From nobody Tue Nov 26 09:25:23 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1709066898476582.7196533011659; Tue, 27 Feb 2024 12:48:18 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rf4Ka-0005qK-Dw; Tue, 27 Feb 2024 15:45:41 -0500 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 1rf1oO-0003F4-Hd for qemu-devel@nongnu.org; Tue, 27 Feb 2024 13:04:17 -0500 Received: from mail.ozlabs.org ([2404:9400:2221:ea00::3] helo=gandalf.ozlabs.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rf1oJ-0001TC-EW for qemu-devel@nongnu.org; Tue, 27 Feb 2024 13:04:16 -0500 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4Tkljd05qnz4wyh; Wed, 28 Feb 2024 05:04:05 +1100 (AEDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4TkljZ2xMPz4wcN; Wed, 28 Feb 2024 05:04:02 +1100 (AEDT) From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= To: qemu-devel@nongnu.org Cc: Peter Xu , Fabiano Rosas , Alex Williamson , Avihai Horon , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Subject: [PATCH v2 03/21] migration: Add documentation for SaveVMHandlers Date: Tue, 27 Feb 2024 19:03:27 +0100 Message-ID: <20240227180345.548960-4-clg@redhat.com> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240227180345.548960-1-clg@redhat.com> References: <20240227180345.548960-1-clg@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2404:9400:2221:ea00::3; envelope-from=SRS0=GitP=KE=redhat.com=clg@ozlabs.org; helo=gandalf.ozlabs.org X-Spam_score_int: -39 X-Spam_score: -4.0 X-Spam_bar: ---- X-Spam_report: (-4.0 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Tue, 27 Feb 2024 15:45:26 -0500 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1709066898780100007 The SaveVMHandlers structure is still in use for complex subsystems and devices. Document the handlers since we are going to modify a few later. Signed-off-by: C=C3=A9dric Le Goater Reviewed-by: Peter Xu --- include/migration/register.h | 257 +++++++++++++++++++++++++++++++---- 1 file changed, 231 insertions(+), 26 deletions(-) diff --git a/include/migration/register.h b/include/migration/register.h index 2e6a7d766e62f64940086b7b511249c9ff21fa62..2cc71ec45f65bf2884c9e7a823d= 2968752f15c20 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -16,30 +16,129 @@ =20 #include "hw/vmstate-if.h" =20 +/** + * struct SaveVMHandlers: handler structure to finely control + * migration of complex subsystems and devices, such as RAM, block and + * VFIO. + */ typedef struct SaveVMHandlers { - /* This runs inside the BQL. */ + + /* The following handlers runs inside the BQL. */ + + /** + * @save_state + * + * Saves state section on the source using the latest state format + * version. + * + * Legacy method. Should be deprecated when all users are ported + * to VMState. + * + * @f: QEMUFile where to send the data + * @opaque: data pointer passed to register_savevm_live() + */ void (*save_state)(QEMUFile *f, void *opaque); =20 - /* - * save_prepare is called early, even before migration starts, and can= be - * used to perform early checks. + /** + * @save_prepare + * + * Called early, even before migration starts, and can be used to + * perform early checks. + * + * @opaque: data pointer passed to register_savevm_live() + * @errp: pointer to Error*, to store an error if it happens. + * + * Returns zero to indicate success and negative for error */ int (*save_prepare)(void *opaque, Error **errp); + + /** + * @save_setup + * + * Initializes the data structures on the source and transmits + * first section containing information on the device + * + * @f: QEMUFile where to send the data + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ int (*save_setup)(QEMUFile *f, void *opaque); + + /** + * @save_cleanup + * + * Performs save related cleanup + * + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ void (*save_cleanup)(void *opaque); + + /** + * @save_live_complete_postcopy + * + * Called at the end of postcopy for all postcopyiable devices. + * + * @f: QEMUFile where to send the data + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ int (*save_live_complete_postcopy)(QEMUFile *f, void *opaque); + + /** + * @save_live_complete_precopy + * + * Transmits the last section for the device containing any + * remaining data. + * + * @f: QEMUFile where to send the data + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ int (*save_live_complete_precopy)(QEMUFile *f, void *opaque); =20 /* This runs both outside and inside the BQL. */ + + /** + * @is_active + * + * Will skip a state section if not active + * + * @opaque: data pointer passed to register_savevm_live() + * + * Returns true if state section is active else false + */ bool (*is_active)(void *opaque); + + /** + * @has_postcopy + * + * checks if a device supports postcopy + * + * @opaque: data pointer passed to register_savevm_live() + * + * Returns true for postcopy support else false + */ bool (*has_postcopy)(void *opaque); =20 - /* is_active_iterate - * If it is not NULL then qemu_savevm_state_iterate will skip iteratio= n if - * it returns false. For example, it is needed for only-postcopy-state= s, - * which needs to be handled by qemu_savevm_state_setup and - * qemu_savevm_state_pending, but do not need iterations until not in - * postcopy stage. + /** + * @is_active_iterate + * + * As #SaveVMHandlers.is_active(), will skip an inactive state + * section in qemu_savevm_state_iterate. + * + * For example, it is needed for only-postcopy-states, which needs + * to be handled by qemu_savevm_state_setup() and + * qemu_savevm_state_pending(), but do not need iterations until + * not in postcopy stage. + * + * @opaque: data pointer passed to register_savevm_live() + * + * Returns true if state section is active else false */ bool (*is_active_iterate)(void *opaque); =20 @@ -48,44 +147,150 @@ typedef struct SaveVMHandlers { * use data that is local to the migration thread or protected * by other locks. */ + + /** + * @save_live_iterate + * + * Should send a chunk of data until the point that stream + * bandwidth limits tell it to stop. Each call generates one + * section. + * + * @f: QEMUFile where to send the data + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ int (*save_live_iterate)(QEMUFile *f, void *opaque); =20 /* This runs outside the BQL! */ - /* Note for save_live_pending: - * must_precopy: - * - must be migrated in precopy or in stopped state - * - i.e. must be migrated before target start - * - * can_postcopy: - * - can migrate in postcopy or in stopped state - * - i.e. can migrate after target start - * - some can also be migrated during precopy (RAM) - * - some must be migrated after source stops (block-dirty-bitmap) - * - * Sum of can_postcopy and must_postcopy is the whole amount of + + /** + * @state_pending_estimate + * + * This estimates the remaining data to transfer + * + * Sum of @can_postcopy and @must_postcopy is the whole amount of * pending data. + * + * @opaque: data pointer passed to register_savevm_live() + * @must_precopy: amount of data that must be migrated in precopy + * or in stopped state, i.e. that must be migrated + * before target start. + * @can_postcopy: amount of data that can be migrated in postcopy + * or in stopped state, i.e. after target start. + * Some can also be migrated during precopy (RAM). + * Some must be migrated after source stops + * (block-dirty-bitmap) */ - /* This estimates the remaining data to transfer */ void (*state_pending_estimate)(void *opaque, uint64_t *must_precopy, uint64_t *can_postcopy); - /* This calculate the exact remaining data to transfer */ + + /** + * @state_pending_exact + * + * This calculate the exact remaining data to transfer + * + * Sum of @can_postcopy and @must_postcopy is the whole amount of + * pending data. + * + * @opaque: data pointer passed to register_savevm_live() + * @must_precopy: amount of data that must be migrated in precopy + * or in stopped state, i.e. that must be migrated + * before target start. + * @can_postcopy: amount of data that can be migrated in postcopy + * or in stopped state, i.e. after target start. + * Some can also be migrated during precopy (RAM). + * Some must be migrated after source stops + * (block-dirty-bitmap) + */ void (*state_pending_exact)(void *opaque, uint64_t *must_precopy, uint64_t *can_postcopy); + + /** + * @load_state + * + * Load sections generated by any of the save functions that + * generate sections. + * + * Legacy method. Should be deprecated when all users are ported + * to VMState. + * + * @f: QEMUFile where to receive the data + * @opaque: data pointer passed to register_savevm_live() + * @version_id: the maximum version_id supported + * + * Returns zero to indicate success and negative for error + */ int (*load_state)(QEMUFile *f, void *opaque, int version_id); + + /** + * @load_setup + * + * Initializes the data structures on the destination. + * + * @f: QEMUFile where to receive the data + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ int (*load_setup)(QEMUFile *f, void *opaque); + + /** + * @load_cleanup + * + * Performs cleanup of load data structures + * + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ int (*load_cleanup)(void *opaque); - /* Called when postcopy migration wants to resume from failure */ + + /** + * @resume_prepare + * + * Called when postcopy migration wants to resume from failure + * + * @s: Current migration state + * @opaque: data pointer passed to register_savevm_live() + * + * Returns zero to indicate success and negative for error + */ int (*resume_prepare)(MigrationState *s, void *opaque); - /* Checks if switchover ack should be used. Called only in dest */ + + /** + * @switchover_ack_needed + * + * Checks if switchover ack should be used. Called only on + * destination. + * + * @opaque: data pointer passed to register_savevm_live() + */ bool (*switchover_ack_needed)(void *opaque); } SaveVMHandlers; =20 +/** + * register_savevm_live: Register a set of custom migration handlers + * + * @idstr: state section identifier + * @instance_id: instance id + * @version_id: version id supported + * @ops: SaveVMHandlers structurex + * @opaque: data pointer passed SaveVMHandlers handlers + */ int register_savevm_live(const char *idstr, uint32_t instance_id, int version_id, const SaveVMHandlers *ops, void *opaque); =20 +/** + * unregister_savevm: Unregister custom migration handlers + * + * @obj: object associated with state section + * @idstr: state section identifier + * @opaque: data pointer passed to register_savevm_live() + */ void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque); =20 #endif --=20 2.43.2