hw/virtio: Support set_config() callback in vhost-user-base

The Virtio input device invokes set_config() callback for retrieving
the event configuration info, but the callback is not supported in
vhost-user-base.

This patch adds support set_config() callback in vhost-user-base.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20231120043721.50555-2-leo.yan@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240104210945.1223134-9-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/vhost-user-base.c

@@ -140,6 +140,22 @@ static void vub_get_config(VirtIODevice *vdev, uint8_t *config)
     }
 }
 
+static void vub_set_config(VirtIODevice *vdev, const uint8_t *config_data)
+{
+    VHostUserBase *vub = VHOST_USER_BASE(vdev);
+    int ret;
+
+    g_assert(vub->config_size && vub->vhost_user.supports_config == true);
+
+    ret = vhost_dev_set_config(&vub->vhost_dev, config_data,
+                               0, vub->config_size,
+                               VHOST_SET_CONFIG_TYPE_FRONTEND);
+    if (ret) {
+        error_report("vhost guest set device config space failed: %d", ret);
+        return;
+    }
+}
+
 /*
  * When the daemon signals an update to the config we just need to
  * signal the guest as we re-read the config on demand above.
@@ -337,6 +353,7 @@ static void vub_class_init(ObjectClass *klass, void *data)
     vdc->unrealize = vub_device_unrealize;
     vdc->get_features = vub_get_features;
     vdc->get_config = vub_get_config;
+    vdc->set_config = vub_set_config;
     vdc->set_status = vub_set_status;
 }