From patchwork Sun Dec 13 11:48:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Straub X-Patchwork-Id: 11970633 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A42DC4361B for ; Sun, 13 Dec 2020 11:51:50 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 6AD1E23105 for ; 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s=dbaedf251592; t=1607860095; bh=b11e9asJoL18FeoBNGbpLYPJRTnbEN+Q1lBSaxI3aFY=; h=X-UI-Sender-Class:Date:From:To:Cc:Subject:In-Reply-To:References; b=TnNRbUUV9Wem9bmLJSIIEl21n2uBjLkBT8TnztxIXaStwwJnfJVRaQNvECooJ/yzI /YUdCXFE+eVuhjh92zaFRBtE9EnVlcJ1TESdB/2WDGBHczDG2kj8pR6De5qE7nY8up K9tSgfozTMJr8GAy1hXJUT8hERnlIUmUBZEYb3zg= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from gecko.fritz.box ([88.130.61.131]) by smtp.web.de (mrweb101 [213.165.67.124]) with ESMTPSA (Nemesis) id 0MQ6PP-1kkGr73Bvn-005KYk; Sun, 13 Dec 2020 12:48:14 +0100 Date: Sun, 13 Dec 2020 12:48:13 +0100 From: Lukas Straub To: qemu-devel Subject: [PATCH v12 1/7] Introduce yank feature Message-ID: In-Reply-To: References: MIME-Version: 1.0 X-Provags-ID: V03:K1:nemxQbkFU6Wp20FaL1gtsFHL6YROEuo4mi+zpqrCYQgzLsrpyGn TCT8SM/WvWt5ZZFW5ozgWKple+9mq3cluiMwp+FZ/gHYqKEAA4alEdjgTpbtpW8Gp0/MdmJ cwqu2B+ReQRMDWOmkQQacj2fTR/ocK0Ztrs4pWCibFUB4D8NTMD2WkMQAp44lSyvVEG4VVE 7VsJFyl8vRibgA0VtwglQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:phYyzDjSuoM=:LtQ+SFUzjx7kJ3PhFbjOaf O+GERMMClzOLfyUvgTFcTN1D1M+IBD36PpKvplTU8u2++mG/y2qOu7tjkXht6x8xdkiMEqWSw DXXMeWUoGZ3qeiLM+/Grxw2Q5eottn+cGYcuZFR0OhG3Hnr3Qvz1UYdqIgpapInzNbg8LRqKy LlJo2/NJz6XEscJ9HDvc2p3DfaQ6Lkg2EJ+RDe+6eQf22j76DJKkmyJb3Nlo/wpbed7kDWI59 0Vfnv9RiFdR8SBcmB7/ygDIKgax0WPinSucHKPpOn1kk92kKtzis+SDfddBIbPMCaGPb9OsXX di3Vx28OpOs+dgFsp2gBwkj/IoSIMRntqNo+X1ThiXHshlAaWhq5+qVyhvzSQ7Ct/ALaQbudK nw9u6ytR+HWToT4xdw/aWj+u3o3SamRhD8AvFrb5xdmQXug7+ksWo5IRmgdwITLzz/b+a4ati 2Vd/4p+lis/ALmmFj/2TnXsJubQvS8Phpwc7S1Keuf1Fd0uOSg5afxIcCcyyFrIqOx8Cc+nIr Z+xFgEqNnBBbdPoUL/DKs616lbcN3u3qheFO7duGv1HnQT9z4HkteJ/HOj2ev0SV/43Oiu25p KBuLGwoFBk/9LbsKZrKg1hkl6MrkeX02BZIoZ00E9T35akYV477fLqqR/PrXYotZ5Kuh+Md2k eWcZl2TXiQ1KP7aq4YyYvwNuYxj3tjb8vAUpRvjL8OT3hCJe5FEA9qWWLT2rgh15QoNpprBl8 CV5/Ob0Avi2CxEMqOdxrlaoX6Ex09qjd2nWvMOHmHte7yeHMK8fu4SKb+K7JMTDskioV+cTLL yxril/s3HXplXJ33oTQzFhOv47dAlEZFnh0+NSBfndMEmb4dWOIqr4kKE9GMqtvoOucmclaPQ k97hWG5kTldHK5OTtesujT5NdqKMQS4LcxwzqVrKQ= Received-SPF: pass client-ip=217.72.192.78; envelope-from=lukasstraub2@web.de; helo=mout.web.de X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "Daniel P. =?utf-8?b?QmVycmFuZ8Op?= " , qemu-block , Juan Quintela , Markus Armbruster , "Dr. David Alan Gilbert" , Max Reitz , =?utf-8?q?Marc-Andr=C3=A9?= Lureau , Paolo Bonzini , =?utf-8?q?Marc-Andr=C3=A9?= Lureau Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The yank feature allows to recover from hanging qemu by "yanking" at various parts. Other qemu systems can register themselves and multiple yank functions. Then all yank functions for selected instances can be called by the 'yank' out-of-band qmp command. Available instances can be queried by a 'query-yank' oob command. Signed-off-by: Lukas Straub Acked-by: Stefan Hajnoczi Reviewed-by: Markus Armbruster --- MAINTAINERS | 7 ++ include/qemu/yank.h | 95 +++++++++++++++++++ qapi/meson.build | 1 + qapi/qapi-schema.json | 1 + qapi/yank.json | 119 +++++++++++++++++++++++ util/meson.build | 1 + util/yank.c | 216 ++++++++++++++++++++++++++++++++++++++++++ 7 files changed, 440 insertions(+) create mode 100644 include/qemu/yank.h create mode 100644 qapi/yank.json create mode 100644 util/yank.c -- 2.20.1 diff --git a/MAINTAINERS b/MAINTAINERS index d48a4e8a8b..5d7e3c0e4b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2705,6 +2705,13 @@ F: util/uuid.c F: include/qemu/uuid.h F: tests/test-uuid.c +Yank feature +M: Lukas Straub +S: Odd fixes +F: util/yank.c +F: include/qemu/yank.h +F: qapi/yank.json + COLO Framework M: zhanghailiang S: Maintained diff --git a/include/qemu/yank.h b/include/qemu/yank.h new file mode 100644 index 0000000000..96f5b2626f --- /dev/null +++ b/include/qemu/yank.h @@ -0,0 +1,95 @@ +/* + * QEMU yank feature + * + * Copyright (c) Lukas Straub + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef YANK_H +#define YANK_H + +#include "qapi/qapi-types-yank.h" + +typedef void (YankFn)(void *opaque); + +/** + * yank_register_instance: Register a new instance. + * + * This registers a new instance for yanking. Must be called before any yank + * function is registered for this instance. + * + * This function is thread-safe. + * + * @instance: The instance. + * @errp: Error object. + */ +void yank_register_instance(const YankInstance *instance, Error **errp); + +/** + * yank_unregister_instance: Unregister a instance. + * + * This unregisters a instance. Must be called only after every yank function + * of the instance has been unregistered. + * + * This function is thread-safe. + * + * @instance: The instance. + */ +void yank_unregister_instance(const YankInstance *instance); + +/** + * yank_register_function: Register a yank function + * + * This registers a yank function. All limitations of qmp oob commands apply + * to the yank function as well. See docs/devel/qapi-code-gen.txt under + * "An OOB-capable command handler must satisfy the following conditions". + * + * This function is thread-safe. + * + * @instance: The instance. + * @func: The yank function. + * @opaque: Will be passed to the yank function. + */ +void yank_register_function(const YankInstance *instance, + YankFn *func, + void *opaque); + +/** + * yank_unregister_function: Unregister a yank function + * + * This unregisters a yank function. + * + * This function is thread-safe. + * + * @instance: The instance. + * @func: func that was passed to yank_register_function. + * @opaque: opaque that was passed to yank_register_function. + */ +void yank_unregister_function(const YankInstance *instance, + YankFn *func, + void *opaque); + +/** + * yank_generic_iochannel: Generic yank function for iochannel + * + * This is a generic yank function which will call qio_channel_shutdown on the + * provided QIOChannel. + * + * @opaque: QIOChannel to shutdown + */ +void yank_generic_iochannel(void *opaque); + +#define BLOCKDEV_YANK_INSTANCE(the_node_name) (&(YankInstance) { \ + .type = YANK_INSTANCE_TYPE_BLOCK_NODE, \ + .u.block_node.node_name = (the_node_name) }) + +#define CHARDEV_YANK_INSTANCE(the_id) (&(YankInstance) { \ + .type = YANK_INSTANCE_TYPE_CHARDEV, \ + .u.chardev.id = (the_id) }) + +#define MIGRATION_YANK_INSTANCE (&(YankInstance) { \ + .type = YANK_INSTANCE_TYPE_MIGRATION }) + +#endif diff --git a/qapi/meson.build b/qapi/meson.build index 0e98146f1f..ab68e7900e 100644 --- a/qapi/meson.build +++ b/qapi/meson.build @@ -47,6 +47,7 @@ qapi_all_modules = [ 'trace', 'transaction', 'ui', + 'yank', ] qapi_storage_daemon_modules = [ diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json index 0b444b76d2..3441c9a9ae 100644 --- a/qapi/qapi-schema.json +++ b/qapi/qapi-schema.json @@ -86,6 +86,7 @@ { 'include': 'machine.json' } { 'include': 'machine-target.json' } { 'include': 'replay.json' } +{ 'include': 'yank.json' } { 'include': 'misc.json' } { 'include': 'misc-target.json' } { 'include': 'audio.json' } diff --git a/qapi/yank.json b/qapi/yank.json new file mode 100644 index 0000000000..167a775594 --- /dev/null +++ b/qapi/yank.json @@ -0,0 +1,119 @@ +# -*- Mode: Python -*- +# vim: filetype=python +# + +## +# = Yank feature +## + +## +# @YankInstanceType: +# +# An enumeration of yank instance types. See @YankInstance for more +# information. +# +# Since: 6.0 +## +{ 'enum': 'YankInstanceType', + 'data': [ 'block-node', 'chardev', 'migration' ] } + +## +# @YankInstanceBlockNode: +# +# Specifies which block graph node to yank. See @YankInstance for more +# information. +# +# @node-name: the name of the block graph node +# +# Since: 6.0 +## +{ 'struct': 'YankInstanceBlockNode', + 'data': { 'node-name': 'str' } } + +## +# @YankInstanceChardev: +# +# Specifies which character device to yank. See @YankInstance for more +# information. +# +# @id: the chardev's ID +# +# Since: 6.0 +## +{ 'struct': 'YankInstanceChardev', + 'data': { 'id': 'str' } } + +## +# @YankInstance: +# +# A yank instance can be yanked with the @yank qmp command to recover from a +# hanging QEMU. +# +# Currently implemented yank instances: +# - nbd block device: +# Yanking it will shut down the connection to the nbd server without +# attempting to reconnect. +# - socket chardev: +# Yanking it will shut down the connected socket. +# - migration: +# Yanking it will shut down all migration connections. Unlike +# @migrate_cancel, it will not notify the migration process, so migration +# will go into @failed state, instead of @cancelled state. @yank should be +# used to recover from hangs. +# +# Since: 6.0 +## +{ 'union': 'YankInstance', + 'base': { 'type': 'YankInstanceType' }, + 'discriminator': 'type', + 'data': { + 'block-node': 'YankInstanceBlockNode', + 'chardev': 'YankInstanceChardev' } } + +## +# @yank: +# +# Try to recover from hanging QEMU by yanking the specified instances. See +# @YankInstance for more information. +# +# Takes a list of @YankInstance as argument. +# +# Returns: - Nothing on success +# - @DeviceNotFound error, if any of the YankInstances doesn't exist +# +# Example: +# +# -> { "execute": "yank", +# "arguments": { +# "instances": [ +# { "type": "block-node", +# "node-name": "nbd0" } +# ] } } +# <- { "return": {} } +# +# Since: 6.0 +## +{ 'command': 'yank', + 'data': { 'instances': ['YankInstance'] }, + 'allow-oob': true } + +## +# @query-yank: +# +# Query yank instances. See @YankInstance for more information. +# +# Returns: list of @YankInstance +# +# Example: +# +# -> { "execute": "query-yank" } +# <- { "return": [ +# { "type": "block-node", +# "node-name": "nbd0" } +# ] } +# +# Since: 6.0 +## +{ 'command': 'query-yank', + 'returns': ['YankInstance'], + 'allow-oob': true } diff --git a/util/meson.build b/util/meson.build index f359af0d46..f7c67344e1 100644 --- a/util/meson.build +++ b/util/meson.build @@ -50,6 +50,7 @@ endif if have_system util_ss.add(when: 'CONFIG_GIO', if_true: [files('dbus.c'), gio]) + util_ss.add(files('yank.c')) endif if have_block diff --git a/util/yank.c b/util/yank.c new file mode 100644 index 0000000000..4a0f538359 --- /dev/null +++ b/util/yank.c @@ -0,0 +1,216 @@ +/* + * QEMU yank feature + * + * Copyright (c) Lukas Straub + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "qemu/thread.h" +#include "qemu/queue.h" +#include "qapi/qapi-commands-yank.h" +#include "qapi/qapi-visit-yank.h" +#include "qapi/clone-visitor.h" +#include "io/channel.h" +#include "qemu/yank.h" + +struct YankFuncAndParam { + YankFn *func; + void *opaque; + QLIST_ENTRY(YankFuncAndParam) next; +}; + +struct YankInstanceEntry { + YankInstance *instance; + QLIST_HEAD(, YankFuncAndParam) yankfns; + QLIST_ENTRY(YankInstanceEntry) next; +}; + +typedef struct YankFuncAndParam YankFuncAndParam; +typedef struct YankInstanceEntry YankInstanceEntry; + +/* + * This lock protects the yank_instance_list below. Because it's taken by + * OOB-capable commands, it must be "fast", i.e. it may only be held for a + * bounded, short time. See docs/devel/qapi-code-gen.txt for additional + * information. + */ +static QemuMutex yank_lock; + +static QLIST_HEAD(, YankInstanceEntry) yank_instance_list + = QLIST_HEAD_INITIALIZER(yank_instance_list); + +static bool yank_compare_instances(const YankInstance *a, const YankInstance *b) +{ + if (a->type != b->type) { + return false; + } + + switch (a->type) { + case YANK_INSTANCE_TYPE_BLOCK_NODE: + return !strcmp(a->u.block_node.node_name, b->u.block_node.node_name); + break; + + case YANK_INSTANCE_TYPE_CHARDEV: + return !strcmp(a->u.chardev.id, b->u.chardev.id); + break; + + case YANK_INSTANCE_TYPE_MIGRATION: + return true; + break; + + default: + abort(); + } +} + +static YankInstanceEntry *yank_find_entry(const YankInstance *instance) +{ + YankInstanceEntry *entry; + + QLIST_FOREACH(entry, &yank_instance_list, next) { + if (yank_compare_instances(entry->instance, instance)) { + return entry; + } + } + return NULL; +} + +void yank_register_instance(const YankInstance *instance, Error **errp) +{ + YankInstanceEntry *entry; + + qemu_mutex_lock(&yank_lock); + + if (yank_find_entry(instance)) { + error_setg(errp, "duplicate yank instance"); + qemu_mutex_unlock(&yank_lock); + return; + } + + entry = g_slice_new(YankInstanceEntry); + entry->instance = QAPI_CLONE(YankInstance, instance); + QLIST_INIT(&entry->yankfns); + QLIST_INSERT_HEAD(&yank_instance_list, entry, next); + + qemu_mutex_unlock(&yank_lock); +} + +void yank_unregister_instance(const YankInstance *instance) +{ + YankInstanceEntry *entry; + + qemu_mutex_lock(&yank_lock); + entry = yank_find_entry(instance); + assert(entry); + + assert(QLIST_EMPTY(&entry->yankfns)); + QLIST_REMOVE(entry, next); + qapi_free_YankInstance(entry->instance); + g_slice_free(YankInstanceEntry, entry); + + qemu_mutex_unlock(&yank_lock); +} + +void yank_register_function(const YankInstance *instance, + YankFn *func, + void *opaque) +{ + YankInstanceEntry *entry; + YankFuncAndParam *func_entry; + + qemu_mutex_lock(&yank_lock); + entry = yank_find_entry(instance); + assert(entry); + + func_entry = g_slice_new(YankFuncAndParam); + func_entry->func = func; + func_entry->opaque = opaque; + + QLIST_INSERT_HEAD(&entry->yankfns, func_entry, next); + qemu_mutex_unlock(&yank_lock); +} + +void yank_unregister_function(const YankInstance *instance, + YankFn *func, + void *opaque) +{ + YankInstanceEntry *entry; + YankFuncAndParam *func_entry; + + qemu_mutex_lock(&yank_lock); + entry = yank_find_entry(instance); + assert(entry); + + QLIST_FOREACH(func_entry, &entry->yankfns, next) { + if (func_entry->func == func && func_entry->opaque == opaque) { + QLIST_REMOVE(func_entry, next); + g_slice_free(YankFuncAndParam, func_entry); + qemu_mutex_unlock(&yank_lock); + return; + } + } + + abort(); +} + +void yank_generic_iochannel(void *opaque) +{ + QIOChannel *ioc = QIO_CHANNEL(opaque); + + qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); +} + +void qmp_yank(YankInstanceList *instances, + Error **errp) +{ + YankInstanceList *tail; + YankInstanceEntry *entry; + YankFuncAndParam *func_entry; + + qemu_mutex_lock(&yank_lock); + for (tail = instances; tail; tail = tail->next) { + entry = yank_find_entry(tail->value); + if (!entry) { + error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, "Instance not found"); + qemu_mutex_unlock(&yank_lock); + return; + } + } + for (tail = instances; tail; tail = tail->next) { + entry = yank_find_entry(tail->value); + assert(entry); + QLIST_FOREACH(func_entry, &entry->yankfns, next) { + func_entry->func(func_entry->opaque); + } + } + qemu_mutex_unlock(&yank_lock); +} + +YankInstanceList *qmp_query_yank(Error **errp) +{ + YankInstanceEntry *entry; + YankInstanceList *ret; + + ret = NULL; + + qemu_mutex_lock(&yank_lock); + QLIST_FOREACH(entry, &yank_instance_list, next) { + YankInstanceList *new_entry; + new_entry = g_new0(YankInstanceList, 1); + new_entry->value = QAPI_CLONE(YankInstance, entry->instance); + new_entry->next = ret; + ret = new_entry; + } + qemu_mutex_unlock(&yank_lock); + + return ret; +} + +static void __attribute__((__constructor__)) yank_init(void) +{ + qemu_mutex_init(&yank_lock); +}