Merge pull request #25 from shlevy/required-kernel-config

Required kernel config

lib/build-vms.nix

@@ -1,4 +1,4 @@
-{ system }:
+{ system, minimal ? false }:
 
 let pkgs = import <nixpkgs> { config = {}; inherit system; }; in
 
@@ -27,7 +27,7 @@ rec {
         [ ../modules/virtualisation/qemu-vm.nix
           ../modules/testing/test-instrumentation.nix # !!! should only get added for automated test runs
           { key = "no-manual"; services.nixosManual.enable = false; }
-        ];
+        ] ++ lib.optional minimal ../modules/testing/minimal-kernel.nix;
       extraArgs = { inherit nodes; };
     };
 

lib/testing.nix

@@ -1,6 +1,6 @@
-{ system }:
+{ system, minimal ? false }:
 
-with import ./build-vms.nix { inherit system; };
+with import ./build-vms.nix { inherit system minimal; };
 with pkgs;
 
 rec {

modules/config/swap.nix

@@ -73,4 +73,10 @@ with pkgs.lib;
 
   };
 
+  config = mkIf ((length config.swapDevices) != 0) {
+    system.requiredKernelConfig = with config.lib.kernelConfig; [
+      (isYes "SWAP")
+    ];
+  };
+
 }

modules/services/hardware/udev.nix

@@ -263,6 +263,11 @@ in
           '';
       };
 
+    system.requiredKernelConfig = with config.lib.kernelConfig; [
+      (isEnabled "UNIX")
+      (isYes "INOTIFY_USER")
+      (isYes "NET")
+    ];
   };
 
 }

modules/system/boot/kernel.nix

@@ -108,6 +108,24 @@ let kernel = config.boot.kernelPackages.kernel; in
       apply = pkgs.aggregateModules;
     };
 
+    system.requiredKernelConfig = mkOption {
+      default = [];
+      example = literalExample ''
+        with config.lib.kernelConfig; [
+          (isYes "MODULES")
+          (isEnabled "FB_CON_DECOR")
+          (isEnabled "BLK_DEV_INITRD")
+        ]
+      '';
+      internal = true;
+      type = types.listOf types.attrs;
+      description = ''
+        This option allows modules to specify the kernel config options that
+        must be set (or unset) for the module to work. Please use the
+        lib.kernelConfig functions to build list elements.
+      '';
+    };
+
   };
 
 
@@ -173,6 +191,53 @@ let kernel = config.boot.kernelPackages.kernel; in
     # The Linux kernel >= 2.6.27 provides firmware.
     hardware.firmware = [ "${kernel}/lib/firmware" ];
 
-  };
+    lib.kernelConfig = {
+      isYes = option: {
+        assertion = config: config.isYes option;
+        message = "CONFIG_${option} is not yes!";
+        configLine = "CONFIG_${option}=y";
+      };
 
+      isNo = option: {
+        assertion = config: config.isNo option;
+        message = "CONFIG_${option} is not no!";
+        configLine = "CONFIG_${option}=n";
+      };
+
+      isModule = option: {
+        assertion = config: config.isModule option;
+        message = "CONFIG_${option} is not built as a module!";
+        configLine = "CONFIG_${option}=m";
+      };
+
+      ### Usually you will just want to use these two
+      # True if yes or module
+      isEnabled = option: {
+        assertion = config: config.isEnabled option;
+        message = "CONFIG_${option} is not enabled!";
+        configLine = "CONFIG_${option}=y";
+      };
+
+      # True if no or omitted
+      isDisabled = option: {
+        assertion = config: config.isDisabled option;
+        message = "CONFIG_${option} is not disabled!";
+        configLine = "CONFIG_${option}=n";
+      };
+    };
+
+    # The config options that all modules can depend upon
+    system.requiredKernelConfig = with config.lib.kernelConfig; [
+      # !!! Should this really be needed?
+      (isYes "MODULES")
+      (isYes "BINFMT_ELF")
+    ];
+
+    # nixpkgs kernels are assumed to have all required features
+    assertions = if config.boot.kernelPackages.kernel ? features then [] else
+      let cfg = config.boot.kernelPackages.kernel.config; in map (attrs:
+        { assertion = attrs.assertion cfg; inherit (attrs) message; }
+      ) config.system.requiredKernelConfig;
+
+  };
 }

modules/system/boot/stage-1.nix

@@ -321,4 +321,8 @@ in {
   system.build.initialRamdisk = initialRamdisk;
   system.build.extraUtils = extraUtils;
 
+  system.requiredKernelConfig = with config.lib.kernelConfig; [
+    (isYes "TMPFS")
+    (isYes "BLK_DEV_INITRD")
+  ];
 }

modules/testing/minimal-kernel.nix

@@ -0,0 +1,28 @@
+{ config, pkgs, ... }:
+
+let
+  configfile = builtins.storePath (builtins.toFile "config" (pkgs.lib.concatStringsSep "\n"
+    (map (builtins.getAttr "configLine") config.system.requiredKernelConfig))
+  );
+
+  origKernel = pkgs.linuxManualConfig {
+    inherit (pkgs.linux) src version;
+    inherit configfile;
+    allowImportFromDerivation = true;
+    kernelPatches = [ pkgs.kernelPatches.cifs_timeout_2_6_38 ];
+  };
+
+  kernel = origKernel // (derivation (origKernel.drvAttrs // {
+    configurePhase = ''
+      runHook preConfigure
+      mkdir ../build
+      make $makeFlags "''${makeFlagsArray[@]}" mrproper
+      make $makeFlags "''${makeFlagsArray[@]}" KCONFIG_ALLCONFIG=${configfile} allnoconfig
+      runHook postConfigure
+    '';
+  }));
+
+   kernelPackages = pkgs.linuxPackagesFor kernel kernelPackages;
+in {
+  boot.kernelPackages = kernelPackages;
+}

modules/testing/test-instrumentation.nix

@@ -5,11 +5,18 @@
 
 with pkgs.lib;
 
+let
+  kernel = config.boot.kernelPackages.kernel;
+
+  hasCIFSTimeout = if kernel ? features then kernel.features ? cifsTimeout
+    else (filter (p: p.name == "cifs-timeout") kernel.kernelPatches) != [];
+in
+
 {
 
   config =
   # Require a patch to the kernel to increase the 15s CIFS timeout.
-  mkAssert (config.boot.kernelPackages.kernel.features ? cifsTimeout) "
+  mkAssert hasCIFSTimeout "
     VM tests require that the kernel has the CIFS timeout patch.
   " {
 
@@ -87,6 +94,11 @@ with pkgs.lib;
 
     system.upstartEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data";
 
+    system.requiredKernelConfig = with config.lib.kernelConfig; [
+      (isYes "SERIAL_8250_CONSOLE")
+      (isYes "SERIAL_8250")
+      (isEnabled "VIRTIO_CONSOLE")
+    ];
   };
 
 }

modules/virtualisation/qemu-vm.nix

@@ -385,4 +385,22 @@ in
 
   # Wireless won't work in the VM.
   networking.wireless.enable = mkOverride 50 false;
+
+  system.requiredKernelConfig = with config.lib.kernelConfig; [
+    (isEnabled "VIRTIO_BLK")
+    (isEnabled "VIRTIO_PCI")
+    (isEnabled "VIRTIO_NET")
+    (isEnabled "EXT3_FS")
+    (isEnabled "CIFS")
+    (isYes "BLK_DEV")
+    (isYes "PCI")
+    (isYes "EXPERIMENTAL")
+    (isYes "NETDEVICES")
+    (isYes "NET_CORE")
+    (isYes "INET")
+    (isYes "NETWORK_FILESYSTEMS")
+  ] ++ optional (!cfg.graphics) [
+    (isYes "SERIAL_8250_CONSOLE")
+    (isYes "SERIAL_8250")
+  ];
 }

release.nix

@@ -1,5 +1,6 @@
 { nixosSrc ? {outPath = ./.; revCount = 1234; shortRev = "abcdef"; }
 , nixpkgs ? {outPath = <nixpkgs>; revCount = 5678; shortRev = "fedcba"; }
+, minimal ? false
 }:
 
 let
@@ -194,8 +195,8 @@ let
 
     tests =
       let
-        t = import ./tests { system = "i686-linux"; };
-        t_64 = import ./tests { system = "x86_64-linux"; };
+        t = import ./tests { system = "i686-linux"; inherit minimal; };
+        t_64 = import ./tests { system = "x86_64-linux"; inherit minimal; };
       in {
         avahi = t.avahi.test;
         bittorrent = t.bittorrent.test;

tests/default.nix

@@ -1,6 +1,6 @@
-{ system ? builtins.currentSystem }:
+{ system ? builtins.currentSystem, minimal ? false }:
 
-with import ../lib/testing.nix { inherit system; };
+with import ../lib/testing.nix { inherit system minimal; };
 
 {
   avahi = makeTest (import ./avahi.nix);