Re: Input to start porting OS to XEN

[Julien Grall <julien@xxxxxxx>]

On 11/06/2020 04:45, AshishKumar Mishra wrote:
> Hi Julien ,
Hi,

Apologies for the late answer.


> Thanks for reverting back .
>
> 1) Currently i was planning on Raspberry pie-4
>       ( As that was simpler w.r.t linux bsp & availability )
I saw you next answer suggesting Zephys doesn't support RPI 4. Unless 
you plan to run Zephyr in Dom0, support for a given board is not necessary.
> 2) w.r.t PV vs PVH vs HVM
> - I was evaluating HVM initially .
>    as based on what I understand , PV will require changes
>    to be done on Zephyr codebase initially.
> - With HVM , based on my reading i can look at getting the binary of zephyr
>     and and xen HVM config file will help me get started
We don't support HVM guest on Arm, instead we support something close to 
PVH. By that, we are taking advantage of the HW virtualization and most 
of the devices are para-virtualized or passthrouhg-ed.
> But , request to please correct if i have mis-understood or mis-planned 
> any thing here.
There are a couple of talks about how to port a new OS to Xen on Arm 
(you can look at [1] for instance).
Most of the efforts would be to support para-virtualized devices. 
Thankfully, there are already multiple implementations existing for some 
of the PV devices.
> 3) Ethernet and CAN interface are what i was looking for on Zephr.
While network PV protocol already exist in Xen, I am not aware of CAN 
interface. You would need to write from scratch an interface.
Cheers,

[1] https://www.youtube.com/watch?v=NksLB29NSpQ

--
Julien Grall