Re: [PATCH] xen: arm: introduce uImage probe function for Dom0

[Julien Grall <julien.grall@linaro.org>]

On 20/08/14 00:17, Andrii Tseglytskyi wrote:
> Hi Julien,

Hello Andrii,

>>> +    /*
>>> +     * Check for an appended DTB.
>>> +     */
>>> +    if ( addr + len + sizeof(dtb_hdr) <= size )
>>> +    {
>>> +        copy_from_paddr(&dtb_hdr, addr + len, sizeof(dtb_hdr));
>>> +
>>> +        if ( be32_to_cpu(dtb_hdr.magic) == DTB_MAGIC )
>>> +            len += be32_to_cpu(dtb_hdr.total_size);
>>> +
>>> +            if ( len - start > addr + size )
>>> +                return -EINVAL;
>>> +    }
>>
>>
>> This is a legacy on zImage, I don't really want to see it on implementation
>> of a new format. Xen is creating the device tree for DOM0, the developer
>> should not append a device tree.
>>
>
> Sorry this is not a topic of this patch, but what about appending
> device tree to domU kernel? I found that similar functionality was
> removed from tools by the following patch:
>
> http://permalink.gmane.org/gmane.comp.emulators.xen.cvs/31110

Only the check has been removed. The full binary is now loading in the 
memory. So appending device tree to kernel should still work.

>
> But in case if some HW is present in domU you may need this
> functionality. Code which supports HW in domU is going to be merged
> (iomem and your irq routing series), so maybe appended devtree is also
> OK?

IIRC, the plan is to allow the user to pass a snippet describing your 
device. The toolstack will add it in the generated device tree.

I don't think someone is working on it.

Regards,

-- 
Julien Grall