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

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

Please don't top post.

On Fri, 2014-12-05 at 14:51 +0530, Sagun Garg wrote:
> Thanks Ian for helping me with the links,
> 
> 
> FYI, I found following link :
> https://blog.xenproject.org/2014/04/01/virtualization-on-arm-with-xen/
> (Here it suggests using Foundation Model and Linaro, basically an
> emulator to get started) though the advanced emulators offered by ARM
> are paid ones)
> 
> 
> Would it be possible to install these ARM emulators on say AWS
> Amazon / Digital Ocean with the free subscription to try and test
> these out ?

Those emulators will run on any x86 system, whether it is virtualised by
Amazon/DO or not. They are quite CPU intensive though.

>  Amazon uses Xen as the underlying virtualization technology and it
> also uses custom kernels since last 2 years so coincidentally it might
> just work though the question is how (I read this somewhere on a blog,
> but I can't point a link to it as I don't remember it, but would you
> know of such a tuturial / link where someone else has pursued the
> same ?)

Amazon offers x86 Xen, not ARM Xen. Xen does not do any kind of
cross-architecture virtualisation (i.e. running ARM OSes on X86, or vice
versa). So the fact that Amazon happens to run x86 Xen is of no use when
you want to run ARM Xen.

> or would you know of any "RISC as a Service with ARM processors" that
> can be provisioned on demand like AWS where we can install XEN on ARM
> directly ? Any cloud offering that can be used would be of great help.

I'm not aware of any cloud service offering ARM at the moment.

> Also I was wondering what are the risks / or rather shortcomings in
> trying directly on the device Nexus / or any other ARM phone which has
> been tested for the same. 

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.

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.

Ian.