Re: [Qemu-devel] [PATCHv2 1/1] Add usb option in machine options to enable/disable usb

[Markus Armbruster]

Li Zhang <address@hidden> writes:

> On Fri, Jun 15, 2012 at 10:34 PM, Markus Armbruster <address@hidden> wrote:
>> Li Zhang <address@hidden> writes:
>>
>>> On Fri, Jun 15, 2012 at 8:04 PM, Markus Armbruster <address@hidden> wrote:
>>>> Li Zhang <address@hidden> writes:
>>>>
>>>>> For pseries machine, it needs to enable usb to add
>>>>> keyboard or usb mouse. -usb option won't be used in
>>>>> the future, and machine options is a better way to
>>>>> enable usb.
>>>>>
>>>>> So this patch is to add usb option to machine options
>>>>> (-machine type=psereis,usb=on/off)to enable/disable
>>>>> usb controller.
>>>>>
>>>>> In this patch, usb_on is an global option which can
>>>>> be checked by machines.
>>>>> For example, on pseries, it will check if usb_on is 1,
>>>>> if it is 1, it will create one usb ohci controller.
>>>>> As the following:
>>>>> if (usb_on == 1) {
>>>>>      pci_create_simple(bus, -1, "pci-ohci");
>>>>> }
>>>>>
>>>>> In this patch, usb is on by default. So, for -nodefault,
>>>>> usb should be set off in the command line as the following:
>>>>>  -machine type=pseries,usb=off.
>>>>>
>>>>> Signed-off-by: Li Zhang <address@hidden>
>>>>>
>>>>> ---
>>>>>  hw/spapr.c |    5 +++++
>>>>>  sysemu.h   |    1 +
>>>>>  vl.c       |   17 +++++++++++++++++
>>>>>  3 files changed, 23 insertions(+)
>>>>>
>>>>> diff --git a/hw/spapr.c b/hw/spapr.c
>>>>> index d0bddbc..1feb739 100644
>>>>> --- a/hw/spapr.c
>>>>> +++ b/hw/spapr.c
>>>>> @@ -661,6 +661,11 @@ static void ppc_spapr_init(ram_addr_t ram_size,
>>>>>          spapr_vscsi_create(spapr->vio_bus);
>>>>>      }
>>>>>
>>>>> +    if (usb_on == 1) {
>>>>> +        pci_create_simple(QLIST_FIRST(&spapr->phbs)->host_state.bus,
>>>>> +                          -1, "pci-ohci");
>>>>> +    }
>>>>> +
>>>>>      if (rma_size < (MIN_RMA_SLOF << 20)) {
>>>>>          fprintf(stderr, "qemu: pSeries SLOF firmware requires >= "
>>>>>                  "%ldM guest RMA (Real Mode Area memory)\n", 
>>>>> MIN_RMA_SLOF);
>>>>> diff --git a/sysemu.h b/sysemu.h
>>>>> index bc2c788..08134ae 100644
>>>>> --- a/sysemu.h
>>>>> +++ b/sysemu.h
>>>>> @@ -109,6 +109,7 @@ extern int vga_interface_type;
>>>>>  #define vmsvga_enabled (vga_interface_type == VGA_VMWARE)
>>>>>  #define qxl_enabled (vga_interface_type == VGA_QXL)
>>>>>
>>>>> +extern int usb_on;
>>>>>  extern int graphic_width;
>>>>>  extern int graphic_height;
>>>>>  extern int graphic_depth;
>>>>> diff --git a/vl.c b/vl.c
>>>>> index 204d85b..b200203 100644
>>>>> --- a/vl.c
>>>>> +++ b/vl.c
>>>>> @@ -202,6 +202,7 @@ int smp_cpus = 1;
>>>>>  int max_cpus = 0;
>>>>>  int smp_cores = 1;
>>>>>  int smp_threads = 1;
>>>>> +int usb_on = 0;
>>>>>  #ifdef CONFIG_VNC
>>>>>  const char *vnc_display;
>>>>>  #endif
>>>>> @@ -758,6 +759,21 @@ static int bt_parse(const char *opt)
>>>>>      return 1;
>>>>>  }
>>>>>
>>>>> +static int get_usb_opt(QemuOpts *opts)
>>>>> +{
>>>>> +    const char *usb_opt = NULL;
>>>>
>>>> Useless initializer.
>>> Thanks. I will remove it.
>>>>
>>>>> +    int usb_on = 0;
>>>>> +
>>>>> +    if (NULL == qemu_opt_get(opts, "usb"))
>>>>> +        qemu_opt_set(opts, "usb", "on");
>>>>
>>>> Why are you changing opts?
>>> USB is enabled by default when there is no usb option setting.
>>> For example,
>>> using  # qemu-system-ppc64 -machine type=pseries
>>> There is no usb option, but usb is set on.
>>
>> Isn't it off by default for at least some machines now?
>>
> OK. This default setting is decided by the machine.
> In the new version, I put this setting in machine.
> It can be set off or on.
> For psereis it sets on.

Makes sense.

Perhaps we really have three kinds of machines, not just two:

1. Must have USB: main() sets usb_enabled to true.

2. May have USB: usb_enabled = -usb or -usbdevice given

3. Can't have USB: fail if the user tries to enable it.

Code sketch:

    /* init USB devices */
    if (!machine->has_usb) {
        if (usb_enabled)
            [report error; should point to the offending options]
            exit(1);
        }
    } else {
        if (machine->has_usb > 0) {
            usb_enabled = 1;
        }
        if (usb_enabled) {
            if (foreach_device_config(DEV_USB, usb_parse) < 0)
                exit(1);
        }
    }


>> Anyway, I don't see why we need to update opts.  Who's using the updated
>> opts?
>>
> psereis will use this opts.
> usb kbd and mouse will be needed  with vga enabled.

Do they use the updated QemuOpts *opts?  I'd expect them to use usb_on,
or whatever flag variable governs USB (now: usb_enabled).

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