foop09

I just wanted to chime in, tried virtiofs for the first time ever today and gosh performance is SO much better than 9p but after coming back to my ubuntu VM it was locked, all cores pegged at 100%. Trying again with a Manjaro VM but I dont see it being any better. Hoping there was a fix but I dont see one yet... I hope this gets resolved because the performance for me with virtiofs vs 9p is night and day!

Responding to this thread because I just spend 2 days looking all over the internet for why my USB audio card was still crackling in my macOS Monteray VM. I do not have any additional PCIe USB cards in my system. I went to VM Manager and enabled "downstream" for PCIe ACS Override, then rebooted. (I turned off the auto-start on the array just because I wanted to be extra safe I don't accidentally pull out the SATA controller from my system for any reason..) Anyway, then when it came back up I found the IOMMU group that contained my motherboard's onboard USB 3.0 controller and set it to "bind to VFIO at boot" and rebooted. This IOMMU group contained my motherboards encryption controller as well as the motherboard audio ports. After the last reboot, I started up the array, and set newly isolated USB 3.0 controller to a pci device for my macOS VM, plugged the USB audio card into the port and it worked like a charm. I can now unplug usb devices from the VM while its running with no issue. TL;DR - don't pass the USB Audio card directly to a macOS VM - it will still crackle. The only way to get around the crackle/popping/dropping out audio is to pass an entire USB controller to the VM.

In my case I have the best luck when my VM's "machine" is set to i440fx and making sure the PCI device is set to "bind to VFIO at boot" in the device settings under the tools menu. With these settings I have had two different GPUs passthrough with no issues. Obviously, before doing any of this ensure your bios is configured properly for PCI-passthrough. However, I have two different AMD GPUs where passthrough NEVER works, I'll get the single core at 100% and the VM will never POST. I'm guessing there's an incompatibility with these cards.

Did you ever find a solution to this? I have the same issue, when I add the GPU with VBIOS the CPU gets pegged and never boots or posts. However, set the graphics back to VNC and it's fine. Could it be my actual GPU? no idea