Allow mapping the current user's keys into the VM

lib/configuration.nix

@@ -16,6 +16,7 @@
         vmConfig = {
           virtualisation = {
             sharedHostKeys = true;
+            sharedUserKeys = true;
             usb-redirect = true;
             virt-viewer = true;
             cores = 4;

lib/modules/custom-build-vm.nix

@@ -36,6 +36,12 @@ in {
           default = false;
         };
 
+        sharedUserKeys = lib.mkOption {
+          type = lib.types.bool;
+          description = lib.mdDoc "Whether to load the current user's keys into every user's homer on the VM.";
+          default = false;
+        };
+
         usb-redirect = lib.mkOption {
           type = lib.types.bool;
           description = lib.mdDoc "Whether to enable USB redirection to the VM.";
@@ -137,7 +143,21 @@ in {
                   source = path;
                   target = path;
                 };
+              } // (lib.optionalAttrs vmVariant.virtualisation.sharedUserKeys (
+                lib.attrsets.concatMapAttrs (
+                  name: user:
+                    let
+                      prefix = if vmVariant.virtualisation.runAsRoot
+                        then "sudo -u#$SUDO_UID "
+                        else "";
+                      homeDir = "$(${prefix}bash -c 'echo $HOME')";
+                    in {
+                      "userKeys-${name}" = {
+                        source = "${homeDir}/.ssh";
+                        target = "/home/${name}/.ssh";
                       };
+                    })
+                  config.users.myUsers));
             };
           };