qemu-pipewire-audio-fix

gistfile1.md

I was pulling my hair out trying to get audio working in my QEMU virtual machines through Virt-Manager. Everything seemed perfect - the VM booted fine, graphics worked, but absolutely no sound. After hours of debugging, I finally found the solution.

The Problem I Faced I had just migrated my Gentoo system from PulseAudio to PipeWire (because, let's be honest, PipeWire is the best :D ). Everything worked beautifully on my host system, but when I tried to run VMs through Virt-Manager, I hit a wall:

• VMs launched perfectly through Virt-Manager GUI
• Graphics, networking, everything worked except audio
• Direct QEMU command-line worked with audio (which was frustrating!)
• Kept seeing GSpice warnings in Virt-Manager output
• No matter what I tried in the Virt-Manager GUI, no audio devices appeared in the VM !!!

My System Setup: When I encountered this issue, I was running:

• Distribution: Gentoo Linux
• Init System: systemd
• Audio Server: PipeWire (migrated from PulseAudio)
• QEMU Version: 8.x+
• Virt-Manager: 4.x+
• Libvirt: Standard setup (emerge with spice tag)

How We Fixed It? After reviewing the documentation and forums we realized the issue and figured out that: Virt-Manager wasn't automatically configuring the audio devices properly for PipeWire. The solution required manually editing the libvirt XML configuration.

Here's exactly what we did:

Step 1: Find Your VM's XML File

First, we located my VM's configuration file. These are stored in /etc/libvirt/qemu/:

/etc/libvirt/qemu/your-vm-name.xml

Step 2: Add the Missing Audio Configuration

I opened the XML file and added these blocks inside the <devices> section:

<sound model="ich9">
  <codec type="micro"/>
  <address type="pci" domain="0x0000" bus="0x00" slot="0x1b" function="0x0"/>
</sound>

<audio id="1" type="pipewire" runtimeDir="/run/user/1000">
  <input name="qemuinput"/>
  <output name="qemuoutput"/>
</audio>

Step 3: Edit the File

I used nano to edit the configuration:

nano /etc/libvirt/qemu/your-vm-name.xml

(You can also use VS Code if you prefer):

$ sudo -E code --no-sandbox --user-data-dir ~/.vscode-root /etc/libvirt/qemu/your-vm-name.xml

Step 4: Restart and Test

After saving the file, I restarted the VM through Virt-Manager. Finally! Audio worked perfectly.

What These Settings Do Let me break down what I learned about these configurations:

The Sound Device

• Sound Model: ich9
• Codec: micro
• Audio Type: pipewire - Tells QEMU to use PipeWire backend
• Runtime Directory: /run/user/1000 - Points to the user session runtime directory

Critical Points I Discovered

• The runtimeDir only works when your user session is active
• Your GUI session must be running with PipeWire active
• Virt-Manager doesn't automatically add the <audio> block for PipeWire
• Manual XML editing is the only way to make this work properly

,What I Tried Before (That Worked, But Not Ideal)

For reference, I knew direct QEMU worked perfectly because this command gave me audio:

qemu-system-x86_64 \
  -enable-kvm \
  -m 4096 \
  -cpu host \
  -machine q35 \
  -device ich9-intel-hda \
  -device hda-duplex,audiodev=audio0 \
  -audiodev pa,id=audio0,out.buffer-length=10000,in.buffer-length=10000 \
  -cdrom /path/to/your/iso/file.iso

This worked fine, but it uses PulseAudio backend (pa), which wasn't ideal for my PipeWire setup. I wanted the proper PipeWire integration through Virt-Manager.

If You're Still Having Issues

Here's what to check if my solution doesn't work for you:

Common Problems I Encountered

1. Still no audio: Make sure PipeWire is actually running and your user session is active
2. XML errors: Double-check the syntax and make sure it's properly nested in the <devices> block

We spent way too many hours on this problem, so hopefully this saves you some time! [Sorry for my bad language]