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Tue, 23 Jun 2020 16:42:42 +0200 Date: Tue, 23 Jun 2020 16:42:41 +0200 From: Lukas Straub To: qemu-devel Subject: [PATCH v5 1/7] Introduce yank feature Message-ID: In-Reply-To: References: MIME-Version: 1.0 X-Provags-ID: V03:K1:Vl4nklLUS5lBfyNzs5mFRO9b1G9jdX6WmxcaAlcE4KCLRBrX4mS gabCHwIdj9jRQekwqo4C0359rxzj5WpQ2xq1RSVFi8e/JmcjeBp+w7JOgJAL4jaDlQNN0U/ UYfImkDEIiWCqMAVgPAx0RnuDa9VC8H7tdhiTj3hoyt3FKsd6SEBuWUlO+Tns/Clvsi2V7e rJVTerGgXUa2Eh1ANbNXw== X-UI-Out-Filterresults: notjunk:1;V03:K0:i2CJ/5jf+Z4=:sJ9SsnjGso6svbpBfx4Tfn W/H4N2ogGxRl+MWpGGcx1ubP9PtDJnx3Z7y7mi6MFIcjFkkkAMLUVJSanK9iaPZ+ZgnlA0uo7 uwVyInhXnW+Q8Bae/sDitzkU5LQwOiujU2xvrR4k2uJUFquwd02xPNOLlnbq25jQZLkP/O7jJ ZDsbQttzF2g56hAlUjblYL7LqB0kzx7jszNDtWHtbGI2UerNa/e3+Z1uvVnr9iWMi1zBK/njr 8f+2Gno46wLUMP+ij4ZEES9npf6FdWe3A7eQ++5SPzrP/SQMSMLKX9PDW6klXo/X7LPJPN+Ak anso1YY63k7qbM3r0fNziLdxezteVPkHHbADQMWh+BjX85v2cNwGGG92dqYMA98NEp5thlleV 6Aq7uxEL4GiYiuCbSg7TyCL7Ad+QkpyVuz5SxHKBiZOYa/8LgZ4DgWNvbm3iUV4e6AoRORgT3 zzdAEuyzS0+3ZmZ354j4fcu3qVdwJ7cm7cHbpmr+sdWpQhbMlJnBi/XTCxC8x3MVGnlbBPv3I foIYZhfHj1JchbWj60MfMPAtT5q2vXGaoSMHldjg0+goaeAOlmwYW2GPvyPFCXZilhZ7FyuOW C6+2rHVqgyneQrG0Jp0cdNbRIE0DQH2AEuVrBr8H9pwMUKtEcd3HGQ9FZKysNsTL6vZn2UGrm decU20z48Ix4FsodpGRT18v9XHwR/2z3GTEIwCiyyYMWQz9I+ZQ1El13RRje75skKLqX89MY0 oVIbeqbR8tzSedvFZywdML33zaVaDP8cOkSDlilA2EuJK8aLkMgs8/PAnsCf3tTFdFvOLk+VZ z3Vw5KpqpVJUkZGecIz2riZ2eVEoEPyFj9qxQyKS/HmRSYtD0OWYTWCfv3d8jtFM3zfNbnSfx bdB54qxgthC5CgOGom/gBrbIctRDVa/Q0PzoYCmf0x7f7ASyTYSz5rjOUsj3QkUxjWh5NnJsE aUMdffW8DSVckat3VD0Hr+Z3F+1lK7M7C8Q/45Qjk0Df9Qm1JQuWMgRQlk3KkZ+oKju8P7xSE UKLdTtGWryav6ytdbokVmltayaNENQ0JSKs3+qCkCLQDopDGvctGSqm7Bq+RgjaqWBA6v0a6d sGwx2iaPNGuov3EYU4RqfoKOzY2+sX9j5+2xtNDoCJx+seM2H4XyPuCGwnhxkSGsAg7OtBcXW +SwYeEuk3W34bTcyU2VcUoQDbFTjIlWbsnKJae+LikC3LOYrZbBo/g5mrALXi2ZUcVzxCiS0o W/937QVWlr2jmW2zm Received-SPF: pass client-ip=212.227.15.3; envelope-from=lukasstraub2@web.de; helo=mout.web.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/23 10:42:47 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 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=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=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 Reviewed-by: Daniel P. Berrangé --- include/qemu/yank.h | 79 +++++++++++++++++++ qapi/misc.json | 45 +++++++++++ util/Makefile.objs | 1 + util/yank.c | 179 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 304 insertions(+) create mode 100644 include/qemu/yank.h create mode 100644 util/yank.c -- 2.20.1 diff --git a/include/qemu/yank.h b/include/qemu/yank.h new file mode 100644 index 0000000000..294094ba74 --- /dev/null +++ b/include/qemu/yank.h @@ -0,0 +1,79 @@ +/* + * 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 + +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(const 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(const 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(const 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(const 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); +#endif diff --git a/qapi/misc.json b/qapi/misc.json index a5a0beb902..794d0afd5d 100644 --- a/qapi/misc.json +++ b/qapi/misc.json @@ -1552,3 +1552,48 @@ ## { '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/util/Makefile.objs b/util/Makefile.objs index cc5e37177a..13faa98425 100644 --- a/util/Makefile.objs +++ b/util/Makefile.objs @@ -45,6 +45,7 @@ util-obj-$(CONFIG_GIO) += dbus.o dbus.o-cflags = $(GIO_CFLAGS) dbus.o-libs = $(GIO_LIBS) util-obj-$(CONFIG_USER_ONLY) += selfmap.o +util-obj-y += yank.o ####################################################################### # code used by both qemu system emulation and qemu-img diff --git a/util/yank.c b/util/yank.c new file mode 100644 index 0000000000..4e66d5a2c2 --- /dev/null +++ b/util/yank.c @@ -0,0 +1,179 @@ +/* + * 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 "qemu/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(const 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(const 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(const 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(const 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(const 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; +} + +static void __attribute__((__constructor__)) yank_init(void) +{ + qemu_mutex_init(&lock); +}