From patchwork Tue Apr 16 14:42:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Maciej S. Szmigiero" X-Patchwork-Id: 13632006 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0C46FC41513 for ; Tue, 16 Apr 2024 14:48:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rwk4M-000789-1R; Tue, 16 Apr 2024 10:45:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rwk3L-00060h-AS for qemu-devel@nongnu.org; Tue, 16 Apr 2024 10:44:57 -0400 Received: from vps-vb.mhejs.net ([37.28.154.113]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rwk3J-0002Qo-Kz for qemu-devel@nongnu.org; Tue, 16 Apr 2024 10:44:55 -0400 Received: from MUA by vps-vb.mhejs.net with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rwk3D-0002i2-SW; Tue, 16 Apr 2024 16:44:47 +0200 From: "Maciej S. Szmigiero" To: Peter Xu , Fabiano Rosas Cc: Alex Williamson , =?utf-8?q?C=C3=A9dric_Le_G?= =?utf-8?q?oater?= , Eric Blake , Markus Armbruster , Avihai Horon , Joao Martins , qemu-devel@nongnu.org Subject: [PATCH RFC 18/26] migration: Add load_finish handler and associated functions Date: Tue, 16 Apr 2024 16:42:57 +0200 Message-ID: <22602ef370c2369519a0ef5e3a6f32ff04193b76.1713269378.git.maciej.szmigiero@oracle.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=37.28.154.113; envelope-from=mail@maciej.szmigiero.name; helo=vps-vb.mhejs.net X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: "Maciej S. Szmigiero" load_finish SaveVMHandler allows migration code to poll whether a device-specific asynchronous device state loading operation had finished. In order to avoid calling this handler needlessly the device is supposed to notify the migration code of its possible readiness via a call to qemu_loadvm_load_finish_ready_broadcast() while holding qemu_loadvm_load_finish_ready_lock. Signed-off-by: Maciej S. Szmigiero --- include/migration/register.h | 21 +++++++++++++++ migration/migration.c | 6 +++++ migration/migration.h | 3 +++ migration/savevm.c | 52 ++++++++++++++++++++++++++++++++++++ migration/savevm.h | 4 +++ 5 files changed, 86 insertions(+) diff --git a/include/migration/register.h b/include/migration/register.h index 7d29b7e0b559..f15881fc87cd 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -272,6 +272,27 @@ typedef struct SaveVMHandlers { int (*load_state_buffer)(void *opaque, char *data, size_t data_size, Error **errp); + /** + * @load_finish + * + * Poll whether all asynchronous device state loading had finished. + * Not called on the load failure path. + * + * Called while holding the qemu_loadvm_load_finish_ready_lock. + * + * If this method signals "not ready" then it might not be called + * again until qemu_loadvm_load_finish_ready_broadcast() is invoked + * while holding qemu_loadvm_load_finish_ready_lock. + * + * @opaque: data pointer passed to register_savevm_live() + * @is_finished: whether the loading had finished (output parameter) + * @errp: pointer to Error*, to store an error if it happens. + * + * Returns zero to indicate success and negative for error + * It's not an error that the loading still hasn't finished. + */ + int (*load_finish)(void *opaque, bool *is_finished, Error **errp); + /** * @load_setup * diff --git a/migration/migration.c b/migration/migration.c index 8fe8be71a0e3..e4f82695a338 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -234,6 +234,9 @@ void migration_object_init(void) qemu_cond_init(¤t_incoming->page_request_cond); current_incoming->page_requested = g_tree_new(page_request_addr_cmp); + g_mutex_init(¤t_incoming->load_finish_ready_mutex); + g_cond_init(¤t_incoming->load_finish_ready_cond); + migration_object_check(current_migration, &error_fatal); blk_mig_init(); @@ -387,6 +390,9 @@ void migration_incoming_state_destroy(void) mis->postcopy_qemufile_dst = NULL; } + g_mutex_clear(&mis->load_finish_ready_mutex); + g_cond_clear(&mis->load_finish_ready_cond); + yank_unregister_instance(MIGRATION_YANK_INSTANCE); } diff --git a/migration/migration.h b/migration/migration.h index a6114405917f..92014ef4cfcc 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -227,6 +227,9 @@ struct MigrationIncomingState { * is needed as this field is updated serially. */ unsigned int switchover_ack_pending_num; + + GCond load_finish_ready_cond; + GMutex load_finish_ready_mutex; }; MigrationIncomingState *migration_incoming_get_current(void); diff --git a/migration/savevm.c b/migration/savevm.c index 2e4d63faca06..30521ad3f340 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2994,6 +2994,37 @@ int qemu_loadvm_state(QEMUFile *f) return ret; } + qemu_loadvm_load_finish_ready_lock(); + while (!ret) { /* Don't call load_finish() handlers on the load failure path */ + bool all_ready = true; + SaveStateEntry *se = NULL; + + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + bool this_ready; + + if (!se->ops || !se->ops->load_finish) { + continue; + } + + ret = se->ops->load_finish(se->opaque, &this_ready, &local_err); + if (ret) { + error_report_err(local_err); + + qemu_loadvm_load_finish_ready_unlock(); + return -EINVAL; + } else if (!this_ready) { + all_ready = false; + } + } + + if (all_ready) { + break; + } + + g_cond_wait(&mis->load_finish_ready_cond, &mis->load_finish_ready_mutex); + } + qemu_loadvm_load_finish_ready_unlock(); + if (ret == 0) { ret = qemu_file_get_error(f); } @@ -3098,6 +3129,27 @@ int qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id, return 0; } +void qemu_loadvm_load_finish_ready_lock(void) +{ + MigrationIncomingState *mis = migration_incoming_get_current(); + + g_mutex_lock(&mis->load_finish_ready_mutex); +} + +void qemu_loadvm_load_finish_ready_unlock(void) +{ + MigrationIncomingState *mis = migration_incoming_get_current(); + + g_mutex_unlock(&mis->load_finish_ready_mutex); +} + +void qemu_loadvm_load_finish_ready_broadcast(void) +{ + MigrationIncomingState *mis = migration_incoming_get_current(); + + g_cond_broadcast(&mis->load_finish_ready_cond); +} + bool save_snapshot(const char *name, bool overwrite, const char *vmstate, bool has_devices, strList *devices, Error **errp) { diff --git a/migration/savevm.h b/migration/savevm.h index c879ba8c970e..85e8b882bd37 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -73,4 +73,8 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, int qemu_loadvm_load_state_buffer(const char *idstr, uint32_t instance_id, char *buf, size_t len, Error **errp); +void qemu_loadvm_load_finish_ready_lock(void); +void qemu_loadvm_load_finish_ready_unlock(void); +void qemu_loadvm_load_finish_ready_broadcast(void); + #endif