Comment 5 for bug 1848556

Quick checks:
- does not depend on the exact image, e.g. https://cloud-images.ubuntu.com/eoan/current/eoan-server-cloudimg-amd64.img or https://download.fedoraproject.org/pub/fedora/linux/releases/30/Cloud/x86_64/images/Fedora-Cloud-Base-30-1.2.x86_64.qcow2 hang as well
- the former qemu 3.1 based qemu-utils work fine

Maybe that helps to identify a known patch that might already exist.
Even it if doesn't the simple repro in comment #2 should still help.

If there is no immediate idea out of the data we have let me know, this seems bisectable to me.