[Qemu-devel] [PATCH 4/6] sysbus: Make devices spawnable via -device

[Alexander Graf]

Now that we can properly map sysbus devices that haven't been connected to
something forcefully by C code, we can allow the -device command line option
to spawn them.

For machines that don't implement dynamic sysbus assignment in their board
files we add a new property "has-dynamic-sysbus" to the machine object.
Without that property available, we bail out when we see dynamically spawned
sysbus devices, like we did before.

Signed-off-by: Alexander Graf <address@hidden>
---
 hw/core/machine.c   | 41 +++++++++++++++++++++++++++++++++++++++++
 hw/core/sysbus.c    |  7 -------
 include/hw/boards.h |  2 ++
 3 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index cbba679..10f0bb1 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -12,6 +12,9 @@
 
 #include "hw/boards.h"
 #include "qapi/visitor.h"
+#include "hw/sysbus.h"
+#include "sysemu/sysemu.h"
+#include "qemu/error-report.h"
 
 static char *machine_get_accel(Object *obj, Error **errp)
 {
@@ -235,8 +238,42 @@ static void machine_set_firmware(Object *obj, const char 
*value, Error **errp)
     ms->firmware = g_strdup(value);
 }
 
+static int search_for_sysbus_device(Object *obj, void *opaque)
+{
+    if (!object_dynamic_cast(obj, TYPE_SYS_BUS_DEVICE)) {
+        /* Container or different device, traverse it for children */
+        return object_child_foreach(obj, search_for_sysbus_device, opaque);
+    }
+
+    error_report("Device '%s' can not be handled by this machine",
+                 qdev_fw_name(DEVICE(obj)));
+    exit(1);
+}
+
+static void machine_init_notify(Notifier *notifier, void *data)
+{
+    Object *machine = qdev_get_machine();
+    Object *container;
+
+    if (object_property_find(machine, "has-dynamic-sysbus", NULL)) {
+        /* Our machine can handle dynamic sysbus devices, we're all good */
+        return;
+    }
+
+    /*
+     * Loop through all dynamically created devices and check whether there
+     * are sysbus devices among them. If there are, error out.
+     */
+    container = container_get(machine, "/peripheral");
+    search_for_sysbus_device(container, NULL);
+    container = container_get(machine, "/peripheral-anon");
+    search_for_sysbus_device(container, NULL);
+}
+
 static void machine_initfn(Object *obj)
 {
+    MachineState *ms = MACHINE(obj);
+
     object_property_add_str(obj, "accel",
                             machine_get_accel, machine_set_accel, NULL);
     object_property_add_bool(obj, "kernel_irqchip",
@@ -274,6 +311,10 @@ static void machine_initfn(Object *obj)
     object_property_add_bool(obj, "usb", machine_get_usb, machine_set_usb, 
NULL);
     object_property_add_str(obj, "firmware",
                             machine_get_firmware, machine_set_firmware, NULL);
+
+    /* Register notifier when init is done for sysbus sanity checks */
+    ms->sysbus_notifier.notify = machine_init_notify;
+    qemu_add_machine_init_done_notifier(&ms->sysbus_notifier);
 }
 
 static void machine_finalize(Object *obj)
diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index 84cd0cf..5d33bb8 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -326,13 +326,6 @@ static void sysbus_device_class_init(ObjectClass *klass, 
void *data)
     DeviceClass *k = DEVICE_CLASS(klass);
     k->init = sysbus_device_init;
     k->bus_type = TYPE_SYSTEM_BUS;
-    /*
-     * device_add plugs devices into suitable bus.  For "real" buses,
-     * that actually connects the device.  For sysbus, the connections
-     * need to be made separately, and device_add can't do that.  The
-     * device would be left unconnected, and could not possibly work.
-     */
-    k->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo sysbus_device_type_info = {
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 605a970..0d93af3 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -110,6 +110,8 @@ struct MachineClass {
 struct MachineState {
     /*< private >*/
     Object parent_obj;
+    Notifier sysbus_notifier;
+
     /*< public >*/
 
     char *accel;
-- 
1.8.1.4