wot i thunk

by having two separate derivations for patching the kernel source tree
and building it, we have to copy said source trees from one store
location to another which takes non-neglible time on spinning rust
(literally minutes on my machine). Replace with a single derivation
that can do more things on one tree in-place

THOUGHTS.txt

@@ -413,3 +413,26 @@ them work with a kernel for the other
 
 As a result: now we have eth0 appearing, but not eth1?  Guessing we
 need to add some kconfig for the switch
+
+Mon Oct 17 21:23:37 BST 2022
+
+we are spending ridiculous amounts of cpu/io time copying kernel source
+trees from place to place, because we have kernel tree preparation
+and actual building as two separate derivations.
+
+I think the answer is to have a generic kernel build derivation
+in the overlay, and then have the device overlays override it with
+an additional phase to do openwrt patching or whatever else they
+need to do.
+
+Tue Oct 18 23:02:43 BST 2022
+
+* previous TODO list is Aug 02, need to review
+* dts is hardcoded to gl-ar750, that needs cleaning up
+* figure out persistent addresses for ethernet
+* fix halt/reboot
+* "link" services have a "device" attribute, would much rather
+  have everything referenced using outputs than having two
+  different mechanisms for reading similar things
+* Kconfig.local do we still need it?
+* check all config instead of differentiating config/checkedConfig

default.nix

@@ -6,7 +6,7 @@
 let
   overlay = import ./overlay.nix;
   nixpkgs = import <nixpkgs> (device.system // {overlays = [overlay device.overlay]; });
-  inherit (nixpkgs.pkgs) callPackage writeText liminix;
+  inherit (nixpkgs) callPackage writeText liminix fetchFromGitHub;
   inherit (nixpkgs.lib) concatStringsSep;
   config = (import ./merge-modules.nix) [
     ./modules/base.nix
@@ -15,25 +15,36 @@ let
     ./modules/s6
     ./modules/users.nix
     (if phram then  ./modules/phram.nix else (args: {}))
-  ] nixpkgs.pkgs;
+  ] nixpkgs;
   squashfs = liminix.builders.squashfs config.filesystem.contents;
-  kernel = callPackage ./kernel {
+
-    inherit (config.kernel) config checkedConfig;
+  openwrt = fetchFromGitHub {
+    name = "openwrt-source";
+    repo = "openwrt";
+    owner = "openwrt";
+    rev = "a5265497a4f6da158e95d6a450cb2cb6dc085cab";
+    hash = "sha256-YYi4gkpLjbOK7bM2MGQjAyEBuXJ9JNXoz/JEmYf8xE8=";
   };
 
   outputs = rec {
-    inherit squashfs kernel;
+    inherit squashfs;
-    dtb =  kernel.dtb {
+    kernel = nixpkgs.kernel.override {
-      dts = "qca9531_glinet_gl-ar750.dts";
+      inherit (config.kernel) config checkedConfig;
-
     };
-    uimage = kernel.uimage {
+    dtb =  (callPackage ./kernel/dtb.nix {}) {
+      dts = "${openwrt}/target/linux/ath79/dts/qca9531_glinet_gl-ar750.dts";
+      includes = [
+        "${openwrt}/target/linux/ath79/dts"
+        "${kernel.headers}/include"
+      ];
+    };
+    uimage = (callPackage ./kernel/uimage.nix {}) {
       commandLine = concatStringsSep " " config.boot.commandLine;
       inherit (device.boot) loadAddress entryPoint;
-      inherit (kernel) vmlinux;
+      inherit kernel;
       inherit dtb;
     };
-    combined-image = nixpkgs.pkgs.runCommand "firmware.bin" {
+    combined-image = nixpkgs.runCommand "firmware.bin" {
       nativeBuildInputs = [ nixpkgs.buildPackages.ubootTools ];
     } ''
       mkdir $out
@@ -48,7 +59,7 @@ let
         squashfsSize = 8;
         cmd = "mtdparts=phram0:${toString squashfsSize}M(nix) phram.phram=phram0,0x${toHexString squashfsStart},${toString squashfsSize}Mi memmap=${toString squashfsSize}M\$0x${toHexString squashfsStart} root=1f00";
       in
-        nixpkgs.pkgs.buildPackages.writeScript "firmware.bin" ''
+        nixpkgs.buildPackages.writeScript "firmware.bin" ''
           setenv serverip 192.168.8.148
           setenv ipaddr 192.168.8.251
           setenv bootargs '${concatStringsSep " " config.boot.commandLine} ${cmd}'
@@ -56,13 +67,13 @@ let
           bootm 0x${toHexString uimageStart}
         '';
 
-    directory = nixpkgs.pkgs.runCommand "liminix" {} (''
+    directory = nixpkgs.runCommand "liminix" {} (''
       mkdir $out
       cd $out
       ln -s ${squashfs} squashfs
-      ln -s ${kernel.vmlinux} vmlinux
+      ln -s ${kernel} vmlinux
       ln -s ${manifest} manifest
-      ln -s ${kernel.vmlinux.modulesupport} build
+      ln -s ${kernel.headers} build
     '' +
     (if device ? boot then ''
       ln -s ${uimage} uimage
@@ -72,7 +83,7 @@ let
     # this exists so that you can run "nix-store -q --tree" on it and find
     # out what's in the image, which is nice if it's unexpectedly huge
     manifest = writeText "manifest.json" (builtins.toJSON config.filesystem.contents);
-    tftpd = nixpkgs.pkgs.buildPackages.tufted;
+    tftpd = nixpkgs.buildPackages.tufted;
   };
 in {
   outputs = outputs // { default = outputs.${device.outputs.default}; };

devices/gl-ar750/default.nix

@@ -32,47 +32,33 @@
 
   overlay = final: prev:
     let
-      inherit (final) fetchFromGitHub fetchgit stdenvNoCC;
+      openwrt = final.fetchFromGitHub {
-      openwrt = fetchFromGitHub {
         name = "openwrt-source";
         repo = "openwrt";
         owner = "openwrt";
         rev = "a5265497a4f6da158e95d6a450cb2cb6dc085cab";
         hash = "sha256-YYi4gkpLjbOK7bM2MGQjAyEBuXJ9JNXoz/JEmYf8xE8=";
       };
-      mainline = fetchFromGitHub {
-        name = "kernel-source";
-        owner = "torvalds";
-        repo = "linux";
-        rev = "90c7e9b400c751dbd73885f494f421f90ca69721";
-        hash = "sha256-pq6QNa0PJVeheaZkuvAPD0rLuEeKrViKk65dz+y4kqo=";
-      };
     in {
-      sources = {
+      kernel = prev.kernel.override {
-        inherit openwrt;
+        src = final.fetchurl {
-        kernel = stdenvNoCC.mkDerivation {
+          name = "linux.tar.gz";
-          name = "spindled-kernel-tree";
+          url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.71.tar.gz";
-          src = mainline;
+          hash = "sha256-yhO2cXIeIgUxkSZf/4aAsF11uxyh+UUZu6D1h92vCD8=";
-          phases = [
-            "unpackPhase" "patchPhase" "openWrtPatchPhase"
-            "patchScripts" "installPhase"
-          ];
-          patches = [ ../../kernel/random.patch ];
-          patchScripts = ''
-            patchShebangs scripts/
-          '';
-          openWrtPatchPhase = ''
-            cp -av ${openwrt}/target/linux/generic/files/* .
-            chmod -R u+w .
-            cp -av ${openwrt}/target/linux/ath79/files/* .
-            chmod -R u+w .
-            for i in ${openwrt}/target/linux/ath79/patches-5.15/* ; do patch --batch --forward -p1 < $i ;done
-          '';
-          installPhase = ''
-            mkdir -p $out
-            cp -a . $out
-          '';
         };
+        extraPatchPhase = ''
+          cp -av ${openwrt}/target/linux/generic/files/* .
+          chmod -R u+w .
+          cp -av ${openwrt}/target/linux/ath79/files/* .
+          chmod -R u+w .
+          patches() {
+            for i in $* ; do patch --batch --forward -p1 < $i ;done
+          }
+          patches ${openwrt}/target/linux/generic/backport-5.15/*.patch
+          patches ${openwrt}/target/linux/generic/pending-5.15/*.patch
+          patches ${openwrt}/target/linux/generic/hack-5.15/*.patch
+          patches ${openwrt}/target/linux/ath79/patches-5.15/*.patch
+        '';
       };
     };
   kernel = rec {
@@ -82,8 +68,6 @@
       USE_OF = "y";
       ATH79 = "y";
 
-      LIMINIX = "y";
-
       SERIAL_8250_CONSOLE = "y";
       SERIAL_8250 = "y";
       SERIAL_CORE_CONSOLE = "y";
@@ -111,10 +95,11 @@
       NET_VENDOR_ATHEROS = "y";
       AG71XX = "y";             # ethernet (qca,qca9530-eth)
       MFD_SYSCON = "y";         # ethernet (compatible "syscon")
+      AR8216_PHY = "y";         # eth1 is behind a switch
 
-    };
+      MTD = "y";
-    config = {
+      MTD_CMDLINE_PARTS = "y";
-      CPU_LITTLE_ENDIAN= "n";
+      MTD_BLOCK = "y";          # fix undefined ref to register_mtd_blktrans_devs
       CPU_BIG_ENDIAN= "y";
 
       # this is all copied from nixwrt ath79 config. Clearly not all
@@ -122,7 +107,6 @@
       # installation method config or ...
 
       "CMDLINE_PARTITION" = "y";
-      "DEBUG_INFO" = "y";
       "EARLY_PRINTK" = "y";
       "FW_LOADER" = "y";
       # we don't have a user helper, so we get multiple 60s pauses
@@ -130,27 +114,11 @@
       "FW_LOADER_USER_HELPER" = "n";
 
       "MODULE_SIG" = "y";
-      "MTD_CMDLINE_PARTS" = "y";
+
       "PARTITION_ADVANCED" = "y";
       "PRINTK_TIME" = "y";
       "SQUASHFS" = "y";
       "SQUASHFS_XZ" = "y";
-      # "ASN1" = "y";
-      # "ASYMMETRIC_KEY_TYPE" = "y";
-      # "ASYMMETRIC_PUBLIC_KEY_SUBTYPE" = "y";
-      # "CRC_CCITT" = "y";
-      # "CRYPTO" = "y";
-      # "CRYPTO_ARC4" = "y";
-      # "CRYPTO_CBC" = "y";
-      # "CRYPTO_CCM" = "y";
-      # "CRYPTO_CMAC" = "y";
-      # "CRYPTO_GCM" = "y";
-      # "CRYPTO_HASH_INFO" = "y";
-      # "CRYPTO_LIB_ARC4" = "y";
-      # "CRYPTO_RSA" = "y";
-      # "CRYPTO_SHA1" = "y";
-      # "ENCRYPTED_KEYS" = "y";
-      # "KEYS" = "y";
     };
   };
   outputs.default = "directory";

devices/qemu/default.nix

@@ -14,157 +14,40 @@
   };
 
   overlay = final: prev:
-    let inherit (final) fetchFromGitHub;
+    let inherit (final) stdenvNoCC fetchFromGitHub;
     in {
-      sources = {
+      kernel = prev.kernel.override {
-        kernel =  fetchFromGitHub {
+        # using fetchurl not fetchzip because it doesn't unpack, and
-          name = "kernel-source";
+        # copying 6GB of data from one store location to another
-          owner = "torvalds";
+        # takes an absolute bloody age
-          repo = "linux";
+        src = final.fetchurl {
-          rev = "3d7cb6b04c3f3115719235cc6866b10326de34cd";  # v5.19
+          name = "linux.tar.gz";
-          hash = "sha256-OVsIRScAnrPleW1vbczRAj5L/SGGht2+GnvZJClMUu4=";
+          url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.19.16.tar.gz";
+          hash = "sha256-m4NeoEsCEK0HSIKTZ6zYTgk1fD3W0PSOMXN6fyHpkP8=";
         };
       };
     };
 
   kernel = {
-    config = {
+    checkedConfig = {
-      SYSVIPC= "y";
-      NO_HZ= "y";
-      HIGH_RES_TIMERS= "y";
-      LOG_BUF_SHIFT = "15";
-      NAMESPACES= "y";
-      RELAY= "y";
-      EXPERT= "y";
-      PERF_EVENTS= "y";
-      COMPAT_BRK= "n";
-      SLAB= "y";
       MIPS_MALTA= "y";
       CPU_LITTLE_ENDIAN= "n";
       CPU_BIG_ENDIAN= "y";
       CPU_MIPS32_R2= "y";
-      PAGE_SIZE_16KB= "y";
-      NR_CPUS= "1";
-      HZ_100= "y";
-      PCI= "y";
-      VIRTUALIZATION= "y";
-      KVM_MIPS_DEBUG_COP0_COUNTERS= "y";
-      MODULES= "y";
-      MODULE_UNLOAD= "y";
-      MODVERSIONS= "y";
-      MODULE_SRCVERSION_ALL= "y";
-      NET= "y";
-      PACKET= "y";
-      UNIX= "y";
-      NET_KEY= "y";
-      NET_KEY_MIGRATE= "y";
-      INET= "y";
-      IP_MULTICAST= "y";
-      IP_ADVANCED_ROUTER= "y";
-      IP_MULTIPLE_TABLES= "y";
-      IP_ROUTE_MULTIPATH= "y";
-      IP_ROUTE_VERBOSE= "y";
-      IP_PNP= "y";
-      IP_PNP_DHCP= "y";
-      IP_PNP_BOOTP= "y";
-      IP_MROUTE= "y";
-      IP_PIMSM_V1= "y";
-      IP_PIMSM_V2= "y";
-      SYN_COOKIES= "y";
-      TCP_MD5SIG= "y";
-      IPV6_ROUTER_PREF= "y";
-      IPV6_ROUTE_INFO= "y";
-      IPV6_OPTIMISTIC_DAD= "y";
-      IPV6_MROUTE= "y";
-      IPV6_PIMSM_V2= "y";
-      NETWORK_SECMARK= "y";
-      NETFILTER= "y";
-      NF_CONNTRACK_SECMARK= "y";
-      NF_CONNTRACK_EVENTS= "y";
-      IP_VS_IPV6= "y";
-      IP_VS_PROTO_TCP= "y";
-      IP_VS_PROTO_UDP= "y";
-      IP_VS_PROTO_ESP= "y";
-      IP_VS_PROTO_AH= "y";
-      VLAN_8021Q_GVRP= "y";
-      IPDDP_ENCAP= "y";
-      NET_SCHED= "y";
-      NET_CLS_ACT= "y";
-      NET_ACT_POLICE= "y";
-      GACT_PROB= "y";
-      MTD= "y";
-      MTD_BLOCK= "y";
-      MTD_CFI= "y";
-      MTD_CFI_INTELEXT= "y";
-      MTD_CFI_AMDSTD= "y";
-      MTD_CFI_STAA= "y";
-      MTD_PHYSMAP_OF= "y";
-      BLK_DEV_RAM= "y";
-      BLK_DEV_SD= "y";
-      BLK_DEV_SR= "y";
-      SCSI_CONSTANTS= "y";
-      SCSI_LOGGING= "y";
-      SCSI_SCAN_ASYNC= "y";
-      AIC7XXX_RESET_DELAY_MS="15000";
-      AIC7XXX_DEBUG_ENABLE= "n";
-      ATA= "y";
-      ATA_PIIX= "y";
-      PATA_OLDPIIX= "y";
-      PATA_MPIIX= "y";
-      ATA_GENERIC= "y";
-      PATA_LEGACY= "y";
-      MD= "y";
-      NETDEVICES= "y";
-      PCNET32= "y";
-      IPW2100_MONITOR= "y";
-      HOSTAP_FIRMWARE= "y";
-      HOSTAP_FIRMWARE_NVRAM= "y";
-      INPUT_MOUSEDEV= "y";
-      SERIAL_8250= "y";
-      SERIAL_8250_CONSOLE= "y";
-      POWER_RESET= "y";
-      POWER_RESET_PIIX4_POWEROFF= "y";
-      POWER_RESET_SYSCON= "y";
-      HWMON= "n";
-      FB= "y";
-      FB_CIRRUS= "y";
-      VGA_CONSOLE= "n";
-      FRAMEBUFFER_CONSOLE= "y";
-      RTC_CLASS= "y";
-      RTC_DRV_CMOS= "y";
-      EXT2_FS= "y";
-      EXT3_FS= "y";
-      JFS_POSIX_ACL= "y";
-      JFS_SECURITY= "y";
-      QUOTA= "y";
-      QFMT_V2= "y";
-      JOLIET= "y";
-      ZISOFS= "y";
-      PROC_KCORE= "y";
-      TMPFS= "y";
-      CONFIGFS_FS= "y";
-      JFFS2_FS_XATTR= "y";
-      JFFS2_COMPRESSION_OPTIONS= "y";
-      JFFS2_RUBIN= "y";
-      # NFS_FS= "y";
-      # ROOT_NFS= "y";
-      # NFSD= "y";
-      # NFSD_V3= "y";
-      CRYPTO_HMAC= "y";
-      RCU_CPU_STALL_TIMEOUT = "60";
-      ENABLE_DEFAULT_TRACERS = "y";
 
-      CFG80211= "y";
-      MAC80211= "y";
-      MAC80211_MESH= "y";
-      RFKILL= "y";
-      WLAN = "y";
-      MAC80211_HWSIM = "y";
       SQUASHFS = "y";
       SQUASHFS_XZ = "y";
+
+      VIRTIO_MENU = "y";
+      PCI = "y";
       VIRTIO_PCI = "y";
+      BLOCK = "y";
       VIRTIO_BLK = "y";
+      NETDEVICES = "y";
       VIRTIO_NET = "y";
+
+      SERIAL_8250= "y";
+      SERIAL_8250_CONSOLE= "y";
     };
   };
   outputs.default = "directory";

kernel/dtb.nix

@@ -1,15 +1,10 @@
 {
   stdenv
-, openwrt
 , dtc
-, kernel
 }:
 { dts
+, includes
 }:let
-  includes = [
-    "${openwrt}/target/linux/ath79/dts"
-    "${kernel}/include"
-  ];
   cppDtSearchFlags = builtins.concatStringsSep " " (map (f: "-I${f}") includes);
   dtcSearchFlags = builtins.concatStringsSep " " (map (f: "-i${f}") includes);
 in stdenv.mkDerivation {
@@ -17,7 +12,7 @@ in stdenv.mkDerivation {
   phases = [ "buildPhase" ];
   nativeBuildInputs = [ dtc ];
   buildPhase = ''
-    ${stdenv.cc.targetPrefix}cpp -nostdinc -x assembler-with-cpp ${cppDtSearchFlags} -undef -D__DTS__  -o dtb.tmp ${openwrt}/target/linux/ath79/dts/${dts}
+    ${stdenv.cc.targetPrefix}cpp -nostdinc -x assembler-with-cpp ${cppDtSearchFlags} -undef -D__DTS__  -o dtb.tmp ${dts}
     dtc ${dtcSearchFlags} -I dts  -O dtb -o $out dtb.tmp
     test -e $out
   '';

kernel/uimage.nix

@@ -7,7 +7,7 @@
 let
   objcopy = "${stdenv.cc.bintools.targetPrefix}objcopy";
 in {
-  vmlinux
+  kernel
 , commandLine
 , entryPoint
 , extraName ? ""                # e.g. socFamily
@@ -28,7 +28,7 @@ stdenv.mkDerivation {
     ubootTools
   ];
   preparePhase = ''
-    cp ${vmlinux} vmlinux.elf; chmod +w vmlinux.elf
+    cp ${kernel} vmlinux.elf; chmod +w vmlinux.elf
   '';
   dtbPhase = ''
     dtc -I dtb -O dts -o tmp.dts ${dtb}

modules/base.nix

@@ -56,6 +56,14 @@ in {
 
         MODULES = "y";
 
+        # basic networking protocols
+        NET = "y";
+        UNIX = "y";
+        INET = "y";
+        IPV6 = "y";
+        PACKET = "y";           # for ppp, tcpdump ...
+        SYSVIPC= "y";
+
         # s6-linux-init mounts this on /dev
         DEVTMPFS = "y";
         # some or all of these may be fix for "tmpfs: Unknown parameter 'mode'" error

modules/wlan.nix

@@ -0,0 +1,38 @@
+{ lib, pkgs, config, ...}:
+let
+  inherit (lib) mkEnableOption mkOption types isDerivation hasAttr ;
+  inherit (pkgs.pseudofile) dir symlink;
+  inherit (pkgs) busybox;
+
+in {
+  config = {
+    kernel = rec {
+      checkedConfig = {
+        CFG80211= "y";
+        MAC80211= "y";
+        MAC80211_MESH= "y";
+        RFKILL= "y";
+        WLAN = "y";
+        # if/when we switch to using backported mac80211 drivers built
+        # as modules, based on nixwrt code we expect we will need this config
+        # to enable them
+        # "ASN1" = "y";
+        # "ASYMMETRIC_KEY_TYPE" = "y";
+        # "ASYMMETRIC_PUBLIC_KEY_SUBTYPE" = "y";
+        # "CRC_CCITT" = "y";
+        # "CRYPTO" = "y";
+        # "CRYPTO_ARC4" = "y";
+        # "CRYPTO_CBC" = "y";
+        # "CRYPTO_CCM" = "y";
+        # "CRYPTO_CMAC" = "y";
+        # "CRYPTO_GCM" = "y";
+        # "CRYPTO_HASH_INFO" = "y";
+        # "CRYPTO_LIB_ARC4" = "y";
+        # "CRYPTO_RSA" = "y";
+        # "CRYPTO_SHA1" = "y";
+        # "ENCRYPTED_KEYS" = "y";
+        # "KEYS" = "y";
+      };
+    };
+  };
+}

overlay.nix

@@ -12,6 +12,7 @@ final: prev: {
   s6-init-bin =  final.callPackage ./pkgs/s6-init-bin {};
   s6-rc-database = final.callPackage ./pkgs/s6-rc-database {};
 
+  kernel = final.callPackage ./pkgs/kernel {};
 
   dnsmasq =
     let d =  prev.dnsmasq.overrideAttrs(o: {

pkgs/kernel/default.nix

@@ -6,7 +6,8 @@
 
  , config
  , checkedConfig ? {}
- , tree
+ , src
+ , extraPatchPhase ? "true"
 } :
 let writeConfig = name : config: writeText name
         (builtins.concatStringsSep
@@ -30,8 +31,8 @@ let writeConfig = name : config: writeText name
     checkedConfigFile = writeConfig "checked_kconfig" checkedConfig ;
     inherit lib; in
 stdenv.mkDerivation rec {
-  name = "vmlinux";
+  name = "kernel";
-
+  inherit src extraPatchPhase;
   hardeningDisable = ["all"];
   nativeBuildInputs = [buildPackages.stdenv.cc] ++
                       (with buildPackages.pkgs;
@@ -44,11 +45,16 @@ stdenv.mkDerivation rec {
   PKG_CONFIG_PATH = "./pkgconfig";
   CROSS_COMPILE = stdenv.cc.bintools.targetPrefix;
   ARCH = "mips";  # kernel uses "mips" here for both mips and mipsel
+  KBUILD_BUILD_HOST = "liminix.builder";
+
   dontStrip = true;
   dontPatchELF = true;
-  outputs = ["out"  "modulesupport"];
+  outputs = ["out" "headers"];
   phases = [
+    "unpackPhase"
     "butcherPkgconfig"
+    "extraPatchPhase"
+    "patchScripts"
     "configurePhase"
     "checkConfigurationPhase"
     "buildPhase"
@@ -67,12 +73,16 @@ stdenv.mkDerivation rec {
     for i in pkgconfig/*.pc; do test -f $i && sed -i 's/^Libs:/Libs: -L''${libdir} /'  $i;done
   '';
 
+  patchScripts = ''
+    patchShebangs scripts/
+  '';
+
   configurePhase = ''
     export KBUILD_OUTPUT=`pwd`
     cp ${kconfigFile} .config
     cp ${kconfigFile} .config.orig
     cp ${kconfigLocal} Kconfig.local
-    ( cd ${tree} && make V=1 olddefconfig )
+    make V=1 olddefconfig
   '';
 
   checkConfigurationPhase = ''
@@ -84,18 +94,15 @@ stdenv.mkDerivation rec {
     echo "OK"
   '';
 
-  KBUILD_BUILD_HOST = "liminix.builder";
   buildPhase = ''
-    make -C ${tree} vmlinux modules_prepare
+    make vmlinux modules_prepare
   '';
 
   installPhase = ''
     ${CROSS_COMPILE}strip -d vmlinux
     cp vmlinux $out
-    mkdir -p $modulesupport
+    mkdir -p $headers
-    cp .config $modulesupport/config
+    cp -a include .config $headers/
-    make clean
-    cp -a . $modulesupport
   '';
 
 }

tests/wlan/configuration.nix

@@ -13,6 +13,13 @@ in rec {
       ];
     };
 
+  imports = [ ../../modules/wlan.nix ];
+
+  kernel.checkedConfig = {
+    MAC80211_HWSIM = "y";
+  };
+
+
   services.wlan = interface { type = "hardware"; device = "wlan0"; };
 
   services.hostap = hostapd (services.wlan) {