Re: Questions about XEN/ARM toolchain, XEN 4.5, Exynos 5420 and Arndale Octaboard.

[Ian Campbell <ian.campbell@citrix.com>]

On Thu, 2015-03-05 at 16:45 +0100, Fabio Canigliula wrote:
> The solution would be having the BL2 to set the processor in HYP mode
> and deliver it to U-Boot already in that mode, so that Xen would boot
> easily. Changing the BL2 requires the signature of the manufacturer,
> as it happens for the Odroid-XU3 board (Exynos 5422)
> (http://forum.odroid.com/viewtopic.php?f=98&t=6147) but Unfortunately
> acting on BL2 is not possible for the Arndale Octaboard, as there is
> no support from the Insignal.

There might be an SMC call which you can make to ask Secure world to
switch you up to NS HYP, or even an HVC to do it, but discovering it
without support from the manufacturer would probably be quite tricky (if
not impossible)

I'm afraid that once you are in NS.SVC without the earlier code having
left behind a handler for such a call there is no way to get back into
HYP mode.

> Is there a solution to overcome these problems, or anyone still
> working on it?

Not that I am aware of. You might have more luck in a forum dedicated to
hacking on these devices and/or SoCs, if there is one.

> When Xen 4.5 was released I read in the notes that support for the
> Exynos 5420 MPSoC was added
> (http://wiki.xenproject.org/wiki/Xen_Project_4.5_Feature_List#ARM_Hypervisor-Specific_Updates). Which is the platform where it was implemented? Is it open or is there private software just like in the Arndale Octaboard case?

I'm afraid that think this might have been a typo and should actually
refer to the 5422 in the Odroid-XU. At least neither my memory nor my
mailbox say anything about the Arndale Octa.

Sorry about this, I'm going to go fix the wiki right now.

> Could you suggest me some boards based on ARMv7 (A7 and/or A15) or
> ARMv8 fully controllable and on which Xen 4.5 works? Any help would be
> greatly appreciated.

My preferred option is the Cubietruck (AKA cubieboard 3).

Ian.