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migration: Move postcopy_ram_listen_thread() to postcopy-ram.c

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This patch addresses a TODO about moving postcopy_ram_listen_thread() to
postcopy file.

Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20251103183301.3840862-4-jmarcin@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
This commit is contained in:
Juraj Marcin 2025-11-03 19:32:52 +01:00 • committed by Peter Xu
parent 26f65c01ed
commit c9aac1ae10
3 changed files with 107 additions and 107 deletions
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105
migration/postcopy-ram.c
View file

@ -2077,3 +2077,108 @@ bool postcopy_is_paused(MigrationStatus status)
return status == MIGRATION_STATUS_POSTCOPY_PAUSED ||
status == MIGRATION_STATUS_POSTCOPY_RECOVER_SETUP;
}
/*
* Triggered by a postcopy_listen command; this thread takes over reading
* the input stream, leaving the main thread free to carry on loading the rest
* of the device state (from RAM).
*/
void *postcopy_ram_listen_thread(void *opaque)
{
MigrationIncomingState *mis = migration_incoming_get_current();
QEMUFile *f = mis->from_src_file;
int load_res;
MigrationState *migr = migrate_get_current();
Error *local_err = NULL;
object_ref(OBJECT(migr));
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
qemu_event_set(&mis->thread_sync_event);
trace_postcopy_ram_listen_thread_start();
rcu_register_thread();
/*
* Because we're a thread and not a coroutine we can't yield
* in qemu_file, and thus we must be blocking now.
*/
qemu_file_set_blocking(f, true, &error_fatal);
/* TODO: sanity check that only postcopiable data will be loaded here */
load_res = qemu_loadvm_state_main(f, mis, &local_err);
/*
* This is tricky, but, mis->from_src_file can change after it
* returns, when postcopy recovery happened. In the future, we may
* want a wrapper for the QEMUFile handle.
*/
f = mis->from_src_file;
/* And non-blocking again so we don't block in any cleanup */
qemu_file_set_blocking(f, false, &error_fatal);
trace_postcopy_ram_listen_thread_exit();
if (load_res < 0) {
qemu_file_set_error(f, load_res);
dirty_bitmap_mig_cancel_incoming();
if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING &&
!migrate_postcopy_ram() && migrate_dirty_bitmaps())
{
error_report("%s: loadvm failed during postcopy: %d: %s. All states "
"are migrated except dirty bitmaps. Some dirty "
"bitmaps may be lost, and present migrated dirty "
"bitmaps are correctly migrated and valid.",
__func__, load_res, error_get_pretty(local_err));
g_clear_pointer(&local_err, error_free);
load_res = 0; /* prevent further exit() */
} else {
error_prepend(&local_err,
"loadvm failed during postcopy: %d: ", load_res);
migrate_set_error(migr, local_err);
g_clear_pointer(&local_err, error_report_err);
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_FAILED);
}
}
if (load_res >= 0) {
/*
* This looks good, but it's possible that the device loading in the
* main thread hasn't finished yet, and so we might not be in 'RUN'
* state yet; wait for the end of the main thread.
*/
qemu_event_wait(&mis->main_thread_load_event);
}
postcopy_ram_incoming_cleanup(mis);
if (load_res < 0) {
/*
* If something went wrong then we have a bad state so exit;
* depending how far we got it might be possible at this point
* to leave the guest running and fire MCEs for pages that never
* arrived as a desperate recovery step.
*/
rcu_unregister_thread();
exit(EXIT_FAILURE);
}
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_COMPLETED);
/*
* If everything has worked fine, then the main thread has waited
* for us to start, and we're the last use of the mis.
* (If something broke then qemu will have to exit anyway since it's
* got a bad migration state).
*/
bql_lock();
migration_incoming_state_destroy();
bql_unlock();
rcu_unregister_thread();
mis->have_listen_thread = false;
postcopy_state_set(POSTCOPY_INCOMING_END);
object_unref(OBJECT(migr));
return NULL;
}

2
migration/postcopy-ram.h
View file

@ -199,4 +199,6 @@ bool postcopy_is_paused(MigrationStatus status);
void mark_postcopy_blocktime_begin(uintptr_t addr, uint32_t ptid,
RAMBlock *rb);
void *postcopy_ram_listen_thread(void *opaque);
#endif

107
migration/savevm.c
View file

@ -2088,113 +2088,6 @@ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
return 0;
}
/*
* Triggered by a postcopy_listen command; this thread takes over reading
* the input stream, leaving the main thread free to carry on loading the rest
* of the device state (from RAM).
* (TODO:This could do with being in a postcopy file - but there again it's
* just another input loop, not that postcopy specific)
*/
static void *postcopy_ram_listen_thread(void *opaque)
{
MigrationIncomingState *mis = migration_incoming_get_current();
QEMUFile *f = mis->from_src_file;
int load_res;
MigrationState *migr = migrate_get_current();
Error *local_err = NULL;
object_ref(OBJECT(migr));
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
qemu_event_set(&mis->thread_sync_event);
trace_postcopy_ram_listen_thread_start();
rcu_register_thread();
/*
* Because we're a thread and not a coroutine we can't yield
* in qemu_file, and thus we must be blocking now.
*/
qemu_file_set_blocking(f, true, &error_fatal);
/* TODO: sanity check that only postcopiable data will be loaded here */
load_res = qemu_loadvm_state_main(f, mis, &local_err);
/*
* This is tricky, but, mis->from_src_file can change after it
* returns, when postcopy recovery happened. In the future, we may
* want a wrapper for the QEMUFile handle.
*/
f = mis->from_src_file;
/* And non-blocking again so we don't block in any cleanup */
qemu_file_set_blocking(f, false, &error_fatal);
trace_postcopy_ram_listen_thread_exit();
if (load_res < 0) {
qemu_file_set_error(f, load_res);
dirty_bitmap_mig_cancel_incoming();
if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING &&
!migrate_postcopy_ram() && migrate_dirty_bitmaps())
{
error_report("%s: loadvm failed during postcopy: %d: %s. All states "
"are migrated except dirty bitmaps. Some dirty "
"bitmaps may be lost, and present migrated dirty "
"bitmaps are correctly migrated and valid.",
__func__, load_res, error_get_pretty(local_err));
g_clear_pointer(&local_err, error_free);
load_res = 0; /* prevent further exit() */
} else {
error_prepend(&local_err,
"loadvm failed during postcopy: %d: ", load_res);
migrate_set_error(migr, local_err);
g_clear_pointer(&local_err, error_report_err);
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_FAILED);
}
}
if (load_res >= 0) {
/*
* This looks good, but it's possible that the device loading in the
* main thread hasn't finished yet, and so we might not be in 'RUN'
* state yet; wait for the end of the main thread.
*/
qemu_event_wait(&mis->main_thread_load_event);
}
postcopy_ram_incoming_cleanup(mis);
if (load_res < 0) {
/*
* If something went wrong then we have a bad state so exit;
* depending how far we got it might be possible at this point
* to leave the guest running and fire MCEs for pages that never
* arrived as a desperate recovery step.
*/
rcu_unregister_thread();
exit(EXIT_FAILURE);
}
migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
MIGRATION_STATUS_COMPLETED);
/*
* If everything has worked fine, then the main thread has waited
* for us to start, and we're the last use of the mis.
* (If something broke then qemu will have to exit anyway since it's
* got a bad migration state).
*/
bql_lock();
migration_incoming_state_destroy();
bql_unlock();
rcu_unregister_thread();
mis->have_listen_thread = false;
postcopy_state_set(POSTCOPY_INCOMING_END);
object_unref(OBJECT(migr));
return NULL;
}
/* After this message we must be able to immediately receive postcopy data */
static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis,
Error **errp)