From: Marc-André Lureau <marcandre.lureau@redhat.com>

This helper is used next by -audio code.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/monitor/qdev.h |  3 +++
 system/qdev-monitor.c  | 25 +++++++++++++++++++++----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/include/monitor/qdev.h b/include/monitor/qdev.h
index 1d57bf6577..de33637869 100644
--- a/include/monitor/qdev.h
+++ b/include/monitor/qdev.h
@@ -1,6 +1,8 @@
 #ifndef MONITOR_QDEV_H
 #define MONITOR_QDEV_H
 
+#include "hw/qdev-core.h"
+
 /*** monitor commands ***/
 
 void hmp_info_qtree(Monitor *mon, const QDict *qdict);
@@ -11,6 +13,7 @@ int qdev_device_help(QemuOpts *opts);
 DeviceState *qdev_device_add(QemuOpts *opts, Error **errp);
 DeviceState *qdev_device_add_from_qdict(const QDict *opts,
                                         bool from_json, Error **errp);
+BusState *qdev_find_default_bus(DeviceClass *dc, Error **errp);
 
 /**
  * qdev_set_id: parent the device and set its id if provided.
diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c
index ec4a2394ce..f2aa400a77 100644
--- a/system/qdev-monitor.c
+++ b/system/qdev-monitor.c
@@ -621,6 +621,25 @@ const char *qdev_set_id(DeviceState *dev, char *id, Error **errp)
     return prop->name;
 }
 
+BusState *qdev_find_default_bus(DeviceClass *dc, Error **errp)
+{
+    BusState *bus = NULL;
+
+    assert(dc->bus_type != NULL);
+    bus = qbus_find_recursive(sysbus_get_default(), NULL, dc->bus_type);
+    if (!bus) {
+        error_setg(errp, "No '%s' bus found for device '%s'",
+                   dc->bus_type, object_class_get_name(OBJECT_CLASS(dc)));
+        return NULL;
+    }
+    if (qbus_is_full(bus)) {
+        error_setg(errp, "A '%s' bus was found but is full", dc->bus_type);
+        return NULL;
+    }
+
+    return bus;
+}
+
 DeviceState *qdev_device_add_from_qdict(const QDict *opts,
                                         bool from_json, Error **errp)
 {
@@ -657,10 +676,8 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts,
             return NULL;
         }
     } else if (dc->bus_type != NULL) {
-        bus = qbus_find_recursive(sysbus_get_default(), NULL, dc->bus_type);
-        if (!bus || qbus_is_full(bus)) {
-            error_setg(errp, "No '%s' bus found for device '%s'",
-                       dc->bus_type, driver);
+        bus = qdev_find_default_bus(dc, errp);
+        if (!bus) {
             return NULL;
         }
     }
-- 
2.51.0

On 27/10/25 16:10, marcandre.lureau@redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
> 
> This helper is used next by -audio code.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>   include/monitor/qdev.h |  3 +++
>   system/qdev-monitor.c  | 25 +++++++++++++++++++++----
>   2 files changed, 24 insertions(+), 4 deletions(-)


>   DeviceState *qdev_device_add_from_qdict(const QDict *opts,
>                                           bool from_json, Error **errp)
>   {
> @@ -657,10 +676,8 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts,
>               return NULL;
>           }
>       } else if (dc->bus_type != NULL) {
> -        bus = qbus_find_recursive(sysbus_get_default(), NULL, dc->bus_type);

I don't understand why we use sysbus here, but this is pre-existing, so:

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> -        if (!bus || qbus_is_full(bus)) {
> -            error_setg(errp, "No '%s' bus found for device '%s'",
> -                       dc->bus_type, driver);
> +        bus = qdev_find_default_bus(dc, errp);
> +        if (!bus) {
>               return NULL;
>           }
>       }