Re: UEFI booting, and compiling Xen

[Paul Leiber <paul@xxxxxxxxxxxxxxxx>]

HI,

Am 08.11.2024 um 11:06 schrieb rb+xen-users@xxxxxxxxxxxxxx:

> I am trying to compile Xen from source in order to experiment with 
> features not available in OS distributions.  Specifically, I want UEFI 
> booting, for which I think I need OVMF <https://wiki.xenproject.org/ 
> wiki/OVMF> in Xen 4.4.  (If anyone has another method for getting that 
> based on e.g. Alpine Linux 3.20 I would like to know!)
AFAIK, Xen is currently on version 4.19. Xen 4.4 has been released in 
2014. Do you really need this old a version?
> The instructions for Compiling Xen From Source <https:// 
> wiki.xenproject.org/wiki/Compiling_Xen_From_Source> seem very out of 
> date.  Many of the build dependencies listed do not even exist in recent 
> distributions.
I managed to compile Xen 4.18 and 4.19 on Debian Bookworm based on the 
same instructions from the wiki. These were the main commands I used:
apt install ninja-build
apt build-dep xen
./configure  --libdir=/usr/lib --sysconfdir=/etc
make dist
make install
update-grub
systemctl enable xencommons
systemctl enable xendomains
systemctl enable xen-watchdog
systemctl enable xendriverdomain

Of course, the Xen sources need to be available on the local system. I 
cloned the Xen git repository.
> I'm sure someone out there has a stable baseline for builds.  For 
> example, someone is likely running automated builds on well known cloud 
> baselines plus some configuration.  I'd like to see that configuration. 
> I've had a look around on <https://xenbits.xen.org/gitweb/> but could do 
> with a pointer.  The sort of information I'm looking for is a setup for 
> a stable build platform, like <https://github.com/Ravenbrook/mps/blob/ 
> master/.github/workflows/build-and-test.yml> (though this isn't a great 
> example as it has no package dependencies).
> If I can get the information together I can post a working recipe and 
> update the wiki.
> My build platform of choice is Ubuntu 22 with LXD.  I'm happy to launch 
> LXD containers for other distributions and older versions.  What I'd 
> like is a working recipe for setting up a build environment from a known 
> baseline.
> Here is an example of such a recipe:
>
>    rb@kiwi:~$ lxc launch -s kiwi-tmp images:debian/12 xen-build
>    rb@kiwi:~$ lxc exec xen-build -- bash --login
>    root@xen-build:~# apt-get install --yes build-essential git
>    root@xen-build:~# git clone -b stable-4.4 git://xenbits.xen.org/xen.git
>    root@xen-build:~# sed -ne 's/^deb /deb-src /p' < /etc/apt/ 
> sources.list >> /etc/apt/sources.list
>    root@xen-build:~# apt-get build-dep xen
>    root@xen-build:~# cd xen
>    root@xen-build:~/xen# ./configure
>
> Unfortunately, this is where things break.  The configure script is 
> looking for Python 2, which is long gone.
Could your issue be due to the fact that Xen 4.4 is actually also "long 
gone"? I am not surprised that trying to compile Xen 4.4 on a modern 
distribution is not working out of the box.
A simple web search brought up some things to try (I didn't test them 
myself). Did you try to put debian stretch into sources.list and 
manually install the Python 2 package? Alternatively, you could compile 
Python 2 from source.
> I can of course build the version from Debian's package repo but that 
> doesn't help much.
>    root@xen-build:~# apt-get source xen
>    root@xen-build:~# cd xen-4.17.3+10-g091466ba55/
>    root@xen-build:~/xen-4.17.3+10-g091466ba55# dpkg-buildpackage
>
> As I mentioned above, the documented build dependencies on the wiki 
> <https://wiki.xenproject.org/wiki/ 
> Compiling_Xen_From_Source#Build_Dependencies_-_Debian_/_Ubuntu> are very 
> out of date.
> The wiki page even talks about Debian Wheezy as if it's new.  It was 
> released in 2016.
Yes, the wiki is out of date, but many of the instructions I have been 
using (mainly the howto and the build instructions) still work, with 
some adjustments of details. (Please don't get me wrong, this does not 
mean that I don't think the wiki deserves updates. AFAIK, there are 
ongoing activities to update the documentation while switching to a 
different documentation platform.)
Paul