Reading the changes and came to the qemu point, then I'm reading qemu4 changes and see this:
Code:
Q35: advertised PCIe root port speeds will now optimally default to maximum link speed (16GT/s) and width (x32) provided by PCIe 4.0 for QEMU 4.0+ machine types; older machine types will retain 2.5GT/x1 defaults for compatibility.
Now I'm confused, does this mean I can set (if my hardware supports it) it to either PCIe v1.0 or PCIe v4.0 - or have I missed something and I could set it to 2.0 or 3.0 too?