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Fri, 03 Jan 2025 22:40:48 -0800 (PST) Received: from localhost ([157.82.207.107]) by smtp.gmail.com with UTF8SMTPSA id d9443c01a7336-219dc962bfasm255265285ad.2.2025.01.03.22.40.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 03 Jan 2025 22:40:48 -0800 (PST) From: Akihiko Odaki Date: Sat, 04 Jan 2025 15:40:40 +0900 Subject: [PATCH v4] hw/core: Unify hotplug decision logic MIME-Version: 1.0 Message-Id: <20250104-bus-v4-1-244cf1c6e2aa@daynix.com> X-B4-Tracking: v=1; b=H4sIAOfXeGcC/2XMQQ6CMBAF0KuYrq1ppx0KrryHcVHaIl0IptUGQ ri7BWIicTPJn/z3JxJd8C6S82EiwSUffd/lII8HYlrd3R31NmcCDATPh9bvSBVqidKgrbAiufk MrvHDunK95dz6+OrDuI4mvnz3PnHKaaNQMid0aQu4WD12fjiZ/kGWgQQ/iLMNQUZCurpBBUWj2 R8SXyQZ8HJDIqNSKQVoXGE57tA8zx84s9bdAQEAAA== To: Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost Cc: qemu-devel@nongnu.org, devel@daynix.com, Akihiko Odaki X-Mailer: b4 0.14-dev-fd6e3 Received-SPF: pass client-ip=2607:f8b0:4864:20::636; envelope-from=akihiko.odaki@daynix.com; helo=mail-pl1-x636.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Commit 03fcbd9dc508 ("qdev: Check for the availability of a hotplug controller before adding a device") says: > The qdev_unplug() function contains a g_assert(hotplug_ctrl) > statement, so QEMU crashes when the user tries to device_add + > device_del a device that does not have a corresponding hotplug > controller. > The code in qdev_device_add() already checks whether the bus has a > proper hotplug controller, but for devices that do not have a > corresponding bus, here is no appropriate check available yet. In that > case we should check whether the machine itself provides a suitable > hotplug controller and refuse to plug the device if none is available. However, it forgot to add the corresponding check to qdev_unplug(). Most checks are comon between the hot-plug and hot-unplug scenarios so extract them and share the implementation, saving some code and fixing the aforementioned bug. Fixes: 7716b8ca74 ("qdev: HotplugHandler: Add support for unplugging BUS-less devices") Signed-off-by: Akihiko Odaki --- Changes in v4: - Rebased. - Link to v3: https://lore.kernel.org/r/20240218-bus-v3-1-877725ce6d15@daynix.com Changes in v3: - Extracted checks common for hot-plug and hot-unplug into a function. - Link to v2: https://lore.kernel.org/r/20231210-bus-v2-1-34ebf5726fa0@daynix.com Changes in v2: - Fixed indention. - Link to v1: https://lore.kernel.org/r/20231202-bus-v1-1-f7540e3a8d62@daynix.com --- include/hw/qdev-core.h | 3 ++- hw/core/qdev-hotplug.c | 42 +++++++++++++++++++++++++++++++++++++++++- system/qdev-monitor.c | 37 +++++-------------------------------- 3 files changed, 48 insertions(+), 34 deletions(-) --- base-commit: 38d0939b86e2eef6f6a622c6f1f7befda0146595 change-id: 20231202-bus-75a454c5d959 Best regards, diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index e6ef80b7fd0e..c417d4f92bdd 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -544,7 +544,8 @@ void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id, int required_for_version); HotplugHandler *qdev_get_bus_hotplug_handler(DeviceState *dev); HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev); -bool qdev_hotplug_allowed(DeviceState *dev, Error **errp); +bool qdev_hotplug_allowed(DeviceState *dev, BusState *bus, Error **errp); +bool qdev_hotunplug_allowed(DeviceState *dev, Error **errp); /** * qdev_get_hotplug_handler() - Get handler responsible for device wiring diff --git a/hw/core/qdev-hotplug.c b/hw/core/qdev-hotplug.c index d495d0e9c70a..e11597acd1f7 100644 --- a/hw/core/qdev-hotplug.c +++ b/hw/core/qdev-hotplug.c @@ -12,6 +12,7 @@ #include "qemu/osdep.h" #include "hw/qdev-core.h" #include "hw/boards.h" +#include "qapi/error.h" HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev) { @@ -30,12 +31,45 @@ HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev) return NULL; } -bool qdev_hotplug_allowed(DeviceState *dev, Error **errp) +static bool qdev_hotplug_unplug_allowed_common(DeviceState *dev, BusState *bus, + Error **errp) +{ + DeviceClass *dc = DEVICE_GET_CLASS(dev); + + if (!dc->hotpluggable) { + error_setg(errp, "Device '%s' does not support hotplugging", + object_get_typename(OBJECT(dev))); + return false; + } + + if (bus) { + if (!qbus_is_hotpluggable(bus)) { + error_setg(errp, "Bus '%s' does not support hotplugging", + bus->name); + return false; + } + } else { + if (!qdev_get_machine_hotplug_handler(dev)) { + /* No bus, no machine hotplug handler --> device is not hotpluggable */ + error_setg(errp, "Device '%s' can not be hotplugged on this machine", + object_get_typename(OBJECT(dev))); + return false; + } + } + + return true; +} + +bool qdev_hotplug_allowed(DeviceState *dev, BusState *bus, Error **errp) { MachineState *machine; MachineClass *mc; Object *m_obj = qdev_get_machine(); + if (!qdev_hotplug_unplug_allowed_common(dev, bus, errp)) { + return false; + } + if (object_dynamic_cast(m_obj, TYPE_MACHINE)) { machine = MACHINE(m_obj); mc = MACHINE_GET_CLASS(machine); @@ -47,6 +81,12 @@ bool qdev_hotplug_allowed(DeviceState *dev, Error **errp) return true; } +bool qdev_hotunplug_allowed(DeviceState *dev, Error **errp) +{ + return !qdev_unplug_blocked(dev, errp) && + qdev_hotplug_unplug_allowed_common(dev, dev->parent_bus, errp); +} + HotplugHandler *qdev_get_bus_hotplug_handler(DeviceState *dev) { if (dev->parent_bus) { diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c index c844f5380255..30f28eb8e4ae 100644 --- a/system/qdev-monitor.c +++ b/system/qdev-monitor.c @@ -263,8 +263,7 @@ static DeviceClass *qdev_get_device_class(const char **driver, Error **errp) } dc = DEVICE_CLASS(oc); - if (!dc->user_creatable || - (phase_check(PHASE_MACHINE_READY) && !dc->hotpluggable)) { + if (!dc->user_creatable) { error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "driver", "a pluggable device type"); return NULL; @@ -675,11 +674,6 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts, return NULL; } - if (phase_check(PHASE_MACHINE_READY) && bus && !qbus_is_hotpluggable(bus)) { - error_setg(errp, "Bus '%s' does not support hotplugging", bus->name); - return NULL; - } - if (migration_is_running()) { error_setg(errp, "device_add not allowed while migrating"); return NULL; @@ -689,17 +683,9 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts, dev = qdev_new(driver); /* Check whether the hotplug is allowed by the machine */ - if (phase_check(PHASE_MACHINE_READY)) { - if (!qdev_hotplug_allowed(dev, errp)) { - goto err_del_dev; - } - - if (!bus && !qdev_get_machine_hotplug_handler(dev)) { - /* No bus, no machine hotplug handler --> device is not hotpluggable */ - error_setg(errp, "Device '%s' can not be hotplugged on this machine", - driver); - goto err_del_dev; - } + if (phase_check(PHASE_MACHINE_READY) && + !qdev_hotplug_allowed(dev, bus, errp)) { + goto err_del_dev; } /* @@ -902,24 +888,11 @@ static DeviceState *find_device_state(const char *id, bool use_generic_error, void qdev_unplug(DeviceState *dev, Error **errp) { - DeviceClass *dc = DEVICE_GET_CLASS(dev); HotplugHandler *hotplug_ctrl; HotplugHandlerClass *hdc; Error *local_err = NULL; - if (qdev_unplug_blocked(dev, errp)) { - return; - } - - if (dev->parent_bus && !qbus_is_hotpluggable(dev->parent_bus)) { - error_setg(errp, "Bus '%s' does not support hotplugging", - dev->parent_bus->name); - return; - } - - if (!dc->hotpluggable) { - error_setg(errp, "Device '%s' does not support hotplugging", - object_get_typename(OBJECT(dev))); + if (!qdev_hotunplug_allowed(dev, errp)) { return; }