Re: Xen on Pi4: Xen doesn't work with overlays from Raspberry Pi 5.4 kernel

[Roman Shaposhnik <roman@xxxxxxxxxx>]

On Wed, Jun 10, 2020 at 11:54 AM Corey Minyard <cminyard@xxxxxxxxxx> wrote:
>
> I had been working on Xen on the Pi4 by throwing kernels I compiled onto
> existing sd cards, and this was working fine.  I finally got to a full
> yocto build of the system, and it didn't boot.
>
> In fact, Xen didn't print anything at all, and nothing happens that
> might suggest it's booting without any console output.
>
> I traced the issue down to the vc4-fkms-v3d dtoverly.  With everything
> else the same, the 4.19 version of that overlay works, and the 5.4
> version does not work.  It also didn't work if I completely removed the
> overlay.  The base device trees are the same between the two kernels.
>
> Looking at the overlay changes between the versions and Xen source, I
> can't trace down anything that would cause an issue.  Has anyone seen
> this issue of have any ideas?

FWIW: I ran into very similar issues, ditched 5.4 kernel and moved to 5.6.x:
    https://github.com/raspberrypi/linux/tree/rpi-5.6.y

The 5.6.14 seems to be working quite nicely with Xen for me (and Stefano).

Thanks,
Roman.