Comment 10 for bug 1894869

You need to configure our PBS repository to get the library:

# echo "deb http://download.proxmox.com/debian/pbs buster pbstest" >> /etc/apt/sources.list.d/pbs.list
# apt update
# apt install libproxmox-backup-qemu0-dev

> I think the most recent version of qemu actually has a fix for all devices that give this error, as there were reports of some HBA cards also causing it.

Hm, not sure about that, the patch I added is against our 5.1 build from the repo. That said, 5.1 is newer than what's currently rolled out, so you can also try just building the repo version without any patches and see if that fixes it. That would be nice, since 5.1 will be rolled out soon-ish anyway :)