* [Qemu-devel] [PATCH v2 0/2] Check for the availability of a hotplug controller before adding a device
@ 2017-10-05 12:32 Thomas Huth
2017-10-05 12:32 ` [Qemu-devel] [PATCH 1/2] qdev_monitor: Simplify error handling in qdev_device_add() Thomas Huth
2017-10-05 12:32 ` [Qemu-devel] [PATCH v2 2/2] qdev: Check for the availability of a hotplug controller before adding a device Thomas Huth
0 siblings, 2 replies; 6+ messages in thread
From: Thomas Huth @ 2017-10-05 12:32 UTC (permalink / raw)
To: qemu-devel, Eduardo Habkost
Cc: Markus Armbruster, Dr. David Alan Gilbert, Igor Mammedov,
Paolo Bonzini
First patch is a small clean up to the error handling code in
qdev_device_add(), and the second patch adds a proper check for
the availability of a hotplug controller to prevent the possibility
of a crash with device_del.
Thomas Huth (2):
qdev_monitor: Simplify error handling in qdev_device_add()
qdev: Check for the availability of a hotplug controller before adding
a device
hw/core/qdev.c | 28 ++++++++++++++++++++--------
include/hw/qdev-core.h | 1 +
qdev-monitor.c | 26 +++++++++++++++-----------
3 files changed, 36 insertions(+), 19 deletions(-)
--
1.8.3.1
^ permalink raw reply [flat|nested] 6+ messages in thread* [Qemu-devel] [PATCH 1/2] qdev_monitor: Simplify error handling in qdev_device_add() 2017-10-05 12:32 [Qemu-devel] [PATCH v2 0/2] Check for the availability of a hotplug controller before adding a device Thomas Huth @ 2017-10-05 12:32 ` Thomas Huth 2017-10-05 13:59 ` Igor Mammedov 2017-10-05 12:32 ` [Qemu-devel] [PATCH v2 2/2] qdev: Check for the availability of a hotplug controller before adding a device Thomas Huth 1 sibling, 1 reply; 6+ messages in thread From: Thomas Huth @ 2017-10-05 12:32 UTC (permalink / raw) To: qemu-devel, Eduardo Habkost Cc: Markus Armbruster, Dr. David Alan Gilbert, Igor Mammedov, Paolo Bonzini Instead of doing the clean-ups on errors multiple times, introduce a jump label at the end of the function that can be used by all error paths that need this cleanup. Suggested-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com> --- qdev-monitor.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/qdev-monitor.c b/qdev-monitor.c index 8fd6df9..cb2b109 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -620,22 +620,21 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) /* set properties */ if (qemu_opt_foreach(opts, set_property, dev, &err)) { - error_propagate(errp, err); - object_unparent(OBJECT(dev)); - object_unref(OBJECT(dev)); - return NULL; + goto err_del_dev; } dev->opts = opts; object_property_set_bool(OBJECT(dev), true, "realized", &err); - if (err != NULL) { - error_propagate(errp, err); - dev->opts = NULL; - object_unparent(OBJECT(dev)); - object_unref(OBJECT(dev)); - return NULL; + if (!err) { + return dev; } - return dev; + dev->opts = NULL; + +err_del_dev: + error_propagate(errp, err); + object_unparent(OBJECT(dev)); + object_unref(OBJECT(dev)); + return NULL; } -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH 1/2] qdev_monitor: Simplify error handling in qdev_device_add() 2017-10-05 12:32 ` [Qemu-devel] [PATCH 1/2] qdev_monitor: Simplify error handling in qdev_device_add() Thomas Huth @ 2017-10-05 13:59 ` Igor Mammedov 2017-10-05 17:11 ` Eduardo Habkost 0 siblings, 1 reply; 6+ messages in thread From: Igor Mammedov @ 2017-10-05 13:59 UTC (permalink / raw) To: Thomas Huth Cc: qemu-devel, Eduardo Habkost, Markus Armbruster, Dr. David Alan Gilbert, Paolo Bonzini On Thu, 5 Oct 2017 14:32:17 +0200 Thomas Huth <thuth@redhat.com> wrote: > Instead of doing the clean-ups on errors multiple times, introduce > a jump label at the end of the function that can be used by all > error paths that need this cleanup. > > Suggested-by: Igor Mammedov <imammedo@redhat.com> > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > qdev-monitor.c | 21 ++++++++++----------- > 1 file changed, 10 insertions(+), 11 deletions(-) > > diff --git a/qdev-monitor.c b/qdev-monitor.c > index 8fd6df9..cb2b109 100644 > --- a/qdev-monitor.c > +++ b/qdev-monitor.c > @@ -620,22 +620,21 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) > > /* set properties */ > if (qemu_opt_foreach(opts, set_property, dev, &err)) { > - error_propagate(errp, err); > - object_unparent(OBJECT(dev)); > - object_unref(OBJECT(dev)); > - return NULL; > + goto err_del_dev; > } > > dev->opts = opts; > object_property_set_bool(OBJECT(dev), true, "realized", &err); > - if (err != NULL) { > - error_propagate(errp, err); > - dev->opts = NULL; > - object_unparent(OBJECT(dev)); > - object_unref(OBJECT(dev)); > - return NULL; > + if (!err) { > + return dev; > } typically the same error check pattern is used through out the function so I'd not do inversion here. i.e. keep normal flow non-branched and jump on error if (err != NULL) { goto err_del_dev; } return dev; err_del_dev: dev->opts = NULL; > - return dev; > + dev->opts = NULL; > + > +err_del_dev: > + error_propagate(errp, err); > + object_unparent(OBJECT(dev)); > + object_unref(OBJECT(dev)); > + return NULL; > } > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH 1/2] qdev_monitor: Simplify error handling in qdev_device_add() 2017-10-05 13:59 ` Igor Mammedov @ 2017-10-05 17:11 ` Eduardo Habkost 0 siblings, 0 replies; 6+ messages in thread From: Eduardo Habkost @ 2017-10-05 17:11 UTC (permalink / raw) To: Igor Mammedov Cc: Thomas Huth, qemu-devel, Markus Armbruster, Dr. David Alan Gilbert, Paolo Bonzini On Thu, Oct 05, 2017 at 03:59:12PM +0200, Igor Mammedov wrote: > On Thu, 5 Oct 2017 14:32:17 +0200 > Thomas Huth <thuth@redhat.com> wrote: > > > Instead of doing the clean-ups on errors multiple times, introduce > > a jump label at the end of the function that can be used by all > > error paths that need this cleanup. > > > > Suggested-by: Igor Mammedov <imammedo@redhat.com> > > Signed-off-by: Thomas Huth <thuth@redhat.com> > > --- > > qdev-monitor.c | 21 ++++++++++----------- > > 1 file changed, 10 insertions(+), 11 deletions(-) > > > > diff --git a/qdev-monitor.c b/qdev-monitor.c > > index 8fd6df9..cb2b109 100644 > > --- a/qdev-monitor.c > > +++ b/qdev-monitor.c > > @@ -620,22 +620,21 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) > > > > /* set properties */ > > if (qemu_opt_foreach(opts, set_property, dev, &err)) { > > - error_propagate(errp, err); > > - object_unparent(OBJECT(dev)); > > - object_unref(OBJECT(dev)); > > - return NULL; > > + goto err_del_dev; > > } > > > > dev->opts = opts; > > object_property_set_bool(OBJECT(dev), true, "realized", &err); > > - if (err != NULL) { > > - error_propagate(errp, err); > > - dev->opts = NULL; > > - object_unparent(OBJECT(dev)); > > - object_unref(OBJECT(dev)); > > - return NULL; > > + if (!err) { > > + return dev; > > } > typically the same error check pattern is used through out the function > so I'd not do inversion here. i.e. keep normal flow non-branched and jump on error > > if (err != NULL) { > goto err_del_dev; > } > return dev; > > err_del_dev: > dev->opts = NULL; I prefer this pattern also. It makes the success/error paths very easy to spot. -- Eduardo ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Qemu-devel] [PATCH v2 2/2] qdev: Check for the availability of a hotplug controller before adding a device 2017-10-05 12:32 [Qemu-devel] [PATCH v2 0/2] Check for the availability of a hotplug controller before adding a device Thomas Huth 2017-10-05 12:32 ` [Qemu-devel] [PATCH 1/2] qdev_monitor: Simplify error handling in qdev_device_add() Thomas Huth @ 2017-10-05 12:32 ` Thomas Huth 2017-10-05 14:13 ` Igor Mammedov 1 sibling, 1 reply; 6+ messages in thread From: Thomas Huth @ 2017-10-05 12:32 UTC (permalink / raw) To: qemu-devel, Eduardo Habkost Cc: Markus Armbruster, Dr. David Alan Gilbert, Igor Mammedov, Paolo Bonzini 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 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. Signed-off-by: Thomas Huth <thuth@redhat.com> --- v2: - Do the check earlier in qdev_device_add - Use common new err_dev_del handler in case of failure 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 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 cb2b109..f93455f 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -614,6 +614,11 @@ 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)); -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH v2 2/2] qdev: Check for the availability of a hotplug controller before adding a device 2017-10-05 12:32 ` [Qemu-devel] [PATCH v2 2/2] qdev: Check for the availability of a hotplug controller before adding a device Thomas Huth @ 2017-10-05 14:13 ` Igor Mammedov 0 siblings, 0 replies; 6+ messages in thread From: Igor Mammedov @ 2017-10-05 14:13 UTC (permalink / raw) To: Thomas Huth Cc: qemu-devel, Eduardo Habkost, Markus Armbruster, Dr. David Alan Gilbert, Paolo Bonzini On Thu, 5 Oct 2017 14:32:18 +0200 Thomas Huth <thuth@redhat.com> 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 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. > > Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Igor Mammedov <imammedo@redhat.com> > --- > v2: > - Do the check earlier in qdev_device_add > - Use common new err_dev_del handler in case of failure > > 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 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 cb2b109..f93455f 100644 > --- a/qdev-monitor.c > +++ b/qdev-monitor.c > @@ -614,6 +614,11 @@ 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)); ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-10-05 17:12 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2017-10-05 12:32 [Qemu-devel] [PATCH v2 0/2] Check for the availability of a hotplug controller before adding a device Thomas Huth 2017-10-05 12:32 ` [Qemu-devel] [PATCH 1/2] qdev_monitor: Simplify error handling in qdev_device_add() Thomas Huth 2017-10-05 13:59 ` Igor Mammedov 2017-10-05 17:11 ` Eduardo Habkost 2017-10-05 12:32 ` [Qemu-devel] [PATCH v2 2/2] qdev: Check for the availability of a hotplug controller before adding a device Thomas Huth 2017-10-05 14:13 ` Igor Mammedov
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