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

[Juergen Gross <jgross@suse.com>]

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 <jgross@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.

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


Juergen