Hey all, I am trying to build a system that brings together multiple computers into one as VMs. I want to do this using a mix of Win 10 (for working computers) and Kodibuntu, so each computer has a separate VM, with a separate GFX card passed thru to that. However, I am hitting some issues.

 

My setup is a powerful PC with 2x8-core Xeon CPUs and 32GB of memory. I've installed 3 GFX cards: a Radeon 7950 and two Radeon 7450 fanless devices. So, I have one VM running with the 7950 (typing this on that now) running Win 10 as a work computer. I have also created another VM with one of the Radeon 7450s running Win 10 again, and that is running fine: both systems are ticking along nicely.

 

However, when I create another VM and assign the other Radeon 7450 running Kodibuntu, the others get very slow and laggy. When I kill of the Kodibuntu VM, they work fine. I am guessing that something in this setup, probably having two similar GFX cards on board, is messing it up. Any thoughts?

 

I've poked through the system log, and have seen this:

 

Mar 19 13:25:21 Bernard kernel: vgaarb: device changed decodes: PCI:0000:82:00.0,olddecodes=io+mem,decodes=io+mem:owns=none
Mar 19 13:25:21 Bernard kernel: vgaarb: device changed decodes: PCI:0000:84:00.0,olddecodes=io+mem,decodes=io+mem:owns=none
Mar 19 13:25:21 Bernard kernel: kvm: zapping shadow pages for mmio generation wraparound
Mar 19 13:25:22 Bernard kernel: vfio-pci 0000:00:1d.0: enabling device (0000 -> 0002)
Mar 19 13:25:22 Bernard kernel: vfio_cap_init: 0000:00:1d.0 hiding cap 0xa
Mar 19 13:25:22 Bernard kernel: vfio-pci 0000:84:00.0: enabling device (0000 -> 0003)
Mar 19 13:25:23 Bernard kernel: device vnet2 entered promiscuous mode
Mar 19 13:25:23 Bernard kernel: br0: port 4(vnet2) entered listening state
Mar 19 13:25:23 Bernard kernel: br0: port 4(vnet2) entered listening state
Mar 19 13:25:24 Bernard kernel: vfio-pci 0000:82:00.0: enabling device (0000 -> 0003)
Mar 19 13:25:25 Bernard kernel: kvm: zapping shadow pages for mmio generation wraparound

 

Anything in there that might help? Any suggestions on which bit to hit with a hammer?

Hmm, did some more poking around and I think this was an HDMI audio issue. Disabling HDMI sound fixed it, as did switching the machine to an i440-fx2.3. Will post a more definitive answer when I figure it out the record.