NIC PCI Throughput on SLES15 Xen

To test speed on an Windows VM, I placed an extra NIC in the server (SLES15SP1) .
As I have done in the past, with the main file server ( OES2018 ) I have also a NIC passthrough for that.
I am doing a the PCI passtrough, selecting the NIC ( Realtek 8111 )
But I am unable to boot the vm. What am I missing ?

@stelgenkamp Hi, check the output from /sbin/lspci might be the extra card has moved the bus id numbers for your passthrough nic (as in vfio-pci passthrough?)

Back again on this same topic, have confirmed with lspci that the card id is correct.
pci-assignable-list shows the correct id.
Then I read something about pciback needed for the free pci.
But then my system errors saying pciback module is not on the system?
Does SLES15 still use pciback ?

@stelgenkamp Hi, as in xen-pciback should be part of the kernel…

Ok, so yes xen-pciback is present.
So on a Linux VM I already have a working PCI passthrough, so everything is there to make it possible.
Now to get this PCI to passthrough to the Windows VM.
Any ideas ?

@stelgenkamp Hi, I’d have to pass as don’t use Xen (I’m a qemu user), suggest a read here: