Re: [Qemu-devel] [PATCH v5 1/2] Add device listener interface

["Andreas Färber" <afaerber@suse.de>]

Am 09.12.2014 um 18:40 schrieb Paolo Bonzini:
> On 08/12/2014 12:12, Paul Durrant wrote:
>>> -----Original Message-----
>>> From: Paolo Bonzini [mailto:pbonzini@redhat.com]
>>> Sent: 05 December 2014 11:45
>>> To: Paul Durrant; qemu-devel@nongnu.org
>>> Cc: Michael S. Tsirkin; Andreas Faerber"; Peter Crosthwaite; Igor
>>> Mammedov; Markus Armbruster; Thomas Huth; Christian Borntraeger
>>> Subject: Re: [PATCH v5 1/2] Add device listener interface
>>>
>>>
>>>
>>> On 05/12/2014 11:50, Paul Durrant wrote:
>>>> The Xen ioreq-server API, introduced in Xen 4.5, requires that PCI device
>>>> models explicitly register with Xen for config space accesses. This patch
>>>> adds a listener interface into qdev-core which can be used by the Xen
>>>> interface code to monitor for arrival and departure of PCI devices.
>>>>
>>>> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
>>>> Cc: Michael S. Tsirkin <mst@redhat.com>
>>>> Cc: Andreas Faerber" <afaerber@suse.de>
>>>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>>>> Cc: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>>>> Cc: Igor Mammedov <imammedo@redhat.com>
>>>> Cc: Markus Armbruster <armbru@redhat.com>
>>>> Cc: Thomas Huth <thuth@linux.vnet.ibm.com>
>>>> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
>>>> ---
>>>>  hw/core/qdev.c          |   53
>>> +++++++++++++++++++++++++++++++++++++++++++++++
>>>>  include/hw/qdev-core.h  |   10 +++++++++
>>>>  include/qemu/typedefs.h |    1 +
>>>>  3 files changed, 64 insertions(+)
>>>>
>>>> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
>>>> index 35fd00d..76ff9ef 100644
>>>> --- a/hw/core/qdev.c
>>>> +++ b/hw/core/qdev.c
>>>> @@ -189,6 +189,56 @@ int qdev_init(DeviceState *dev)
>>>>      return 0;
>>>>  }
>>>>
>>>> +static QTAILQ_HEAD(device_listeners, DeviceListener) device_listeners
>>>> +    = QTAILQ_HEAD_INITIALIZER(device_listeners);
>>>> +
>>>> +enum ListenerDirection { Forward, Reverse };
>>>> +
>>>> +#define DEVICE_LISTENER_CALL(_callback, _direction, _args...)     \
>>>> +    do {                                                          \
>>>> +        DeviceListener *_listener;                                \
>>>> +                                                                  \
>>>> +        switch (_direction) {                                     \
>>>> +        case Forward:                                             \
>>>> +            QTAILQ_FOREACH(_listener, &device_listeners, link) {  \
>>>> +                if (_listener->_callback) {                       \
>>>> +                    _listener->_callback(_listener, ##_args);     \
>>>> +                }                                                 \
>>>> +            }                                                     \
>>>> +            break;                                                \
>>>> +        case Reverse:                                             \
>>>> +            QTAILQ_FOREACH_REVERSE(_listener, &device_listeners,  \
>>>> +                                   device_listeners, link) {      \
>>>> +                if (_listener->_callback) {                       \
>>>> +                    _listener->_callback(_listener, ##_args);     \
>>>> +                }                                                 \
>>>> +            }                                                     \
>>>> +            break;                                                \
>>>> +        default:                                                  \
>>>> +            abort();                                              \
>>>> +        }                                                         \
>>>> +    } while (0)
>>>> +
>>>> +static int device_listener_add(DeviceState *dev, void *opaque)
>>>> +{
>>>> +    DEVICE_LISTENER_CALL(realize, Forward, dev);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +void device_listener_register(DeviceListener *listener)
>>>> +{
>>>> +    QTAILQ_INSERT_TAIL(&device_listeners, listener, link);
>>>> +
>>>> +    qbus_walk_children(sysbus_get_default(), NULL, NULL,
>>> device_listener_add,
>>>> +                       NULL, NULL);
>>>> +}
>>>> +
>>>> +void device_listener_unregister(DeviceListener *listener)
>>>> +{
>>>> +    QTAILQ_REMOVE(&device_listeners, listener, link);
>>>> +}
>>>> +
>>>>  static void device_realize(DeviceState *dev, Error **errp)
>>>>  {
>>>>      DeviceClass *dc = DEVICE_GET_CLASS(dev);
>>>> @@ -994,6 +1044,8 @@ static void device_set_realized(Object *obj, bool
>>> value, Error **errp)
>>>>              goto fail;
>>>>          }
>>>>
>>>> +        DEVICE_LISTENER_CALL(realize, Forward, dev);
>>>> +
>>>>          hotplug_ctrl = qdev_get_hotplug_handler(dev);
>>>>          if (hotplug_ctrl) {
>>>>              hotplug_handler_plug(hotplug_ctrl, dev, &local_err);
>>>> @@ -1035,6 +1087,7 @@ static void device_set_realized(Object *obj, bool
>>> value, Error **errp)
>>>>              dc->unrealize(dev, local_errp);
>>>>          }
>>>>          dev->pending_deleted_event = true;
>>>> +        DEVICE_LISTENER_CALL(unrealize, Reverse, dev);
>>>>      }
>>>>
>>>>      if (local_err != NULL) {
>>>> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
>>>> index 589bbe7..15a226f 100644
>>>> --- a/include/hw/qdev-core.h
>>>> +++ b/include/hw/qdev-core.h
>>>> @@ -165,6 +165,12 @@ struct DeviceState {
>>>>      int alias_required_for_version;
>>>>  };
>>>>
>>>> +struct DeviceListener {
>>>> +    void (*realize)(DeviceListener *listener, DeviceState *dev);
>>>> +    void (*unrealize)(DeviceListener *listener, DeviceState *dev);
>>>> +    QTAILQ_ENTRY(DeviceListener) link;
>>>> +};
>>>> +
>>>>  #define TYPE_BUS "bus"
>>>>  #define BUS(obj) OBJECT_CHECK(BusState, (obj), TYPE_BUS)
>>>>  #define BUS_CLASS(klass) OBJECT_CLASS_CHECK(BusClass, (klass),
>>> TYPE_BUS)
>>>> @@ -376,4 +382,8 @@ static inline bool qbus_is_hotpluggable(BusState
>>> *bus)
>>>>  {
>>>>     return bus->hotplug_handler;
>>>>  }
>>>> +
>>>> +void device_listener_register(DeviceListener *listener);
>>>> +void device_listener_unregister(DeviceListener *listener);
>>>> +
>>>>  #endif
>>>> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>>>> index 3475177..4bb4938 100644
>>>> --- a/include/qemu/typedefs.h
>>>> +++ b/include/qemu/typedefs.h
>>>> @@ -20,6 +20,7 @@ typedef struct Property Property;
>>>>  typedef struct PropertyInfo PropertyInfo;
>>>>  typedef struct CompatProperty CompatProperty;
>>>>  typedef struct DeviceState DeviceState;
>>>> +typedef struct DeviceListener DeviceListener;
>>>>  typedef struct BusState BusState;
>>>>  typedef struct BusClass BusClass;
>>>>
>>>>
>>>
>>> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
>>>
>>
>> Great. Thanks for that. All I need now is an ack on this from a maintainer.
> 
> I think my reviewed-by is pretty close to an Ack.
> 
> Stefano, feel free to pick this patch up together with 2/2.

In that case,

Reviewed-by: Andreas Färber <afaerber@suse.de>

If I should still pick it up, just let me know.

Regards,
Andreas

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