I love virtualization in Linux and I would like to have operating system which will work only as minimal, air-gapped as much is possible host for my guest operating systems. Qubes OS project really interested me but it’s based on Xen hypervisor so it might cause troubles with GPU Passthrough which is really important for me also I’m more interested in KVM. In my case it’s not only about security and privacy but also about fun and learning. What can you recommend? I think that good choice might be Gentoo Linux because it allows for minimal installation and remove unnecessary software like CUPS, Bluetooth entirely with flags which will be great option for host only OS. But I had experience with Gentoo and it’s not easiest way 😅 Debian might be easier option but I will have less control over my system. Maybe you have other interesting options?
Proxmox is based on debian, with it’s own virtualization packages and system services that do something very similar to what libvirt does.
Libvirr + virt manager also uses qemu kvm as it’s underlying virtual machine software, meaning performance will be identical.
Although perhaps there will be a tiny difference due to libvirt’s use of the more performant spice for graphics vs proxmox’s novnc but it doesn’t really matter.
The true minimal setup is to just use qemu kvm directly, but the virtual machine performance will be the same as libvirt, in exchange for a very small reduction in overhead.