VFIO of Intel Audio Breaks Ethernet Controller?

[js2]

I was able to use VFIO to passthrough my audio card just fine (see below). I added the "8086:06c8" address in /etc/modprobe.d/vfio.conf

00:1f.3 Audio device [0403]: Intel Corporation Device [8086:06c8]

This was great! My audio worked, until I noticed that I couldn't get to my host, outside of my Desktop VM...! My website (hosted on proxmox) was also unavailable.

I noticed that my Intel ethernet controller is in the "00:1f" family.

00:1f.6 Ethernet controller [0200]: Intel Corporation Device [8086:0d4d]

So through testing, I know that if I remove the audio device, everyone is happy. It's weird, because I would think my "8086:06c8" declaration would let it separate the ethernet card from the audio controller.

Is there a way to passthrough my audio controller, without breaking my ethernet port? I have a second Realtek NIC, so I was considering switching my host over to that, but I would prefer to use the Intel card.

For hte record, any way to get a 3.5mm source of audio would be great. I tried virtual audio devices, and I also looked for my audio card to VFIO, but neither of those options worked for me.

As always, thank you for your time!

 

[Stefan_R]

Check your IOMMU groups (as described here). An IOMMU group is the smallest assignable unit, so if your audio and ethernet adapters share a group, you can only pass them through as one.

Three solutions come to mind:

• Use a seperate PCIe audio or ethernet card and hope that your motherboard isolates their slots
• Add pcie_acs_override=downstream to your kernel commandline and hope for the best - keep in mind that this is a hacky workaround that might make things go kaput very badly
• Don't pass through an audio device and instead let the host handle it, then use something like scream

 

[js2]

That makes perfect sense, thank you for clarifying. I remmeber the pcie_acs_override=downstream option from back when I was initially learning about vfio. I will probably skip that, and just stick with a USB sound card for now. I could also switch to my Realtek NIC, but the internet makes me think I should stick with Intel.

Scream is really interesting, I appreciate you sharing it.