---
layout: post
title: Windows VM under Devuan with QEMU / libvirt
date: 2021-03-23 20:32 +0100
categories: tech
---
So, I'm running Devuan Beowulf (Debian Buster based). Recently, I was in the need of running a
tax software which only supports Windows (also has a web-based solution, which is okay, but I prefer
to keep my data local).

I started running the software with Wine 5. A system upgrade to Wine 6 broke the software. I managed to downgrade
wine, however, the software was really running flaky and unreliably from that on.

So I convinced myself to run a Windows VM. VirtualBox is "too easy", also, there seem to be performance issues.
Also, I wanted to learn something, so I dove into the libvirt/qemu/KVM stack.

Boy, did I lose some hair over this.

[With](https://linuxhint.com/libvirt_qemu_kvm_debian/) [some](https://www.florian-fritsch.com/kvm-unter-debian-10-mit-windows-10-vm/)
[help](https://dennisnotes.com/note/20180614-ubuntu-18.04-qemu-setup/) from the internet, I managed to get a Windows machine running.

From what I figured out, I need the following packages. I don't remember what apt installed as recommended/suggested packages
anymore, though.

- virt-manager: GUI for managing VMs
- gir1.2-spice-client-gtk-3.0: Needed for viewing the VM
- spice-vdagent: Desktop integration (copy/paste, auto-resize)
- dnsmasq: Needed for NAT networking (daemon can be disabled)
- libguestfs-tools: Command line tools for managing disk images
- qemu-kvm qemu: Actual virtualization software
- virt-viewer: Additional tool for viewing guest, has additional feature of folder sharing (?)
- libvirt-daemon libvirt-daemon-system: Virtualization daemon. Calls QEMU? (also supports LXC and others)
- libvirt-clients: Command line tool to manage VMs
- ovmf: For UEFI support

A word about ovmf: I created the VM before installing it. Once the VM is created, it's not possible
to change the firmware from BIOS to UEFI. So better install it first.

So

```
# apt install virt-manager gir1.2-spice-client-gtk-3.0 spice-vdagent dnsmasq libguestfs-tools qemu-kvm qemu virt-viewer libvirt-daemon libvirt-daemon-system libvirt-clients ovmf
```

Next, there was a suggestion to add a libvirt group - or libvirtd, whatever you prefer (which Devuan doesn't seem to do automatically).
Next, add your user to the group.

```
# groupadd --system libvirt
# gpasswd -a <username> libvirt
# gpasswd -a <username> libvirt-qemu
```

Next, there are some config file changes to do.

First, edit `/etc/libvirt/libvirtd.conf`. Search for the respective settings.

```
unix_sock_group = "libvirt"
unix_sock_rw_perms = "0770"
```

Then, edit `/etc/libvirt/qemu.conf`. 

```
user = "libvirt-qemu"
group = "libvirt-qemu"

nvram = [
   "/usr/share/OVMF/OVMF_CODE.fd:/usr/share/OVMF/OVMF_VARS.fd"
]
# Important! You need to remove all other default entries, even if they
# are comments. The config parser seems to have problems with comments
# inside the array. So this won't work:
#  nvram = [
#     "/usr/share/OVMF/OVMF_CODE.fd:/usr/share/OVMF/OVMF_VARS.fd"
#  # other....
#  # entries...
#  ]
```

You might also want to copy `/etc/libvirt/libvirt.conf` to `$HOME/.config/libvirt/` and adjust the
default connection URL, so virsh on command line will use the system qemu connection.

```
# $HOME/.config/libvirt/libvirt.conf
uri_default = "qemu:///system"
```

After these changes, you must restart the libvirtd daemon. Also, logout and login so you're member
of the correct groups. You're better off with restarting the system probably.

Finally, you can create a VM with virt-manager, which I won't detail in here. Look at the other guides ;)

However, I should mention I had severe problems with virt-manager complaining about
insufficient permissions for the disk image when creating the VM, although it was owned by the
libvirt-qemu group, which I was a member of.

I ended up creating the VM as root, which is less than ideal. Somehow the image
ended up being owned by root:root, although, from my understanding, it should've been created
for the group libvirt-qemu. Input is welcome.