defiant: add libvirtd

hosts/defiant/configuration.nix

@@ -6,6 +6,7 @@
       ../../base.nix
       ../../common/metrics-exporters.nix
       ./hardware-configuration.nix
+      ./libvirt.nix
 
       ./services/nginx.nix
       ./services/pihole.nix

hosts/defiant/libvirt.nix

@@ -0,0 +1,18 @@
+{ config, pkgs, lib, ... }:
+{
+  virtualisation.libvirtd.enable = true;
+  programs.dconf.enable = true;
+
+  boot.extraModprobeConfig = "options kvm_amd nested=1";
+  boot.kernelModules = [ "kvm-amd" "kvm-intel" ];
+
+  users.users.felixalb.extraGroups = [ "libvirtd" ];
+
+  fileSystems."/var/lib/libvirt/images" = {
+    device = "/tank/iso";
+    options = [ "bind" ];
+  };
+
+  # On a gui-enabled machine, connect with:
+  # $ virt-manager --connect "qemu+ssh://defiant/system?socket=/var/run/libvirt/libvirt-sock"
+}