From 03fcbd9dc5084ff4676c153fbe04fb0fcf939d09 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 2 Nov 2017 11:10:06 +0100 Subject: [PATCH] qdev: Check for the availability of a hotplug controller before adding a device 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. This could be provoked for a couple of devices in the past (see commit 4c93950659487c7ad or 84ebd3e8c7d4fe955 for example), and can currently for example also be triggered like this: $ s390x-softmmu/qemu-system-s390x -M none -nographic QEMU 2.10.50 monitor - type 'help' for more information (qemu) device_add qemu-s390x-cpu,id=x (qemu) device_del x ** ERROR:qemu/qdev-monitor.c:872:qdev_unplug: assertion failed: (hotplug_ctrl) Aborted (core dumped) So devices clearly need a hotplug controller when they should be usable with device_add. 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, there 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. Reviewed-by: Igor Mammedov Signed-off-by: Thomas Huth Message-Id: <1509617407-21191-3-git-send-email-thuth@redhat.com> Reviewed-by: Cornelia Huck Signed-off-by: Eduardo Habkost --- hw/core/qdev.c | 28 ++++++++++++++++++++-------- include/hw/qdev-core.h | 1 + qdev-monitor.c | 5 +++++ 3 files changed, 26 insertions(+), 8 deletions(-) diff --git a/hw/core/qdev.c b/hw/core/qdev.c index 11112951a5..f739753e3a 100644 --- a/hw/core/qdev.c +++ b/hw/core/qdev.c @@ -253,19 +253,31 @@ void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id, dev->alias_required_for_version = required_for_version; } +HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev) +{ + MachineState *machine; + MachineClass *mc; + Object *m_obj = qdev_get_machine(); + + if (object_dynamic_cast(m_obj, TYPE_MACHINE)) { + machine = MACHINE(m_obj); + mc = MACHINE_GET_CLASS(machine); + if (mc->get_hotplug_handler) { + return mc->get_hotplug_handler(machine, dev); + } + } + + return NULL; +} + HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev) { - HotplugHandler *hotplug_ctrl = NULL; + HotplugHandler *hotplug_ctrl; if (dev->parent_bus && dev->parent_bus->hotplug_handler) { hotplug_ctrl = dev->parent_bus->hotplug_handler; - } else if (object_dynamic_cast(qdev_get_machine(), TYPE_MACHINE)) { - MachineState *machine = MACHINE(qdev_get_machine()); - MachineClass *mc = MACHINE_GET_CLASS(machine); - - if (mc->get_hotplug_handler) { - hotplug_ctrl = mc->get_hotplug_handler(machine, dev); - } + } else { + hotplug_ctrl = qdev_get_machine_hotplug_handler(dev); } return hotplug_ctrl; } diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index 0a71bf83f0..51473eee7b 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -286,6 +286,7 @@ DeviceState *qdev_try_create(BusState *bus, const char *name); void qdev_init_nofail(DeviceState *dev); void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id, int required_for_version); +HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev); HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev); void qdev_unplug(DeviceState *dev, Error **errp); void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev, diff --git a/qdev-monitor.c b/qdev-monitor.c index 2abb80d7e4..c436616446 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -613,6 +613,11 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) if (bus) { qdev_set_parent_bus(dev, bus); + } else if (qdev_hotplug && !qdev_get_machine_hotplug_handler(dev)) { + /* No bus, no machine hotplug handler --> device is not hotpluggable */ + error_setg(&err, "Device '%s' can not be hotplugged on this machine", + driver); + goto err_del_dev; } qdev_set_id(dev, qemu_opts_id(opts));