Re: [Qemu-devel] [PATCH v8 0/3] hw/arm: Add 'virt' platform

[Alexander Graf]

On 18.10.2013, at 13:12, Peter Maydell <address@hidden> wrote:

> On 17 October 2013 17:48, Peter Maydell <address@hidden> wrote:
>> This patch series adds a 'virt' platform which uses the
>> kernel's mach-virt (fully device-tree driven) support
>> to create a simple minimalist platform intended for
>> use for KVM VM guests.
> 
>> Changes v7->v8:
>> * iterate through virtio-mmio nodes the opposite way round so
>>   that they appear in the device tree lowest-address-first;
>>   this matches PPC behaviour and the vexpress code
> 
> ...it turns out this isn't quite right. We need to create
> the actual devices in forwards order (so that devices created
> on the qemu command line populate the transports lowest address
> first) and then create the dtb nodes in reverse order (so that
> the transports appear in the final dtb lowest address first). Ugh.
> 
> Given this plus the fact that you still need a kernel patch to
> get the thing to boot at all [would anybody on the kernel side
> like to pick up that particular ball?], I'm leaning toward not
> putting this in 1.7 now.

We could add a fdt_append_subnode_namelen() function that instead of putting it 
after the parent's properties puts the new node after all subnodes. While we're 
waiting for it to trickle into libfdt we could keep a copy in device_tree.c.

Then we just switch everything to "natural" non-reverse order append_subnode().


Alex