Issues with network device since Qemu 6.0.0 (German Windows Server 2022)

[Mike Höhn]

Hello,

I'm having a problem with a german Windows Server 2022 Standard. With Qemu 
versions 6.0.0 and following the network device isn't working. Right after 
installation Windows shows the following status in the device manager:

"Die Klassenkonfiguration für dieses Gerät wird von Windows noch eingerichtet. 
(Code 56)."
English translation should be:
"Windows is still setting up the class configuration for this device. (Code 
56)"

I doesn't matter if I use virtio or e1000 for the network device. When 
installing the virtio driver (I tried 215, 217 and 221) it takes several 
minutes until an error message appears. With e1000 the Windows installation 
process takes significantly longer, as if it's doing something for several 
minutes, like when installing the virtio driver.

So I guess it's not the virtio driver. I have tried so many things, but 
nothing helps. Interestingly i can get Windows Server 2022 to work without 
problems using Qemu 5.2.0. The virtio driver installs quickly and without 
problems.

The same problem occurs when installing Windows with Qemu 5.2.0 and then 
booting the working Windows with Qemu 6.0.0 or newer. After windows has booted 
with Qemu 6.0.0, the network device is not functional anymore.

There's this thread in a Proxmox forum (I don't know Proxmox, but it seems to 
use Qemu):

https://forum.proxmox.com/threads/windows-server-2022-virtio.97887/

I hope this links works for translating the whole page to english:
https://forum-proxmox-com.translate.goog/threads/windows-server-2022-virtio.
97887/?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=de&_x_tr_pto=wapp

People there say they have the exact same problem with the German edition of 
Windows Server 2022, but the english version would work. Unfortunately I don't 
have access to the english version.
Some say q35 5.1 and 6.0 would work, 6.1 not. I tried this all, but with Qemu 
6.0.0 or newer it just doesn't work at all.

I think it's clear that something must have changed between Qemu 5.2.0 and 
6.0.0. But what and why? Is this a bug? Or do I need to configure Qemu 
differently? I have no clue.

Does anyone have an idea what the reason for this problem could be and how it 
could be solved?

Here's my configuration:

Host is Slackware 15.0 64 bit. CPU is a AMD Ryzen 9 5900X.
This is the build script used to compile Qemu:
https://www.slackbuilds.org/slackbuilds/15.0/system/qemu/qemu.SlackBuild
I tried from 5.2.0 to 7.0.0 and also the master branch using this script.

The guest is using UEFI with OVMF 20220719.209.

Windows is the following version:
Windows Server 2022 Standard, German. Version 21H2, Build 20348.169.

This is how I start Qemu:

/usr/bin/qemu-kvm -enable-kvm -name dc1 -m 8G -k de -drive 
if=pflash,format=raw,readonly=on,file=/root/ovmf/usr/share/edk2.git/ovmf-x64/
OVMF_CODE-pure-efi.fd -drive if=pflash,format=raw,file=/var/lib/kvm/dc1/
vars.fd -drive id=disk0,if=none,cache=unsafe,format=qcow2,file=/var/lib/kvm/
dc1/dc1.qcow2 -drive id=cd0,if=none,format=raw,readonly=on,file=/root/
WindowsServer2022.iso -drive id=virtiocd,if=none,format=raw,file=/root/virtio-
win-0.1.215.iso -vnc :20 -usb -device driver=virtio-scsi-pci,id=scsi0 -device 
scsi-hd,drive=disk0 -device driver=ide-cd,bus=ide.0,drive=cd0 -device 
driver=ide-cd,bus=ide.1,drive=virtiocd -device usb-tablet -net 
nic,macaddr=DE:DE:DE:DE:DE:DE,model=e1000 -net tap,script=/etc/qemu-ifup -
monitor telnet:localhost:1020,server,nowait -daemonize -boot menu=on -smp 2 -
cpu host

I hope someone can help. Let me know if there is something I can do to find 
the reason for this problem.

Thank you in advance
Mike