Openstack RDO && KVM Hypervisor: Just another KVM setup on Debian Buster 10.3

Sequence of steps and bridge network configuration on native Debian Buster 10.3 host seemed to me a bit different from manuals which are available in meantime on the Net. Specifically I've undertaken some additional steps to fix error with Radeon kernel modesetting enabling also configuration bridge to physical LAN is supposed to be done in the way different from how it works on LMDE 4.

We intend to start with adding two following lines to /etc/apt/sources.list
deb http://ftp.us.debian.org/debian/ testing main non-free contrib
deb-src http://ftp.us.debian.org/debian/ testing main non-free contrib
and afterwards run
$ sudo apt-get update
$ sudo apt-get install firmware-amd-graphics
It would resolve for myself two issues :-
1. Radeon kernel modesetting enabled
[ 1.583423] [drm] radeon kernel modesetting enabled.
[ 1.583588] [drm] initializing kernel modesetting (CAICOS 0x1002:0x6779 0x1458:0x22A3 0x00).
[ 1.583622] resource sanity check: requesting [mem 0x000c0000-0x000dffff], which spans more than PCI Bus 0000:00 [mem 0x000d0000-0x000d3fff window]

2. Makes core setup free from workarounds

when installing "Virtualization Server"
======================================
Now install required packages :-
======================================
$ sudo apt -y install qemu-kvm \
libvirt-daemon bridge-utils \
virtinst libvirt-daemon-system
$ sudo apt -y install virt-top libguestfs-tools \
libosinfo-bin qemu-system virt-manager
===================================
Load "virt-host" and update /etc/modules.
===================================
$ sudo modprobe vhost_net
$ lsmod | grep vhost
vhost_net 24576 0
tun 49152 1 vhost_net
vhost 49152 1 vhost_net
tap 28672 1 vhost_net
$ echo vhost_net | sudo tee -a /etc/modules
=================================================================

At this point create bridge br1 on native Debian Buster 10.3

=================================================================

root@boris-pchsw:~# apt install bridge-utils

root@boris-pchsw:~# cd /etc/network

root@boris-pchsw:/etc/network# cat interfaces

source-directory /etc/network/interfaces.d

root@boris-pchsw:/etc/network# cd interfaces.d

root@boris-pchsw:/etc/network/interfaces.d# cat br1

#Primary network interface(enp3s0)

auto enp3s0

iface enp3s0 inet manual

#Configure bridge and give it a static ip