GNU Guix: The 64-bit Hurd is Here!
Fifteen months have passed since our last Guix/Hurd on a Thinkpad X60
post and a lot
has happened with respect to the Hurd.
And most of you will have guessed, unless you skipped the title of
this post, the rumored x86_64
support has
landed in Guix!
Here is a not-so-short overview of our Hurd work over the past 1.5 years:
-
The build daemon fails when invoking
guix authenticateon the
Hurd bug was fixed. This was our
most pressing problem as it meant that we could not keep our
substitutes up to date. It took 15 comments and 13 weeks to get it
resolved. Phew! -
Installer support for (cross)-installing the
Hurd. Also adding developer
support for running the installer directly from the source tree;
Guix 1.5.0 lets you install the Hurd on bare
metal. -
Add support for a cross-built
gnumach, allowing the removal
of an ugly workaround when cross-building for the Hurd. -
Update rumpkernel to
0-20250111. -
Support for different childhurd
types, a.k.a. 64-bit
childhurds in da
house. -
The syslogd used by default is now from the Shepherd streamio,
gnumach, and the
Shepherd, to make
the kernel log work. -
Update hurd to 0.9.git20251029, gnumach: to
1.8+git20250731. -
Now that the
go-teambranch has been merged, gccgo now
works (native only). -
Fix proc server for zombie
processes which caused a
shepherd test to fail. -
Fix all the dependencies of the
guixpackage, again: -
Resurrect password hashing.
-
Installer: Fixes for the
Hurd. -
Installer: More clearly mark the Hurd as
experimental. -
Installer: Add Hurd x86_64 as an
option. This took 15
comments, uncovering and fixing several bugs. -
Add support for
x86_64-gnu, aka the 64-bit
Hurd. The an initial patch
set of 31 patches. This patch set
set
took
four iterations and 208
messages before its final
58 patches were merged to
`core-packages-team'. Janneke writes: "Lo and behold, the 64-bit
Hurd boots! Again, thanks to the help from the kind folks over at
libera #hurd and their excellent work. Do something like:"
./pre-inst-env guix system image --image-type=hurd64-qcow2 \
gnu/system/examples/bare-hurd64.tmpl
Pushed a `core-packages-team' with (this one) GCC 14 commit. Let the
fun begin :)
We had a lot of fun...
-
Request for merging "core-packages-team"
branch: 247 commits, took 114
comments 8
weeks
and 24 iterations with 247 commits from 9
people
before presenting the initial merge. -
The actual merge
"core-packages-team":
85 more commits to a total of 332, by 17 people and 27 weeks
before actual merge. 173 packages with build fixes to relax
GCC 14's strictness, 109 package updates to fix build with GCC 14. -
With this all in place we can have ci build a 64-bit hurd
image, and -
Report what packages still need to be
fixed
for that image to build. -
For convenience we added
i586-pc-gnuandx86_64-pc-gnucross
toolchains.
Summarizing, building the Guix manifest for the 32-bit Hurd
(i586-gnu) should work really well. Sadly, for the 64-bit Hurd
(x86_64-gnu) is still a bit problematic as some tests in e.g.,
openssl, python, cmake, .... hang. This is still under
investigation.
What Took You So Long?
We're so glad you asked! Usually, adding a new architecture should
just take a couple of commits:
- Add cross-compilation support for the
x86_64-pc-gnutarget, aka
64-bit
Hurd,
and then - Add support for
x86_64-gnu, aka the 64-bit
Hurd.
pretty neat, right? So, what's the story with the 64-bit Hurd? There
are two problems: 64-bit Hurd support was added in GCC
14, while Guix was still at
GCC 11. This means we "only" had to
- Update the gcc cross compiler to
GCC 14
(one, simple commit), and - Fix all cross builds (initially "just" 23
commits).
The second step involves building for all architectures and fixing all
breakage. Sometimes, fixing one architecture breaks another.
When Guix supported cross-building with GCC 14, and supported the
64-bit Hurd, we could create and boot a 64-bit childhurd. After that,
we could start building 64-bit Hurd packages...but only after also
This, however does not support offloading. For that, we would need
to:
-
Update gcc, gcc-toolchain, libgccjit to 14, and
-
Make sure that all packages in
commencement.scm
successfully build natively onx86_64-hurd, which took only
some 35
commits.
This can simply be verified by building the hello package:
guix build --system=x86_64-gnu hello
However, GCC 14 is not a regular update: it is waaay more
strict with respect to C
code compilation. This means that, before actually switching, we had
to fix 173 package builds and update another 109 packages to not break
all of Guix. This took a total of 17 people and 35
weeks to complete.
You can understand that we are excited that the NLnet
Foundation has been sponsoring this
work!
Installing and Using the 64-bit Hurd
Easiest is to change your 32-bit childhurd definition into 64-bit, by
adding
(type 'hurd64-qcow2)
to your hurd-vm-configuration. And if you don't have a
hurd-vm-configuration yet?. Easy, in that case just add
(hurd-vm-configuration (type 'hurd64-qcow2))
into your your hurd-vm-service-type definition! And if you don't
have a hurd-vm-service-type yet?. Easy, in that case just add
(service hurd-vm-service-type
(hurd-vm-configuration (type 'hurd64-qcow2)))
to your operating system definition. Reconfigure your system and
you'd be able to:

(if you don't have a childhurd
definition in your
~/.ssh/config you will have to use: ssh root@localhost:10022).
And if you don't have a Guix operating system definition...The 64-bit
Hurd is now an option in the installer:

and can be installed in a VM. Make sure to use --machine q35
with qemu.
To build a disk image for a virtual machine, do:
./pre-inst-env guix system image --image-type=hurd64-qcow2 \
gnu/system/examples/bare-hurd64.tmpl
You may run it like so:
guix shell qemu -- qemu-system-x86_64 -m 2048 -M q35 \
--enable-kvm \
--device e1000,netdev=net0 \
--netdev user,id=net0,hostfwd=tcp:127.0.0.1:10022-:2222 \
--snapshot \
--hda /gnu/store/...-disk-image
(note that the 64-bit Hurd does not seem to show a login prompt)
and use it like:
ssh -p 10022 root@localhost
guix build -e '(@@ (gnu packages commencement) gnu-make-boot0)'
or even, if you build the image with at least --image-size=3G:
guix build hello
RumpNET Support
Upstream has added support for Intel i8254x Gigabit
Ethernet using RumpNET.
Damien Zammit wrote:
This adds a working rump driver for /dev/wmX cards, which are Intel
i8254x Gigabit Ethernet devices. (See man.netbsd.org for "wm(4)")
This should be easily extended to support other NICs by contributing
some makefile foo to netbsd/rump.
Example usage:
settrans -fgap /dev/rumpnet /hurd/rumpnet
settrans -fgap /dev/wm0 /hurd/devnode -M /dev/rumpnet wm0
settrans -fgap /servers/socket/2 /hurd/pfinet -i /dev/wm0
ifup /dev/wm0
With our updated hurd and rumpkernel packages, this should be
available in Guix now too. Please let us know if you got it to work!
(If you tried and didn't get it to work, we'd also like to know!)
Status
One of the most frequently asked questions
is probably:
Does X work on the Hurd yet?. The canonical answer to that question
is: Please read the GNU/Hurd
FAQ.
A good summary of current status was presented by Samuel Thibault in
his GNU/Hurd
progress
at FOSDEM'26, in which he also makes a
compelling arguments for the Hurd, such as: Freedom from the system
administrator and sharing the GNU heritage and values it's no
coincidence that Guix also solves a part of that problem, allowing any
user to install packages.
Debian GNU/Hurd has been a
reality for some years now, reaching 75% of Debian packages being
available for the Hurd.
As a comparison, in Guix only about 1.7%
(32-bit) and 0.9%
(64-bit) of packages
are available for the Hurd. These percentages fluctuate a bit but
continue to grow (both grew with a couple tenth percent point during
the preparation of this blog post), and as always, might grow faster
with your help.
So while Guix GNU/Hurd has an exciting future, please be aware that it
lacks many packages and services, including Xorg.
If you would simply like to install the Hurd on bare metal running
your favorite window manager (e.g.: i3, icewm, etc.) or lightweight
desktop environment (Xfce) right now, then installing Debian
GNU/Hurd
is a good choice. Though we hope to catch up to them soon!
Last October, the 64-bit Hurd was reported to
run
on bare metal. Now that Guix 1.5.0's installer also lets you install
the Hurd on bare
metal, we'd be
thrilled to year from you if you manage to replicate this!
What's Next?
In an earlier
post
we tried to answer the question “Why bother with the Hurd anyway?” An
obvious question because it is all too easy to get
discouraged, to downplay or underestimate the
potential social impact of GNU and the Hurd.
Echoing Samuel Thibault's talk we would like to add: because it offers
a better:
- Freedom #0: the
freedom to run the program as you wish, for any purpose. - Freedom from the System Administrator.
guix pull is known to work but only by pulling from a local branch
doing something like:
mkdir -p src/guix
cd src/guix
git clone https://git.guix.gnu.org/guix.git master
cd master
git branch keyring origin/keyring
guix pull --url=$HOME/src/guix/master
kinda like we did it in the old days.
Other interesting task for Guix include:
- Have
guix pullfrom a non-local URL work on the Hurd, - Have
guix system reconfigurework on the Hurd, - Figure out WiFi support with NetDDE (and add it to installer!),
- Figure out WiFi support with RumpNET (and add it to installer!),
- An isolated build environment
(or better wait for, err, contribute to the Guile build
daemon?), - An installer running the Hurd, and,
- Packages, packages, packages!
We tried to make Hurd development as easy and as pleasant as we could.
As you have seen, things start to work pretty nicely and there is
still plenty of work to do in Guix. In a way this is “merely
packaging” the amazing work of others. Some of the real work that
needs to be done and which is being discussed and is in progress right
now includes:
- Audio support (this was
sponsored by NLnet, thanks!), - RumpNET,
- SMP,
- Journaling for
ext2, - AArch64,
- RISC-V.
With the exception maybe of adding RumpNET NICs, these tasks look
daunting, and indeed that’s a lot of work ahead. But the development
environment is certainly an advantage. Take an example: surely anyone
who’s hacked on device drivers or file systems before would have loved
to be able to GDB into the code, restart it, add breakpoints and so
on—that’s exactly the experience that the Hurd offers. As for Guix,
it will make it easy to test changes to the micro-kernel and to the
Hurd servers, and that too has the potential to speed up development
and make it a very nice experience.
SMP support for the 64-bit Hurd
During the preparation of this blog post a patch set fixing SMP for
the 64-bit
Hurd,
(well, gnumach actually) was presented by Damien Zammit. So most
probably we'll have 64-bit multiprocessing real soon now! It seems
however, that we will need new bootstrap
binaries for that.
Join #guix and #hurd on
libera.chat or the mailing
lists and get involved!
Source: Planet GNU