xen: introduce new 'XenBus' and 'XenDevice' object hierarchy

This patch adds the basic boilerplate for a 'XenBus' object that will act
as a parent to 'XenDevice' PV backends.
A new 'XenBridge' object is also added to connect XenBus to the system bus.

The XenBus object is instantiated by a new xen_bus_init() function called
from the same sites as the legacy xen_be_init() function.

Subsequent patches will flesh-out the functionality of these objects.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony Perard <anthony.perard@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

3 files changed, 134 insertions, 1 deletions

diff --git a/hw/xen/Makefile.objs b/hw/xen/Makefile.objs
index 3f64a44051..d9d6d7b4f9 100644
--- a/hw/xen/Makefile.objs
+++ b/hw/xen/Makefile.objs
@@ -1,5 +1,5 @@
 # xen backend driver support
-common-obj-$(CONFIG_XEN) += xen-legacy-backend.o xen_devconfig.o xen_pvdev.o xen-common.o
+common-obj-$(CONFIG_XEN) += xen-legacy-backend.o xen_devconfig.o xen_pvdev.o xen-common.o xen-bus.o
 
 obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen-host-pci-device.o
 obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pt.o xen_pt_config_init.o xen_pt_graphics.o xen_pt_msi.o
diff --git a/hw/xen/trace-events b/hw/xen/trace-events
index c7e7a3b523..0172cd4e26 100644
--- a/hw/xen/trace-events
+++ b/hw/xen/trace-events
@@ -12,3 +12,9 @@ xen_unmap_portio_range(uint32_t id, uint64_t start_addr, uint64_t end_addr) "id:
 xen_map_pcidev(uint32_t id, uint8_t bus, uint8_t dev, uint8_t func) "id: %u bdf: %02x.%02x.%02x"
 xen_unmap_pcidev(uint32_t id, uint8_t bus, uint8_t dev, uint8_t func) "id: %u bdf: %02x.%02x.%02x"
 xen_domid_restrict(int err) "err: %u"
+
+# include/hw/xen/xen-bus.c
+xen_bus_realize(void) ""
+xen_bus_unrealize(void) ""
+xen_device_realize(const char *type) "type: %s"
+xen_device_unrealize(const char *type) "type: %s"
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
new file mode 100644
index 0000000000..bc04da748b
--- /dev/null
+++ b/hw/xen/xen-bus.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2018  Citrix Systems Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "hw/xen/xen-bus.h"
+#include "qapi/error.h"
+#include "trace.h"
+
+static void xen_bus_unrealize(BusState *bus, Error **errp)
+{
+    trace_xen_bus_unrealize();
+}
+
+static void xen_bus_realize(BusState *bus, Error **errp)
+{
+    trace_xen_bus_realize();
+}
+
+static void xen_bus_class_init(ObjectClass *class, void *data)
+{
+    BusClass *bus_class = BUS_CLASS(class);
+
+    bus_class->realize = xen_bus_realize;
+    bus_class->unrealize = xen_bus_unrealize;
+}
+
+static const TypeInfo xen_bus_type_info = {
+    .name = TYPE_XEN_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(XenBus),
+    .class_size = sizeof(XenBusClass),
+    .class_init = xen_bus_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_HOTPLUG_HANDLER },
+        { }
+    },
+};
+
+static void xen_device_unrealize(DeviceState *dev, Error **errp)
+{
+    XenDevice *xendev = XEN_DEVICE(dev);
+    XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
+    const char *type = object_get_typename(OBJECT(xendev));
+
+    trace_xen_device_unrealize(type);
+
+    if (xendev_class->unrealize) {
+        xendev_class->unrealize(xendev, errp);
+    }
+}
+
+static void xen_device_realize(DeviceState *dev, Error **errp)
+{
+    XenDevice *xendev = XEN_DEVICE(dev);
+    XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
+    const char *type = object_get_typename(OBJECT(xendev));
+    Error *local_err = NULL;
+
+    trace_xen_device_realize(type);
+
+    if (xendev_class->realize) {
+        xendev_class->realize(xendev, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            goto unrealize;
+        }
+    }
+
+    return;
+
+unrealize:
+    xen_device_unrealize(dev, &error_abort);
+}
+
+static void xen_device_class_init(ObjectClass *class, void *data)
+{
+    DeviceClass *dev_class = DEVICE_CLASS(class);
+
+    dev_class->realize = xen_device_realize;
+    dev_class->unrealize = xen_device_unrealize;
+    dev_class->bus_type = TYPE_XEN_BUS;
+}
+
+static const TypeInfo xen_device_type_info = {
+    .name = TYPE_XEN_DEVICE,
+    .parent = TYPE_DEVICE,
+    .instance_size = sizeof(XenDevice),
+    .abstract = true,
+    .class_size = sizeof(XenDeviceClass),
+    .class_init = xen_device_class_init,
+};
+
+typedef struct XenBridge {
+    SysBusDevice busdev;
+} XenBridge;
+
+#define TYPE_XEN_BRIDGE "xen-bridge"
+
+static const TypeInfo xen_bridge_type_info = {
+    .name = TYPE_XEN_BRIDGE,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(XenBridge),
+};
+
+static void xen_register_types(void)
+{
+    type_register_static(&xen_bridge_type_info);
+    type_register_static(&xen_bus_type_info);
+    type_register_static(&xen_device_type_info);
+}
+
+type_init(xen_register_types)
+
+void xen_bus_init(void)
+{
+    DeviceState *dev = qdev_create(NULL, TYPE_XEN_BRIDGE);
+    BusState *bus = qbus_create(TYPE_XEN_BUS, dev, NULL);
+
+    qdev_init_nofail(dev);
+    qbus_set_bus_hotplug_handler(bus, &error_abort);
+}