[Qemu-devel] [RFC v4 06/13] qdev core: generic enumerate_slots implementation

[Eduardo Habkost <ehabkost@redhat.com>]

Implement a generic enumerate_slots method on TYPE_BUS
The generic implementation will just report a opts-complete=false
entry, listing the "bus" option.  This will let clients know that
the bus is available, but that detailed slot information is not
available by the running QEMU version.

We disable the implementation on TYPE_SYS_BUS as sysbus is an
exceptional case where only a handful of device types are
actually user-creatable.  This will be handled later by
sysbus-specific slot enumeration code.

TODO: write sysbus-specific slot enumeration code, based on
sysbus device whitelist.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 hw/core/bus.c    | 42 ++++++++++++++++++++++++++++++++++++++++++
 hw/core/sysbus.c |  7 +++++++
 2 files changed, 49 insertions(+)

diff --git a/hw/core/bus.c b/hw/core/bus.c
index 4651f24..227c092 100644
--- a/hw/core/bus.c
+++ b/hw/core/bus.c
@@ -20,6 +20,7 @@
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "hw/qdev.h"
+#include "hw/qdev-slotinfo.h"
 #include "qapi/error.h"
 
 static void qbus_set_hotplug_handler_internal(BusState *bus, Object *handler,
@@ -208,12 +209,53 @@ static char *default_bus_get_fw_dev_path(DeviceState *dev)
     return g_strdup(object_get_typename(OBJECT(dev)));
 }
 
+static void class_check_user_creatable(ObjectClass *oc, void *opaque)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+    bool *r = opaque;
+
+    if (dc->user_creatable) {
+        *r = true;
+    }
+}
+
+static bool bus_class_is_user_pluggable(BusClass *bc)
+{
+    bool r = false;
+
+    object_class_foreach(class_check_user_creatable,
+                         bc->device_type, false, &r);
+    return r;
+}
+
+static DeviceSlotInfoList *bus_generic_enumerate_slots(BusState *bus)
+{
+    DeviceSlotInfoList *r = NULL;
+    BusChild *kid = NULL;
+
+    if (!bus_class_is_user_pluggable(BUS_GET_CLASS(bus))) {
+        return NULL;
+    }
+
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceSlotInfo *slot = make_slot(bus);
+        slot->available = false;
+        slot->has_device = true;
+        slot->device = object_get_canonical_path(OBJECT(kid->child));
+        slot_list_add_slot(&r, slot);
+    }
+
+    slot_list_add_slot(&r, make_slot(bus));
+    return r;
+}
+
 static void bus_class_init(ObjectClass *class, void *data)
 {
     BusClass *bc = BUS_CLASS(class);
 
     class->unparent = bus_unparent;
     bc->get_fw_dev_path = default_bus_get_fw_dev_path;
+    bc->enumerate_slots = bus_generic_enumerate_slots;
 }
 
 static void qbus_finalize(Object *obj)
diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index 9259931..06cb4d8 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -77,6 +77,13 @@ static void system_bus_class_init(ObjectClass *klass, void *data)
     k->print_dev = sysbus_dev_print;
     k->get_fw_dev_path = sysbus_get_fw_dev_path;
     k->device_type = TYPE_SYS_BUS_DEVICE;
+    /*
+     * We won't return sysbus devices on query-device-slots by now.
+     *
+     * TODO: return user-creatable whitelisted sybus devices
+     * if the machine supports dynamic sysbus devices.
+     */
+    k->enumerate_slots = NULL;
 }
 
 static const TypeInfo system_bus_info = {
-- 
2.9.4