From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40511) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dzhz7-00074l-MV for qemu-devel@nongnu.org; Wed, 04 Oct 2017 07:37:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dzhz6-0002KN-4W for qemu-devel@nongnu.org; Wed, 04 Oct 2017 07:37:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56418) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dzhz5-0002Jq-RB for qemu-devel@nongnu.org; Wed, 04 Oct 2017 07:37:04 -0400 Date: Wed, 4 Oct 2017 13:36:59 +0200 From: Igor Mammedov Message-ID: <20171004133659.1f656303@nial.brq.redhat.com> In-Reply-To: <1507049162-27026-1-git-send-email-thuth@redhat.com> References: <1507049162-27026-1-git-send-email-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] qdev: Check for the availability of a hotplug controller before adding a device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: qemu-devel@nongnu.org, Eduardo Habkost , Paolo Bonzini , Markus Armbruster , "Dr. David Alan Gilbert" , Peter Maydell On Tue, 3 Oct 2017 18:46:02 +0200 Thomas Huth wrote: > 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). So devices clearly need a hotplug > controller when they are suitable for 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. 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. > > Signed-off-by: Thomas Huth > --- > This is the follow-up patch from my earlier try "hw/core/qdev: Do not > allow hot-plugging without hotplug controller" ... AFAICS the function > qdev_device_add() is now the right spot to do the check. > > hw/core/qdev.c | 28 ++++++++++++++++++++-------- > include/hw/qdev-core.h | 1 + > qdev-monitor.c | 9 +++++++++ > 3 files changed, 30 insertions(+), 8 deletions(-) > > diff --git a/hw/core/qdev.c b/hw/core/qdev.c > index 606ab53..a953ec9 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 0891461..5aa536d 100644 > --- a/include/hw/qdev-core.h > +++ b/include/hw/qdev-core.h > @@ -285,6 +285,7 @@ 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 8fd6df9..2891dde 100644 > --- a/qdev-monitor.c > +++ b/qdev-monitor.c > @@ -626,6 +626,15 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) > return NULL; > } > > + /* In case we don't have a bus, there must be a machine hotplug handler */ > + if (qdev_hotplug && !bus && !qdev_get_machine_hotplug_handler(dev)) { current machine hotplug handler serves both cold and hot-plug so in reality it's just 'plug' handler. Is there a point -device/device_add devices on board that doesn't have 'hotplug' handler that would wire device up properly? Do we have such devices? > + error_setg(errp, "Device '%s' can not be hotplugged on this machine", > + driver); > + object_unparent(OBJECT(dev)); > + object_unref(OBJECT(dev)); > + return NULL; > + } > + > dev->opts = opts; > object_property_set_bool(OBJECT(dev), true, "realized", &err); > if (err != NULL) {