Comment # 5 on bug 1157366 from Gary Ching-Pang Lin

The "-nodefaults" parameter seems to be the key.

Here is my qemu command for the VM with seabios:

qemu-system-x86_64 \
  -enable-kvm -s -S -smp 2 -machine type=q35 \
  -drive file=opensuse-15.1.img,if=virtio \
  -m 2048 \
  -virtfs
local,id=fsdev,path=share,security_model=passthrough,mount_tag=v_share \
  -monitor stdio \
  -debugcon file:debug.log -global isa-debugcon.iobase=0x402 \
  -serial unix:serial,server,nowait \
  -display none \
  -netdev user,id=hostnet0 -device virtio-net-pci,romfile=,netdev=hostnet0

It worked fine until I appended "-nodefaults". Maybe some default device was
disabled and caused the problem.