unable to start kvm (qemu 4.0) because of pulseaudio after upgrade to ubuntu 19.10

Question

When starting the KVM (that was working fine in ubuntu 19.04) I am getting the following error:

Error starting domain: internal error: qemu unexpectedly closed the monitor: pulseaudio: pa_context_connect() failed pulseaudio: Reason: Connection refused pulseaudio: Failed to initialize PA contextaudio: warning: Using timer based audio emulation

Traceback (most recent call last):   File "/usr/share/virt-manager/virtManager/asyncjob.py", line 75, in cb_wrapper
    callback(asyncjob, *args, **kwargs)   File "/usr/share/virt-manager/virtManager/asyncjob.py", line 111, in tmpcb
    callback(*args, **kwargs)   File "/usr/share/virt-manager/virtManager/object/libvirtobject.py", line 66, in newfn
    ret = fn(self, *args, **kwargs)   File "/usr/share/virt-manager/virtManager/object/domain.py", line 1279, in startup
    self._backend.create()   File "/usr/lib/python3/dist-packages/libvirt.py", line 1080, in create
    if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self) libvirt.libvirtError: internal error: qemu unexpectedly closed the monitor: pulseaudio: pa_context_connect() failed pulseaudio: Reason: Connection refused pulseaudio: Failed to initialize PA contextaudio: warning: Using timer based audio emulation

I have made the changes to the config file. I have added the following lines to reflect the change from qemu 3.1 to 4.0

  <qemu:commandline>
    <qemu:env name="QEMU_AUDIO_DRV" value="pa"/>
    <qemu:env name="QEMU_PA_SERVER" value="/run/user/1000/pulse/native"/>
  </qemu:commandline>

If I remove these lines I cannot passthrough sound to pulseaudio.

yes the kvm audio user is me.

Any help will be appreciated. Is this a bug or a setup issue. my guest is windows 10 (1903)

Solution

This is because change in audio configuration since qemu 4.0. You need to edit your vm configuration:

sudo virsh edit <your_vm>

Then replace your lines:

   <qemu:commandline>
    <qemu:env name="QEMU_AUDIO_DRV" value="pa"/>
    <qemu:env name="QEMU_PA_SERVER" value="/run/user/1000/pulse/native"/>
  </qemu:commandline>

with:

<qemu:commandline>
  <qemu:arg value='-audiodev'/>
  <qemu:arg value='pa,id=pa1,server=/run/user/1000/pulse/native'/>
</qemu:commandline>

I found this here: https://www.reddit.com/r/VFIO/comments/b1crpi/qemu_40_due_soon_might_bring_superb_audio_test_now/

Comments

[user63726]

My host is ubuntu 19.10 and the guest is windows 10. The KVM was created on ubuntu 19.04. I know that I need to change the config file to match the new version of qemu. Everything that I found did not work for me. It is not well documented how to change the config to the new version of qemu.

[user63726]

Thanks. I have a windows quest. The sound is not passed to pulseaudio. There is something else that I am missing. It is playing it in windows on "High definition audio device". I hear nothing because is is not passed.

[randomei]

When you start vm, open in ubuntu pavucontrol program, and check if there is qemu in playback programs. If no, then try to check for problem in qemu log: /var/log/libvirt/qemu/your_vm.log

[user63726]

I got this error in the log file.

[user63726]

pulseaudio: pa_context_connect() failed pulseaudio: Reason: Connection refused pulseaudio: Failed to initialize PA contextaudio: Could not init `pa' audio driver

[user63726]

yes I am user 1000, and I am in the libvirt group

[randomei]

I had the same problem, I've tried to configure apparmor without success and simpliest solution was to enable tcp protocol for pulse. Copy /etc/pulse/default.pa to ~/.config/pulse/ then find: #load-module module-native-protocol-tcp change this line to: load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1 then edit your vm configuration: <qemu:commandline> <qemu:arg value='-audiodev'/> <qemu:arg value='pa,id=pa1,server=127.0.0.1'/> </qemu:commandline>

[randomei]

P.S. You should also restart pulsaudio with pulseaudio -k