Fix everything.

system/services/general/libvirtd/default.nix

@@ -0,0 +1,39 @@
+{ config, lib, pkgs, ... }:
+{
+  options.system.libvirtd.enable = lib.mkEnableOption "Enable libvirtd services";
+
+  config = lib.mkIf config.system.libvirtd.enable {
+    virtualisation.libvirtd = {
+      enable = true;
+      onBoot = "ignore";
+      onShutdown = "shutdown";
+      qemu = {
+        ovmf = {
+          enable = true;
+          packages = with pkgs; [ OVMFFull.fd ];
+        };
+        vhostUserPackages = with pkgs; [ virtiofsd ];
+        swtpm.enable = true;
+      };
+    };
+
+    programs.virt-manager.enable = true;
+
+    environment.persistence."/persist".directories = [
+      "/var/lib/libvirt/dnsmasq"
+      "/var/lib/libvirt/nwfilter"
+      "/var/lib/libvirt/qemu"
+      "/var/lib/libvirt/secrets"
+      "/var/lib/libvirt/storage"
+      "/var/lib/libvirt/swtpm"
+    ];
+
+    # Needed to make NAT work
+    networking.firewall.trustedInterfaces = [
+      "virbr0"
+      "virbr1"
+    ];
+
+    systemd.tmpfiles.rules = [ "f /dev/shm/looking-glass 0660 - libvirtd -" ];
+  };
+}