Assertion failed: (error == 0), function modify_bar_registration, file /usr/src/usr.sbin/bhyve/pci_emul.c, line 706.

On a 15.0-ALPHA3 host, bhyve fails when I try to start a 9front VM.
Error:

Assertion failed: (error == 0), function modify_bar_registration, file /usr/src/usr.sbin/bhyve/pci_emul.c, line 706.
fbuf frame buffer base: 0x38bfae800000 [sz 33554432]

I don't see any recent changes in bhyve/pci_emul.c recently.

>>>This used to work fine when the same machine ran stable/14....<<<

I can boot bsd and linux vms that I tried fine but not 9front.

This is what I run:
bhyve -c 1 \
        -s 0,hostbridge \
        -s 5,virtio-blk,9front.img \
        -s 10,virtio-net,tap1,mac=XXXXXXXXXXXX \
        -s 11,fbuf,tcp=0.0.0.0:5900,w=1920,h=1080,wait \
        -s 20,xhci,tablet \
        -s 31,lpc \
        -l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \
        -m 4G -H -w \
        9front

Any hints on how to debug this?

Thanks,
Bakul

PS: stable/15 kernels also seem to be a bit unstable. Once in a
while the machine just freezes. Happened twice in 4 days. Haven't
looked into this yet.