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qemu/migration/migration.c
Markus Armbruster 01fa559826 migration: Use JSON null instead of "" to reset parameter to default 
migrate-set-parameters sets migration parameters according to is
arguments like this:

* Present means "set the parameter to this value"

* Absent means "leave the parameter unchanged"

* Except for parameters tls_creds and tls_hostname, "" means "reset
  the parameter to its default value

The first two are perfectly normal: presence of the parameter makes
the command do something.

The third one overloads the parameter with a second meaning.  The
overloading is *implicit*, i.e. it's not visible in the types.  Works
here, because "" is neither a valid TLS credentials ID, nor a valid
host name.

Pressing argument values the schema accepts, but are semantically
invalid, into service to mean "reset to default" is not general, as
suitable invalid values need not exist.  I also find it ugly.

To clean this up, we could add a separate flag argument to ask for
"reset to default", or add a distinct value to @tls_creds and
@tls_hostname.  This commit implements the latter: add JSON null to
the values of @tls_creds and @tls_hostname, deprecate "".

Because we're so close to the 2.10 freeze, implement it in the
stupidest way possible: have qmp_migrate_set_parameters() rewrite null
to "" before anything else can see the null.  The proper way to do it
would be rewriting "" to null, but that requires fixing up code to
work with null.  Add TODO comments for that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-07-24 13:35:11 +02:00

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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.
*
* 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 "migration/blocker.h"
#include "exec.h"
#include "fd.h"
#include "socket.h"
#include "rdma.h"
#include "ram.h"
#include "migration/global_state.h"
#include "migration/misc.h"
#include "migration.h"
#include "savevm.h"
#include "qemu-file-channel.h"
#include "qemu-file.h"
#include "migration/vmstate.h"
#include "block/block.h"
#include "qapi/qmp/qerror.h"
#include "qapi/util.h"
#include "qemu/rcu.h"
#include "block.h"
#include "postcopy-ram.h"
#include "qemu/thread.h"
#include "qmp-commands.h"
#include "trace.h"
#include "qapi-event.h"
#include "exec/target_page.h"
#include "io/channel-buffer.h"
#include "migration/colo.h"
#include "hw/boards.h"
#include "monitor/monitor.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;
/* Messages sent on the return path from destination to source */
enum mig_rp_message_type {
MIG_RP_MSG_INVALID = 0, /* Must be 0 */
MIG_RP_MSG_SHUT, /* sibling will not send any more RP messages */
MIG_RP_MSG_PONG, /* Response to a PING; data (seq: be32 ) */
MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */
MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */
MIG_RP_MSG_MAX
};
/* When we add fault tolerance, we could have several
migrations at once. For now we don't need to add
dynamic creation of migration */
static MigrationState *current_migration;
static bool migration_object_check(MigrationState *ms, Error **errp);
void migration_object_init(void)
{
MachineState *ms = MACHINE(qdev_get_machine());
Error *err = NULL;
/* This can only be called once. */
assert(!current_migration);
current_migration = MIGRATION_OBJ(object_new(TYPE_MIGRATION));
if (!migration_object_check(current_migration, &err)) {
error_report_err(err);
exit(1);
}
/*
* We cannot really do this in migration_instance_init() since at
* that time global properties are not yet applied, then this
* value will be definitely replaced by something else.
*/
if (ms->enforce_config_section) {
current_migration->send_configuration = true;
}
}
/* For outgoing */
MigrationState *migrate_get_current(void)
{
/* This can only be called after the object created. */
assert(current_migration);
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));
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();
if (mis->to_src_file) {
/* Tell source that we are done */
migrate_send_rp_shut(mis, qemu_file_get_error(mis->from_src_file) != 0);
qemu_fclose(mis->to_src_file);
mis->to_src_file = NULL;
}
if (mis->from_src_file) {
qemu_fclose(mis->from_src_file);
mis->from_src_file = NULL;
}
qemu_event_destroy(&mis->main_thread_load_event);
}
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;
}
/*
* Send a message on the return channel back to the source
* of the migration.
*/
static 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);
}
/* 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());
}
/*
* 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));
qemu_fclose(mis->from_src_file);
exit(EXIT_FAILURE);
}
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);
qemu_file_set_blocking(f, false);
qemu_coroutine_enter(co);
}
/*
* 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++) {
#ifndef CONFIG_LIVE_BLOCK_MIGRATION
if (i == MIGRATION_CAPABILITY_BLOCK) {
continue;
}
#endif
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();
/* TODO use QAPI_CLONE() instead of duplicating it inline */
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 = true;
params->tls_creds = g_strdup(s->parameters.tls_creds);
params->has_tls_hostname = true;
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;
params->has_block_incremental = true;
params->block_incremental = s->parameters.block_incremental;
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 populate_ram_info(MigrationInfo *info, MigrationState *s)
{
info->has_ram = true;
info->ram = g_malloc0(sizeof(*info->ram));
info->ram->transferred = ram_counters.transferred;
info->ram->total = ram_bytes_total();
info->ram->duplicate = ram_counters.duplicate;
/* legacy value. It is not used anymore */
info->ram->skipped = 0;
info->ram->normal = ram_counters.normal;
info->ram->normal_bytes = ram_counters.normal *
qemu_target_page_size();
info->ram->mbps = s->mbps;
info->ram->dirty_sync_count = ram_counters.dirty_sync_count;
info->ram->postcopy_requests = ram_counters.postcopy_requests;
info->ram->page_size = qemu_target_page_size();
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_counters.bytes;
info->xbzrle_cache->pages = xbzrle_counters.pages;
info->xbzrle_cache->cache_miss = xbzrle_counters.cache_miss;
info->xbzrle_cache->cache_miss_rate = xbzrle_counters.cache_miss_rate;
info->xbzrle_cache->overflow = xbzrle_counters.overflow;
}
if (cpu_throttle_active()) {
info->has_cpu_throttle_percentage = true;
info->cpu_throttle_percentage = cpu_throttle_get_percentage();
}
if (s->state != MIGRATION_STATUS_COMPLETED) {
info->ram->remaining = ram_bytes_remaining();
info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate;
}
}
static void populate_disk_info(MigrationInfo *info)
{
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();
}
}
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:
case MIGRATION_STATUS_POSTCOPY_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);
populate_disk_info(info);
break;
case MIGRATION_STATUS_COLO:
info->has_status = true;
/* TODO: display COLO specific information (checkpoint info etc.) */
break;
case MIGRATION_STATUS_COMPLETED:
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;
}
/**
* @migration_caps_check - check capability validity
*
* @cap_list: old capability list, array of bool
* @params: new capabilities to be applied soon
* @errp: set *errp if the check failed, with reason
*
* Returns true if check passed, otherwise false.
*/
static bool migrate_caps_check(bool *cap_list,
MigrationCapabilityStatusList *params,
Error **errp)
{
MigrationCapabilityStatusList *cap;
bool old_postcopy_cap;
old_postcopy_cap = cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM];
for (cap = params; cap; cap = cap->next) {
cap_list[cap->value->capability] = cap->value->state;
}
#ifndef CONFIG_LIVE_BLOCK_MIGRATION
if (cap_list[MIGRATION_CAPABILITY_BLOCK]) {
error_setg(errp, "QEMU compiled without old-style (blk/-b, inc/-i) "
"block migration");
error_append_hint(errp, "Use drive_mirror+NBD instead.\n");
return false;
}
#endif
if (cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
if (cap_list[MIGRATION_CAPABILITY_COMPRESS]) {
/* 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_setg(errp, "Postcopy is not currently compatible "
"with compression");
return 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_setg(errp, "Postcopy is not supported");
return false;
}
}
return true;
}
void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
Error **errp)
{
MigrationState *s = migrate_get_current();
MigrationCapabilityStatusList *cap;
if (migration_is_setup_or_active(s->state)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return;
}
if (!migrate_caps_check(s->enabled_capabilities, params, errp)) {
return;
}
for (cap = params; cap; cap = cap->next) {
s->enabled_capabilities[cap->value->capability] = cap->value->state;
}
}
/*
* Check whether the parameters are valid. Error will be put into errp
* (if provided). Return true if valid, otherwise false.
*/
static bool migrate_params_check(MigrationParameters *params, Error **errp)
{
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 false;
}
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 false;
}
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 false;
}
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 false;
}
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 false;
}
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 false;
}
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 false;
}
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");
return false;
}
return true;
}
static void migrate_params_test_apply(MigrateSetParameters *params,
MigrationParameters *dest)
{
*dest = migrate_get_current()->parameters;
/* TODO use QAPI_CLONE() instead of duplicating it inline */
if (params->has_compress_level) {
dest->compress_level = params->compress_level;
}
if (params->has_compress_threads) {
dest->compress_threads = params->compress_threads;
}
if (params->has_decompress_threads) {
dest->decompress_threads = params->decompress_threads;
}
if (params->has_cpu_throttle_initial) {
dest->cpu_throttle_initial = params->cpu_throttle_initial;
}
if (params->has_cpu_throttle_increment) {
dest->cpu_throttle_increment = params->cpu_throttle_increment;
}
if (params->has_tls_creds) {
assert(params->tls_creds->type == QTYPE_QSTRING);
dest->tls_creds = g_strdup(params->tls_creds->u.s);
}
if (params->has_tls_hostname) {
assert(params->tls_hostname->type == QTYPE_QSTRING);
dest->tls_hostname = g_strdup(params->tls_hostname->u.s);
}
if (params->has_max_bandwidth) {
dest->max_bandwidth = params->max_bandwidth;
}
if (params->has_downtime_limit) {
dest->downtime_limit = params->downtime_limit;
}
if (params->has_x_checkpoint_delay) {
dest->x_checkpoint_delay = params->x_checkpoint_delay;
}
if (params->has_block_incremental) {
dest->block_incremental = params->block_incremental;
}
}
static void migrate_params_apply(MigrateSetParameters *params)
{
MigrationState *s = migrate_get_current();
/* TODO use QAPI_CLONE() instead of duplicating it inline */
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);
assert(params->tls_creds->type == QTYPE_QSTRING);
s->parameters.tls_creds = g_strdup(params->tls_creds->u.s);
}
if (params->has_tls_hostname) {
g_free(s->parameters.tls_hostname);
assert(params->tls_hostname->type == QTYPE_QSTRING);
s->parameters.tls_hostname = g_strdup(params->tls_hostname->u.s);
}
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);
}
}
if (params->has_block_incremental) {
s->parameters.block_incremental = params->block_incremental;
}
}
void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
{
MigrationParameters tmp;
/* TODO Rewrite "" to null instead */
if (params->has_tls_creds
&& params->tls_creds->type == QTYPE_QNULL) {
QDECREF(params->tls_creds->u.n);
params->tls_creds->type = QTYPE_QSTRING;
params->tls_creds->u.s = strdup("");
}
/* TODO Rewrite "" to null instead */
if (params->has_tls_hostname
&& params->tls_hostname->type == QTYPE_QNULL) {
QDECREF(params->tls_hostname->u.n);
params->tls_hostname->type = QTYPE_QSTRING;
params->tls_hostname->u.s = strdup("");
}
migrate_params_test_apply(params, &tmp);
if (!migrate_params_check(&tmp, errp)) {
/* Invalid parameter */
return;
}
migrate_params_apply(params);
}
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 MigrationCapabilityStatusList *migrate_cap_add(
MigrationCapabilityStatusList *list,
MigrationCapability index,
bool state)
{
MigrationCapabilityStatusList *cap;
cap = g_new0(MigrationCapabilityStatusList, 1);
cap->value = g_new0(MigrationCapabilityStatus, 1);
cap->value->capability = index;
cap->value->state = state;
cap->next = list;
return cap;
}
void migrate_set_block_enabled(bool value, Error **errp)
{
MigrationCapabilityStatusList *cap;
cap = migrate_cap_add(NULL, MIGRATION_CAPABILITY_BLOCK, value);
qmp_migrate_set_capabilities(cap, errp);
qapi_free_MigrationCapabilityStatusList(cap);
}
static void migrate_set_block_incremental(MigrationState *s, bool value)
{
s->parameters.block_incremental = value;
}
static void block_cleanup_parameters(MigrationState *s)
{
if (s->must_remove_block_options) {
/* setting to false can never fail */
migrate_set_block_enabled(false, &error_abort);
migrate_set_block_incremental(s, false);
s->must_remove_block_options = false;
}
}
static void migrate_fd_cleanup(void *opaque)
{
MigrationState *s = opaque;
qemu_bh_delete(s->cleanup_bh);
s->cleanup_bh = NULL;
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();
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);
block_cleanup_parameters(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);
block_cleanup_parameters(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;
}
}
block_cleanup_parameters(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_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(void)
{
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->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 (migrate_get_current()->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);
}
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) {
error_propagate(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();
const char *p;
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;
}
if ((has_blk && blk) || (has_inc && inc)) {
if (migrate_use_block() || migrate_use_block_incremental()) {
error_setg(errp, "Command options are incompatible with "
"current migration capabilities");
return;
}
migrate_set_block_enabled(true, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
s->must_remove_block_options = true;
}
if (has_inc && inc) {
migrate_set_block_incremental(s, true);
}
s = migrate_init();
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)
{
MigrateSetParameters 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));
MigrateSetParameters 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;
}
bool migrate_use_block(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_BLOCK];
}
bool migrate_use_return_path(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_RETURN_PATH];
}
bool migrate_use_block_incremental(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.block_incremental;
}
/* 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, false);
/*
* 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, 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) {
bool inactivate = !migrate_colo_enabled();
ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
if (ret >= 0) {
qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false,
inactivate);
}
if (inactivate && ret >= 0) {
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).
*/
if (s->rp_state.from_dst_file) {
int rp_error;
trace_migration_return_path_end_before();
rp_error = await_return_path_close_on_source(s);
trace_migration_return_path_end_after(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 we opened the return path, we need to make sure dst has it
* opened as well.
*/
if (s->rp_state.from_dst_file) {
/* 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);
}
if (migrate_postcopy_ram()) {
/*
* 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_setup(s->to_dst_file);
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_counters.dirty_pages_rate && transferred_bytes > 10000) {
s->expected_downtime = ram_counters.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. For postcopy, it is used exclusively. For
* precopy, only if user specified "return-path" capability would
* QEMU uses the return path.
*/
if (migrate_postcopy_ram() || migrate_use_return_path()) {
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;
}
}
qemu_thread_create(&s->thread, "live_migration", migration_thread, s,
QEMU_THREAD_JOINABLE);
s->migration_thread_running = true;
}
void migration_global_dump(Monitor *mon)
{
MigrationState *ms = migrate_get_current();
monitor_printf(mon, "globals: store-global-state=%d, only_migratable=%d, "
"send-configuration=%d, send-section-footer=%d\n",
ms->store_global_state, ms->only_migratable,
ms->send_configuration, ms->send_section_footer);
}
#define DEFINE_PROP_MIG_CAP(name, x) \
DEFINE_PROP_BOOL(name, MigrationState, enabled_capabilities[x], false)
static Property migration_properties[] = {
DEFINE_PROP_BOOL("store-global-state", MigrationState,
store_global_state, true),
DEFINE_PROP_BOOL("only-migratable", MigrationState, only_migratable, false),
DEFINE_PROP_BOOL("send-configuration", MigrationState,
send_configuration, true),
DEFINE_PROP_BOOL("send-section-footer", MigrationState,
send_section_footer, true),
/* Migration parameters */
DEFINE_PROP_INT64("x-compress-level", MigrationState,
parameters.compress_level,
DEFAULT_MIGRATE_COMPRESS_LEVEL),
DEFINE_PROP_INT64("x-compress-threads", MigrationState,
parameters.compress_threads,
DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT),
DEFINE_PROP_INT64("x-decompress-threads", MigrationState,
parameters.decompress_threads,
DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT),
DEFINE_PROP_INT64("x-cpu-throttle-initial", MigrationState,
parameters.cpu_throttle_initial,
DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL),
DEFINE_PROP_INT64("x-cpu-throttle-increment", MigrationState,
parameters.cpu_throttle_increment,
DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT),
DEFINE_PROP_INT64("x-max-bandwidth", MigrationState,
parameters.max_bandwidth, MAX_THROTTLE),
DEFINE_PROP_INT64("x-downtime-limit", MigrationState,
parameters.downtime_limit,
DEFAULT_MIGRATE_SET_DOWNTIME),
DEFINE_PROP_INT64("x-checkpoint-delay", MigrationState,
parameters.x_checkpoint_delay,
DEFAULT_MIGRATE_X_CHECKPOINT_DELAY),
/* Migration capabilities */
DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
DEFINE_PROP_MIG_CAP("x-rdma-pin-all", MIGRATION_CAPABILITY_RDMA_PIN_ALL),
DEFINE_PROP_MIG_CAP("x-auto-converge", MIGRATION_CAPABILITY_AUTO_CONVERGE),
DEFINE_PROP_MIG_CAP("x-zero-blocks", MIGRATION_CAPABILITY_ZERO_BLOCKS),
DEFINE_PROP_MIG_CAP("x-compress", MIGRATION_CAPABILITY_COMPRESS),
DEFINE_PROP_MIG_CAP("x-events", MIGRATION_CAPABILITY_EVENTS),
DEFINE_PROP_MIG_CAP("x-postcopy-ram", MIGRATION_CAPABILITY_POSTCOPY_RAM),
DEFINE_PROP_MIG_CAP("x-colo", MIGRATION_CAPABILITY_X_COLO),
DEFINE_PROP_MIG_CAP("x-release-ram", MIGRATION_CAPABILITY_RELEASE_RAM),
DEFINE_PROP_MIG_CAP("x-block", MIGRATION_CAPABILITY_BLOCK),
DEFINE_PROP_MIG_CAP("x-return-path", MIGRATION_CAPABILITY_RETURN_PATH),
DEFINE_PROP_END_OF_LIST(),
};
static void migration_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->user_creatable = false;
dc->props = migration_properties;
}
static void migration_instance_init(Object *obj)
{
MigrationState *ms = MIGRATION_OBJ(obj);
MigrationParameters *params = &ms->parameters;
ms->state = MIGRATION_STATUS_NONE;
ms->xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE;
ms->mbps = -1;
params->tls_hostname = g_strdup("");
params->tls_creds = g_strdup("");
/* Set has_* up only for parameter checks */
params->has_compress_level = true;
params->has_compress_threads = true;
params->has_decompress_threads = true;
params->has_cpu_throttle_initial = true;
params->has_cpu_throttle_increment = true;
params->has_max_bandwidth = true;
params->has_downtime_limit = true;
params->has_x_checkpoint_delay = true;
params->has_block_incremental = true;
}
/*
* Return true if check pass, false otherwise. Error will be put
* inside errp if provided.
*/
static bool migration_object_check(MigrationState *ms, Error **errp)
{
MigrationCapabilityStatusList *head = NULL;
/* Assuming all off */
bool cap_list[MIGRATION_CAPABILITY__MAX] = { 0 }, ret;
int i;
if (!migrate_params_check(&ms->parameters, errp)) {
return false;
}
for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
if (ms->enabled_capabilities[i]) {
head = migrate_cap_add(head, i, true);
}
}
ret = migrate_caps_check(cap_list, head, errp);
/* It works with head == NULL */
qapi_free_MigrationCapabilityStatusList(head);
return ret;
}
static const TypeInfo migration_type = {
.name = TYPE_MIGRATION,
/*
* NOTE: TYPE_MIGRATION is not really a device, as the object is
* not created using qdev_create(), it is not attached to the qdev
* device tree, and it is never realized.
*
* TODO: Make this TYPE_OBJECT once QOM provides something like
* TYPE_DEVICE's "-global" properties.
*/
.parent = TYPE_DEVICE,
.class_init = migration_class_init,
.class_size = sizeof(MigrationClass),
.instance_size = sizeof(MigrationState),
.instance_init = migration_instance_init,
};
static void register_migration_types(void)
{
type_register_static(&migration_type);
}
type_init(register_migration_types);
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