1 files changed, 24 insertions, 0 deletions
diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix
index 760f69121612b..74f6521462b85 100644
--- a/nixos/modules/virtualisation/qemu-vm.nix
+++ b/nixos/modules/virtualisation/qemu-vm.nix
@@ -923,6 +923,8 @@ in
       mkVMOverride (cfg.fileSystems //
       {
         "/".device = cfg.bootDevice;
+        "/".fsType = "ext4";
+        "/".autoFormat = true;
 
         "/tmp" = mkIf config.boot.tmpOnTmpfs
           { device = "tmpfs";
@@ -953,6 +955,28 @@ in
           };
       } // lib.mapAttrs' mkSharedDir cfg.sharedDirectories);
 
+    boot.initrd.systemd = lib.mkIf (config.boot.initrd.systemd.enable && cfg.writableStore) {
+      mounts = [{
+        where = "/sysroot/nix/store";
+        what = "overlay";
+        type = "overlay";
+        options = "lowerdir=/sysroot/nix/.ro-store,upperdir=/sysroot/nix/.rw-store/store,workdir=/sysroot/nix/.rw-store/work";
+        wantedBy = ["local-fs.target"];
+        before = ["local-fs.target"];
+        requires = ["sysroot-nix-.ro\\x2dstore.mount" "sysroot-nix-.rw\\x2dstore.mount" "rw-store.service"];
+        after = ["sysroot-nix-.ro\\x2dstore.mount" "sysroot-nix-.rw\\x2dstore.mount" "rw-store.service"];
+        unitConfig.IgnoreOnIsolate = true;
+      }];
+      services.rw-store = {
+        after = ["sysroot-nix-.rw\\x2dstore.mount"];
+        unitConfig.DefaultDependencies = false;
+        serviceConfig = {
+          Type = "oneshot";
+          ExecStart = "/bin/mkdir -p 0755 /sysroot/nix/.rw-store/store /sysroot/nix/.rw-store/work /sysroot/nix/store";
+        };
+      };
+    };
+
     swapDevices = mkVMOverride [ ];
     boot.initrd.luks.devices = mkVMOverride {};