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qemu-e2k/migration/migration.c
Peter Xu 6621883f93 migration: Fix potential race on postcopy_qemufile_src 
postcopy_qemufile_src object should be owned by one thread, either the main
thread (e.g. when at the beginning, or at the end of migration), or by the
return path thread (when during a preempt enabled postcopy migration).  If
that's not the case the access to the object might be racy.

postcopy_preempt_shutdown_file() can be potentially racy, because it's
called at the end phase of migration on the main thread, however during
which the return path thread hasn't yet been recycled; the recycle happens
in await_return_path_close_on_source() which is after this point.

It means, logically it's posslbe the main thread and the return path thread
are both operating on the same qemufile.  While I don't think qemufile is
thread safe at all.

postcopy_preempt_shutdown_file() used to be needed because that's where we
send EOS to dest so that dest can safely shutdown the preempt thread.

To avoid the possible race, remove this only place that a race can happen.
Instead we figure out another way to safely close the preempt thread on
dest.

The core idea during postcopy on deciding "when to stop" is that dest will
send a postcopy SHUT message to src, telling src that all data is there.
Hence to shut the dest preempt thread maybe better to do it directly on
dest node.

This patch proposed such a way that we change postcopy_prio_thread_created
into PreemptThreadStatus, so that we kick the preempt thread on dest qemu
by a sequence of:

  mis->preempt_thread_status = PREEMPT_THREAD_QUIT;
  qemu_file_shutdown(mis->postcopy_qemufile_dst);

While here shutdown() is probably so far the easiest way to kick preempt
thread from a blocked qemu_get_be64().  Then it reads preempt_thread_status
to make sure it's not a network failure but a willingness to quit the
thread.

We could have avoided that extra status but just rely on migration status.
The problem is postcopy_ram_incoming_cleanup() is just called early enough
so we're still during POSTCOPY_ACTIVE no matter what.. So just make it
simple to have the status introduced.

One flag x-preempt-pre-7-2 is added to keep old pre-7.2 behaviors of
postcopy preempt.

Fixes: 9358982744 ("migration: Send requested page directly in rp-return thread")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-04-12 21:44:38 +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 "qemu/main-loop.h"
#include "migration/blocker.h"
#include "exec.h"
#include "fd.h"
#include "socket.h"
#include "sysemu/runstate.h"
#include "sysemu/sysemu.h"
#include "sysemu/cpu-throttle.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.h"
#include "channel.h"
#include "migration/vmstate.h"
#include "block/block.h"
#include "qapi/error.h"
#include "qapi/clone-visitor.h"
#include "qapi/qapi-visit-migration.h"
#include "qapi/qapi-visit-sockets.h"
#include "qapi/qapi-commands-migration.h"
#include "qapi/qapi-events-migration.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qnull.h"
#include "qemu/rcu.h"
#include "block.h"
#include "postcopy-ram.h"
#include "qemu/thread.h"
#include "trace.h"
#include "exec/target_page.h"
#include "io/channel-buffer.h"
#include "io/channel-tls.h"
#include "migration/colo.h"
#include "hw/boards.h"
#include "hw/qdev-properties.h"
#include "hw/qdev-properties-system.h"
#include "monitor/monitor.h"
#include "net/announce.h"
#include "qemu/queue.h"
#include "multifd.h"
#include "threadinfo.h"
#include "qemu/yank.h"
#include "sysemu/cpus.h"
#include "yank_functions.h"
#include "sysemu/qtest.h"
#include "ui/qemu-spice.h"
#define MAX_THROTTLE (128 << 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_THROTTLE_TRIGGER_THRESHOLD 50
#define DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL 20
#define DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT 10
#define DEFAULT_MIGRATE_MAX_CPU_THROTTLE 99
/* Migration XBZRLE default cache size */
#define DEFAULT_MIGRATE_XBZRLE_CACHE_SIZE (64 * 1024 * 1024)
/* The delay time (in ms) between two COLO checkpoints */
#define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY (200 * 100)
#define DEFAULT_MIGRATE_MULTIFD_CHANNELS 2
#define DEFAULT_MIGRATE_MULTIFD_COMPRESSION MULTIFD_COMPRESSION_NONE
/* 0: means nocompress, 1: best speed, ... 9: best compress ratio */
#define DEFAULT_MIGRATE_MULTIFD_ZLIB_LEVEL 1
/* 0: means nocompress, 1: best speed, ... 20: best compress ratio */
#define DEFAULT_MIGRATE_MULTIFD_ZSTD_LEVEL 1
/* Background transfer rate for postcopy, 0 means unlimited, note
* that page requests can still exceed this limit.
*/
#define DEFAULT_MIGRATE_MAX_POSTCOPY_BANDWIDTH 0
/*
* Parameters for self_announce_delay giving a stream of RARP/ARP
* packets after migration.
*/
#define DEFAULT_MIGRATE_ANNOUNCE_INITIAL 50
#define DEFAULT_MIGRATE_ANNOUNCE_MAX 550
#define DEFAULT_MIGRATE_ANNOUNCE_ROUNDS 5
#define DEFAULT_MIGRATE_ANNOUNCE_STEP 100
static NotifierList migration_state_notifiers =
NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
/* 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_RECV_BITMAP, /* send recved_bitmap back to source */
MIG_RP_MSG_RESUME_ACK, /* tell source that we are ready to resume */
MIG_RP_MSG_MAX
};
/* Migration capabilities set */
struct MigrateCapsSet {
int size; /* Capability set size */
MigrationCapability caps[]; /* Variadic array of capabilities */
};
typedef struct MigrateCapsSet MigrateCapsSet;
/* Define and initialize MigrateCapsSet */
#define INITIALIZE_MIGRATE_CAPS_SET(_name, ...) \
MigrateCapsSet _name = { \
.size = sizeof((int []) { __VA_ARGS__ }) / sizeof(int), \
.caps = { __VA_ARGS__ } \
}
/* Background-snapshot compatibility check list */
static const
INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
MIGRATION_CAPABILITY_POSTCOPY_RAM,
MIGRATION_CAPABILITY_DIRTY_BITMAPS,
MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME,
MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE,
MIGRATION_CAPABILITY_RETURN_PATH,
MIGRATION_CAPABILITY_MULTIFD,
MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER,
MIGRATION_CAPABILITY_AUTO_CONVERGE,
MIGRATION_CAPABILITY_RELEASE_RAM,
MIGRATION_CAPABILITY_RDMA_PIN_ALL,
MIGRATION_CAPABILITY_COMPRESS,
MIGRATION_CAPABILITY_XBZRLE,
MIGRATION_CAPABILITY_X_COLO,
MIGRATION_CAPABILITY_VALIDATE_UUID,
MIGRATION_CAPABILITY_ZERO_COPY_SEND);
/* 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 MigrationIncomingState *current_incoming;
static GSList *migration_blockers;
static bool migration_object_check(MigrationState *ms, Error **errp);
static int migration_maybe_pause(MigrationState *s,
int *current_active_state,
int new_state);
static void migrate_fd_cancel(MigrationState *s);
static bool migration_needs_multiple_sockets(void)
{
return migrate_use_multifd() || migrate_postcopy_preempt();
}
static bool uri_supports_multi_channels(const char *uri)
{
return strstart(uri, "tcp:", NULL) || strstart(uri, "unix:", NULL) ||
strstart(uri, "vsock:", NULL);
}
static bool
migration_channels_and_uri_compatible(const char *uri, Error **errp)
{
if (migration_needs_multiple_sockets() &&
!uri_supports_multi_channels(uri)) {
error_setg(errp, "Migration requires multi-channel URIs (e.g. tcp)");
return false;
}
return true;
}
static gint page_request_addr_cmp(gconstpointer ap, gconstpointer bp)
{
uintptr_t a = (uintptr_t) ap, b = (uintptr_t) bp;
return (a > b) - (a < b);
}
void migration_object_init(void)
{
/* This can only be called once. */
assert(!current_migration);
current_migration = MIGRATION_OBJ(object_new(TYPE_MIGRATION));
/*
* Init the migrate incoming object as well no matter whether
* we'll use it or not.
*/
assert(!current_incoming);
current_incoming = g_new0(MigrationIncomingState, 1);
current_incoming->state = MIGRATION_STATUS_NONE;
current_incoming->postcopy_remote_fds =
g_array_new(FALSE, TRUE, sizeof(struct PostCopyFD));
qemu_mutex_init(&current_incoming->rp_mutex);
qemu_mutex_init(&current_incoming->postcopy_prio_thread_mutex);
qemu_event_init(&current_incoming->main_thread_load_event, false);
qemu_sem_init(&current_incoming->postcopy_pause_sem_dst, 0);
qemu_sem_init(&current_incoming->postcopy_pause_sem_fault, 0);
qemu_sem_init(&current_incoming->postcopy_pause_sem_fast_load, 0);
qemu_sem_init(&current_incoming->postcopy_qemufile_dst_done, 0);
qemu_mutex_init(&current_incoming->page_request_mutex);
current_incoming->page_requested = g_tree_new(page_request_addr_cmp);
migration_object_check(current_migration, &error_fatal);
blk_mig_init();
ram_mig_init();
dirty_bitmap_mig_init();
}
void migration_cancel(const Error *error)
{
if (error) {
migrate_set_error(current_migration, error);
}
migrate_fd_cancel(current_migration);
}
void migration_shutdown(void)
{
/*
* When the QEMU main thread exit, the COLO thread
* may wait a semaphore. So, we should wakeup the
* COLO thread before migration shutdown.
*/
colo_shutdown();
/*
* Cancel the current migration - that will (eventually)
* stop the migration using this structure
*/
migration_cancel(NULL);
object_unref(OBJECT(current_migration));
/*
* Cancel outgoing migration of dirty bitmaps. It should
* at least unref used block nodes.
*/
dirty_bitmap_mig_cancel_outgoing();
/*
* Cancel incoming migration of dirty bitmaps. Dirty bitmaps
* are non-critical data, and their loss never considered as
* something serious.
*/
dirty_bitmap_mig_cancel_incoming();
}
/* 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)
{
assert(current_incoming);
return current_incoming;
}
void migration_incoming_transport_cleanup(MigrationIncomingState *mis)
{
if (mis->socket_address_list) {
qapi_free_SocketAddressList(mis->socket_address_list);
mis->socket_address_list = NULL;
}
if (mis->transport_cleanup) {
mis->transport_cleanup(mis->transport_data);
mis->transport_data = mis->transport_cleanup = NULL;
}
}
void migration_incoming_state_destroy(void)
{
struct MigrationIncomingState *mis = migration_incoming_get_current();
multifd_load_cleanup();
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) {
migration_ioc_unregister_yank_from_file(mis->from_src_file);
qemu_fclose(mis->from_src_file);
mis->from_src_file = NULL;
}
if (mis->postcopy_remote_fds) {
g_array_free(mis->postcopy_remote_fds, TRUE);
mis->postcopy_remote_fds = NULL;
}
migration_incoming_transport_cleanup(mis);
qemu_event_reset(&mis->main_thread_load_event);
if (mis->page_requested) {
g_tree_destroy(mis->page_requested);
mis->page_requested = NULL;
}
if (mis->postcopy_qemufile_dst) {
migration_ioc_unregister_yank_from_file(mis->postcopy_qemufile_dst);
qemu_fclose(mis->postcopy_qemufile_dst);
mis->postcopy_qemufile_dst = NULL;
}
yank_unregister_instance(MIGRATION_YANK_INSTANCE);
}
static void migrate_generate_event(int new_state)
{
if (migrate_use_events()) {
qapi_event_send_migration(new_state);
}
}
static bool migrate_late_block_activate(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[
MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE];
}
/*
* Send a message on the return channel back to the source
* of the migration.
*/
static int migrate_send_rp_message(MigrationIncomingState *mis,
enum mig_rp_message_type message_type,
uint16_t len, void *data)
{
int ret = 0;
trace_migrate_send_rp_message((int)message_type, len);
QEMU_LOCK_GUARD(&mis->rp_mutex);
/*
* It's possible that the file handle got lost due to network
* failures.
*/
if (!mis->to_src_file) {
ret = -EIO;
return ret;
}
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);
/* It's possible that qemu file got error during sending */
ret = qemu_file_get_error(mis->to_src_file);
return ret;
}
/* Request one page from the source VM at the given start address.
* rb: the RAMBlock to request the page in
* Start: Address offset within the RB
* Len: Length in bytes required - must be a multiple of pagesize
*/
int migrate_send_rp_message_req_pages(MigrationIncomingState *mis,
RAMBlock *rb, ram_addr_t start)
{
uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname up to 256 */
size_t msglen = 12; /* start + len */
size_t len = qemu_ram_pagesize(rb);
enum mig_rp_message_type msg_type;
const char *rbname;
int rbname_len;
*(uint64_t *)bufc = cpu_to_be64((uint64_t)start);
*(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len);
/*
* We maintain the last ramblock that we requested for page. Note that we
* don't need locking because this function will only be called within the
* postcopy ram fault thread.
*/
if (rb != mis->last_rb) {
mis->last_rb = rb;
rbname = qemu_ram_get_idstr(rb);
rbname_len = strlen(rbname);
assert(rbname_len < 256);
bufc[msglen++] = rbname_len;
memcpy(bufc + msglen, rbname, rbname_len);
msglen += rbname_len;
msg_type = MIG_RP_MSG_REQ_PAGES_ID;
} else {
msg_type = MIG_RP_MSG_REQ_PAGES;
}
return migrate_send_rp_message(mis, msg_type, msglen, bufc);
}
int migrate_send_rp_req_pages(MigrationIncomingState *mis,
RAMBlock *rb, ram_addr_t start, uint64_t haddr)
{
void *aligned = (void *)(uintptr_t)ROUND_DOWN(haddr, qemu_ram_pagesize(rb));
bool received = false;
WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) {
received = ramblock_recv_bitmap_test_byte_offset(rb, start);
if (!received && !g_tree_lookup(mis->page_requested, aligned)) {
/*
* The page has not been received, and it's not yet in the page
* request list. Queue it. Set the value of element to 1, so that
* things like g_tree_lookup() will return TRUE (1) when found.
*/
g_tree_insert(mis->page_requested, aligned, (gpointer)1);
mis->page_requested_count++;
trace_postcopy_page_req_add(aligned, mis->page_requested_count);
}
}
/*
* If the page is there, skip sending the message. We don't even need the
* lock because as long as the page arrived, it'll be there forever.
*/
if (received) {
return 0;
}
return migrate_send_rp_message_req_pages(mis, rb, start);
}
static bool migration_colo_enabled;
bool migration_incoming_colo_enabled(void)
{
return migration_colo_enabled;
}
void migration_incoming_disable_colo(void)
{
ram_block_discard_disable(false);
migration_colo_enabled = false;
}
int migration_incoming_enable_colo(void)
{
if (ram_block_discard_disable(true)) {
error_report("COLO: cannot disable RAM discard");
return -EBUSY;
}
migration_colo_enabled = true;
return 0;
}
void migrate_add_address(SocketAddress *address)
{
MigrationIncomingState *mis = migration_incoming_get_current();
QAPI_LIST_PREPEND(mis->socket_address_list,
QAPI_CLONE(SocketAddress, address));
}
static void qemu_start_incoming_migration(const char *uri, Error **errp)
{
const char *p = NULL;
/* URI is not suitable for migration? */
if (!migration_channels_and_uri_compatible(uri, errp)) {
return;
}
qapi_event_send_migration(MIGRATION_STATUS_SETUP);
if (strstart(uri, "tcp:", &p) ||
strstart(uri, "unix:", NULL) ||
strstart(uri, "vsock:", NULL)) {
socket_start_incoming_migration(p ? p : uri, 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, "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;
/* If capability late_block_activate is set:
* Only fire up the block code now if we're going to restart the
* VM, else 'cont' will do it.
* This causes file locking to happen; so we don't want it to happen
* unless we really are starting the VM.
*/
if (!migrate_late_block_activate() ||
(autostart && (!global_state_received() ||
global_state_get_runstate() == RUN_STATE_RUNNING))) {
/* Make sure all file formats throw away their mutable metadata.
* If we get an error here, just don't restart the VM yet. */
bdrv_activate_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(&mis->announce_timer, migrate_announce_params());
multifd_load_shutdown();
dirty_bitmap_mig_before_vm_start();
if (!global_state_received() ||
global_state_get_runstate() == RUN_STATE_RUNNING) {
if (autostart) {
vm_start();
} else {
runstate_set(RUN_STATE_PAUSED);
}
} else if (migration_incoming_colo_enabled()) {
migration_incoming_disable_colo();
vm_start();
} 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 coroutine_fn
process_incoming_migration_co(void *opaque)
{
MigrationIncomingState *mis = migration_incoming_get_current();
PostcopyState ps;
int ret;
Error *local_err = NULL;
assert(mis->from_src_file);
mis->migration_incoming_co = qemu_coroutine_self();
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(mis->from_src_file);
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_colo_enabled()) {
/* Make sure all file formats throw away their mutable metadata */
bdrv_activate_all(&local_err);
if (local_err) {
error_report_err(local_err);
goto fail;
}
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();
qemu_mutex_unlock_iothread();
/* Wait checkpoint incoming thread exit before free resource */
qemu_thread_join(&mis->colo_incoming_thread);
qemu_mutex_lock_iothread();
/* We hold the global iothread lock, so it is safe here */
colo_release_ram_cache();
}
if (ret < 0) {
error_report("load of migration failed: %s", strerror(-ret));
goto fail;
}
mis->bh = qemu_bh_new(process_incoming_migration_bh, mis);
qemu_bh_schedule(mis->bh);
mis->migration_incoming_co = NULL;
return;
fail:
local_err = NULL;
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_FAILED);
qemu_fclose(mis->from_src_file);
multifd_load_cleanup();
exit(EXIT_FAILURE);
}
/**
* migration_incoming_setup: Setup incoming migration
* @f: file for main migration channel
* @errp: where to put errors
*
* Returns: %true on success, %false on error.
*/
static bool migration_incoming_setup(QEMUFile *f, Error **errp)
{
MigrationIncomingState *mis = migration_incoming_get_current();
if (!mis->from_src_file) {
mis->from_src_file = f;
}
qemu_file_set_blocking(f, false);
return true;
}
void migration_incoming_process(void)
{
Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, NULL);
qemu_coroutine_enter(co);
}
/* Returns true if recovered from a paused migration, otherwise false */
static bool postcopy_try_recover(void)
{
MigrationIncomingState *mis = migration_incoming_get_current();
if (mis->state == MIGRATION_STATUS_POSTCOPY_PAUSED) {
/* Resumed from a paused postcopy migration */
/* This should be set already in migration_incoming_setup() */
assert(mis->from_src_file);
/* Postcopy has standalone thread to do vm load */
qemu_file_set_blocking(mis->from_src_file, true);
/* Re-configure the return path */
mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_PAUSED,
MIGRATION_STATUS_POSTCOPY_RECOVER);
/*
* Here, we only wake up the main loading thread (while the
* rest threads will still be waiting), so that we can receive
* commands from source now, and answer it if needed. The
* rest threads will be woken up afterwards until we are sure
* that source is ready to reply to page requests.
*/
qemu_sem_post(&mis->postcopy_pause_sem_dst);
return true;
}
return false;
}
void migration_fd_process_incoming(QEMUFile *f, Error **errp)
{
if (!migration_incoming_setup(f, errp)) {
return;
}
if (postcopy_try_recover()) {
return;
}
migration_incoming_process();
}
/*
* Returns true when we want to start a new incoming migration process,
* false otherwise.
*/
static bool migration_should_start_incoming(bool main_channel)
{
/* Multifd doesn't start unless all channels are established */
if (migrate_use_multifd()) {
return migration_has_all_channels();
}
/* Preempt channel only starts when the main channel is created */
if (migrate_postcopy_preempt()) {
return main_channel;
}
/*
* For all the rest types of migration, we should only reach here when
* it's the main channel that's being created, and we should always
* proceed with this channel.
*/
assert(main_channel);
return true;
}
void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
{
MigrationIncomingState *mis = migration_incoming_get_current();
Error *local_err = NULL;
QEMUFile *f;
bool default_channel = true;
uint32_t channel_magic = 0;
int ret = 0;
if (migrate_use_multifd() && !migrate_postcopy_ram() &&
qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_READ_MSG_PEEK)) {
/*
* With multiple channels, it is possible that we receive channels
* out of order on destination side, causing incorrect mapping of
* source channels on destination side. Check channel MAGIC to
* decide type of channel. Please note this is best effort, postcopy
* preempt channel does not send any magic number so avoid it for
* postcopy live migration. Also tls live migration already does
* tls handshake while initializing main channel so with tls this
* issue is not possible.
*/
ret = migration_channel_read_peek(ioc, (void *)&channel_magic,
sizeof(channel_magic), &local_err);
if (ret != 0) {
error_propagate(errp, local_err);
return;
}
default_channel = (channel_magic == cpu_to_be32(QEMU_VM_FILE_MAGIC));
} else {
default_channel = !mis->from_src_file;
}
if (multifd_load_setup(errp) != 0) {
error_setg(errp, "Failed to setup multifd channels");
return;
}
if (default_channel) {
f = qemu_file_new_input(ioc);
if (!migration_incoming_setup(f, errp)) {
return;
}
} else {
/* Multiple connections */
assert(migration_needs_multiple_sockets());
if (migrate_use_multifd()) {
multifd_recv_new_channel(ioc, &local_err);
} else {
assert(migrate_postcopy_preempt());
f = qemu_file_new_input(ioc);
postcopy_preempt_new_channel(mis, f);
}
if (local_err) {
error_propagate(errp, local_err);
return;
}
}
if (migration_should_start_incoming(default_channel)) {
/* If it's a recovery, we're done */
if (postcopy_try_recover()) {
return;
}
migration_incoming_process();
}
}
/**
* @migration_has_all_channels: We have received all channels that we need
*
* Returns true when we have got connections to all the channels that
* we need for migration.
*/
bool migration_has_all_channels(void)
{
MigrationIncomingState *mis = migration_incoming_get_current();
if (!mis->from_src_file) {
return false;
}
if (migrate_use_multifd()) {
return multifd_recv_all_channels_created();
}
if (migrate_postcopy_preempt()) {
return mis->postcopy_qemufile_dst != NULL;
}
return true;
}
/*
* 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);
}
void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,
char *block_name)
{
char buf[512];
int len;
int64_t res;
/*
* First, we send the header part. It contains only the len of
* idstr, and the idstr itself.
*/
len = strlen(block_name);
buf[0] = len;
memcpy(buf + 1, block_name, len);
if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) {
error_report("%s: MSG_RP_RECV_BITMAP only used for recovery",
__func__);
return;
}
migrate_send_rp_message(mis, MIG_RP_MSG_RECV_BITMAP, len + 1, buf);
/*
* Next, we dump the received bitmap to the stream.
*
* TODO: currently we are safe since we are the only one that is
* using the to_src_file handle (fault thread is still paused),
* and it's ok even not taking the mutex. However the best way is
* to take the lock before sending the message header, and release
* the lock after sending the bitmap.
*/
qemu_mutex_lock(&mis->rp_mutex);
res = ramblock_recv_bitmap_send(mis->to_src_file, block_name);
qemu_mutex_unlock(&mis->rp_mutex);
trace_migrate_send_rp_recv_bitmap(block_name, res);
}
void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value)
{
uint32_t buf;
buf = cpu_to_be32(value);
migrate_send_rp_message(mis, MIG_RP_MSG_RESUME_ACK, sizeof(buf), &buf);
}
MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
{
MigrationCapabilityStatusList *head = NULL, **tail = &head;
MigrationCapabilityStatus *caps;
MigrationState *s = migrate_get_current();
int i;
for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
#ifndef CONFIG_LIVE_BLOCK_MIGRATION
if (i == MIGRATION_CAPABILITY_BLOCK) {
continue;
}
#endif
caps = g_malloc0(sizeof(*caps));
caps->capability = i;
caps->state = s->enabled_capabilities[i];
QAPI_LIST_APPEND(tail, caps);
}
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_compress_wait_thread = true;
params->compress_wait_thread = s->parameters.compress_wait_thread;
params->has_decompress_threads = true;
params->decompress_threads = s->parameters.decompress_threads;
params->has_throttle_trigger_threshold = true;
params->throttle_trigger_threshold = s->parameters.throttle_trigger_threshold;
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_cpu_throttle_tailslow = true;
params->cpu_throttle_tailslow = s->parameters.cpu_throttle_tailslow;
params->tls_creds = g_strdup(s->parameters.tls_creds);
params->tls_hostname = g_strdup(s->parameters.tls_hostname);
params->tls_authz = g_strdup(s->parameters.tls_authz ?
s->parameters.tls_authz : "");
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;
params->has_multifd_channels = true;
params->multifd_channels = s->parameters.multifd_channels;
params->has_multifd_compression = true;
params->multifd_compression = s->parameters.multifd_compression;
params->has_multifd_zlib_level = true;
params->multifd_zlib_level = s->parameters.multifd_zlib_level;
params->has_multifd_zstd_level = true;
params->multifd_zstd_level = s->parameters.multifd_zstd_level;
params->has_xbzrle_cache_size = true;
params->xbzrle_cache_size = s->parameters.xbzrle_cache_size;
params->has_max_postcopy_bandwidth = true;
params->max_postcopy_bandwidth = s->parameters.max_postcopy_bandwidth;
params->has_max_cpu_throttle = true;
params->max_cpu_throttle = s->parameters.max_cpu_throttle;
params->has_announce_initial = true;
params->announce_initial = s->parameters.announce_initial;
params->has_announce_max = true;
params->announce_max = s->parameters.announce_max;
params->has_announce_rounds = true;
params->announce_rounds = s->parameters.announce_rounds;
params->has_announce_step = true;
params->announce_step = s->parameters.announce_step;
if (s->parameters.has_block_bitmap_mapping) {
params->has_block_bitmap_mapping = true;
params->block_bitmap_mapping =
QAPI_CLONE(BitmapMigrationNodeAliasList,
s->parameters.block_bitmap_mapping);
}
return params;
}
void qmp_client_migrate_info(const char *protocol, const char *hostname,
bool has_port, int64_t port,
bool has_tls_port, int64_t tls_port,
const char *cert_subject,
Error **errp)
{
if (strcmp(protocol, "spice") == 0) {
if (!qemu_using_spice(errp)) {
return;
}
if (!has_port && !has_tls_port) {
error_setg(errp, QERR_MISSING_PARAMETER, "port/tls-port");
return;
}
if (qemu_spice.migrate_info(hostname,
has_port ? port : -1,
has_tls_port ? tls_port : -1,
cert_subject)) {
error_setg(errp, "Could not set up display for migration");
return;
}
return;
}
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "protocol", "'spice'");
}
AnnounceParameters *migrate_announce_params(void)
{
static AnnounceParameters ap;
MigrationState *s = migrate_get_current();
ap.initial = s->parameters.announce_initial;
ap.max = s->parameters.announce_max;
ap.rounds = s->parameters.announce_rounds;
ap.step = s->parameters.announce_step;
return &ap;
}
/*
* Return true if we're already in the middle of a migration
* (i.e. any of the active or setup states)
*/
bool migration_is_setup_or_active(int state)
{
switch (state) {
case MIGRATION_STATUS_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_PAUSED:
case MIGRATION_STATUS_POSTCOPY_RECOVER:
case MIGRATION_STATUS_SETUP:
case MIGRATION_STATUS_PRE_SWITCHOVER:
case MIGRATION_STATUS_DEVICE:
case MIGRATION_STATUS_WAIT_UNPLUG:
case MIGRATION_STATUS_COLO:
return true;
default:
return false;
}
}
bool migration_is_running(int state)
{
switch (state) {
case MIGRATION_STATUS_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_PAUSED:
case MIGRATION_STATUS_POSTCOPY_RECOVER:
case MIGRATION_STATUS_SETUP:
case MIGRATION_STATUS_PRE_SWITCHOVER:
case MIGRATION_STATUS_DEVICE:
case MIGRATION_STATUS_WAIT_UNPLUG:
case MIGRATION_STATUS_CANCELLING:
return true;
default:
return false;
}
}
static bool migrate_show_downtime(MigrationState *s)
{
return (s->state == MIGRATION_STATUS_COMPLETED) || migration_in_postcopy();
}
static void populate_time_info(MigrationInfo *info, MigrationState *s)
{
info->has_status = true;
info->has_setup_time = true;
info->setup_time = s->setup_time;
if (s->state == MIGRATION_STATUS_COMPLETED) {
info->has_total_time = true;
info->total_time = s->total_time;
} else {
info->has_total_time = true;
info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) -
s->start_time;
}
if (migrate_show_downtime(s)) {
info->has_downtime = true;
info->downtime = s->downtime;
} else {
info->has_expected_downtime = true;
info->expected_downtime = s->expected_downtime;
}
}
static void populate_ram_info(MigrationInfo *info, MigrationState *s)
{
size_t page_size = qemu_target_page_size();
info->ram = g_malloc0(sizeof(*info->ram));
info->ram->transferred = stat64_get(&ram_atomic_counters.transferred);
info->ram->total = ram_bytes_total();
info->ram->duplicate = stat64_get(&ram_atomic_counters.duplicate);
/* legacy value. It is not used anymore */
info->ram->skipped = 0;
info->ram->normal = stat64_get(&ram_atomic_counters.normal);
info->ram->normal_bytes = info->ram->normal * page_size;
info->ram->mbps = s->mbps;
info->ram->dirty_sync_count = ram_counters.dirty_sync_count;
info->ram->dirty_sync_missed_zero_copy =
ram_counters.dirty_sync_missed_zero_copy;
info->ram->postcopy_requests = ram_counters.postcopy_requests;
info->ram->page_size = page_size;
info->ram->multifd_bytes = ram_counters.multifd_bytes;
info->ram->pages_per_second = s->pages_per_second;
info->ram->precopy_bytes = ram_counters.precopy_bytes;
info->ram->downtime_bytes = ram_counters.downtime_bytes;
info->ram->postcopy_bytes = stat64_get(&ram_atomic_counters.postcopy_bytes);
if (migrate_use_xbzrle()) {
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->encoding_rate = xbzrle_counters.encoding_rate;
info->xbzrle_cache->overflow = xbzrle_counters.overflow;
}
if (migrate_use_compression()) {
info->compression = g_malloc0(sizeof(*info->compression));
info->compression->pages = compression_counters.pages;
info->compression->busy = compression_counters.busy;
info->compression->busy_rate = compression_counters.busy_rate;
info->compression->compressed_size =
compression_counters.compressed_size;
info->compression->compression_rate =
compression_counters.compression_rate;
}
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->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();
}
}
static void fill_source_migration_info(MigrationInfo *info)
{
MigrationState *s = migrate_get_current();
int state = qatomic_read(&s->state);
GSList *cur_blocker = migration_blockers;
info->blocked_reasons = NULL;
/*
* There are two types of reasons a migration might be blocked;
* a) devices marked in VMState as non-migratable, and
* b) Explicit migration blockers
* We need to add both of them here.
*/
qemu_savevm_non_migratable_list(&info->blocked_reasons);
while (cur_blocker) {
QAPI_LIST_PREPEND(info->blocked_reasons,
g_strdup(error_get_pretty(cur_blocker->data)));
cur_blocker = g_slist_next(cur_blocker);
}
info->has_blocked_reasons = info->blocked_reasons != NULL;
switch (state) {
case MIGRATION_STATUS_NONE:
/* no migration has happened ever */
/* do not overwrite destination migration status */
return;
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:
case MIGRATION_STATUS_PRE_SWITCHOVER:
case MIGRATION_STATUS_DEVICE:
case MIGRATION_STATUS_POSTCOPY_PAUSED:
case MIGRATION_STATUS_POSTCOPY_RECOVER:
/* TODO add some postcopy stats */
populate_time_info(info, s);
populate_ram_info(info, s);
populate_disk_info(info);
populate_vfio_info(info);
break;
case MIGRATION_STATUS_COLO:
info->has_status = true;
/* TODO: display COLO specific information (checkpoint info etc.) */
break;
case MIGRATION_STATUS_COMPLETED:
populate_time_info(info, s);
populate_ram_info(info, s);
populate_vfio_info(info);
break;
case MIGRATION_STATUS_FAILED:
info->has_status = true;
if (s->error) {
info->error_desc = g_strdup(error_get_pretty(s->error));
}
break;
case MIGRATION_STATUS_CANCELLED:
info->has_status = true;
break;
case MIGRATION_STATUS_WAIT_UNPLUG:
info->has_status = true;
break;
}
info->status = state;
}
typedef enum WriteTrackingSupport {
WT_SUPPORT_UNKNOWN = 0,
WT_SUPPORT_ABSENT,
WT_SUPPORT_AVAILABLE,
WT_SUPPORT_COMPATIBLE
} WriteTrackingSupport;
static
WriteTrackingSupport migrate_query_write_tracking(void)
{
/* Check if kernel supports required UFFD features */
if (!ram_write_tracking_available()) {
return WT_SUPPORT_ABSENT;
}
/*
* Check if current memory configuration is
* compatible with required UFFD features.
*/
if (!ram_write_tracking_compatible()) {
return WT_SUPPORT_AVAILABLE;
}
return WT_SUPPORT_COMPATIBLE;
}
/**
* @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;
MigrationIncomingState *mis = migration_incoming_get_current();
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
#ifndef CONFIG_REPLICATION
if (cap_list[MIGRATION_CAPABILITY_X_COLO]) {
error_setg(errp, "QEMU compiled without replication module"
" can't enable COLO");
error_append_hint(errp, "Please enable replication before COLO.\n");
return false;
}
#endif
if (cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
/* 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(mis)) {
/* postcopy_ram_supported_by_host will have emitted a more
* detailed message
*/
error_setg(errp, "Postcopy is not supported");
return false;
}
if (cap_list[MIGRATION_CAPABILITY_X_IGNORE_SHARED]) {
error_setg(errp, "Postcopy is not compatible with ignore-shared");
return false;
}
}
if (cap_list[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]) {
WriteTrackingSupport wt_support;
int idx;
/*
* Check if 'background-snapshot' capability is supported by
* host kernel and compatible with guest memory configuration.
*/
wt_support = migrate_query_write_tracking();
if (wt_support < WT_SUPPORT_AVAILABLE) {
error_setg(errp, "Background-snapshot is not supported by host kernel");
return false;
}
if (wt_support < WT_SUPPORT_COMPATIBLE) {
error_setg(errp, "Background-snapshot is not compatible "
"with guest memory configuration");
return false;
}
/*
* Check if there are any migration capabilities
* incompatible with 'background-snapshot'.
*/
for (idx = 0; idx < check_caps_background_snapshot.size; idx++) {
int incomp_cap = check_caps_background_snapshot.caps[idx];
if (cap_list[incomp_cap]) {
error_setg(errp,
"Background-snapshot is not compatible with %s",
MigrationCapability_str(incomp_cap));
return false;
}
}
}
#ifdef CONFIG_LINUX
if (cap_list[MIGRATION_CAPABILITY_ZERO_COPY_SEND] &&
(!cap_list[MIGRATION_CAPABILITY_MULTIFD] ||
cap_list[MIGRATION_CAPABILITY_COMPRESS] ||
cap_list[MIGRATION_CAPABILITY_XBZRLE] ||
migrate_multifd_compression() ||
migrate_use_tls())) {
error_setg(errp,
"Zero copy only available for non-compressed non-TLS multifd migration");
return false;
}
#else
if (cap_list[MIGRATION_CAPABILITY_ZERO_COPY_SEND]) {
error_setg(errp,
"Zero copy currently only available on Linux");
return false;
}
#endif
if (cap_list[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT]) {
if (!cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
error_setg(errp, "Postcopy preempt requires postcopy-ram");
return false;
}
/*
* Preempt mode requires urgent pages to be sent in separate
* channel, OTOH compression logic will disorder all pages into
* different compression channels, which is not compatible with the
* preempt assumptions on channel assignments.
*/
if (cap_list[MIGRATION_CAPABILITY_COMPRESS]) {
error_setg(errp, "Postcopy preempt not compatible with compress");
return false;
}
}
if (cap_list[MIGRATION_CAPABILITY_MULTIFD]) {
if (cap_list[MIGRATION_CAPABILITY_COMPRESS]) {
error_setg(errp, "Multifd is not compatible with compress");
return false;
}
}
return true;
}
static void fill_destination_migration_info(MigrationInfo *info)
{
MigrationIncomingState *mis = migration_incoming_get_current();
if (mis->socket_address_list) {
info->has_socket_address = true;
info->socket_address =
QAPI_CLONE(SocketAddressList, mis->socket_address_list);
}
switch (mis->state) {
case MIGRATION_STATUS_NONE:
return;
case MIGRATION_STATUS_SETUP:
case MIGRATION_STATUS_CANCELLING:
case MIGRATION_STATUS_CANCELLED:
case MIGRATION_STATUS_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_PAUSED:
case MIGRATION_STATUS_POSTCOPY_RECOVER:
case MIGRATION_STATUS_FAILED:
case MIGRATION_STATUS_COLO:
info->has_status = true;
break;
case MIGRATION_STATUS_COMPLETED:
info->has_status = true;
fill_destination_postcopy_migration_info(info);
break;
}
info->status = mis->state;
}
MigrationInfo *qmp_query_migrate(Error **errp)
{
MigrationInfo *info = g_malloc0(sizeof(*info));
fill_destination_migration_info(info);
fill_source_migration_info(info);
return info;
}
void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
Error **errp)
{
MigrationState *s = migrate_get_current();
MigrationCapabilityStatusList *cap;
bool cap_list[MIGRATION_CAPABILITY__MAX];
if (migration_is_running(s->state)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return;
}
memcpy(cap_list, s->enabled_capabilities, sizeof(cap_list));
if (!migrate_caps_check(cap_list, 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 > 9)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level",
"a value between 0 and 9");
return false;
}
if (params->has_compress_threads && (params->compress_threads < 1)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"compress_threads",
"a value between 1 and 255");
return false;
}
if (params->has_decompress_threads && (params->decompress_threads < 1)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"decompress_threads",
"a value between 1 and 255");
return false;
}
if (params->has_throttle_trigger_threshold &&
(params->throttle_trigger_threshold < 1 ||
params->throttle_trigger_threshold > 100)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"throttle_trigger_threshold",
"an integer in the range of 1 to 100");
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 > SIZE_MAX)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"max_bandwidth",
"an integer in the range of 0 to "stringify(SIZE_MAX)
" bytes/second");
return false;
}
if (params->has_downtime_limit &&
(params->downtime_limit > MAX_MIGRATE_DOWNTIME)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"downtime_limit",
"an integer in the range of 0 to "
stringify(MAX_MIGRATE_DOWNTIME)" ms");
return false;
}
/* x_checkpoint_delay is now always positive */
if (params->has_multifd_channels && (params->multifd_channels < 1)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"multifd_channels",
"a value between 1 and 255");
return false;
}
if (params->has_multifd_zlib_level &&
(params->multifd_zlib_level > 9)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "multifd_zlib_level",
"a value between 0 and 9");
return false;
}
if (params->has_multifd_zstd_level &&
(params->multifd_zstd_level > 20)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "multifd_zstd_level",
"a value between 0 and 20");
return false;
}
if (params->has_xbzrle_cache_size &&
(params->xbzrle_cache_size < qemu_target_page_size() ||
!is_power_of_2(params->xbzrle_cache_size))) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"xbzrle_cache_size",
"a power of two no less than the target page size");
return false;
}
if (params->has_max_cpu_throttle &&
(params->max_cpu_throttle < params->cpu_throttle_initial ||
params->max_cpu_throttle > 99)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"max_cpu_throttle",
"an integer in the range of cpu_throttle_initial to 99");
return false;
}
if (params->has_announce_initial &&
params->announce_initial > 100000) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"announce_initial",
"a value between 0 and 100000");
return false;
}
if (params->has_announce_max &&
params->announce_max > 100000) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"announce_max",
"a value between 0 and 100000");
return false;
}
if (params->has_announce_rounds &&
params->announce_rounds > 1000) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"announce_rounds",
"a value between 0 and 1000");
return false;
}
if (params->has_announce_step &&
(params->announce_step < 1 ||
params->announce_step > 10000)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
"announce_step",
"a value between 0 and 10000");
return false;
}
if (params->has_block_bitmap_mapping &&
!check_dirty_bitmap_mig_alias_map(params->block_bitmap_mapping, errp)) {
error_prepend(errp, "Invalid mapping given for block-bitmap-mapping: ");
return false;
}
#ifdef CONFIG_LINUX
if (migrate_use_zero_copy_send() &&
((params->has_multifd_compression && params->multifd_compression) ||
(params->tls_creds && *params->tls_creds))) {
error_setg(errp,
"Zero copy only available for non-compressed non-TLS multifd migration");
return false;
}
#endif
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_compress_wait_thread) {
dest->compress_wait_thread = params->compress_wait_thread;
}
if (params->has_decompress_threads) {
dest->decompress_threads = params->decompress_threads;
}
if (params->has_throttle_trigger_threshold) {
dest->throttle_trigger_threshold = params->throttle_trigger_threshold;
}
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_cpu_throttle_tailslow) {
dest->cpu_throttle_tailslow = params->cpu_throttle_tailslow;
}
if (params->tls_creds) {
assert(params->tls_creds->type == QTYPE_QSTRING);
dest->tls_creds = params->tls_creds->u.s;
}
if (params->tls_hostname) {
assert(params->tls_hostname->type == QTYPE_QSTRING);
dest->tls_hostname = 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;
}
if (params->has_multifd_channels) {
dest->multifd_channels = params->multifd_channels;
}
if (params->has_multifd_compression) {
dest->multifd_compression = params->multifd_compression;
}
if (params->has_xbzrle_cache_size) {
dest->xbzrle_cache_size = params->xbzrle_cache_size;
}
if (params->has_max_postcopy_bandwidth) {
dest->max_postcopy_bandwidth = params->max_postcopy_bandwidth;
}
if (params->has_max_cpu_throttle) {
dest->max_cpu_throttle = params->max_cpu_throttle;
}
if (params->has_announce_initial) {
dest->announce_initial = params->announce_initial;
}
if (params->has_announce_max) {
dest->announce_max = params->announce_max;
}
if (params->has_announce_rounds) {
dest->announce_rounds = params->announce_rounds;
}
if (params->has_announce_step) {
dest->announce_step = params->announce_step;
}
if (params->has_block_bitmap_mapping) {
dest->has_block_bitmap_mapping = true;
dest->block_bitmap_mapping = params->block_bitmap_mapping;
}
}
static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
{
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_compress_wait_thread) {
s->parameters.compress_wait_thread = params->compress_wait_thread;
}
if (params->has_decompress_threads) {
s->parameters.decompress_threads = params->decompress_threads;
}
if (params->has_throttle_trigger_threshold) {
s->parameters.throttle_trigger_threshold = params->throttle_trigger_threshold;
}
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_cpu_throttle_tailslow) {
s->parameters.cpu_throttle_tailslow = params->cpu_throttle_tailslow;
}
if (params->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->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->tls_authz) {
g_free(s->parameters.tls_authz);
assert(params->tls_authz->type == QTYPE_QSTRING);
s->parameters.tls_authz = g_strdup(params->tls_authz->u.s);
}
if (params->has_max_bandwidth) {
s->parameters.max_bandwidth = params->max_bandwidth;
if (s->to_dst_file && !migration_in_postcopy()) {
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;
}
if (params->has_multifd_channels) {
s->parameters.multifd_channels = params->multifd_channels;
}
if (params->has_multifd_compression) {
s->parameters.multifd_compression = params->multifd_compression;
}
if (params->has_xbzrle_cache_size) {
s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
xbzrle_cache_resize(params->xbzrle_cache_size, errp);
}
if (params->has_max_postcopy_bandwidth) {
s->parameters.max_postcopy_bandwidth = params->max_postcopy_bandwidth;
if (s->to_dst_file && migration_in_postcopy()) {
qemu_file_set_rate_limit(s->to_dst_file,
s->parameters.max_postcopy_bandwidth / XFER_LIMIT_RATIO);
}
}
if (params->has_max_cpu_throttle) {
s->parameters.max_cpu_throttle = params->max_cpu_throttle;
}
if (params->has_announce_initial) {
s->parameters.announce_initial = params->announce_initial;
}
if (params->has_announce_max) {
s->parameters.announce_max = params->announce_max;
}
if (params->has_announce_rounds) {
s->parameters.announce_rounds = params->announce_rounds;
}
if (params->has_announce_step) {
s->parameters.announce_step = params->announce_step;
}
if (params->has_block_bitmap_mapping) {
qapi_free_BitmapMigrationNodeAliasList(
s->parameters.block_bitmap_mapping);
s->parameters.has_block_bitmap_mapping = true;
s->parameters.block_bitmap_mapping =
QAPI_CLONE(BitmapMigrationNodeAliasList,
params->block_bitmap_mapping);
}
}
void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
{
MigrationParameters tmp;
/* TODO Rewrite "" to null instead */
if (params->tls_creds
&& params->tls_creds->type == QTYPE_QNULL) {
qobject_unref(params->tls_creds->u.n);
params->tls_creds->type = QTYPE_QSTRING;
params->tls_creds->u.s = strdup("");
}
/* TODO Rewrite "" to null instead */
if (params->tls_hostname
&& params->tls_hostname->type == QTYPE_QNULL) {
qobject_unref(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, errp);
}
void qmp_migrate_start_postcopy(Error **errp)
{
MigrationState *s = migrate_get_current();
if (!migrate_postcopy()) {
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.
*/
qatomic_set(&s->start_postcopy, true);
}
/* shared migration helpers */
void migrate_set_state(int *state, int old_state, int new_state)
{
assert(new_state < MIGRATION_STATUS__MAX);
if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
trace_migrate_set_state(MigrationStatus_str(new_state));
migrate_generate_event(new_state);
}
}
static MigrationCapabilityStatus *migrate_cap_add(MigrationCapability index,
bool state)
{
MigrationCapabilityStatus *cap;
cap = g_new0(MigrationCapabilityStatus, 1);
cap->capability = index;
cap->state = state;
return cap;
}
void migrate_set_block_enabled(bool value, Error **errp)
{
MigrationCapabilityStatusList *cap = NULL;
QAPI_LIST_PREPEND(cap, migrate_cap_add(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(MigrationState *s)
{
qemu_bh_delete(s->cleanup_bh);
s->cleanup_bh = NULL;
g_free(s->hostname);
s->hostname = NULL;
json_writer_free(s->vmdesc);
s->vmdesc = NULL;
qemu_savevm_state_cleanup();
if (s->to_dst_file) {
QEMUFile *tmp;
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();
multifd_save_cleanup();
qemu_mutex_lock(&s->qemu_file_lock);
tmp = s->to_dst_file;
s->to_dst_file = NULL;
qemu_mutex_unlock(&s->qemu_file_lock);
/*
* Close the file handle without the lock to make sure the
* critical section won't block for long.
*/
migration_ioc_unregister_yank_from_file(tmp);
qemu_fclose(tmp);
}
if (s->postcopy_qemufile_src) {
migration_ioc_unregister_yank_from_file(s->postcopy_qemufile_src);
qemu_fclose(s->postcopy_qemufile_src);
s->postcopy_qemufile_src = NULL;
}
assert(!migration_is_active(s));
if (s->state == MIGRATION_STATUS_CANCELLING) {
migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING,
MIGRATION_STATUS_CANCELLED);
}
if (s->error) {
/* It is used on info migrate. We can't free it */
error_report_err(error_copy(s->error));
}
notifier_list_notify(&migration_state_notifiers, s);
block_cleanup_parameters(s);
yank_unregister_instance(MIGRATION_YANK_INSTANCE);
}
static void migrate_fd_cleanup_schedule(MigrationState *s)
{
/*
* Ref the state for bh, because it may be called when
* there're already no other refs
*/
object_ref(OBJECT(s));
qemu_bh_schedule(s->cleanup_bh);
}
static void migrate_fd_cleanup_bh(void *opaque)
{
MigrationState *s = opaque;
migrate_fd_cleanup(s);
object_unref(OBJECT(s));
}
void migrate_set_error(MigrationState *s, const Error *error)
{
QEMU_LOCK_GUARD(&s->error_mutex);
if (!s->error) {
s->error = error_copy(error);
}
}
static void migrate_error_free(MigrationState *s)
{
QEMU_LOCK_GUARD(&s->error_mutex);
if (s->error) {
error_free(s->error);
s->error = NULL;
}
}
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);
migrate_set_error(s, error);
}
static void migrate_fd_cancel(MigrationState *s)
{
int old_state ;
QEMUFile *f = migrate_get_current()->to_dst_file;
trace_migrate_fd_cancel();
WITH_QEMU_LOCK_GUARD(&s->qemu_file_lock) {
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_running(old_state)) {
break;
}
/* If the migration is paused, kick it out of the pause */
if (old_state == MIGRATION_STATUS_PRE_SWITCHOVER) {
qemu_sem_post(&s->pause_sem);
}
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_activate_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();
switch (s->state) {
case MIGRATION_STATUS_POSTCOPY_ACTIVE:
case MIGRATION_STATUS_POSTCOPY_PAUSED:
case MIGRATION_STATUS_POSTCOPY_RECOVER:
return true;
default:
return false;
}
}
bool migration_in_postcopy_after_devices(MigrationState *s)
{
return migration_in_postcopy() && s->postcopy_after_devices;
}
bool migration_in_incoming_postcopy(void)
{
PostcopyState ps = postcopy_state_get();
return ps >= POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END;
}
bool migration_incoming_postcopy_advised(void)
{
PostcopyState ps = postcopy_state_get();
return ps >= POSTCOPY_INCOMING_ADVISE && ps < POSTCOPY_INCOMING_END;
}
bool migration_in_bg_snapshot(void)
{
MigrationState *s = migrate_get_current();
return migrate_background_snapshot() &&
migration_is_setup_or_active(s->state);
}
bool migration_is_idle(void)
{
MigrationState *s = current_migration;
if (!s) {
return true;
}
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:
case MIGRATION_STATUS_PRE_SWITCHOVER:
case MIGRATION_STATUS_DEVICE:
case MIGRATION_STATUS_WAIT_UNPLUG:
return false;
case MIGRATION_STATUS__MAX:
g_assert_not_reached();
}
return false;
}
bool migration_is_active(MigrationState *s)
{
return (s->state == MIGRATION_STATUS_ACTIVE ||
s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
}
void migrate_init(MigrationState *s)
{
/*
* Reinitialise all migration state, except
* parameters/capabilities that the user set, and
* locks.
*/
s->cleanup_bh = 0;
s->vm_start_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->pages_per_second = 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;
s->hostname = NULL;
migrate_set_state(&s->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP);
s->start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
s->total_time = 0;
s->vm_was_running = false;
s->iteration_initial_bytes = 0;
s->threshold_size = 0;
}
int migrate_add_blocker_internal(Error *reason, Error **errp)
{
/* Snapshots are similar to migrations, so check RUN_STATE_SAVE_VM too. */
if (runstate_check(RUN_STATE_SAVE_VM) || !migration_is_idle()) {
error_propagate_prepend(errp, error_copy(reason),
"disallowing migration blocker "
"(migration/snapshot in progress) for: ");
return -EBUSY;
}
migration_blockers = g_slist_prepend(migration_blockers, reason);
return 0;
}
int migrate_add_blocker(Error *reason, Error **errp)
{
if (only_migratable) {
error_propagate_prepend(errp, error_copy(reason),
"disallowing migration blocker "
"(--only-migratable) for: ");
return -EACCES;
}
return migrate_add_blocker_internal(reason, errp);
}
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 (!once) {
error_setg(errp, "The incoming migration has already been started");
return;
}
if (!runstate_check(RUN_STATE_INMIGRATE)) {
error_setg(errp, "'-incoming' was not specified on the command line");
return;
}
if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
return;
}
qemu_start_incoming_migration(uri, &local_err);
if (local_err) {
yank_unregister_instance(MIGRATION_YANK_INSTANCE);
error_propagate(errp, local_err);
return;
}
once = false;
}
void qmp_migrate_recover(const char *uri, Error **errp)
{
MigrationIncomingState *mis = migration_incoming_get_current();
/*
* Don't even bother to use ERRP_GUARD() as it _must_ always be set by
* callers (no one should ignore a recover failure); if there is, it's a
* programming error.
*/
assert(errp);
if (mis->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
error_setg(errp, "Migrate recover can only be run "
"when postcopy is paused.");
return;
}
/* If there's an existing transport, release it */
migration_incoming_transport_cleanup(mis);
/*
* Note that this call will never start a real migration; it will
* only re-setup the migration stream and poke existing migration
* to continue using that newly established channel.
*/
qemu_start_incoming_migration(uri, errp);
}
void qmp_migrate_pause(Error **errp)
{
MigrationState *ms = migrate_get_current();
MigrationIncomingState *mis = migration_incoming_get_current();
int ret;
if (ms->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
/* Source side, during postcopy */
qemu_mutex_lock(&ms->qemu_file_lock);
ret = qemu_file_shutdown(ms->to_dst_file);
qemu_mutex_unlock(&ms->qemu_file_lock);
if (ret) {
error_setg(errp, "Failed to pause source migration");
}
return;
}
if (mis->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
ret = qemu_file_shutdown(mis->from_src_file);
if (ret) {
error_setg(errp, "Failed to pause destination migration");
}
return;
}
error_setg(errp, "migrate-pause is currently only supported "
"during postcopy-active state");
}
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;
}
/* Returns true if continue to migrate, or false if error detected */
static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
bool resume, Error **errp)
{
Error *local_err = NULL;
if (resume) {
if (s->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
error_setg(errp, "Cannot resume if there is no "
"paused migration");
return false;
}
/*
* Postcopy recovery won't work well with release-ram
* capability since release-ram will drop the page buffer as
* long as the page is put into the send buffer. So if there
* is a network failure happened, any page buffers that have
* not yet reached the destination VM but have already been
* sent from the source VM will be lost forever. Let's refuse
* the client from resuming such a postcopy migration.
* Luckily release-ram was designed to only be used when src
* and destination VMs are on the same host, so it should be
* fine.
*/
if (migrate_release_ram()) {
error_setg(errp, "Postcopy recovery cannot work "
"when release-ram capability is set");
return false;
}
/* This is a resume, skip init status */
return true;
}
if (migration_is_running(s->state)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return false;
}
if (runstate_check(RUN_STATE_INMIGRATE)) {
error_setg(errp, "Guest is waiting for an incoming migration");
return false;
}
if (runstate_check(RUN_STATE_POSTMIGRATE)) {
error_setg(errp, "Can't migrate the vm that was paused due to "
"previous migration");
return false;
}
if (migration_is_blocked(errp)) {
return false;
}
if (blk || blk_inc) {
if (migrate_colo_enabled()) {
error_setg(errp, "No disk migration is required in COLO mode");
return false;
}
if (migrate_use_block() || migrate_use_block_incremental()) {
error_setg(errp, "Command options are incompatible with "
"current migration capabilities");
return false;
}
migrate_set_block_enabled(true, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return false;
}
s->must_remove_block_options = true;
}
if (blk_inc) {
migrate_set_block_incremental(s, true);
}
migrate_init(s);
/*
* set ram_counters compression_counters memory to zero for a
* new migration
*/
memset(&ram_counters, 0, sizeof(ram_counters));
memset(&compression_counters, 0, sizeof(compression_counters));
return true;
}
void qmp_migrate(const char *uri, bool has_blk, bool blk,
bool has_inc, bool inc, bool has_detach, bool detach,
bool has_resume, bool resume, Error **errp)
{
Error *local_err = NULL;
MigrationState *s = migrate_get_current();
const char *p = NULL;
/* URI is not suitable for migration? */
if (!migration_channels_and_uri_compatible(uri, errp)) {
return;
}
if (!migrate_prepare(s, has_blk && blk, has_inc && inc,
has_resume && resume, errp)) {
/* Error detected, put into errp */
return;
}
if (!(has_resume && resume)) {
if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
return;
}
}
if (strstart(uri, "tcp:", &p) ||
strstart(uri, "unix:", NULL) ||
strstart(uri, "vsock:", NULL)) {
socket_start_outgoing_migration(s, p ? p : uri, &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, "fd:", &p)) {
fd_start_outgoing_migration(s, p, &local_err);
} else {
if (!(has_resume && resume)) {
yank_unregister_instance(MIGRATION_YANK_INSTANCE);
}
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
"a valid migration protocol");
migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_FAILED);
block_cleanup_parameters(s);
return;
}
if (local_err) {
if (!(has_resume && resume)) {
yank_unregister_instance(MIGRATION_YANK_INSTANCE);
}
migrate_fd_error(s, local_err);
error_propagate(errp, local_err);
return;
}
}
void qmp_migrate_cancel(Error **errp)
{
migration_cancel(NULL);
}
void qmp_migrate_continue(MigrationStatus state, Error **errp)
{
MigrationState *s = migrate_get_current();
if (s->state != state) {
error_setg(errp, "Migration not in expected state: %s",
MigrationStatus_str(s->state));
return;
}
qemu_sem_post(&s->pause_sem);
}
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_postcopy(void)
{
return migrate_postcopy_ram() || migrate_dirty_bitmaps();
}
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_postcopy_blocktime(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME];
}
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_compress_wait_thread(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.compress_wait_thread;
}
int migrate_decompress_threads(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.decompress_threads;
}
bool migrate_dirty_bitmaps(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS];
}
bool migrate_ignore_shared(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_X_IGNORE_SHARED];
}
bool migrate_validate_uuid(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_VALIDATE_UUID];
}
bool migrate_use_events(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS];
}
bool migrate_use_multifd(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_MULTIFD];
}
bool migrate_pause_before_switchover(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[
MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER];
}
int migrate_multifd_channels(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.multifd_channels;
}
MultiFDCompression migrate_multifd_compression(void)
{
MigrationState *s;
s = migrate_get_current();
assert(s->parameters.multifd_compression < MULTIFD_COMPRESSION__MAX);
return s->parameters.multifd_compression;
}
int migrate_multifd_zlib_level(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.multifd_zlib_level;
}
int migrate_multifd_zstd_level(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.multifd_zstd_level;
}
#ifdef CONFIG_LINUX
bool migrate_use_zero_copy_send(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_COPY_SEND];
}
#endif
int migrate_use_tls(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.tls_creds && *s->parameters.tls_creds;
}
int migrate_use_xbzrle(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
}
uint64_t migrate_xbzrle_cache_size(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.xbzrle_cache_size;
}
static int64_t migrate_max_postcopy_bandwidth(void)
{
MigrationState *s;
s = migrate_get_current();
return s->parameters.max_postcopy_bandwidth;
}
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;
}
bool migrate_background_snapshot(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT];
}
bool migrate_postcopy_preempt(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT];
}
/* 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_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" },
[MIG_RP_MSG_RESUME_ACK] = { .len = 4, .name = "RESUME_ACK" },
[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 = qemu_real_host_page_size();
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 (!QEMU_IS_ALIGNED(start, our_host_ps) ||
!QEMU_IS_ALIGNED(len, our_host_ps)) {
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);
}
}
/* Return true to retry, false to quit */
static bool postcopy_pause_return_path_thread(MigrationState *s)
{
trace_postcopy_pause_return_path();
qemu_sem_wait(&s->postcopy_pause_rp_sem);
trace_postcopy_pause_return_path_continued();
return true;
}
static int migrate_handle_rp_recv_bitmap(MigrationState *s, char *block_name)
{
RAMBlock *block = qemu_ram_block_by_name(block_name);
if (!block) {
error_report("%s: invalid block name '%s'", __func__, block_name);
return -EINVAL;
}
/* Fetch the received bitmap and refresh the dirty bitmap */
return ram_dirty_bitmap_reload(s, block);
}
static int migrate_handle_rp_resume_ack(MigrationState *s, uint32_t value)
{
trace_source_return_path_thread_resume_ack(value);
if (value != MIGRATION_RESUME_ACK_VALUE) {
error_report("%s: illegal resume_ack value %"PRIu32,
__func__, value);
return -1;
}
/* Now both sides are active. */
migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_RECOVER,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
/* Notify send thread that time to continue send pages */
qemu_sem_post(&s->rp_state.rp_sem);
return 0;
}
/*
* Release ms->rp_state.from_dst_file (and postcopy_qemufile_src if
* existed) in a safe way.
*/
static void migration_release_dst_files(MigrationState *ms)
{
QEMUFile *file;
WITH_QEMU_LOCK_GUARD(&ms->qemu_file_lock) {
/*
* Reset the from_dst_file pointer first before releasing it, as we
* can't block within lock section
*/
file = ms->rp_state.from_dst_file;
ms->rp_state.from_dst_file = NULL;
}
/*
* Do the same to postcopy fast path socket too if there is. No
* locking needed because this qemufile should only be managed by
* return path thread.
*/
if (ms->postcopy_qemufile_src) {
migration_ioc_unregister_yank_from_file(ms->postcopy_qemufile_src);
qemu_file_shutdown(ms->postcopy_qemufile_src);
qemu_fclose(ms->postcopy_qemufile_src);
ms->postcopy_qemufile_src = NULL;
}
qemu_fclose(file);
}
/*
* 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();
rcu_register_thread();
retry:
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 (qemu_file_get_error(rp)) {
mark_source_rp_bad(ms);
goto out;
}
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);
qemu_sem_post(&ms->rp_state.rp_pong_acks);
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;
case MIG_RP_MSG_RECV_BITMAP:
if (header_len < 1) {
error_report("%s: missing block name", __func__);
mark_source_rp_bad(ms);
goto out;
}
/* Format: len (1B) + idstr (<255B). This ends the idstr. */
buf[buf[0] + 1] = '\0';
if (migrate_handle_rp_recv_bitmap(ms, (char *)(buf + 1))) {
mark_source_rp_bad(ms);
goto out;
}
break;
case MIG_RP_MSG_RESUME_ACK:
tmp32 = ldl_be_p(buf);
if (migrate_handle_rp_resume_ack(ms, tmp32)) {
mark_source_rp_bad(ms);
goto out;
}
break;
default:
break;
}
}
out:
res = qemu_file_get_error(rp);
if (res) {
if (res && migration_in_postcopy()) {
/*
* Maybe there is something we can do: it looks like a
* network down issue, and we pause for a recovery.
*/
migration_release_dst_files(ms);
rp = NULL;
if (postcopy_pause_return_path_thread(ms)) {
/*
* Reload rp, reset the rest. Referencing it is safe since
* it's reset only by us above, or when migration completes
*/
rp = ms->rp_state.from_dst_file;
ms->rp_state.error = false;
goto retry;
}
}
trace_source_return_path_thread_bad_end();
mark_source_rp_bad(ms);
}
trace_source_return_path_thread_end();
migration_release_dst_files(ms);
rcu_unregister_thread();
return NULL;
}
static int open_return_path_on_source(MigrationState *ms,
bool create_thread)
{
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();
if (!create_thread) {
/* We're done */
return 0;
}
qemu_thread_create(&ms->rp_state.rp_thread, "return path",
source_return_path_thread, ms, QEMU_THREAD_JOINABLE);
ms->rp_state.rp_thread_created = true;
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);
ms->rp_state.rp_thread_created = false;
trace_await_return_path_close_on_source_close();
return ms->rp_state.error;
}
static inline void
migration_wait_main_channel(MigrationState *ms)
{
/* Wait until one PONG message received */
qemu_sem_wait(&ms->rp_state.rp_pong_acks);
}
/*
* Switch from normal iteration to postcopy
* Returns non-0 on error
*/
static int postcopy_start(MigrationState *ms)
{
int ret;
QIOChannelBuffer *bioc;
QEMUFile *fb;
int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
int64_t bandwidth = migrate_max_postcopy_bandwidth();
bool restart_block = false;
int cur_state = MIGRATION_STATUS_ACTIVE;
if (migrate_postcopy_preempt()) {
migration_wait_main_channel(ms);
if (postcopy_preempt_establish_channel(ms)) {
migrate_set_state(&ms->state, ms->state, MIGRATION_STATUS_FAILED);
return -1;
}
}
if (!migrate_pause_before_switchover()) {
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, NULL);
global_state_store();
ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
if (ret < 0) {
goto fail;
}
ret = migration_maybe_pause(ms, &cur_state,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
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 (migrate_postcopy_ram()) {
ram_postcopy_send_discard_bitmap(ms);
}
/*
* 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
*/
/* 0 max-postcopy-bandwidth means unlimited */
if (!bandwidth) {
qemu_file_set_rate_limit(ms->to_dst_file, INT64_MAX);
} else {
qemu_file_set_rate_limit(ms->to_dst_file, bandwidth / XFER_LIMIT_RATIO);
}
if (migrate_postcopy_ram()) {
/* 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_file_new_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);
if (migrate_postcopy_ram()) {
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();
if (migrate_postcopy_ram()) {
/*
* 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);
}
trace_postcopy_preempt_enabled(migrate_postcopy_preempt());
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_activate_all(&local_err);
if (local_err) {
error_report_err(local_err);
}
}
qemu_mutex_unlock_iothread();
return -1;
}
/**
* migration_maybe_pause: Pause if required to by
* migrate_pause_before_switchover called with the iothread locked
* Returns: 0 on success
*/
static int migration_maybe_pause(MigrationState *s,
int *current_active_state,
int new_state)
{
if (!migrate_pause_before_switchover()) {
return 0;
}
/* Since leaving this state is not atomic with posting the semaphore
* it's possible that someone could have issued multiple migrate_continue
* and the semaphore is incorrectly positive at this point;
* the docs say it's undefined to reinit a semaphore that's already
* init'd, so use timedwait to eat up any existing posts.
*/
while (qemu_sem_timedwait(&s->pause_sem, 1) == 0) {
/* This block intentionally left blank */
}
/*
* If the migration is cancelled when it is in the completion phase,
* the migration state is set to MIGRATION_STATUS_CANCELLING.
* So we don't need to wait a semaphore, otherwise we would always
* wait for the 'pause_sem' semaphore.
*/
if (s->state != MIGRATION_STATUS_CANCELLING) {
qemu_mutex_unlock_iothread();
migrate_set_state(&s->state, *current_active_state,
MIGRATION_STATUS_PRE_SWITCHOVER);
qemu_sem_wait(&s->pause_sem);
migrate_set_state(&s->state, MIGRATION_STATUS_PRE_SWITCHOVER,
new_state);
*current_active_state = new_state;
qemu_mutex_lock_iothread();
}
return s->state == new_state ? 0 : -EINVAL;
}
/**
* migration_completion: Used by migration_thread when there's not much left.
* The caller 'breaks' the loop when this returns.
*
* @s: Current migration state
*/
static void migration_completion(MigrationState *s)
{
int ret;
int current_active_state = s->state;
if (s->state == MIGRATION_STATUS_ACTIVE) {
qemu_mutex_lock_iothread();
s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
s->vm_was_running = runstate_is_running();
ret = global_state_store();
if (!ret) {
bool inactivate = !migrate_colo_enabled();
ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
trace_migration_completion_vm_stop(ret);
if (ret >= 0) {
ret = migration_maybe_pause(s, &current_active_state,
MIGRATION_STATUS_DEVICE);
}
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_mutex_lock_iothread();
qemu_savevm_state_complete_postcopy(s->to_dst_file);
qemu_mutex_unlock_iothread();
/*
* Shutdown the postcopy fast path thread. This is only needed
* when dest QEMU binary is old (7.1/7.2). QEMU 8.0+ doesn't need
* this.
*/
if (migrate_postcopy_preempt() && s->preempt_pre_7_2) {
postcopy_preempt_shutdown_file(s);
}
trace_migration_completion_postcopy_end_after_complete();
} else {
goto fail;
}
/*
* 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.rp_thread_created) {
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() && s->state == MIGRATION_STATUS_ACTIVE) {
/* COLO does not support postcopy */
migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_COLO);
} else {
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 ||
s->state == MIGRATION_STATUS_DEVICE) {
Error *local_err = NULL;
qemu_mutex_lock_iothread();
bdrv_activate_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);
}
/**
* bg_migration_completion: Used by bg_migration_thread when after all the
* RAM has been saved. The caller 'breaks' the loop when this returns.
*
* @s: Current migration state
*/
static void bg_migration_completion(MigrationState *s)
{
int current_active_state = s->state;
/*
* Stop tracking RAM writes - un-protect memory, un-register UFFD
* memory ranges, flush kernel wait queues and wake up threads
* waiting for write fault to be resolved.
*/
ram_write_tracking_stop();
if (s->state == MIGRATION_STATUS_ACTIVE) {
/*
* By this moment we have RAM content saved into the migration stream.
* The next step is to flush the non-RAM content (device state)
* right after the ram content. The device state has been stored into
* the temporary buffer before RAM saving started.
*/
qemu_put_buffer(s->to_dst_file, s->bioc->data, s->bioc->usage);
qemu_fflush(s->to_dst_file);
} else if (s->state == MIGRATION_STATUS_CANCELLING) {
goto fail;
}
if (qemu_file_get_error(s->to_dst_file)) {
trace_migration_completion_file_err();
goto fail;
}
migrate_set_state(&s->state, current_active_state,
MIGRATION_STATUS_COMPLETED);
return;
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];
}
typedef enum MigThrError {
/* No error detected */
MIG_THR_ERR_NONE = 0,
/* Detected error, but resumed successfully */
MIG_THR_ERR_RECOVERED = 1,
/* Detected fatal error, need to exit */
MIG_THR_ERR_FATAL = 2,
} MigThrError;
static int postcopy_resume_handshake(MigrationState *s)
{
qemu_savevm_send_postcopy_resume(s->to_dst_file);
while (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
qemu_sem_wait(&s->rp_state.rp_sem);
}
if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
return 0;
}
return -1;
}
/* Return zero if success, or <0 for error */
static int postcopy_do_resume(MigrationState *s)
{
int ret;
/*
* Call all the resume_prepare() hooks, so that modules can be
* ready for the migration resume.
*/
ret = qemu_savevm_state_resume_prepare(s);
if (ret) {
error_report("%s: resume_prepare() failure detected: %d",
__func__, ret);
return ret;
}
/*
* If preempt is enabled, re-establish the preempt channel. Note that
* we do it after resume prepare to make sure the main channel will be
* created before the preempt channel. E.g. with weak network, the
* dest QEMU may get messed up with the preempt and main channels on
* the order of connection setup. This guarantees the correct order.
*/
ret = postcopy_preempt_establish_channel(s);
if (ret) {
error_report("%s: postcopy_preempt_establish_channel(): %d",
__func__, ret);
return ret;
}
/*
* Last handshake with destination on the resume (destination will
* switch to postcopy-active afterwards)
*/
ret = postcopy_resume_handshake(s);
if (ret) {
error_report("%s: handshake failed: %d", __func__, ret);
return ret;
}
return 0;
}
/*
* We don't return until we are in a safe state to continue current
* postcopy migration. Returns MIG_THR_ERR_RECOVERED if recovered, or
* MIG_THR_ERR_FATAL if unrecovery failure happened.
*/
static MigThrError postcopy_pause(MigrationState *s)
{
assert(s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
while (true) {
QEMUFile *file;
/*
* Current channel is possibly broken. Release it. Note that this is
* guaranteed even without lock because to_dst_file should only be
* modified by the migration thread. That also guarantees that the
* unregister of yank is safe too without the lock. It should be safe
* even to be within the qemu_file_lock, but we didn't do that to avoid
* taking more mutex (yank_lock) within qemu_file_lock. TL;DR: we make
* the qemu_file_lock critical section as small as possible.
*/
assert(s->to_dst_file);
migration_ioc_unregister_yank_from_file(s->to_dst_file);
qemu_mutex_lock(&s->qemu_file_lock);
file = s->to_dst_file;
s->to_dst_file = NULL;
qemu_mutex_unlock(&s->qemu_file_lock);
qemu_file_shutdown(file);
qemu_fclose(file);
migrate_set_state(&s->state, s->state,
MIGRATION_STATUS_POSTCOPY_PAUSED);
error_report("Detected IO failure for postcopy. "
"Migration paused.");
/*
* We wait until things fixed up. Then someone will setup the
* status back for us.
*/
while (s->state == MIGRATION_STATUS_POSTCOPY_PAUSED) {
qemu_sem_wait(&s->postcopy_pause_sem);
}
if (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
/* Woken up by a recover procedure. Give it a shot */
/*
* Firstly, let's wake up the return path now, with a new
* return path channel.
*/
qemu_sem_post(&s->postcopy_pause_rp_sem);
/* Do the resume logic */
if (postcopy_do_resume(s) == 0) {
/* Let's continue! */
trace_postcopy_pause_continued();
return MIG_THR_ERR_RECOVERED;
} else {
/*
* Something wrong happened during the recovery, let's
* pause again. Pause is always better than throwing
* data away.
*/
continue;
}
} else {
/* This is not right... Time to quit. */
return MIG_THR_ERR_FATAL;
}
}
}
static MigThrError migration_detect_error(MigrationState *s)
{
int ret;
int state = s->state;
Error *local_error = NULL;
if (state == MIGRATION_STATUS_CANCELLING ||
state == MIGRATION_STATUS_CANCELLED) {
/* End the migration, but don't set the state to failed */
return MIG_THR_ERR_FATAL;
}
/*
* Try to detect any file errors. Note that postcopy_qemufile_src will
* be NULL when postcopy preempt is not enabled.
*/
ret = qemu_file_get_error_obj_any(s->to_dst_file,
s->postcopy_qemufile_src,
&local_error);
if (!ret) {
/* Everything is fine */
assert(!local_error);
return MIG_THR_ERR_NONE;
}
if (local_error) {
migrate_set_error(s, local_error);
error_free(local_error);
}
if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret) {
/*
* For postcopy, we allow the network to be down for a
* while. After that, it can be continued by a
* recovery phase.
*/
return postcopy_pause(s);
} else {
/*
* For precopy (or postcopy with error outside IO), we fail
* with no time.
*/
migrate_set_state(&s->state, state, MIGRATION_STATUS_FAILED);
trace_migration_thread_file_err();
/* Time to stop the migration, now. */
return MIG_THR_ERR_FATAL;
}
}
/* How many bytes have we transferred since the beginning of the migration */
static uint64_t migration_total_bytes(MigrationState *s)
{
return qemu_file_total_transferred(s->to_dst_file) +
ram_counters.multifd_bytes;
}
static void migration_calculate_complete(MigrationState *s)
{
uint64_t bytes = migration_total_bytes(s);
int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
int64_t transfer_time;
s->total_time = end_time - s->start_time;
if (!s->downtime) {
/*
* It's still not set, so we are precopy migration. For
* postcopy, downtime is calculated during postcopy_start().
*/
s->downtime = end_time - s->downtime_start;
}
transfer_time = s->total_time - s->setup_time;
if (transfer_time) {
s->mbps = ((double) bytes * 8.0) / transfer_time / 1000;
}
}
static void update_iteration_initial_status(MigrationState *s)
{
/*
* Update these three fields at the same time to avoid mismatch info lead
* wrong speed calculation.
*/
s->iteration_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
s->iteration_initial_bytes = migration_total_bytes(s);
s->iteration_initial_pages = ram_get_total_transferred_pages();
}
static void migration_update_counters(MigrationState *s,
int64_t current_time)
{
uint64_t transferred, transferred_pages, time_spent;
uint64_t current_bytes; /* bytes transferred since the beginning */
double bandwidth;
if (current_time < s->iteration_start_time + BUFFER_DELAY) {
return;
}
current_bytes = migration_total_bytes(s);
transferred = current_bytes - s->iteration_initial_bytes;
time_spent = current_time - s->iteration_start_time;
bandwidth = (double)transferred / time_spent;
s->threshold_size = bandwidth * s->parameters.downtime_limit;
s->mbps = (((double) transferred * 8.0) /
((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
transferred_pages = ram_get_total_transferred_pages() -
s->iteration_initial_pages;
s->pages_per_second = (double) transferred_pages /
(((double) time_spent / 1000.0));
/*
* 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 > 10000) {
s->expected_downtime = ram_counters.remaining / bandwidth;
}
qemu_file_reset_rate_limit(s->to_dst_file);
update_iteration_initial_status(s);
trace_migrate_transferred(transferred, time_spent,
bandwidth, s->threshold_size);
}
/* Migration thread iteration status */
typedef enum {
MIG_ITERATE_RESUME, /* Resume current iteration */
MIG_ITERATE_SKIP, /* Skip current iteration */
MIG_ITERATE_BREAK, /* Break the loop */
} MigIterateState;
/*
* Return true if continue to the next iteration directly, false
* otherwise.
*/
static MigIterateState migration_iteration_run(MigrationState *s)
{
uint64_t must_precopy, can_postcopy;
bool in_postcopy = s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE;
qemu_savevm_state_pending_estimate(&must_precopy, &can_postcopy);
uint64_t pending_size = must_precopy + can_postcopy;
trace_migrate_pending_estimate(pending_size, must_precopy, can_postcopy);
if (must_precopy <= s->threshold_size) {
qemu_savevm_state_pending_exact(&must_precopy, &can_postcopy);
pending_size = must_precopy + can_postcopy;
trace_migrate_pending_exact(pending_size, must_precopy, can_postcopy);
}
if (!pending_size || pending_size < s->threshold_size) {
trace_migration_thread_low_pending(pending_size);
migration_completion(s);
return MIG_ITERATE_BREAK;
}
/* Still a significant amount to transfer */
if (!in_postcopy && must_precopy <= s->threshold_size &&
qatomic_read(&s->start_postcopy)) {
if (postcopy_start(s)) {
error_report("%s: postcopy failed to start", __func__);
}
return MIG_ITERATE_SKIP;
}
/* Just another iteration step */
qemu_savevm_state_iterate(s->to_dst_file, in_postcopy);
return MIG_ITERATE_RESUME;
}
static void migration_iteration_finish(MigrationState *s)
{
/* If we enabled cpu throttling for auto-converge, turn it off. */
cpu_throttle_stop();
qemu_mutex_lock_iothread();
switch (s->state) {
case MIGRATION_STATUS_COMPLETED:
migration_calculate_complete(s);
runstate_set(RUN_STATE_POSTMIGRATE);
break;
case MIGRATION_STATUS_COLO:
if (!migrate_colo_enabled()) {
error_report("%s: critical error: calling COLO code without "
"COLO enabled", __func__);
}
migrate_start_colo_process(s);
s->vm_was_running = true;
/* Fallthrough */
case MIGRATION_STATUS_FAILED:
case MIGRATION_STATUS_CANCELLED:
case MIGRATION_STATUS_CANCELLING:
if (s->vm_was_running) {
if (!runstate_check(RUN_STATE_SHUTDOWN)) {
vm_start();
}
} else {
if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
runstate_set(RUN_STATE_POSTMIGRATE);
}
}
break;
default:
/* Should not reach here, but if so, forgive the VM. */
error_report("%s: Unknown ending state %d", __func__, s->state);
break;
}
migrate_fd_cleanup_schedule(s);
qemu_mutex_unlock_iothread();
}
static void bg_migration_iteration_finish(MigrationState *s)
{
qemu_mutex_lock_iothread();
switch (s->state) {
case MIGRATION_STATUS_COMPLETED:
migration_calculate_complete(s);
break;
case MIGRATION_STATUS_ACTIVE:
case MIGRATION_STATUS_FAILED:
case MIGRATION_STATUS_CANCELLED:
case MIGRATION_STATUS_CANCELLING:
break;
default:
/* Should not reach here, but if so, forgive the VM. */
error_report("%s: Unknown ending state %d", __func__, s->state);
break;
}
migrate_fd_cleanup_schedule(s);
qemu_mutex_unlock_iothread();
}
/*
* Return true if continue to the next iteration directly, false
* otherwise.
*/
static MigIterateState bg_migration_iteration_run(MigrationState *s)
{
int res;
res = qemu_savevm_state_iterate(s->to_dst_file, false);
if (res > 0) {
bg_migration_completion(s);
return MIG_ITERATE_BREAK;
}
return MIG_ITERATE_RESUME;
}
void migration_make_urgent_request(void)
{
qemu_sem_post(&migrate_get_current()->rate_limit_sem);
}
void migration_consume_urgent_request(void)
{
qemu_sem_wait(&migrate_get_current()->rate_limit_sem);
}
/* Returns true if the rate limiting was broken by an urgent request */
bool migration_rate_limit(void)
{
int64_t now = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
MigrationState *s = migrate_get_current();
bool urgent = false;
migration_update_counters(s, now);
if (qemu_file_rate_limit(s->to_dst_file)) {
if (qemu_file_get_error(s->to_dst_file)) {
return false;
}
/*
* Wait for a delay to do rate limiting OR
* something urgent to post the semaphore.
*/
int ms = s->iteration_start_time + BUFFER_DELAY - now;
trace_migration_rate_limit_pre(ms);
if (qemu_sem_timedwait(&s->rate_limit_sem, ms) == 0) {
/*
* We were woken by one or more urgent things but
* the timedwait will have consumed one of them.
* The service routine for the urgent wake will dec
* the semaphore itself for each item it consumes,
* so add this one we just eat back.
*/
qemu_sem_post(&s->rate_limit_sem);
urgent = true;
}
trace_migration_rate_limit_post(urgent);
}
return urgent;
}
/*
* if failover devices are present, wait they are completely
* unplugged
*/
static void qemu_savevm_wait_unplug(MigrationState *s, int old_state,
int new_state)
{
if (qemu_savevm_state_guest_unplug_pending()) {
migrate_set_state(&s->state, old_state, MIGRATION_STATUS_WAIT_UNPLUG);
while (s->state == MIGRATION_STATUS_WAIT_UNPLUG &&
qemu_savevm_state_guest_unplug_pending()) {
qemu_sem_timedwait(&s->wait_unplug_sem, 250);
}
if (s->state != MIGRATION_STATUS_WAIT_UNPLUG) {
int timeout = 120; /* 30 seconds */
/*
* migration has been canceled
* but as we have started an unplug we must wait the end
* to be able to plug back the card
*/
while (timeout-- && qemu_savevm_state_guest_unplug_pending()) {
qemu_sem_timedwait(&s->wait_unplug_sem, 250);
}
if (qemu_savevm_state_guest_unplug_pending() &&
!qtest_enabled()) {
warn_report("migration: partially unplugged device on "
"failure");
}
}
migrate_set_state(&s->state, MIGRATION_STATUS_WAIT_UNPLUG, new_state);
} else {
migrate_set_state(&s->state, old_state, new_state);
}
}
/*
* 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;
MigrationThread *thread = NULL;
int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
MigThrError thr_error;
bool urgent = false;
thread = MigrationThreadAdd("live_migration", qemu_get_thread_id());
rcu_register_thread();
object_ref(OBJECT(s));
update_iteration_initial_status(s);
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.rp_thread_created) {
/* 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()) {
/*
* 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);
}
if (migrate_colo_enabled()) {
/* Notify migration destination that we enable COLO */
qemu_savevm_send_colo_enable(s->to_dst_file);
}
qemu_savevm_state_setup(s->to_dst_file);
qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_ACTIVE);
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
trace_migration_thread_setup_complete();
while (migration_is_active(s)) {
if (urgent || !qemu_file_rate_limit(s->to_dst_file)) {
MigIterateState iter_state = migration_iteration_run(s);
if (iter_state == MIG_ITERATE_SKIP) {
continue;
} else if (iter_state == MIG_ITERATE_BREAK) {
break;
}
}
/*
* Try to detect any kind of failures, and see whether we
* should stop the migration now.
*/
thr_error = migration_detect_error(s);
if (thr_error == MIG_THR_ERR_FATAL) {
/* Stop migration */
break;
} else if (thr_error == MIG_THR_ERR_RECOVERED) {
/*
* Just recovered from a e.g. network failure, reset all
* the local variables. This is important to avoid
* breaking transferred_bytes and bandwidth calculation
*/
update_iteration_initial_status(s);
}
urgent = migration_rate_limit();
}
trace_migration_thread_after_loop();
migration_iteration_finish(s);
object_unref(OBJECT(s));
rcu_unregister_thread();
MigrationThreadDel(thread);
return NULL;
}
static void bg_migration_vm_start_bh(void *opaque)
{
MigrationState *s = opaque;
qemu_bh_delete(s->vm_start_bh);
s->vm_start_bh = NULL;
vm_start();
s->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - s->downtime_start;
}
/**
* Background snapshot thread, based on live migration code.
* This is an alternative implementation of live migration mechanism
* introduced specifically to support background snapshots.
*
* It takes advantage of userfault_fd write protection mechanism introduced
* in v5.7 kernel. Compared to existing dirty page logging migration much
* lesser stream traffic is produced resulting in smaller snapshot images,
* simply cause of no page duplicates can get into the stream.
*
* Another key point is that generated vmstate stream reflects machine state
* 'frozen' at the beginning of snapshot creation compared to dirty page logging
* mechanism, which effectively results in that saved snapshot is the state of VM
* at the end of the process.
*/
static void *bg_migration_thread(void *opaque)
{
MigrationState *s = opaque;
int64_t setup_start;
MigThrError thr_error;
QEMUFile *fb;
bool early_fail = true;
rcu_register_thread();
object_ref(OBJECT(s));
qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
/*
* We want to save vmstate for the moment when migration has been
* initiated but also we want to save RAM content while VM is running.
* The RAM content should appear first in the vmstate. So, we first
* stash the non-RAM part of the vmstate to the temporary buffer,
* then write RAM part of the vmstate to the migration stream
* with vCPUs running and, finally, write stashed non-RAM part of
* the vmstate from the buffer to the migration stream.
*/
s->bioc = qio_channel_buffer_new(512 * 1024);
qio_channel_set_name(QIO_CHANNEL(s->bioc), "vmstate-buffer");
fb = qemu_file_new_output(QIO_CHANNEL(s->bioc));
object_unref(OBJECT(s->bioc));
update_iteration_initial_status(s);
/*
* Prepare for tracking memory writes with UFFD-WP - populate
* RAM pages before protecting.
*/
#ifdef __linux__
ram_write_tracking_prepare();
#endif
qemu_savevm_state_header(s->to_dst_file);
qemu_savevm_state_setup(s->to_dst_file);
qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_ACTIVE);
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
trace_migration_thread_setup_complete();
s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
qemu_mutex_lock_iothread();
/*
* If VM is currently in suspended state, then, to make a valid runstate
* transition in vm_stop_force_state() we need to wakeup it up.
*/
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
s->vm_was_running = runstate_is_running();
if (global_state_store()) {
goto fail;
}
/* Forcibly stop VM before saving state of vCPUs and devices */
if (vm_stop_force_state(RUN_STATE_PAUSED)) {
goto fail;
}
/*
* Put vCPUs in sync with shadow context structures, then
* save their state to channel-buffer along with devices.
*/
cpu_synchronize_all_states();
if (qemu_savevm_state_complete_precopy_non_iterable(fb, false, false)) {
goto fail;
}
/*
* Since we are going to get non-iterable state data directly
* from s->bioc->data, explicit flush is needed here.
*/
qemu_fflush(fb);
/* Now initialize UFFD context and start tracking RAM writes */
if (ram_write_tracking_start()) {
goto fail;
}
early_fail = false;
/*
* Start VM from BH handler to avoid write-fault lock here.
* UFFD-WP protection for the whole RAM is already enabled so
* calling VM state change notifiers from vm_start() would initiate
* writes to virtio VQs memory which is in write-protected region.
*/
s->vm_start_bh = qemu_bh_new(bg_migration_vm_start_bh, s);
qemu_bh_schedule(s->vm_start_bh);
qemu_mutex_unlock_iothread();
while (migration_is_active(s)) {
MigIterateState iter_state = bg_migration_iteration_run(s);
if (iter_state == MIG_ITERATE_SKIP) {
continue;
} else if (iter_state == MIG_ITERATE_BREAK) {
break;
}
/*
* Try to detect any kind of failures, and see whether we
* should stop the migration now.
*/
thr_error = migration_detect_error(s);
if (thr_error == MIG_THR_ERR_FATAL) {
/* Stop migration */
break;
}
migration_update_counters(s, qemu_clock_get_ms(QEMU_CLOCK_REALTIME));
}
trace_migration_thread_after_loop();
fail:
if (early_fail) {
migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_FAILED);
qemu_mutex_unlock_iothread();
}
bg_migration_iteration_finish(s);
qemu_fclose(fb);
object_unref(OBJECT(s));
rcu_unregister_thread();
return NULL;
}
void migrate_fd_connect(MigrationState *s, Error *error_in)
{
Error *local_err = NULL;
int64_t rate_limit;
bool resume = s->state == MIGRATION_STATUS_POSTCOPY_PAUSED;
/*
* If there's a previous error, free it and prepare for another one.
* Meanwhile if migration completes successfully, there won't have an error
* dumped when calling migrate_fd_cleanup().
*/
migrate_error_free(s);
s->expected_downtime = s->parameters.downtime_limit;
if (resume) {
assert(s->cleanup_bh);
} else {
assert(!s->cleanup_bh);
s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup_bh, s);
}
if (error_in) {
migrate_fd_error(s, error_in);
if (resume) {
/*
* Don't do cleanup for resume if channel is invalid, but only dump
* the error. We wait for another channel connect from the user.
* The error_report still gives HMP user a hint on what failed.
* It's normally done in migrate_fd_cleanup(), but call it here
* explicitly.
*/
error_report_err(error_copy(s->error));
} else {
migrate_fd_cleanup(s);
}
return;
}
if (resume) {
/* This is a resumed migration */
rate_limit = s->parameters.max_postcopy_bandwidth /
XFER_LIMIT_RATIO;
} else {
/* This is a fresh new migration */
rate_limit = s->parameters.max_bandwidth / XFER_LIMIT_RATIO;
/* Notify before starting migration thread */
notifier_list_notify(&migration_state_notifiers, s);
}
qemu_file_set_rate_limit(s->to_dst_file, rate_limit);
qemu_file_set_blocking(s->to_dst_file, true);
/*
* 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, !resume)) {
error_report("Unable to open return-path for postcopy");
migrate_set_state(&s->state, s->state, MIGRATION_STATUS_FAILED);
migrate_fd_cleanup(s);
return;
}
}
if (resume) {
/* Wakeup the main migration thread to do the recovery */
migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_PAUSED,
MIGRATION_STATUS_POSTCOPY_RECOVER);
qemu_sem_post(&s->postcopy_pause_sem);
return;
}
if (multifd_save_setup(&local_err) != 0) {
error_report_err(local_err);
migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_FAILED);
migrate_fd_cleanup(s);
return;
}
if (migrate_background_snapshot()) {
qemu_thread_create(&s->thread, "bg_snapshot",
bg_migration_thread, s, QEMU_THREAD_JOINABLE);
} else {
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:\n");
monitor_printf(mon, "store-global-state: %s\n",
ms->store_global_state ? "on" : "off");
monitor_printf(mon, "only-migratable: %s\n",
only_migratable ? "on" : "off");
monitor_printf(mon, "send-configuration: %s\n",
ms->send_configuration ? "on" : "off");
monitor_printf(mon, "send-section-footer: %s\n",
ms->send_section_footer ? "on" : "off");
monitor_printf(mon, "decompress-error-check: %s\n",
ms->decompress_error_check ? "on" : "off");
monitor_printf(mon, "clear-bitmap-shift: %u\n",
ms->clear_bitmap_shift);
}
#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("send-configuration", MigrationState,
send_configuration, true),
DEFINE_PROP_BOOL("send-section-footer", MigrationState,
send_section_footer, true),
DEFINE_PROP_BOOL("decompress-error-check", MigrationState,
decompress_error_check, true),
DEFINE_PROP_UINT8("x-clear-bitmap-shift", MigrationState,
clear_bitmap_shift, CLEAR_BITMAP_SHIFT_DEFAULT),
DEFINE_PROP_BOOL("x-preempt-pre-7-2", MigrationState,
preempt_pre_7_2, false),
/* Migration parameters */
DEFINE_PROP_UINT8("x-compress-level", MigrationState,
parameters.compress_level,
DEFAULT_MIGRATE_COMPRESS_LEVEL),
DEFINE_PROP_UINT8("x-compress-threads", MigrationState,
parameters.compress_threads,
DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT),
DEFINE_PROP_BOOL("x-compress-wait-thread", MigrationState,
parameters.compress_wait_thread, true),
DEFINE_PROP_UINT8("x-decompress-threads", MigrationState,
parameters.decompress_threads,
DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT),
DEFINE_PROP_UINT8("x-throttle-trigger-threshold", MigrationState,
parameters.throttle_trigger_threshold,
DEFAULT_MIGRATE_THROTTLE_TRIGGER_THRESHOLD),
DEFINE_PROP_UINT8("x-cpu-throttle-initial", MigrationState,
parameters.cpu_throttle_initial,
DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL),
DEFINE_PROP_UINT8("x-cpu-throttle-increment", MigrationState,
parameters.cpu_throttle_increment,
DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT),
DEFINE_PROP_BOOL("x-cpu-throttle-tailslow", MigrationState,
parameters.cpu_throttle_tailslow, false),
DEFINE_PROP_SIZE("x-max-bandwidth", MigrationState,
parameters.max_bandwidth, MAX_THROTTLE),
DEFINE_PROP_UINT64("x-downtime-limit", MigrationState,
parameters.downtime_limit,
DEFAULT_MIGRATE_SET_DOWNTIME),
DEFINE_PROP_UINT32("x-checkpoint-delay", MigrationState,
parameters.x_checkpoint_delay,
DEFAULT_MIGRATE_X_CHECKPOINT_DELAY),
DEFINE_PROP_UINT8("multifd-channels", MigrationState,
parameters.multifd_channels,
DEFAULT_MIGRATE_MULTIFD_CHANNELS),
DEFINE_PROP_MULTIFD_COMPRESSION("multifd-compression", MigrationState,
parameters.multifd_compression,
DEFAULT_MIGRATE_MULTIFD_COMPRESSION),
DEFINE_PROP_UINT8("multifd-zlib-level", MigrationState,
parameters.multifd_zlib_level,
DEFAULT_MIGRATE_MULTIFD_ZLIB_LEVEL),
DEFINE_PROP_UINT8("multifd-zstd-level", MigrationState,
parameters.multifd_zstd_level,
DEFAULT_MIGRATE_MULTIFD_ZSTD_LEVEL),
DEFINE_PROP_SIZE("xbzrle-cache-size", MigrationState,
parameters.xbzrle_cache_size,
DEFAULT_MIGRATE_XBZRLE_CACHE_SIZE),
DEFINE_PROP_SIZE("max-postcopy-bandwidth", MigrationState,
parameters.max_postcopy_bandwidth,
DEFAULT_MIGRATE_MAX_POSTCOPY_BANDWIDTH),
DEFINE_PROP_UINT8("max-cpu-throttle", MigrationState,
parameters.max_cpu_throttle,
DEFAULT_MIGRATE_MAX_CPU_THROTTLE),
DEFINE_PROP_SIZE("announce-initial", MigrationState,
parameters.announce_initial,
DEFAULT_MIGRATE_ANNOUNCE_INITIAL),
DEFINE_PROP_SIZE("announce-max", MigrationState,
parameters.announce_max,
DEFAULT_MIGRATE_ANNOUNCE_MAX),
DEFINE_PROP_SIZE("announce-rounds", MigrationState,
parameters.announce_rounds,
DEFAULT_MIGRATE_ANNOUNCE_ROUNDS),
DEFINE_PROP_SIZE("announce-step", MigrationState,
parameters.announce_step,
DEFAULT_MIGRATE_ANNOUNCE_STEP),
DEFINE_PROP_STRING("tls-creds", MigrationState, parameters.tls_creds),
DEFINE_PROP_STRING("tls-hostname", MigrationState, parameters.tls_hostname),
DEFINE_PROP_STRING("tls-authz", MigrationState, parameters.tls_authz),
/* 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-postcopy-preempt",
MIGRATION_CAPABILITY_POSTCOPY_PREEMPT),
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_MIG_CAP("x-multifd", MIGRATION_CAPABILITY_MULTIFD),
DEFINE_PROP_MIG_CAP("x-background-snapshot",
MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT),
#ifdef CONFIG_LINUX
DEFINE_PROP_MIG_CAP("x-zero-copy-send",
MIGRATION_CAPABILITY_ZERO_COPY_SEND),
#endif
DEFINE_PROP_END_OF_LIST(),
};
static void migration_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->user_creatable = false;
device_class_set_props(dc, migration_properties);
}
static void migration_instance_finalize(Object *obj)
{
MigrationState *ms = MIGRATION_OBJ(obj);
qemu_mutex_destroy(&ms->error_mutex);
qemu_mutex_destroy(&ms->qemu_file_lock);
qemu_sem_destroy(&ms->wait_unplug_sem);
qemu_sem_destroy(&ms->rate_limit_sem);
qemu_sem_destroy(&ms->pause_sem);
qemu_sem_destroy(&ms->postcopy_pause_sem);
qemu_sem_destroy(&ms->postcopy_pause_rp_sem);
qemu_sem_destroy(&ms->rp_state.rp_sem);
qemu_sem_destroy(&ms->rp_state.rp_pong_acks);
qemu_sem_destroy(&ms->postcopy_qemufile_src_sem);
error_free(ms->error);
}
static void migration_instance_init(Object *obj)
{
MigrationState *ms = MIGRATION_OBJ(obj);
MigrationParameters *params = &ms->parameters;
ms->state = MIGRATION_STATUS_NONE;
ms->mbps = -1;
ms->pages_per_second = -1;
qemu_sem_init(&ms->pause_sem, 0);
qemu_mutex_init(&ms->error_mutex);
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_compress_wait_thread = true;
params->has_decompress_threads = true;
params->has_throttle_trigger_threshold = true;
params->has_cpu_throttle_initial = true;
params->has_cpu_throttle_increment = true;
params->has_cpu_throttle_tailslow = true;
params->has_max_bandwidth = true;
params->has_downtime_limit = true;
params->has_x_checkpoint_delay = true;
params->has_block_incremental = true;
params->has_multifd_channels = true;
params->has_multifd_compression = true;
params->has_multifd_zlib_level = true;
params->has_multifd_zstd_level = true;
params->has_xbzrle_cache_size = true;
params->has_max_postcopy_bandwidth = true;
params->has_max_cpu_throttle = true;
params->has_announce_initial = true;
params->has_announce_max = true;
params->has_announce_rounds = true;
params->has_announce_step = true;
qemu_sem_init(&ms->postcopy_pause_sem, 0);
qemu_sem_init(&ms->postcopy_pause_rp_sem, 0);
qemu_sem_init(&ms->rp_state.rp_sem, 0);
qemu_sem_init(&ms->rp_state.rp_pong_acks, 0);
qemu_sem_init(&ms->rate_limit_sem, 0);
qemu_sem_init(&ms->wait_unplug_sem, 0);
qemu_sem_init(&ms->postcopy_qemufile_src_sem, 0);
qemu_mutex_init(&ms->qemu_file_lock);
}
/*
* 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]) {
QAPI_LIST_PREPEND(head, migrate_cap_add(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_new(), 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,
.instance_finalize = migration_instance_finalize,
};
static void register_migration_types(void)
{
type_register_static(&migration_type);
}
type_init(register_migration_types);
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