Re: [Qemu-devel] Setting up PPC440 Virtex Image for Qemu

[Suzuki Poulose <suzuki@in.ibm.com>]

On 06/30/11 18:40, Edgar E. Iglesias wrote:
> On Thu, Jun 30, 2011 at 06:30:04PM +0530, Suzuki Poulose wrote:
>> On 06/30/11 18:02, Edgar E. Iglesias wrote:
>>> On Thu, Jun 30, 2011 at 05:45:23PM +0530, Suzuki Poulose wrote:
>>>> Hi,
>>>>
>>>> I am working on enabling the KEXEC on PPC440 chipsets. To debug my patches,
>>>> I would like to use the Qemu. The only available PPC440 support in Qemu is
>>>> for the ppc-virtex. (Thanks for adding the support).
>>>>
>>>> I was trying to use the default image provided at
>>>>
>>>> http://wiki.qemu.org/download/ppc-virtexml507-linux-2_6_34.tgz
>>>>
>>>> However I cannot get the network up for the board to use the nfs root file
>>>> system.
>>>
>>> Hi,
>>>
>>> The problem is that there is no model of the LL-TEMAC in qemu, the one in
>>> the refdesign beeing emulated. An easy way out is probably to connect
>>> a xilinx,ethlite instead. You'll need to modify both QEMU and the dtb.
>>>
>>> IIRC, the dtb published with the image has the lltemac removed.
>>>
>>> I've got a working LL-temac model here, will try to post it this weekend.
>>> Or if you're interested in hacking on it, I could probably code dump it as
>>> is.
>>
>> Edgar,
>>
>> Thanks a lot for the quick reply.
>>>>
>>>> Is there something I can do to get the networking up ? I think this may need to
>>>> be fixed in the dtb.
>>>>
>>>>     Or is there any other mechanism to use a different file system ?
>>>> ( I have the tool chain to build the kernel etc)
>>>
>>>
>>> Another way is to create ramdisks with all the stuff you need and just
>>> not use networking. Thats how the image from the wiki does it.
>>
>> I think I can try this option. By the way, could you pass on the steps to
>> attach the ramdisks to the image ?
>
> Hi,
>
> If I dont remember wrong, the image on the wiki contains a kernelconfig file.
> The config file sets the CONFIG_INITRAMFS_SOURCE option to "./romfs".
> In my case I created a romfs subdir right in my linux-2.6 kernel tree,
> e.g linux-2.6/romfs/.
>
> You'll then have to populate the romfs directory with all the things
> you need. romfs/dev/xxx, romfs/lib/xxx etc etc.
>
> Then, once you build the kernel, an image of the romfs/ will be baked
> into the kernel image. You then need to choose your init cmd by
> passing an rdinit option in ther kernel cmd line.
>
> With qemu:
> -append "rdinit=/bin/sh"
>
> The qemu-run.sh script from the wiki does that aswell.
>
> There are probably other better ways to do it that I am not aware
> of at the moment. But I hope it helps as example.

Thanks a lot for the pointers. Somehow, the INITRAMFS_SOURCE was not working
  for me even with the kernelconfig that is attached in the tar.gz. Btw, the
kernelconfig enabled additional image types, simpleImage.virtex507 etc, which
  had no rules to build. I tried with the xilinix-2.6 git tree with no luck.

However, I have got it working using an initrd.img (7M) which I pass using -initrd option.

I have also hacked qemu to display the tlb entries (which is very much needed for my
work) with "info registers" and gdb works like a charm.  Nothing more, I could ask for.


Cheers
Suzuki