Re: [Qemu-devel] [PATCH v4 REPOST 1/2] Add device listener interface

[Stefano Stabellini]

The second patch is already Acked.
You just need a review on this one to move forward, right?

Andreas, Michael?

On Wed, 3 Dec 2014, 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 <address@hidden>
> Cc: Michael S. Tsirkin <address@hidden>
> Cc: Andreas Faerber" <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> Cc: Peter Crosthwaite <address@hidden>
> Cc: Igor Mammedov <address@hidden>
> Cc: Markus Armbruster <address@hidden>
> Cc: Thomas Huth <address@hidden>
> Cc: Christian Borntraeger <address@hidden>
> ---
>  hw/core/qdev.c          |   54 
> +++++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/qdev-core.h  |   10 +++++++++
>  include/qemu/typedefs.h |    1 +
>  3 files changed, 65 insertions(+)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index fcb1638..4a9c1f6 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -175,6 +175,56 @@ int qdev_init(DeviceState *dev)
>      return 0;
>  }
>  
> +static QTAILQ_HEAD(qdev_listeners, DeviceListener) qdev_listeners
> +    = QTAILQ_HEAD_INITIALIZER(qdev_listeners);
> +
> +enum ListenerDirection { Forward, Reverse };
> +
> +#define QDEV_LISTENER_CALL(_callback, _direction, _args...)     \
> +    do {                                                        \
> +        DeviceListener *_listener;                              \
> +                                                                \
> +        switch (_direction) {                                   \
> +        case Forward:                                           \
> +            QTAILQ_FOREACH(_listener, &qdev_listeners, link) {  \
> +                if (_listener->_callback) {                     \
> +                    _listener->_callback(_listener, ##_args);   \
> +                }                                               \
> +            }                                                   \
> +            break;                                              \
> +        case Reverse:                                           \
> +            QTAILQ_FOREACH_REVERSE(_listener, &qdev_listeners,  \
> +                                   qdev_listeners, link) {      \
> +                if (_listener->_callback) {                     \
> +                    _listener->_callback(_listener, ##_args);   \
> +                }                                               \
> +            }                                                   \
> +            break;                                              \
> +        default:                                                \
> +            abort();                                            \
> +        }                                                       \
> +    } while (0)
> +
> +static int qdev_listener_add(DeviceState *dev, void *opaque)
> +{
> +    QDEV_LISTENER_CALL(realize, Forward, dev);
> +
> +    return 0;
> +}
> +
> +void qdev_listener_register(DeviceListener *listener)
> +{
> +    QTAILQ_INSERT_TAIL(&qdev_listeners, listener, link);
> +
> +    qbus_walk_children(sysbus_get_default(), NULL, NULL, qdev_listener_add,
> +                       NULL, NULL);
> +}
> +
> +void qdev_listener_unregister(DeviceListener *listener)
> +{
> +    QTAILQ_REMOVE(&qdev_listeners, listener, link);
> +}
> +
>  static void device_realize(DeviceState *dev, Error **errp)
>  {
>      DeviceClass *dc = DEVICE_GET_CLASS(dev);
> @@ -186,12 +236,16 @@ static void device_realize(DeviceState *dev, Error 
> **errp)
>              return;
>          }
>      }
> +
> +    QDEV_LISTENER_CALL(realize, Forward, dev);
>  }
>  
>  static void device_unrealize(DeviceState *dev, Error **errp)
>  {
>      DeviceClass *dc = DEVICE_GET_CLASS(dev);
>  
> +    QDEV_LISTENER_CALL(unrealize, Reverse, dev);
> +
>      if (dc->exit) {
>          int rc = dc->exit(dev);
>          if (rc < 0) {
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index 178fee2..f2dc267 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -167,6 +167,12 @@ 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)
> @@ -368,4 +374,8 @@ static inline void qbus_set_hotplug_handler(BusState 
> *bus, DeviceState *handler,
>                               QDEV_HOTPLUG_HANDLER_PROPERTY, errp);
>      bus->allow_hotplug = 1;
>  }
> +
> +void qdev_listener_register(DeviceListener *listener);
> +void qdev_listener_unregister(DeviceListener *listener);
> +
>  #endif
> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
> index 04df51b..e32bca2 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;
>  
> -- 
> 1.7.10.4
> 
>