steelsoap

I added my PCI bridge's id to the syslinux configuration as pcie_acs_override, like so:
Find this id at Tools System devices; looks like this for me: [<PCI bridge id>] 03:00.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] 400 Series Chipset PCIe Bridge (rev 01) Go to Main tab, find your Flash device, click on it Scoll down to Syslinux Configuration At Unraid OS section change "append initrd=/bzroot" to "append initrd=/bzroot pcie_acs_override=id:<PCI bridge id>" I tried vfio-pci.ids=... method but that resulted in erroneous boot.
 
This guided me:
 
EDIT:
On ther other hand, unfortunately, the virtualized guest functions way slower so something's not right.