Re: [Xen-devel] Xen on ARMv8

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

On Fri, Dec 6, 2013 at 8:55 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> On Fri, 2013-12-06 at 19:48 +0530, Vijay Kilari wrote:
>> On Thu, Dec 5, 2013 at 8:27 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
>> > On Thu, 2013-12-05 at 20:21 +0530, Vijay Kilari wrote:
>> >> Hi Ian,
>> >>
>> >> Thanks for the information
>> >>
>> >>  I was successful to boot Xen on our ARMv8 simulator to some extent,
>> >> but facing following issues:
>> >>
>> >> 1) With Stable 4.3 version, Xen boots, but fails in ctxt_switch_from()
>> >>  call from schedule_tail().
>> >>     This happens to be because it does not support 64-bit guest. I was
>> >> using 64-bit guest
>> >
>> > 4.3 is probably not the best option for bringing up a new platform TBH.
>> >
>> >> 2) I see that staging branch has support for 64-bit guest, but it
>> >> fails to boot completely.
>> >>     I see continuous IRQ 37 which is not seen with stable version
>> >
>> > That's pretty strange. What is IRQ37 in your system?
>> >
>> > I know that Julien and Stefano are looking at some interrupt stuff, in
>> > particular there was a patch series way back in June which is currently
>> > been reworked titled "Fix multiple issues with the interrupts on ARM",
>> > of which "Only enable physical IRQs when the guest asks" sounds like it
>> > might be relevant given the symptom you describe.
>> >
>>
>> IRQ 37 is uart interrupt. The problem is with the pl011 driver changes which
>> are not compatible with our ARMv8 simulator. After reverting changes to pl011
>> to inline with stable branch, issue is not seen. I will identify the exact 
>> patch
>> that is causing this problem later.
>
> Please do, there are a few interrupt logic changes since 4.3 in that
> driver, if there is a problem there it would be good to get to the
> bottom of it before Xen 4.4 comes out (in Jan/Feb next year). That said
> it works on at least midway, vexpress and the arm fast models.
>

> Did you work around this with the patch from Julien? Or some other
> method?
>
I don't have any work around as of now. I just reverted changes made
to pl011 driver in staging branch on top of stable 4.3. I see couple of
patches that has changed pl011 registers initialization.

I will check once I get the my setup is up & running.

>> (XEN) Using PSCI for SMP bringup
[..]
>> (XEN) Panic on CPU 0:
>> (XEN) Unable to copy the DTB to dom0 memory (rc = 18446744073709551602)
>> (XEN) ****************************************
>
> It looks like you are trying to load an ELF format kernel, which
> probably doesn't work for Linux. Try passing it the
> arch/arm64/boot/Image and it should work.
>
> (ELF is useful for *BSD I think, which is why we don't just nuke this
> support right now)
>
Yes, I have set my Image to vmlinux (stripped) for 4.3 stable as it  was failing
to load plain arch/arm64/boot/Image
I forget to revert back this change with staging branch. Now I could
boot Xen hypervisor.

Thanks for this help.

But my console on dom0 is not showing any logs.
However ARMv8 simulator shows that dom0 is booted and
cpu has entered idle loop.

> Ian.
>

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