I have QubesOS 4.1.1 with Xen 4.14.5 hypervisor system on which I want to
install OpenBSD as a HVM and pass through my NICs to it (Intel Wireless
AC-9560 and Realtek 8168 rev 0x15: RTL8168H/8111H). I tested that when
installing OpenBSD on actual hardware both NICs seems to working properly.
But on hvm ethernet spamming me with: re0: watchdog timeout messages and
not working. Wireless causing OpenBSD Panic! first throwing errors like
this: iwm0: fw chunk addr 0x404000 len 712 failed to load.

I previously try to report it on OpenBSD mailing list, with my dmesg when
only eth passad through attached:
https://marc.info/?l=openbsd-bugs&m=166318676430481&w=2
and also on QubesOS issue tracker:
https://github.com/QubesOS/qubes-issues/issues/7765

I found also an similar issue with bhyve (re fw on guest not working when
passed through the same eth NIC to OpenBSD) on FreeBSD mailing list:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=245392

If You think that error is on the driver side please let me know, I will
try to forced it on Open BSD mailing list or report to the fw vendor.