Re: Question about xen and Rasp 4B

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 2 Feb 2021, Jukka Kaartinen wrote:
> Hi Roman,
> 
> > > > 
> > > Good catch.
> > > GPU works now and I can start X! Thanks! I was also able to create domU
> > > that runs Raspian OS.
> > 
> > This is very interesting that you were able to achieve that - congrats!
> > 
> > Now, sorry to be a bit dense -- but since this thread went into all
> > sorts of interesting
> > directions all at once -- I just have a very particular question: what is
> > exact
> > combination of versions of Xen, Linux kernel and a set of patches that went
> > on top that allowed you to do that? I'd love to obviously see it
> > productized in Xen
> > upstream, but for now -- I'd love to make available to Project EVE/Xen
> > community
> > since there seems to be a few folks interested in EVE/Xen combo being able
> > to
> > do that.
> 
> I have tried Xen Release 4.14.0, 4.14.1 and master (from week 4, 2021).
> 
> Kernel rpi-5.9.y and rpi-5.10.y branches from
> https://github.com/raspberrypi/linux
> 
> and
> 
> U-boot (master).
> 
> For the GPU to work it was enough to disable swiotlb from the kernel(s) as
> suggested in this thread.

How are you configuring and installing the kernel?

make bcm2711_defconfig
make Image.gz
make modules_install

?

The device tree is the one from the rpi-5.9.y build? How are you loading
the kernel and device tree with uboot? Do you have any interesting
changes to config.txt?

I am asking because I cannot get to the point of reproducing what you
are seeing: I can boot my rpi-5.9.y kernel on recent Xen but I cannot
get any graphics output on my screen. (The serial works.) I am using the
default Ubuntu Desktop rpi-install target as rootfs and uboot master.