On Thu, Oct 30, 2025 at 10:49:06PM +0100, Juraj Marcin wrote: > From: Juraj Marcin <[email protected]> > > This patch addresses a TODO about moving postcopy_ram_listen_thread() to > postcopy file. > > Signed-off-by: Juraj Marcin <[email protected]> > --- > migration/postcopy-ram.c | 107 +++++++++++++++++++++++++++++++++++++++ > migration/postcopy-ram.h | 2 + > migration/savevm.c | 107 --------------------------------------- > 3 files changed, 109 insertions(+), 107 deletions(-) > > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > index 5471efb4f0..36d5415554 100644 > --- a/migration/postcopy-ram.c > +++ b/migration/postcopy-ram.c > @@ -2077,3 +2077,110 @@ 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). > + * (TODO:This could do with being in a postcopy file - but there again it's > + * just another input loop, not that postcopy specific)
I suppose touching the comment while moving (as long as explicitly mentioned in the commit message) would be fine, when the comment is exactly about "we should move it". :) Not a big deal, thanks for the split. Reviewed-by: Peter Xu <[email protected]> > + */ > +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 232cae090b..97fdd08c08 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -2087,113 +2087,6 @@ 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) > -- > 2.51.0 > -- Peter Xu
