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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1761579703; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=t180PYNalySODgaWYpV7NHiAYPKhiHRd9Vru2Y5LYN0=; b=duYo6PkkvGmiLjF843zZI1strkjhb8mHNNio1J82ge8zReX2eLogz9rlbl2u2ocrz8hB54 1Lf7aRdm/XOiD/ev5pEHOJAIKJM6hGG7Ix7Z6aI6gB5ndH1v/jfMstv7W9u0d9q9c/LgMC agsYAJoIPlQHQxqBsFJhWgCqjOmMPCg= X-MC-Unique: YTB0RVUrPLiUyx-3MlzZmw-1 X-Mimecast-MFC-AGG-ID: YTB0RVUrPLiUyx-3MlzZmw_1761579699 From: Juraj Marcin To: qemu-devel@nongnu.org Cc: Juraj Marcin , Peter Xu , "Dr. David Alan Gilbert" , Jiri Denemark , Fabiano Rosas Subject: [PATCH v2 2/4] migration: Move postcopy_ram_listen_thread() to postcopy-ram.c Date: Mon, 27 Oct 2025 16:41:09 +0100 Message-ID: <20251027154115.4138677-3-jmarcin@redhat.com> In-Reply-To: <20251027154115.4138677-1-jmarcin@redhat.com> References: <20251027154115.4138677-1-jmarcin@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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charset="utf-8" From: Juraj Marcin This patch addresses a TODO about moving postcopy_ram_listen_thread() to postcopy file. Furthermore, this patch adds a pair of functions, postcopy_incoming_setup() and postcopy_incoming_cleanup(), which sets up and cleans the postcopy_ram_incoming state and the listen thread. Signed-off-by: Juraj Marcin --- migration/migration.c | 2 +- migration/postcopy-ram.c | 144 +++++++++++++++++++++++++++++++++++++++ migration/postcopy-ram.h | 3 + migration/savevm.c | 131 +---------------------------------- 4 files changed, 150 insertions(+), 130 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index e9acd0f63b..8827884a15 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -892,7 +892,7 @@ process_incoming_migration_co(void *opaque) * but managed to complete within the precopy period, we can u= se * the normal exit. */ - postcopy_ram_incoming_cleanup(mis); + postcopy_incoming_cleanup(mis); } else if (ret >=3D 0) { /* * Postcopy was started, cleanup should happen at the end of t= he diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 5471efb4f0..dbbb2dfb78 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -2077,3 +2077,147 @@ bool postcopy_is_paused(MigrationStatus status) return status =3D=3D MIGRATION_STATUS_POSTCOPY_PAUSED || status =3D=3D 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). + */ +static void *postcopy_listen_thread(void *opaque) +{ + MigrationIncomingState *mis =3D migration_incoming_get_current(); + QEMUFile *f =3D mis->from_src_file; + int load_res; + MigrationState *migr =3D migrate_get_current(); + Error *local_err =3D 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 =3D 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 =3D 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() =3D=3D POSTCOPY_INCOMING_RUNNING && + !migrate_postcopy_ram() && migrate_dirty_bitmaps()) + { + error_report("%s: loadvm failed during postcopy: %d. All state= s " + "are migrated except dirty bitmaps. Some dirty " + "bitmaps may be lost, and present migrated dirty " + "bitmaps are correctly migrated and valid.", + __func__, load_res); + load_res =3D 0; /* prevent further exit() */ + } else { + error_prepend(&local_err, + "loadvm failed during postcopy: %d: ", load_res); + migrate_set_error(migr, local_err); + error_report_err(local_err); + migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIV= E, + MIGRATION_STATUS_FAILED); + } + } + if (load_res >=3D 0) { + /* + * This looks good, but it's possible that the device loading in t= he + * 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_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 =3D false; + postcopy_state_set(POSTCOPY_INCOMING_END); + + object_unref(OBJECT(migr)); + + return NULL; +} + +int postcopy_incoming_setup(MigrationIncomingState *mis, Error **errp) +{ + /* + * Sensitise RAM - can now generate requests for blocks that don't exi= st + * However, at this point the CPU shouldn't be running, and the IO + * shouldn't be doing anything yet so don't actually expect requests + */ + if (migrate_postcopy_ram()) { + if (postcopy_ram_incoming_setup(mis)) { + postcopy_ram_incoming_cleanup(mis); + error_setg(errp, "Failed to setup incoming postcopy RAM blocks= "); + return -1; + } + } + + trace_loadvm_postcopy_handle_listen("after uffd"); + + if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_LISTEN, errp)) { + return -1; + } + + mis->have_listen_thread =3D true; + postcopy_thread_create(mis, &mis->listen_thread, + MIGRATION_THREAD_DST_LISTEN, + postcopy_listen_thread, QEMU_THREAD_DETACHED); + + return 0; +} + +int postcopy_incoming_cleanup(MigrationIncomingState *mis) +{ + int rc =3D 0; + + if (migrate_postcopy_ram()) { + rc =3D postcopy_ram_incoming_cleanup(mis); + } + + return rc; +} diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h index ca19433b24..a080dd65a7 100644 --- a/migration/postcopy-ram.h +++ b/migration/postcopy-ram.h @@ -199,4 +199,7 @@ bool postcopy_is_paused(MigrationStatus status); void mark_postcopy_blocktime_begin(uintptr_t addr, uint32_t ptid, RAMBlock *rb); =20 +int postcopy_incoming_setup(MigrationIncomingState *mis, Error **errp); +int postcopy_incoming_cleanup(MigrationIncomingState *mis); + #endif diff --git a/migration/savevm.c b/migration/savevm.c index 7b35ec4dd0..96a2699ca7 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2087,112 +2087,6 @@ static int loadvm_postcopy_ram_handle_discard(Migra= tionIncomingState *mis, return 0; } =20 -/* - * 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 =3D migration_incoming_get_current(); - QEMUFile *f =3D mis->from_src_file; - int load_res; - MigrationState *migr =3D migrate_get_current(); - Error *local_err =3D 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 =3D 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 =3D 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() =3D=3D POSTCOPY_INCOMING_RUNNING && - !migrate_postcopy_ram() && migrate_dirty_bitmaps()) - { - error_report("%s: loadvm failed during postcopy: %d. All state= s " - "are migrated except dirty bitmaps. Some dirty " - "bitmaps may be lost, and present migrated dirty " - "bitmaps are correctly migrated and valid.", - __func__, load_res); - load_res =3D 0; /* prevent further exit() */ - } else { - error_prepend(&local_err, - "loadvm failed during postcopy: %d: ", load_res); - migrate_set_error(migr, local_err); - error_report_err(local_err); - migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIV= E, - MIGRATION_STATUS_FAILED); - } - } - if (load_res >=3D 0) { - /* - * This looks good, but it's possible that the device loading in t= he - * 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 =3D 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) @@ -2218,32 +2112,11 @@ static int loadvm_postcopy_handle_listen(MigrationI= ncomingState *mis, =20 trace_loadvm_postcopy_handle_listen("after discard"); =20 - /* - * Sensitise RAM - can now generate requests for blocks that don't exi= st - * However, at this point the CPU shouldn't be running, and the IO - * shouldn't be doing anything yet so don't actually expect requests - */ - if (migrate_postcopy_ram()) { - if (postcopy_ram_incoming_setup(mis)) { - postcopy_ram_incoming_cleanup(mis); - error_setg(errp, "Failed to setup incoming postcopy RAM blocks= "); - return -1; - } - } + int rc =3D postcopy_incoming_setup(mis, errp); =20 - trace_loadvm_postcopy_handle_listen("after uffd"); - - if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_LISTEN, errp)) { - return -1; - } - - mis->have_listen_thread =3D true; - postcopy_thread_create(mis, &mis->listen_thread, - MIGRATION_THREAD_DST_LISTEN, - postcopy_ram_listen_thread, QEMU_THREAD_DETACHE= D); trace_loadvm_postcopy_handle_listen("return"); =20 - return 0; + return rc; } =20 static void loadvm_postcopy_handle_run_bh(void *opaque) --=20 2.51.0