[fedora-arm] Fwd: KVM on Samsung Chromebook A15

Jon jdisnard at gmail.com
Mon Aug 12 20:40:27 UTC 2013 

Hi Will

The recently released[1] HYP enabled nv-u-boot does not allow saveenv.

We can use setenv to make changes, but they are not persistent.
It might be possible to import or source the ENV from boot.scr or
uEnv.txt, but haven't tried.


Regardless I was unable to boot Fedora using that firmware.
I tried booting legacy uImages+uInitrd, and FIT image.
Both methods did  not work for me.

At some point I may try to follow the instruction to boot whatever
other Linux distro is described in the link [1].
I was surprised that Fedora was not booting, and hoping I made some
kind of silly mistake.

If anybody is able to get it working please let em know.



[1] https://lists.cs.columbia.edu/pipermail/kvmarm/2013-July/006481.html

On Mon, Aug 12, 2013 at 3:27 PM, William Cohen <wcohen at redhat.com> wrote:
> On 08/10/2013 11:23 PM, Jon wrote:
>> Enabling HYP seem conceptually easy.
>> From what I gather it involves initializing the cores one at a time,
>> then touching 16 registers.
>> (something like that)
>>
>> The nv-u-boot does not seem to support saveenv, so might be worthwhile
>> to rebuild with better default env.
>> (known issue)
>>
>> If somebody can get this working I'll be happy to integrate with the
>> f19 remix for chromebook.
>> My experience so far was that the HYP enabled u-boot does not work.
>> Meaning the bootm of the FIT image fails, and also the case of legacy
>> uImages also fail to bootm.
>>
>> regards,
>> -Jon Disnard
>
>
>
> Hi Jon,
>
> I don't know how you have things set up for uboot and the kernel.  One of the problems that I found when setting up to use nv-uboot on the sd card is the uboot is looking for partition 12 (0xc) for the uboot/uboot.scr.uimg, which probably doesn't exist on the card.   I found after careful reading of the following URL that I needed to adjust $script_part to point to the proper partition EFI-SYSTEM:
>
>  http://www.chromium.org/chromium-os/u-boot-porting-guide/using-nv-u-boot-on-the-samsung-arm-chromebook
>
> That should at least allow you to set the variable more easily even if the saveenv isn't working on uboot.
>
> There are also two different versions of nv_uboot for chrome book.  From what I have read upstream kernels need to use the one that supports the simple frame buffer and that the support for the simple framebuffer needs to be enabled in the kernel.
>
> -Will
>
>>
>> On Sat, Aug 10, 2013 at 10:12 PM, Jonathan Masters <jcm at redhat.com> wrote:
>>> I'll try this out.
>>>
>>> --
>>> Sent from my iPad
>>>
>>> On Aug 7, 2013, at 12:02, Jon <jdisnard at gmail.com> wrote:
>>>
>>>> There is a HYP enabled u-boot floating around.
>>>>
>>>> http://www.virtualopensystems.com/media/chromebook/nv_u-boot-snow.kpart
>>>>
>>>> So far I've been unable to get it to boot Fedora, but others are welcome to try.
>>>>
>>>> Here is the git for the above:
>>>> https://github.com/virtualopensystems/u-boot
>>>>
>>>> They also have some  documentation:
>>>> https://lists.cs.columbia.edu/pipermail/kvmarm/2013-July/006481.html
>>>>
>>>> Regards,
>>>>
>>>> -Jon Disnard
>>>> fas: parasense
>>>> irc: masta
>>>>
>>>> On Wed, Aug 7, 2013 at 10:51 AM, Peter Robinson <pbrobinson at gmail.com> wrote:
>>>>> On Wed, Aug 7, 2013 at 4:47 PM, Adam Goode <adam at spicenitz.org> wrote:
>>>>>> Was there ever a resolution to this? I am happy to file a bug in the
>>>>>> chromium tracker to get this looked at, if needed.
>>>>>
>>>>> None that I'm aware of but if you could file a bug in the chromium
>>>>> tracker that would be fab.
>>>>>
>>>>> Peter
>>>>>
>>>>>> Adam
>>>>>>
>>>>>>
>>>>>> On Fri, Jul 5, 2013 at 12:16 PM, Richard W.M. Jones <rjones at redhat.com> wrote:
>>>>>>> On Fri, Jul 05, 2013 at 11:30:01AM -0400, Jon Masters wrote:
>>>>>>>> On 07/05/2013 05:07 AM, Richard W.M. Jones wrote:
>>>>>>>>> On Wed, Jul 03, 2013 at 11:59:28AM -0500, Jon wrote:
>>>>>>>>>> I'm pleased to announce the availability of Fedora 19 for the 2012 Samsung
>>>>>>>>>> Chromebook featuring ARM Exynos dual core A15 processor.
>>>>>>>>>
>>>>>>>>> Sorry to slightly hijack this thread.  I will try your remix later.
>>>>>>>>>
>>>>>>>>> Reading the comments on https://lwn.net/Articles/557132/#Comments
>>>>>>>>> it seems as if the news on KVM on the Chromebook is not good.  It
>>>>>>>>> doesn't boot into HYP mode, and there's no way to make it boot into
>>>>>>>>> HYP mode, so KVM won't be supported.  Is that right?
>>>>>>>>
>>>>>>>> That's roughly what I'd expect to be the case. There might be a signed
>>>>>>>> U-Boot someone has hacked that does enable HYP mode, but otherwise I
>>>>>>>> suspect you're out of luck. I'll ask around during Linaro Connect.
>>>>>>>
>>>>>>> I asked about this on #kvm-arm earlier today and got this long reply:
>>>>>>>
>>>>>>> 11:58 < rwmjones> I'm reading a comment here:
>>>>>>> 11:58 < rwmjones> https://lwn.net/Articles/557561/
>>>>>>> 11:58 < rwmjones> which suggests that KVM on the Samsung Chromebook 2012 (ARM A15 version) isn't possible because the
>>>>>>>                  bootloader doesn't boot into HYP mode
>>>>>>> 11:58 < rwmjones> is this true?  if so is there a way around it?
>>>>>>> 11:59 < pm215> IIRC the bootloader gets control in secure-SVC
>>>>>>> 11:59 < pm215> it is from there possible to get to NS-HYP
>>>>>>> 11:59 < pm215> it's just that the stock bootloader doesn't do this before booting the kernel
>>>>>>> 11:59 < rwmjones> so what's involved in making it work?
>>>>>>> 11:59 < pm215> somebody needs to write some code and get it into the bootloader
>>>>>>> 12:00 < rwmjones> ok, and the bootloader can be replaced (next comment down suggests this requires soldering)?
>>>>>>> 12:01 < pm215> I believe this to be true, though I don't have a chromebook
>>>>>>> 12:01 < pm215> I think you get the google bootloader to chain boot some other bootloader which you do have control of, and then
>>>>>>>               that can actually boot your os
>>>>>>> 12:02 < suihkulokki> or maybe we could just prepend some code in front of the kernel zimage that switches to HYP mode?
>>>>>>> 12:02 < pm215> nope
>>>>>>> 12:02 < suihkulokki> damn
>>>>>>> 12:02 < pm215> we spent quite a long time being very firm that the ABI here is "bootloader's job to get this right"
>>>>>>> 12:03 < pm215> there are some u-boot patches currently going through code review to do the go-to-hyp-mode thing properly for
>>>>>>>               arndale
>>>>>>> 12:03 < pm215> hopefully if they get upstream it will be more straightforward to say "ok, I have $other-board and it needs to
>>>>>>>               do this too"
>>>>>>> 12:05 < apritzel> which would require that the Chromebook u-boot support is upstream as well
>>>>>>> 12:05 < apritzel> AFAIK this is not the case currently
>>>>>>>
>>>>>>> [There's more of this, but that seems to cover the main points]
>>>>>>>
>>>>>>> Reading around this, it does seem as if it's possible to get from
>>>>>>> secure SVC to HYP (although not easy).
>>>>>>>
>>>>>>> Rich.
>>>>>>>
>>>>>>> --
>>>>>>> Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
>>>>>>> virt-top is 'top' for virtual machines.  Tiny program with many
>>>>>>> powerful monitoring features, net stats, disk stats, logging, etc.
>>>>>>> http://people.redhat.com/~rjones/virt-top
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>>>>
>>>>
>>>> --
>>>>
>>>> -Jon
>>>>
>>>>
>>>> --
>>>>
>>>> -Jon
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>>
>>



-- 

-Jon

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