feat: enable libvirt(qemu/kvm) for ai

modules/nixos/libvirt.nix

@@ -0,0 +1,38 @@
+
+{ lib, pkgs, ... }:
+
+{
+  ###################################################################################
+  #
+  #  Enable Libvirt(QEMU/KVM)
+  #
+  ###################################################################################
+
+  virtualisation = {
+    libvirtd = {
+      enable = true;
+      # hanging this option to false may cause file permission issues for existing guests. 
+      # To fix these, manually change ownership of affected files in /var/lib/libvirt/qemu to qemu-libvirtd.
+      qemu.runAsRoot = true;
+    };
+
+    qemu = {
+      # default to QEMU/KVM
+      package = pkgs.qemu_kvm;
+    };
+  };
+  programs.dconf.enable = true;
+  environment.systemPackages = with pkgs; [ virt-manager ];
+
+  boot.kernelModules = [ "kvm-amd" "kvm-intel" ];
+  # Enable nested virsualization, required by security containers and nested vm.
+  boot.extraModprobeConfig = "options kvm_intel nested=1";  # for intel cpu
+  # boot.extraModprobeConfig = "options kvm_amd nested=1";  # for amd cpu
+
+
+  # NixOS VM should enable this:
+  # services.qemuGuest = {
+  #   enable = true;
+  #   package = pkgs.qemu_kvm.ga;
+  # };
+}