I manage a large farm of hundreds of VMs for various O/Ses and CPU architectures that we use for software testing of numerous GNU and
other open source projects, and for the annual TeX Live releases, such
as documented here:

https://www.math.utah.edu/pub/texlive-utah/

Among the VMs are numerous ones running Debian versions 5 to 13 on
alpha, amd64 (x86_64), arm64, hppa, loong64, m68k, mips32, mips64,
ppc64le, s390x, and sparc64.

When Debian 12.8 was announced in early November, I readily created a
new VM for it for qemu-system-mips32el. However, a similar installer
script for qemu-system-mips64el was not successful.

I have made numerous attempts on four independent physical machines
running CentOS 7, Ubuntu 22, and Ubuntu 24, with both
distribution-provided, and locally built-from-source, QEMU
installations from versionss 2.0.0 to 9.2.0-rc1, plus a git-tree
snapshot of 23-Nov-2024 that identifies itself as version 9.1.91.

As an independent check, I also tried MIPS64el installations from ISO
images for Debian versions 7 to 11: they were successful, but versions
7 to 10 are useless to me because apt-get cannot find package
repositories, making it impossible to install the scores of packages
that I need for software development in various programming languages.

In every attempt on every physical host and QEMU version for Debian
12.8 on MIPS64el, the VM starts up, the text-mode installer proceeds
in its familiar way past account and network setup, begins to install
packages, and then, depending on the O/S / QEMU-version / physical
host combination, reaches either 75% or 79% completion in its
red-on-blue progress bar, then reports "CPU stuck" errors. I have
even left some of the VMs running for a day or more at that point, but
none ever made further progress.

The installer script has this typical fragment:

QEMU=`which qemu-system-mips64el`

$QEMU \
-machine malta \
-cpu 5KEc \
-m 2G \
-nographic \
-kernel vmlinuz-6.1.0-27-4kc-malta \
-initrd initrd-malta.gz \
-drive if=none,file=debian-12-8-mips64el.qcow2,format=qcow2,id=hd \
-device virtio-blk-pci,drive=hd \
-drive file=/local/iso/debian-12.8.0-mipsel-netinst.iso,format=raw,media=cdrom \
-netdev user,id=qemunet \
-device virtio-net-pci,netdev=qemunet \
-append "console=ttyS0"

The .qcow2 file is an 80GB one. The PATH changes with experiments,
which is why $QEMU is set to the full pathname, so that I can tell
from a "ps auxww" or "top" display which version of QEMU is in use.

I have tried different -cpu options, such as 5KEf, without getting a
successful installation.

I also tried different ISO images

-r--r--r-- 1 4616241152 Nov 9 07:29 debian-12.8.0-mips64el-DVD-1.iso
-r--r--r-- 1 4694515712 Nov 9 07:22 debian-12.8.0-mipsel-DVD-1.iso
-r--r--r-- 1 535429120 Nov 9 07:21 debian-12.8.0-mipsel-netinst.iso

but all had the same installer hangs.

The top of the installer window has options to switch views, but
despite attempts with Ctl, Ctl-Alt, Alt-, and ESC prefixes on 1, 2, 3
and 4, I cannot leave view 1 (installer) to get to view 4 for the
installation log: it is held in a memory filesystem that is lost when
the hung VM is eventually killed (by C-a C to reach the (qemu) prompt,
the q to quit).

My questions for this group are:

(1) Have any of you succeeded for Debian 12.8 on MIPS64el
emulated by QEMU?

(2) If so, what is your recipe for the installation command?

(3) If not, did you see the 75%--79% completion, then a hang?

(4) What is the magic keyboard sequence for switching to
others of the 4 offered views in the installer window?

(5) Is it possible to capture the installer log on the
underlying filesystem, in the hope that is might give
clues about the hang?

(6) Is there an alternate source of package repositories for
Debian versions before 11?

Thanks in advance for your experience, ideas, insight, and
suggestions.

------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah - - Department of Mathematics, 110 LCB Internet e-mail: [email protected] - - 155 S 1400 E RM 233 [email protected] [email protected] - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------

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I would like to extend my deep thanks for Mateusz Jo{\'n}czyk for the
helpful suggestions in postings to this list on 6-Jan-2025

https://lists.debian.org/debian-mips/2025/01/msg00000.html
https://lists.debian.org/debian-mips/2025/01/msg00001.html

in response to my problem report of 5-Dec-2024

https://lists.debian.org/debian-mips/2024/12/msg00000.html

Two key points raised by Mateusz are the (previously unknown to me)
distinction between the 5KEc and 5KEf CPU variants (the 5KEc lacks
hardware floating-point instructions, while the 5KEf has them), and
the suggestion to try a different vmlinuz kernel version.

I'm pleased to report that the kernel switch was the needed fix to my
installer script: I change it to use vmlinuz-6.1.0-27-5kc-malta. The
job then completed successfully, and gave me a working virtual
machine. It now uses the vmlinuz-6.1.0-28-5kc-malta kernel that became available after Debian 12 system updates.

It is, however, still puzzling that, in numerous attempts, the
installer could reach 75% to 79% completion with the vmlinuz-5.10.0-20-5kc-malta kernel, before going into a hung state
with repeated stuck-CPU complaints. That is why I didn't think to try
a kernel switch. That is probably a good lesson for the future when
installers fail!

My Debian 12 build farm now has VMs with these CPUs:

alpha hppa mips32 s390x
arm64 loong64 mips64 sparc64
armhf m68k ppc64le x86

They run with several different versions of qemu-system-xxx.

I made experiments with one of the more recent versions of the qemu-system-mips64el, trying all combinations of -machine and -cpu
options, while requesting 32GB of DRAM. Alas, the largest memory size supported by QEMU appears to be just 2GB, addressable with 31 bits,
despite the processor being a 64-bit one.

Our site has had numerous SGI MIPS-based physical systems since 1992,
but the last of them, an SGI O2 R10000-SC, died with a power-supply
failure about a year ago. My records show that I once had guest
access to a large SGI Origin 2000 with 64 R10000 CPUs and 8GB DRAM,
which is why I expected to find QEMU support for larger memory sizes.

------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah - - Department of Mathematics, 110 LCB Internet e-mail: [email protected] - - 155 S 1400 E RM 233 [email protected] [email protected] - - Salt Lake City, UT 84112-0090, USA URL: https://www.math.utah.edu/~beebe - -------------------------------------------------------------------------------

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