Re: [Qemu-devel] [Xen-devel] [Patch V1 1/3] xen: introduce dummy system device

[Juergen Gross]

On 09/07/2015 05:29 PM, Stefano Stabellini wrote:
> 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 <address@hidden>
> > ---
> >   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.

Sure I could. OTOH I think this system device could really be of common
interest.


Juergen