From: Juraj Marcin Date: Mon, 3 Nov 2025 18:32:52 +0000 (+0100) Subject: migration: Move postcopy_ram_listen_thread() to postcopy-ram.c X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c9aac1ae106e58be1c4f714793ee9170f91c5e7d;p=thirdparty%2Fqemu.git migration: Move postcopy_ram_listen_thread() to postcopy-ram.c This patch addresses a TODO about moving postcopy_ram_listen_thread() to postcopy file. Signed-off-by: Juraj Marcin Reviewed-by: Peter Xu Link: https://lore.kernel.org/r/20251103183301.3840862-4-jmarcin@redhat.com Signed-off-by: Peter Xu --- diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 5471efb4f0..880b11f154 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -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; +} diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h index ca19433b24..3e26db3e6b 100644 --- a/migration/postcopy-ram.h +++ b/migration/postcopy-ram.h @@ -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 diff --git a/migration/savevm.c b/migration/savevm.c index fa017378db..2f7ed0db64 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -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)