On Thu, 3 Sep 2015, Juergen Gross wrote:
> Introduce a new dummy system device serving as parent for virtual
> buses. This will enable new pv backends to introduce virtual buses
> which are removable again opposed to system buses which are meant
> to stay once added.
>
> Signed-off-by: Juergen Gross <jgr...@suse.com>
> ---
> hw/xenpv/xen_machine_pv.c | 39 +++++++++++++++++++++++++++++++++++++++
> include/hw/xen/xen_backend.h | 1 +
> 2 files changed, 40 insertions(+)
>
> diff --git a/hw/xenpv/xen_machine_pv.c b/hw/xenpv/xen_machine_pv.c
> index 2e545d2..57bc071 100644
> --- a/hw/xenpv/xen_machine_pv.c
> +++ b/hw/xenpv/xen_machine_pv.c
> @@ -24,10 +24,15 @@
>
> #include "hw/hw.h"
> #include "hw/boards.h"
> +#include "hw/sysbus.h"
> #include "hw/xen/xen_backend.h"
> #include "xen_domainbuild.h"
> #include "sysemu/block-backend.h"
>
> +#define TYPE_XENSYSDEV "xensysdev"
> +
> +DeviceState *xen_sysdev;
> +
> static void xen_init_pv(MachineState *machine)
> {
> const char *kernel_filename = machine->kernel_filename;
> @@ -59,6 +64,9 @@ static void xen_init_pv(MachineState *machine)
> break;
> }
>
> + xen_sysdev = qdev_create(NULL, TYPE_XENSYSDEV);
> + qdev_init_nofail(xen_sysdev);
> +
> xen_be_register("console", &xen_console_ops);
> xen_be_register("vkbd", &xen_kbdmouse_ops);
> xen_be_register("vfb", &xen_framebuffer_ops);
> @@ -93,6 +101,31 @@ static void xen_init_pv(MachineState *machine)
> xen_init_display(xen_domid);
> }
>
> +static int xen_sysdev_init(SysBusDevice *dev)
> +{
> + return 0;
> +}
> +
> +static Property xen_sysdev_properties[] = {
> + {/* end of property list */},
> +};
> +
> +static void xen_sysdev_class_init(ObjectClass *klass, void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> + SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
> +
> + k->init = xen_sysdev_init;
> + dc->props = xen_sysdev_properties;
> +}
> +
> +static const TypeInfo xensysdev_info = {
> + .name = TYPE_XENSYSDEV,
> + .parent = TYPE_SYS_BUS_DEVICE,
> + .instance_size = sizeof(SysBusDevice),
> + .class_init = xen_sysdev_class_init,
> +};
> +
> static QEMUMachine xenpv_machine = {
> .name = "xenpv",
> .desc = "Xen Para-virtualized PC",
> @@ -101,9 +134,15 @@ static QEMUMachine xenpv_machine = {
> .default_machine_opts = "accel=xen",
> };
>
> +static void xenpv_register_types(void)
> +{
> + type_register_static(&xensysdev_info);
> +}
Given that you need this just for usbback, I wonder if you could
move xen_sysdev and its initalization to usbback_init.
