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

[Paul Durrant]

> -----Original Message-----
> From: Paolo Bonzini [mailto:address@hidden
> Sent: 03 December 2014 13:56
> To: Michael S. Tsirkin; Stefano Stabellini
> Cc: Paul Durrant; address@hidden; Peter Crosthwaite; Thomas
> Huth; Markus Armbruster; Christian Borntraeger; Igor Mammedov; Andreas
> Faerber
> Subject: Re: [Qemu-devel] [PATCH v4 REPOST 1/2] Add device listener
> interface
> 
> 
> 
> On 03/12/2014 14:40, Michael S. Tsirkin wrote:
> > On Wed, Dec 03, 2014 at 12:29:43PM +0000, Stefano Stabellini wrote:
> >> The second patch is already Acked.
> >> You just need a review on this one to move forward, right?
> >>
> >> Andreas, Michael?
> >
> > Looks like a generic qdev thing, nothing to do with me.
> >
> >> 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);
> 
> These need to be in device_set_realized.  device_realize and
> device_unrealize are just for backwards-compatibility to devices that
> still use init/exit.
> 
> Also, this has to be call to be _after_ unrealization, i.e. after
> setting dev->pending_deleted_event in device_set_realize.
> 

Ok. Thanks. I'll move the calls.

  Paul

> Paolo
> 
> >>>      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
> >>>
> >>>