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Wed, 20 May 2020 23:05:41 +0200 Date: Wed, 20 May 2020 23:05:39 +0200 From: Lukas Straub To: qemu-devel Subject: [PATCH v2 1/4] Introduce yank feature Message-ID: <20005a15c708fbda983f9be602c55fc0b1979a18.1590008051.git.lukasstraub2@web.de> In-Reply-To: References: MIME-Version: 1.0 X-Provags-ID: V03:K1:YGPfmkpSDnW8lNP4O/ZXcylaYIeQqOBkBTY+EERF6pj/7GGo5d3 zAD8nu/K4eSW4U3p+aMYi2AKxhbY9BgTk98SSAVdR2tqbgilxoLKx77fGQUQO3ZiNgYzI33 mPOAUzp48e6z1xmaVbqPz8qdzsQD/ztzwFlvhwXLm+d7ByBnldL02cvDzhUslawoQLCFa0Q roEkQxL/0Oi/as0xRpVXA== X-UI-Out-Filterresults: notjunk:1;V03:K0:ShOSo1su23Q=:LTyuxCXuKUHicytMKr1HX7 xOlBkbhjLRW3GjscR0nLUV6X2Ag5HWQ6xYu/TDsnEsJCyiU3nSQ+RmWuCNL0EJIhWennvlfuA 4adD3FwgU1YDWencb559v+WFJKAo7ac+Uvv4BXwPP03+kmiJu44YIW5GsNjn25M/hqXIRGjXH 3ZOzOVD8HJTK93j0T1nKWSNdv9+FYzLtZk7rUQ044S37Jk3JAeyibOGqhDH28CxGML5aDmWCI 5vWjJM0XESKNdHxusQdBwKrTmScuzttrkNQWfEjFIWq/Ij5vRPfB+7qbACFIfQNp/rbwMbE9R V1KFKTSNzJZynZQTCdE7bHI4qEc/1+Sb2L5dWVreXDBsdrZplbNiE8x9+Ysv/Qm5fCuF+N4aj RsPPPwcVwTaiyEZ3agoK/04MxVEVsjZQHwfzRwcWQZ6kLnlCmBxqCtMOJfVo0a20/6UyxOQLT V6J3wJcN/duR8532XzuGE0Jqq/RLzk29BhIJyig3bHsrGVL+OZjkeX1FKKP5FzA3fuIXIAF2D Tv+Xc8ZtMBFO+DGYm10341DX3QJokPvKm9sFp5BzCeD2Ij+IznBl2J2GQ9P9VLy5vxLN0A3Il 6yAKi903+/G/ZsqbAgXZZhlSVAmr57mo8Bs7v+cs43hmlALosHN75l7tWmA6/P9Gi0cyKZmEl BvK3nGc9tMGm6uWCrRrM/YA7vOEQ8sEFNZSQNPW9QmFyWDO3I2qRHni3Z/CFnuwjertX2oBmT q1FwQWu/M5GB8S3zxvFWb2R4NkjLgYfk6XOLgSvAywa9Y69M2vD4B0c6xreMW+Y0Qe3rWbx6f v0CTWzeaA4uz4xtEZUlVP5bnDwpBsNx7kQJewtN/SsKifO7l2mbvLluJtBcOQJ0TgPTmPulGn AHEeUprC8+LhX34HtrXhyilFJRRUmTj3I2ZrV5Hww1S3uXrYDh8GTNiXhvsTKQgjN9QfOVaio sYtlr7GPl6+e0+58fBs6J44ploRQjJhvr0xwKdYd5i35L1ilDZBi2OgcrgUsmyfkJ3qTT5p7Z itAK3rpULjccKoB7j3NiA7onJSPubRoVUAk2NKUNOXIUuwiDZoPumELmZCFR5+Fysycspbn2x kdNS34dbYNgG0RtELlstkyUvl7t61/6yWfvhLsBIy6/oINYNPOT5fSmMGrhXM6IF8bB8GRJjc 8CtI64pmeZyTJ8CjzhpNI4y8Vkre+1wTu1b24+biEJYEM2VQdj/aKOP9TIijobAWumrZXdapn H/sMGL++pvG/qpTAp Received-SPF: pass client-ip=212.227.17.11; envelope-from=lukasstraub2@web.de; helo=mout.web.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/20 16:42:25 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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 , "Dr. David Alan Gilbert" , Max Reitz , Paolo Bonzini , =?utf-8?q?Marc-Andr=C3=A9?= Lureau Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.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 --- qapi/misc.json | 45 +++++++++++++ softmmu/vl.c | 2 + yank.c | 174 +++++++++++++++++++++++++++++++++++++++++++++++++ yank.h | 69 ++++++++++++++++++++ 4 files changed, 290 insertions(+) create mode 100644 yank.c create mode 100644 yank.h -- 2.20.1 diff --git a/qapi/misc.json b/qapi/misc.json index 99b90ac80b..f5228b2502 100644 --- a/qapi/misc.json +++ b/qapi/misc.json @@ -1550,3 +1550,48 @@ ## { 'command': 'query-vm-generation-id', 'returns': 'GuidInfo' } +## +# @YankInstances: +# +# @instances: List of yank instances. +# +# Yank instances are named after the following schema: +# "blockdev:", "chardev:" and "migration" +# +# Since: 5.1 +## +{ 'struct': 'YankInstances', 'data': {'instances': ['str'] } } + +## +# @yank: +# +# Recover from hanging qemu by yanking the specified instances. +# +# Takes @YankInstances as argument. +# +# Returns: nothing. +# +# Example: +# +# -> { "execute": "yank", "arguments": { "instances": ["blockdev:nbd0"] } } +# <- { "return": {} } +# +# Since: 5.1 +## +{ 'command': 'yank', 'data': 'YankInstances', 'allow-oob': true } + +## +# @query-yank: +# +# Query yank instances. +# +# Returns: @YankInstances +# +# Example: +# +# -> { "execute": "query-yank" } +# <- { "return": { "instances": ["blockdev:nbd0"] } } +# +# Since: 5.1 +## +{ 'command': 'query-yank', 'returns': 'YankInstances', 'allow-oob': true } diff --git a/softmmu/vl.c b/softmmu/vl.c index 32c0047889..5d99749d29 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -112,6 +112,7 @@ #include "qapi/qmp/qerror.h" #include "sysemu/iothread.h" #include "qemu/guest-random.h" +#include "yank.h" #define MAX_VIRTIO_CONSOLES 1 @@ -2906,6 +2907,7 @@ void qemu_init(int argc, char **argv, char **envp) precopy_infrastructure_init(); postcopy_infrastructure_init(); monitor_init_globals(); + yank_init(); if (qcrypto_init(&err) < 0) { error_reportf_err(err, "cannot initialize crypto: "); diff --git a/yank.c b/yank.c new file mode 100644 index 0000000000..bfce19185e --- /dev/null +++ b/yank.c @@ -0,0 +1,174 @@ +/* + * 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-misc.h" +#include "io/channel.h" +#include "yank.h" + +struct YankFuncAndParam { + YankFn *func; + void *opaque; + QLIST_ENTRY(YankFuncAndParam) next; +}; + +struct YankInstance { + char *name; + QLIST_HEAD(, YankFuncAndParam) yankfns; + QLIST_ENTRY(YankInstance) next; +}; + +static QemuMutex lock; +static QLIST_HEAD(yankinst_list, YankInstance) head + = QLIST_HEAD_INITIALIZER(head); + +static struct YankInstance *yank_find_instance(char *name) +{ + struct YankInstance *tmp, *instance; + instance = NULL; + QLIST_FOREACH(tmp, &head, next) { + if (!strcmp(tmp->name, name)) { + instance = tmp; + } + } + return instance; +} + +void yank_register_instance(char *instance_name) +{ + struct YankInstance *instance; + + qemu_mutex_lock(&lock); + assert(!yank_find_instance(instance_name)); + + instance = g_slice_new(struct YankInstance); + instance->name = g_strdup(instance_name); + QLIST_INIT(&instance->yankfns); + QLIST_INSERT_HEAD(&head, instance, next); + + qemu_mutex_unlock(&lock); +} + +void yank_unregister_instance(char *instance_name) +{ + struct YankInstance *instance; + + qemu_mutex_lock(&lock); + instance = yank_find_instance(instance_name); + assert(instance); + + assert(QLIST_EMPTY(&instance->yankfns)); + QLIST_REMOVE(instance, next); + g_free(instance->name); + g_slice_free(struct YankInstance, instance); + + qemu_mutex_unlock(&lock); +} + +void yank_register_function(char *instance_name, YankFn *func, void *opaque) +{ + struct YankInstance *instance; + struct YankFuncAndParam *entry; + + qemu_mutex_lock(&lock); + instance = yank_find_instance(instance_name); + assert(instance); + + entry = g_slice_new(struct YankFuncAndParam); + entry->func = func; + entry->opaque = opaque; + + QLIST_INSERT_HEAD(&instance->yankfns, entry, next); + qemu_mutex_unlock(&lock); +} + +void yank_unregister_function(char *instance_name, YankFn *func, void *opaque) +{ + struct YankInstance *instance; + struct YankFuncAndParam *entry; + + qemu_mutex_lock(&lock); + instance = yank_find_instance(instance_name); + assert(instance); + + QLIST_FOREACH(entry, &instance->yankfns, next) { + if (entry->func == func && entry->opaque == opaque) { + QLIST_REMOVE(entry, next); + g_slice_free(struct YankFuncAndParam, entry); + qemu_mutex_unlock(&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(strList *instances, Error **errp) +{ + strList *tmp; + struct YankInstance *instance; + struct YankFuncAndParam *entry; + + qemu_mutex_lock(&lock); + tmp = instances; + for (; tmp; tmp = tmp->next) { + instance = yank_find_instance(tmp->value); + if (!instance) { + error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, + "Instance '%s' not found", tmp->value); + qemu_mutex_unlock(&lock); + return; + } + } + tmp = instances; + for (; tmp; tmp = tmp->next) { + instance = yank_find_instance(tmp->value); + assert(instance); + QLIST_FOREACH(entry, &instance->yankfns, next) { + entry->func(entry->opaque); + } + } + qemu_mutex_unlock(&lock); +} + +YankInstances *qmp_query_yank(Error **errp) +{ + struct YankInstance *instance; + YankInstances *ret; + + ret = g_new0(YankInstances, 1); + ret->instances = NULL; + + qemu_mutex_lock(&lock); + QLIST_FOREACH(instance, &head, next) { + strList *entry; + entry = g_new0(strList, 1); + entry->value = g_strdup(instance->name); + entry->next = ret->instances; + ret->instances = entry; + } + qemu_mutex_unlock(&lock); + + return ret; +} + +void yank_init(void) +{ + qemu_mutex_init(&lock); +} diff --git a/yank.h b/yank.h new file mode 100644 index 0000000000..f01b370999 --- /dev/null +++ b/yank.h @@ -0,0 +1,69 @@ + +#ifndef YANK_H +#define 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_name: The globally unique name of the instance. + */ +void yank_register_instance(char *instance_name); + +/** + * 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_name: The name of the instance. + */ +void yank_unregister_instance(char *instance_name); + +/** + * 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. + * + * This function is thread-safe. + * + * @instance_name: The name of the instance + * @func: The yank function + * @opaque: Will be passed to the yank function + */ +void yank_register_function(char *instance_name, YankFn *func, void *opaque); + +/** + * yank_unregister_function: Unregister a yank function + * + * This unregisters a yank function. + * + * This function is thread-safe. + * + * @instance_name: The name of the instance + * @func: func that was passed to yank_register_function + * @opaque: opaque that was passed to yank_register_function + */ +void yank_unregister_function(char *instance_name, YankFn *func, void *opaque); + +/** + * yank_unregister_function: 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); + +void yank_init(void); +#endif