *might* want to do postcopy later;
* if the other end can't do postcopy it should fail now, nice and
* early.
*/
qemu_savevm_send_postcopy_advise(s->to_dst_file);
}
qemu_savevm_state_begin(s->to_dst_file, &s->params);
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_ACTIVE);
trace_migration_thread_setup_complete();
while (s->state == MIGRATION_STATUS_ACTIVE ||
s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
int64_t current_time;
uint64_t pending_size;
if (!qemu_file_rate_limit(s->to_dst_file)) {
uint64_t pend_post, pend_nonpost;
qemu_savevm_state_pending(s->to_dst_file, threshold_size,
&pend_nonpost, &pend_post);
pending_size = pend_nonpost + pend_post;
trace_migrate_pending(pending_size, threshold_size,
pend_post, pend_nonpost);
if (pending_size && pending_size >= threshold_size) {
/* Still a significant amount to transfer */
if (migrate_postcopy_ram() &&
s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE &&
pend_nonpost <= threshold_size &&
atomic_read(&s->start_postcopy)) {
if (!postcopy_start(s, &old_vm_running)) {
current_active_state = MIGRATION_STATUS_POSTCOPY_ACTIVE;
entered_postcopy = true;
}
continue;
}
/* Just another iteration step */
qemu_savevm_state_iterate(s->to_dst_file, entered_postcopy);
} else {
trace_migration_thread_low_pending(pending_size);
migration_completion(s, current_active_state,
&old_vm_running, &start_time);
break;
}
}
if (qemu_file_get_error(s->to_dst_file)) {
migrate_set_state(&s->state, current_active_state,
MIGRATION_STATUS_FAILED);
trace_migration_thread_file_err();
break;
}
current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
if (current_time >= initial_time + BUFFER_DELAY) {
uint64_t transferred_bytes = qemu_ftell(s->to_dst_file) -
initial_bytes;
uint64_t time_spent = current_time - initial_time;
double bandwidth = (double)transferred_bytes / time_spent;
threshold_size = bandwidth * s->parameters.downtime_limit;
s->mbps = (((double) transferred_bytes * 8.0) /
((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
trace_migrate_transferred(transferred_bytes, time_spent,
bandwidth, threshold_size);
/* if we haven't sent anything, we don't want to recalculate
10000 is a small enough number for our purposes */
if (ram_dirty_pages_rate() && transferred_bytes > 10000) {
s->expected_downtime = ram_dirty_pages_rate() *
qemu_target_page_size() / bandwidth;
}
qemu_file_reset_rate_limit(s->to_dst_file);
initial_time = current_time;
initial_bytes = qemu_ftell(s->to_dst_file);
}
if (qemu_file_rate_limit(s->to_dst_file)) {
/* usleep expects microseconds */
g_usleep((initial_time + BUFFER_DELAY - current_time)*1000);
}
}
trace_migration_thread_after_loop();
/* If we enabled cpu throttling for auto-converge, turn it off. */
cpu_throttle_stop();
end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
qemu_mutex_lock_iothread();
/*
* The resource has been allocated by migration will be reused in COLO
* process, so don't release them.
*/
if (!enable_colo) {
qemu_savevm_state_cleanup();
}
if (s->state == MIGRATION_STATUS_COMPLETED) {
uint64_t transferred_bytes = qemu_ftell(s->to_dst_file);
s->total_time = end_time - s->total_time;
if (!entered_postcopy) {
s->downtime = end_time - start_time;
}
if (s->total_time) {
s->mbps = (((double) transferred_bytes * 8.0) /
((double) s->total_time)) / 1000;
}
runstate_set(RUN_STATE_POSTMIGRATE);
} else {
if (s->state == MIGRATION_STATUS_ACTIVE && enable_colo) {
migrate_start_colo_process(s);
qemu_savevm_state_cleanup();
/*
* Fixme: we will run VM in COLO no matter its old running state.
* After exited COLO, we will keep running.
*/
old_vm_running = true;
}
if (old_vm_running && !entered_postcopy) {
vm_start();
} else {
if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
runstate_set(RUN_STATE_POSTMIGRATE);
}
}
}
qemu_bh_schedule(s->cleanup_bh);
qemu_mutex_unlock_iothread();
rcu_unregister_thread();
return NULL;
}
void migrate_fd_connect(MigrationState *s)
{
s->expected_downtime = s->parameters.downtime_limit;
s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
qemu_file_set_blocking(s->to_dst_file, true);
qemu_file_set_rate_limit(s->to_dst_file,
s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
/* Notify before starting migration thread */
notifier_list_notify(&migration_state_notifiers, s);
/*
* Open the return path; currently for postcopy but other things might
* also want it.
*/
if (migrate_postcopy_ram()) {
if (open_return_path_on_source(s)) {
error_report("Unable to open return-path for postcopy");
migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_FAILED);
migrate_fd_cleanup(s);
return;
}
}
migrate_compress_threads_create();
qemu_thread_create(&s->thread, "live_migration", migration_thread, s,
QEMU_THREAD_JOINABLE);
s->migration_thread_running = true;
}
PostcopyState postcopy_state_get(void)
{
return atomic_mb_read(&incoming_postcopy_state);
}
/* Set the state and return the old state */
PostcopyState postcopy_state_set(PostcopyState new_state)
{
return atomic_xchg(&incoming_postcopy_state, new_state);
}
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