Problem/Justification
SPICE can accomplish audio and USB redirection between a Linux VM and the SPICE client and allow sharing of a client-side folder to the VM. However, all these capabilities are currently disabled in the libvirt XML generated when a SPICE display device is added to a VM in 25.10.
Impact
VM admins will need to roll their own redirection solutions instead of taking advantage of native capabilities. Configuring PulseAudio to default to TCP sockets works for audio redirection but is clunky. USB redirection requires 3rd party software, which introduces additional licensing costs.
User Story
Adding a SPICE display device to a VM should, in addition to creating the QXL paravirtualized video adapter, add the following to the libvirt XML for the VM:
- Switch the machine type to Q35
- Enable ich9-intel-hda
- Add the virtual serial ports needed for the SPICE vdagent and folder sharing
- Add virtual USB ports for USB redirection. (Note, these are different from the USB passthrough settings currently in the UI, as these are the server-side USB ports, not the client-side.)
This will establish parity with ProxMox, and greatly increase the usability of the VMs in TrueNAS.