Re: Request for Documentation on Bringing Up Xen on R-Car H3e (H3ULCB)

[Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>]

Hi John,

Sorry, I hit wrong "reply" button last time. So I'm re-sending this mail
with xen-devel ML included.

"L, John Preetham (893)" <john_preetham.l@xxxxxxxxxxxxxxxx> writes:

> Dear Xen Community,
>
> I hope this message finds you well.
>
> I am currently working on a project that involves bringing up Xen on the 
> Renesas R-Car H3e (H3ULCB) platform. I am seeking guidance on
> where I can find the proper documentation for this process. Specifically, I 
> am looking for comprehensive documentation that covers everything
> from scratch to the end, including the required versions and any specific 
> configurations.
>
> Could anyone point me to the relevant resources or share any documentation 
> that might be helpful?

Well, you can build all from the scratch. I can guide you through all
the steps if you wish. But I recommend you to try this approach first:

https://github.com/xen-troops/meta-xt-prod-devel-rcar

This will build you a full system with Xen and (multiple domains of you
want) on SD card image. Just follow the instruction in the
README.md. You can use this as a starting point and/or reference for
your own setup.

Just be aware that this approach will build you highly customized setup
with "thin" Dom0 and separate driver domain. But anyways, this is a good
start.

Alternatively, you start with official Renesas manual on building BSP:

https://elinux.org/R-Car/Boards/H3SK#Quick_Start_How_To

and then build on top of. But this will require many manual steps. On
other hand, this will give your much better understanding on what goes
on. There are two ways:

1. You can build Xen hypervisor separately, but you will have issues
with building Xen Tools for your dom0, as you will need to create and
install Yocto SDK and then resolve incompatibilities between Yocto SDK
and Xen's own build system.

2. Easier approach is to add meta-virtualization meta-layer to your BSP
and build Xen hypervisor together will toolstack using this meta-layer.

Apart from building Xen Hypervisor and Xen Tools you also need to:

1. Ensure that ARM-TF boots the system in EL2. There is a
Renesas-specific makefile option for that.

2a. Alter BSP device tree, so it can be used by Xen. You need to provide
IO-MMU mappings.  Sadly, Renesas does not provide them by default. We
have custom dtsi just for that:
https://github.com/xen-troops/meta-xt-prod-devel-rcar/blob/master/layers/meta-xt-domd-gen3/recipes-kernel/linux/files/r8a77951-h3ulcb-4x2g-xen.dts

2b. Alter BSP device tree, so it can be used by Xen. Apart from IO-MMU
configuration you need to tell Xen where to look for module. You can use
ImageBuilder, mentioned by Stefano or do this by hand, like this:
https://github.com/xen-troops/meta-xt-rcar/blob/master/meta-xt-rcar-driver-domain/recipes-kernel/linux/files/pvr/xen-chosen.dtsi

3. Hide SCIF2 clock from Linux (or use "clk_ignore_unused" dom0 kernel
argument). Otherwise Dom0 will disable console during the boot.


-- 
WBR, Volodymyr