[V3,2/7] virtio-bus: introduce virtio-bus

diff --git a/hw/Makefile.objs b/hw/Makefile.objs
index 74b07a7..23ac249 100644
--- a/hw/Makefile.objs
+++ b/hw/Makefile.objs
@@ -8,6 +8,7 @@  common-obj-y += loader.o
 common-obj-$(CONFIG_VIRTIO) += virtio-console.o
 common-obj-$(CONFIG_VIRTIO) += virtio-rng.o
 common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
+common-obj-$(CONFIG_VIRTIO) += virtio-bus.o
 common-obj-y += fw_cfg.o
 common-obj-$(CONFIG_PCI) += pci_bridge_dev.o
 common-obj-$(CONFIG_PCI) += ioh3420.o xio3130_upstream.o xio3130_downstream.o
diff --git a/hw/virtio-bus.c b/hw/virtio-bus.c
new file mode 100644
index 0000000..b8f656e
--- /dev/null
+++ b/hw/virtio-bus.c
@@ -0,0 +1,129 @@ 
+/*
+ * VirtioBus
+ *
+ *  Copyright (C) 2012 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Developed by :
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "hw.h"
+#include "qemu/error-report.h"
+#include "qdev.h"
+#include "virtio-bus.h"
+#include "virtio.h"
+
+/* #define DEBUG_VIRTIO_BUS */
+
+#ifdef DEBUG_VIRTIO_BUS
+#define DPRINTF(fmt, ...) \
+do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) do { } while (0)
+#endif
+
+/* Plug the VirtIODevice */
+int virtio_bus_plug_device(VirtIODevice *vdev)
+{
+    DeviceState *qdev = DEVICE(vdev);
+    BusState *qbus = BUS(qdev_get_parent_bus(qdev));
+    VirtioBusState *bus = VIRTIO_BUS(qbus);
+    VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
+    DPRINTF("%s: plug device.\n", qbus->name);
+
+    bus->vdev = vdev;
+
+    /*
+     * The lines below will disappear when we drop VirtIOBindings, at the end
+     * of the series.
+     */
+    bus->bindings.notify = klass->notify;
+    bus->bindings.save_config = klass->save_config;
+    bus->bindings.save_queue = klass->save_queue;
+    bus->bindings.load_config = klass->load_config;
+    bus->bindings.load_queue = klass->load_queue;
+    bus->bindings.load_done = klass->load_done;
+    bus->bindings.get_features = klass->get_features;
+    bus->bindings.query_guest_notifiers = klass->query_guest_notifiers;
+    bus->bindings.set_guest_notifiers = klass->set_guest_notifiers;
+    bus->bindings.set_host_notifier = klass->set_host_notifier;
+    bus->bindings.vmstate_change = klass->vmstate_change;
+    virtio_bind_device(bus->vdev, &bus->bindings, qbus->parent);
+
+    if (klass->device_plugged != NULL) {
+        klass->device_plugged(qbus->parent);
+    }
+
+    return 0;
+}
+
+/* Reset the virtio_bus */
+void virtio_bus_reset(VirtioBusState *bus)
+{
+    DPRINTF("%s: reset device.\n", qbus->name);
+    if (bus->vdev != NULL) {
+        virtio_reset(bus->vdev);
+    }
+}
+
+/* Destroy the VirtIODevice */
+void virtio_bus_destroy_device(VirtioBusState *bus)
+{
+    DeviceState *qdev;
+    BusState *qbus = BUS(bus);
+    VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
+    DPRINTF("%s: remove device.\n", qbus->name);
+
+    if (bus->vdev != NULL) {
+        if (klass->device_unplug != NULL) {
+            klass->device_unplug(qbus->parent);
+        }
+        qdev = DEVICE(bus->vdev);
+        qdev_free(qdev);
+        bus->vdev = NULL;
+    }
+}
+
+/* Get the device id of the plugged device. */
+uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
+{
+    assert(bus->vdev != NULL);
+    return bus->vdev->device_id;
+}
+
+/* Get the config_len field of the plugged device. */
+size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
+{
+    assert(bus->vdev != NULL);
+    return bus->vdev->config_len;
+}
+
+static const TypeInfo virtio_bus_info = {
+    .name = TYPE_VIRTIO_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(VirtioBusState),
+    .abstract = true,
+    .class_size = sizeof(VirtioBusClass),
+};
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_bus_info);
+}
+
+type_init(virtio_register_types)
diff --git a/hw/virtio-bus.h b/hw/virtio-bus.h
new file mode 100644
index 0000000..f378897
--- /dev/null
+++ b/hw/virtio-bus.h
@@ -0,0 +1,87 @@ 
+/*
+ * VirtioBus
+ *
+ *  Copyright (C) 2012 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Developed by :
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef VIRTIO_BUS_H
+#define VIRTIO_BUS_H
+
+#include "qdev.h"
+#include "sysemu/sysemu.h"
+#include "virtio.h"
+
+#define TYPE_VIRTIO_BUS "virtio-bus"
+#define VIRTIO_BUS_GET_CLASS(obj) \
+        OBJECT_GET_CLASS(VirtioBusClass, obj, TYPE_VIRTIO_BUS)
+#define VIRTIO_BUS_CLASS(klass) \
+        OBJECT_CLASS_CHECK(VirtioBusClass, klass, TYPE_VIRTIO_BUS)
+#define VIRTIO_BUS(obj) OBJECT_CHECK(VirtioBusState, (obj), TYPE_VIRTIO_BUS)
+
+typedef struct VirtioBusState VirtioBusState;
+
+typedef struct VirtioBusClass {
+    /* This is what a VirtioBus must implement */
+    BusClass parent;
+    void (*notify)(DeviceState *d, uint16_t vector);
+    void (*save_config)(DeviceState *d, QEMUFile *f);
+    void (*save_queue)(DeviceState *d, int n, QEMUFile *f);
+    int (*load_config)(DeviceState *d, QEMUFile *f);
+    int (*load_queue)(DeviceState *d, int n, QEMUFile *f);
+    int (*load_done)(DeviceState *d, QEMUFile *f);
+    unsigned (*get_features)(DeviceState *d);
+    bool (*query_guest_notifiers)(DeviceState *d);
+    int (*set_guest_notifiers)(DeviceState *d, int nvqs, bool assign);
+    int (*set_host_notifier)(DeviceState *d, int n, bool assigned);
+    void (*vmstate_change)(DeviceState *d, bool running);
+    /*
+     * transport independent init function.
+     * This is called by virtio-bus just after the device is plugged.
+     */
+    void (*device_plugged)(DeviceState *d);
+    /*
+     * transport independent exit function.
+     * This is called by virtio-bus just before the device is unplugged.
+     */
+    void (*device_unplug)(DeviceState *d);
+} VirtioBusClass;
+
+struct VirtioBusState {
+    BusState parent_obj;
+    /*
+     * Only one VirtIODevice can be plugged on the bus.
+     */
+    VirtIODevice *vdev;
+    /*
+     * This will be removed at the end of the series.
+     */
+    VirtIOBindings bindings;
+};
+
+int virtio_bus_plug_device(VirtIODevice *vdev);
+void virtio_bus_reset(VirtioBusState *bus);
+void virtio_bus_destroy_device(VirtioBusState *bus);
+/* Get the device id of the plugged device. */
+uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus);
+/* Get the config_len field of the plugged device. */
+size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus);
+
+#endif /* VIRTIO_BUS_H */