From patchwork Fri Oct 30 16:41:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Straub X-Patchwork-Id: 1391155 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=web.de Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; secure) header.d=web.de header.i=@web.de header.a=rsa-sha256 header.s=dbaedf251592 header.b=YQIYX7XD; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 4CN7QL61CQz9s0b for ; Sat, 31 Oct 2020 03:42:34 +1100 (AEDT) Received: from localhost ([::1]:60418 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kYXU0-0004hW-Ft for incoming@patchwork.ozlabs.org; Fri, 30 Oct 2020 12:42:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55780) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kYXSv-0004R8-7E; Fri, 30 Oct 2020 12:41:28 -0400 Received: from mout.web.de ([212.227.15.14]:42949) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kYXSm-0002z6-8h; Fri, 30 Oct 2020 12:41:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1604076070; bh=oR7eWk0m4L2PKomamyzxI8Kt4wkjcH6V3b2Zzh0NqeI=; h=X-UI-Sender-Class:Date:From:To:Cc:Subject:In-Reply-To:References; b=YQIYX7XDv1y8tozm6cOsKvowuokGfEogdmk8EOzLN9LSsUw/WtWnHGdsgtnW2TnDs cqGhO0OXcugIMVwq6rxtfzegrDPHA/nkimCgIfjaZGbYtYQdxxHHoVlHG0DsqN2pbD eiVzWBVIejDLfQyXHh5B+a+T+2sLCocR9d7uBiEc= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from luklap ([87.123.206.100]) by smtp.web.de (mrweb005 [213.165.67.108]) with ESMTPSA (Nemesis) id 1N79NA-1kIApe0IJQ-017LWi; Fri, 30 Oct 2020 17:41:10 +0100 Date: Fri, 30 Oct 2020 17:41:08 +0100 From: Lukas Straub To: qemu-devel Subject: [PATCH v10 1/8] Introduce yank feature Message-ID: <20201030174108.1c88195b@luklap> In-Reply-To: References: MIME-Version: 1.0 X-Provags-ID: V03:K1:kXSGI1mIsEvfRuqdVE1BXzhaMa4EOzibVz0C7rDVDtapXMSPxNN ooM5OyCaoceMdU33ABMtE0rSauK3DSqV6aqnz3rMw0JgIobzgvFROQlehLaK/d+HIGkoKY0 a/SUNA8gFPCsw4RWtrAN5YNenLfgSxiVVngC6e947I4NH136maDyhZjOErvZCCNCenxIpyV 2IXr2Gwm5vIURhulRzyaw== X-UI-Out-Filterresults: notjunk:1;V03:K0:CU3cQd23/0s=:oUtbNbuLHGz+s+nvKIdaz3 /vGRy553jEeBUE2ekHRiW9HroaNTZWnrZjtubcnXj6oj3xHMKwMwGacUqtPEQIFkglN+mpSqP ExvrmLgAgV+o1UN3ql9kWX8sx7cpazKYrTR4kE2aIAtsjf7WNNwNwo0UF/q5yBIpLZYW68ieZ mkcHJAv8ZDlEMAI5n3YkmxMnIPPQNKP1ehMc7lW5+oKBrkW9OIsr7mdIiiDXqzDh873QNFD/7 p8Hxa2bFA6VtSdE3g14gXUVb4bbAnQ7LyuC1Cmt2E0Eh2xKwhQ5UxK/CXf5XPrKlZ1cM3jrM3 oqyXAx310BgmlDPpjk5RCAelqND9SQMgkWKFjEuXEXD+ozdpVqDQhsFFwzKcMhscWF5tM4KlB aKbapPLkOsNtGbvzWnX9Fv4MAcQd/FY4AZZrXakdhqjPGXVlg4Q5Jft4va3TSr8SeF80g3bMT +XsKuN+KXx1/KHtE/oR9URIjrL/IomFfM60nvOYjx7a7VIeZaGnYCGwG57B3/3qiniQ1WeFIi yvOElnDNskM56nw10KAdkzPz21+QRnQ4isa39UBnrgj/UQxfcaMpDkh+pwXvdjkrkkUGj/eKR NxepElpR4CSVkTHs1v74/eT+/ecM19s+tnDtJk+EaMATLBSrizBUhH0BFFUeVMAwfvm0YhSo1 zjeksSjt3N95OWWJeh54lU5/KGiffRepU49H7VhbKOipw1gGJXFi42UFjb48+XAMBx/N47AKn Xdyp2DrF8OcC5AVlcLRZs2zKe5SWwDlB0U1WCL0x6bEuGO9BaYksAQNqY4DWtk6f+bMofjIgc Zbe/qR+QkEDLIJSYTPBnhsmkokUokOTg6YE+y9JmoxqvWv2i/2xGkFGmkBesvNDsPgLqQWDEc W1uKggqB1NL/ilGN+PnA== Received-SPF: pass client-ip=212.227.15.14; envelope-from=lukasstraub2@web.de; helo=mout.web.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/30 12:41:14 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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 , Paolo Bonzini , =?utf-8?q?Marc-Andr=C3=A9?= Lureau Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.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 --- include/qemu/yank.h | 95 +++++++++++++++++++ qapi/meson.build | 1 + qapi/qapi-schema.json | 1 + qapi/yank.json | 115 ++++++++++++++++++++++ util/meson.build | 1 + util/yank.c | 216 ++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 429 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/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..79c1705ed7 100644 --- a/qapi/qapi-schema.json +++ b/qapi/qapi-schema.json @@ -91,3 +91,4 @@ { 'include': 'audio.json' } { 'include': 'acpi.json' } { 'include': 'pci.json' } +{ 'include': 'yank.json' } diff --git a/qapi/yank.json b/qapi/yank.json new file mode 100644 index 0000000000..1964a2202e --- /dev/null +++ b/qapi/yank.json @@ -0,0 +1,115 @@ +# -*- Mode: Python -*- +# vim: filetype=python +# + +## +# @YankInstanceType: +# +# An enumeration of yank instance types. See @YankInstance for more +# information. +# +# Since: 5.2 +## +{ '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: 5.2 +## +{ 'struct': 'YankInstanceBlockNode', + 'data': { 'node-name': 'str' } } + +## +# @YankInstanceChardev: +# +# Specifies which character device to yank. See @YankInstance for more +# information. +# +# @id: the chardev's ID +# +# Since: 5.2 +## +{ '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: 5.2 +## +{ '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: 5.2 +## +{ '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: 5.2 +## +{ 'command': 'query-yank', + 'returns': ['YankInstance'], + 'allow-oob': true } diff --git a/util/meson.build b/util/meson.build index c5159ad79d..dbda9d9123 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); +}