Re: Install Xen on ARM in a bare metal fashion on a Nexus Phone/Tablet or an ARM emulator

[Julien Grall <julien.grall@linaro.org>]

Hello,

On 05/12/2014 09:32, Ian Campbell wrote:
> On Fri, 2014-12-05 at 14:51 +0530, Sagun Garg wrote:
> Not sure what sorts of risks you mean, I don't think there is anything
> Xen specific here, just the usual stuff with running an untested OS on
> any new platform.
>
> I don't know if Nexus devices are brickable, but if so then that might
> be an issue with trying any untested OS on them.

Nexus platform tend to be a good platform for development. I would be 
surprised if you can brick it with untested OS. Though, I would not try 
to change the bootloader and I don't know if they support HYP mode.

>
> Phones and the like aren't typically very good debug platforms (i.e. no
> serial, no JTAG etc) so running an untested OS on them can end up being
> hard (but not impossible) to debug if it doesn't work, that's why
> platforms such as the Arndale exist -- they are mobile phones with all
> the extra useful debug stuff brought out to headers.

Nexus smartphone (at least 4) has an UART hidden in the headphone jack.
I don't know it's possible to buy the specific cable but you would be 
able to build your own. Though, I haven't tried myself.

The Linux kernel provided on AOSP has the code to enable the UART. So 
you should be able to get the log.

For Xen, you will have to implement yourself the debug UART.

-- 
Julien Grall