Issues with libvirtd after upgrade to latest stable

I've just upgraded to latest stable and libvirtd simply didn't start. Thankfully I was able to find #11117 and then 2f32bfc7 and 25038632 that references it and get myself qemu user. Without that I was getting:

2020-06-07 10:50:59.924+0000: 3500: error : virGetUserID:838 : invalid argument: Failed to parse user 'qemu'
2020-06-07 10:50:59.924+0000: 3500: error : virStateInitialize:660 : Initialization of QEMU state driver failed: invalid argument: Failed to parse user 'qemu'
2020-06-07 10:50:59.924+0000: 3500: error : daemonRunStateInit:603 : Driver state initialization failed

So upgrade wasn't flawless to say the least, if something can be fixed there is would be nice.

What I didn't solve yet is inability to use vfio:

internal error: process exited while connecting to monitor: 2020-06-07T12:06:46.392905Z qemu-system-x86_64: -device vfio-pci,host=0000:04:00.0,id=hostdev0,bus=pci.1,addr=0x0,rombar=0: vfio 0000:04:00.0: failed to setup container for group 14: failed to open /dev/vfio/vfio: Permission denied

UPD: It also often hangs when I try to use vfio, probably related to #11602 (closed)