Re: [Qemu-devel] [RFC PATCH 5/7] vl.c: added -kerndtb option

[Anthony Liguori <anthony@codemonkey.ws>]

On 01/24/2012 12:23 PM, Stefan Weil wrote:
> Am 24.01.2012 08:22, schrieb Andreas Färber:
>> Am 23.01.2012 08:20, schrieb Peter A. G. Crosthwaite:
>>> Added linux specific kernel dtb option. This option can be specified to inject
>>> an argument device tree blob (dtb) into linux.
>>>
>>> Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
>>> ---
>>> qemu-options.hx | 3 +++
>>> vl.c | 4 ++++
>>> 2 files changed, 7 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/qemu-options.hx b/qemu-options.hx
>>> index 6295cde..43cddff 100644
>>> --- a/qemu-options.hx
>>> +++ b/qemu-options.hx
>>> @@ -1931,6 +1931,9 @@ ETEXI
>>>
>>> DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \
>>> "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL)
>>> +DEF("kern-dtb", HAS_ARG, QEMU_OPTION_kerndtb, \
>>> + "-kern-dtb dtb device tree blob passed to kernel boot\n", QEMU_ARCH_ALL)
>>
>> We should probably call it -kernel-dtb. If there's some strncmp() from
>> -kernel interfering, we should fix that instead.
>>
>> I don't see this variable being used anywhere in this series though.
>> Would it have been in the missing zynq machine of 7/7?
>>
>> Andreas
>
> I'd prefer a different solution. As far as I have understood,
> the dtb is only useful with a kernel, so it could be handled
> as an optional attribute to the -kernel parameter:
>
> -kernel IMAGE[,dtb=DTB]

If it looks like a device, acts like a device, and smells like a device...

The best thing to do here is to make an arm-kernel-loader device that hangs off 
of sysbus and takes four string properties.

I was going to do this shortly for PC anyway.

BTW, for unknown command line options, we should probably assume they are 
-device and treat accordingly.  So -arm-kernel-loader 
dtb=DTB,kernel=/path/to/vmlinux would Just Work.

Regards,

Anthony Liguori

>
> Of course the same applies to -append, but that's a different issue.
>
> Regards,
> Stefan
>
>