# WARNING/NOTE: whenever you want to add an option here you need to either # * mark it as an optional one with `option`, # * or make sure it works for all the versions in nixpkgs, # * or check for which kernel versions it will work (using kernel # changelog, google or whatever) and mark it with `whenOlder` or # `whenAtLeast`. # Then do test your change by building all the kernels (or at least # their configs) in Nixpkgs or else you will guarantee lots and lots # of pain to users trying to switch to an older kernel because of some # hardware problems with a new one. # Configuration { stdenv, version # to let user override values, aka converting modules to included and vice-versa , mkValueOverride ? null # new extraConfig as a flattened set , structuredExtraConfig ? {} # legacy extraConfig as string , extraConfig ? "" , features ? { grsecurity = false; xen_dom0 = false; } }: assert (mkValueOverride == null) || (builtins.isFunction mkValueOverride); with stdenv.lib; with import ../../../../lib/kernel.nix { inherit (stdenv) lib; inherit version; }; let # configuration items have to be part of a subattrs flattenKConf = nested: mapAttrs (_: head) (zipAttrs (attrValues nested)); options = { debug = { DEBUG_INFO = if (features.debug or false) then yes else no; DEBUG_KERNEL = yes; DEBUG_DEVRES = no; DYNAMIC_DEBUG = yes; TIMER_STATS = whenOlder "4.11" yes; DEBUG_NX_TEST = whenOlder "4.11" no; CPU_NOTIFIER_ERROR_INJECT = whenOlder "4.4" (option no); DEBUG_STACK_USAGE = no; DEBUG_STACKOVERFLOW = when (!features.grsecurity) no; RCU_TORTURE_TEST = no; SCHEDSTATS = no; DETECT_HUNG_TASK = yes; CRASH_DUMP = option no; # Easier debugging of NFS issues. SUNRPC_DEBUG = yes; }; power-management = { PM_ADVANCED_DEBUG = yes; X86_INTEL_LPSS = yes; X86_INTEL_PSTATE = yes; INTEL_IDLE = yes; CPU_FREQ_DEFAULT_GOV_PERFORMANCE = yes; PM_WAKELOCKS = yes; }; external-firmware = { # Support drivers that need external firmware. STANDALONE = no; }; proc-config-gz = { # Make /proc/config.gz available IKCONFIG = yes; IKCONFIG_PROC = yes; }; optimization = { # Optimize with -O2, not -Os CC_OPTIMIZE_FOR_SIZE = no; }; memtest = { MEMTEST = yes; }; # Include the CFQ I/O scheduler in the kernel, rather than as a # module, so that the initrd gets a good I/O scheduler. scheduler = { IOSCHED_CFQ = yes; BLK_CGROUP = yes; # required by CFQ" IOSCHED_DEADLINE = yes; MQ_IOSCHED_DEADLINE = whenAtLeast "4.11" yes; BFQ_GROUP_IOSCHED = whenAtLeast "4.12" yes; MQ_IOSCHED_KYBER = whenAtLeast "4.12" yes; IOSCHED_BFQ = whenAtLeast "4.12" module; }; # Enable NUMA. numa = { NUMA = option yes; }; networking = { NET = yes; IP_PNP = no; NETFILTER = yes; NETFILTER_ADVANCED = yes; IP_VS_PROTO_TCP = yes; IP_VS_PROTO_UDP = yes; IP_VS_PROTO_ESP = yes; IP_VS_PROTO_AH = yes; IP_DCCP_CCID3 = no; # experimental CLS_U32_PERF = yes; CLS_U32_MARK = yes; BPF_JIT = when (stdenv.system == "x86_64-linux") yes; WAN = yes; # Required by systemd per-cgroup firewalling CGROUP_BPF = option yes; CGROUP_NET_PRIO = yes; # Required by systemd IP_ROUTE_VERBOSE = yes; IP_MROUTE_MULTIPLE_TABLES = yes; IP_MULTICAST = yes; IPV6_ROUTER_PREF = yes; IPV6_ROUTE_INFO = yes; IPV6_OPTIMISTIC_DAD = yes; IPV6_MULTIPLE_TABLES = yes; IPV6_SUBTREES = yes; IPV6_MROUTE = yes; IPV6_MROUTE_MULTIPLE_TABLES = yes; IPV6_PIMSM_V2 = yes; IPV6_FOU_TUNNEL = whenAtLeast "4.7" module; NET_CLS_BPF = whenAtLeast "4.4" module; NET_ACT_BPF = whenAtLeast "4.4" module; L2TP_V3 = yes; L2TP_IP = module; L2TP_ETH = module; BRIDGE_VLAN_FILTERING = yes; BONDING = module; NET_L3_MASTER_DEV = option yes; NET_FOU_IP_TUNNELS = option yes; IP_NF_TARGET_REDIRECT = module; PPP_MULTILINK = yes; # PPP multilink support PPP_FILTER = yes; # needed for iwd WPS support (wpa_supplicant replacement) KEY_DH_OPERATIONS = whenAtLeast "4.7" yes; }; wireless = { CFG80211_WEXT = option yes; # Without it, ipw2200 drivers don't build IPW2100_MONITOR = option yes; # support promiscuous mode IPW2200_MONITOR = option yes; # support promiscuous mode HOSTAP_FIRMWARE = option yes; # Support downloading firmware images with Host AP driver HOSTAP_FIRMWARE_NVRAM = option yes; ATH9K_PCI = option yes; # Detect Atheros AR9xxx cards on PCI(e) bus ATH9K_AHB = option yes; # Ditto, AHB bus B43_PHY_HT = option yes; BCMA_HOST_PCI = option yes; }; fb = { FB = yes; FB_EFI = yes; FB_NVIDIA_I2C = yes; # Enable DDC Support FB_RIVA_I2C = yes; FB_ATY_CT = yes; # Mach64 CT/VT/GT/LT (incl. 3D RAGE) support FB_ATY_GX = yes; # Mach64 GX support FB_SAVAGE_I2C = yes; FB_SAVAGE_ACCEL = yes; FB_SIS_300 = yes; FB_SIS_315 = yes; FB_3DFX_ACCEL = yes; FB_VESA = yes; FRAMEBUFFER_CONSOLE = yes; FRAMEBUFFER_CONSOLE_ROTATION = yes; FB_GEODE = when (stdenv.system == "i686-linux") yes; }; video = { # Enable KMS for devices whose X.org driver supports it DRM_I915_KMS = whenOlder "4.3" yes; # Allow specifying custom EDID on the kernel command line DRM_LOAD_EDID_FIRMWARE = yes; VGA_SWITCHEROO = yes; # Hybrid graphics support DRM_GMA600 = yes; DRM_GMA3600 = yes; # necessary for amdgpu polaris support DRM_AMD_POWERPLAY = whenBetween "4.5" "4.9" yes; # (experimental) amdgpu support for verde and newer chipsets DRM_AMDGPU_SI = whenAtLeast "4.9" yes; # (stable) amdgpu support for bonaire and newer chipsets DRM_AMDGPU_CIK = whenAtLeast "4.9" yes; } // optionalAttrs (stdenv.hostPlatform.system == "x86_64-linux") { # Intel GVT-g graphics virtualization supports 64-bit only DRM_I915_GVT = whenAtLeast "4.16" yes; DRM_I915_GVT_KVMGT = whenAtLeast "4.16" module; }; sound = { SND_DYNAMIC_MINORS = yes; SND_AC97_POWER_SAVE = yes; # AC97 Power-Saving Mode SND_HDA_INPUT_BEEP = yes; # Support digital beep via input layer SND_HDA_RECONFIG = yes; # Support reconfiguration of jack functions # Support configuring jack functions via fw mechanism at boot SND_HDA_PATCH_LOADER = yes; SND_USB_CAIAQ_INPUT = yes; # Enable PSS mixer (Beethoven ADSP-16 and other compatible) PSS_MIXER = whenOlder "4.12" yes; }; # Include firmware for various USB serial devices. # Only applicable for kernels below 4.16, after that no firmware is shipped in the kernel tree. usb-serial = { USB_SERIAL_GENERIC = yes; # USB Generic Serial Driver } // optionalAttrs (versionOlder version "4.16") { # include firmware for various USB serial devices USB_SERIAL_KEYSPAN_MPR = yes; USB_SERIAL_KEYSPAN_USA28 = yes; USB_SERIAL_KEYSPAN_USA28X = yes; USB_SERIAL_KEYSPAN_USA28XA = yes; USB_SERIAL_KEYSPAN_USA28XB = yes; USB_SERIAL_KEYSPAN_USA19 = yes; USB_SERIAL_KEYSPAN_USA18X = yes; USB_SERIAL_KEYSPAN_USA19W = yes; USB_SERIAL_KEYSPAN_USA19QW = yes; USB_SERIAL_KEYSPAN_USA19QI = yes; USB_SERIAL_KEYSPAN_USA49W = yes; USB_SERIAL_KEYSPAN_USA49WLC = yes; }; usb = { USB_DEBUG = option no; USB_EHCI_ROOT_HUB_TT = yes; # Root Hub Transaction Translators USB_EHCI_TT_NEWSCHED = yes; # Improved transaction translator scheduling }; # Filesystem options - in particular, enable extended attributes and # ACLs for all filesystems that support them. filesystem = { FANOTIFY = yes; TMPFS = yes; TMPFS_POSIX_ACL = yes; FS_ENCRYPTION = option (whenAtLeast "4.9" module); EXT2_FS_XATTR = yes; EXT2_FS_POSIX_ACL = yes; EXT2_FS_SECURITY = yes; EXT2_FS_XIP = whenOlder "4.0" yes; # Ext2 execute in place support EXT3_FS_POSIX_ACL = yes; EXT3_FS_SECURITY = yes; EXT4_FS_POSIX_ACL = yes; EXT4_FS_SECURITY = yes; EXT4_ENCRYPTION = option ((if (versionOlder version "4.8") then module else yes)); REISERFS_FS_XATTR = option yes; REISERFS_FS_POSIX_ACL = option yes; REISERFS_FS_SECURITY = option yes; JFS_POSIX_ACL = option yes; JFS_SECURITY = option yes; XFS_QUOTA = option yes; XFS_POSIX_ACL = option yes; XFS_RT = option yes; # XFS Realtime subvolume support OCFS2_DEBUG_MASKLOG = option no; BTRFS_FS_POSIX_ACL = yes; UBIFS_FS_ADVANCED_COMPR = option yes; F2FS_FS = module; F2FS_FS_SECURITY = option yes; F2FS_FS_ENCRYPTION = option yes; UDF_FS = module; NFSD_PNFS = whenBetween "4.0" "4.6" yes; NFSD_V2_ACL = yes; NFSD_V3 = yes; NFSD_V3_ACL = yes; NFSD_V4 = yes; NFSD_V4_SECURITY_LABEL = yes; NFS_FSCACHE = yes; NFS_SWAP = yes; NFS_V3_ACL = yes; NFS_V4_1 = yes; # NFSv4.1 client support NFS_V4_2 = yes; NFS_V4_SECURITY_LABEL = yes; CIFS_XATTR = yes; CIFS_POSIX = yes; CIFS_FSCACHE = yes; CIFS_STATS = yes; CIFS_WEAK_PW_HASH = yes; CIFS_UPCALL = yes; CIFS_ACL = yes; CIFS_DFS_UPCALL = yes; CIFS_SMB2 = whenOlder "4.13" yes; CEPH_FSCACHE = yes; CEPH_FS_POSIX_ACL = yes; SQUASHFS_FILE_DIRECT = yes; SQUASHFS_DECOMP_MULTI_PERCPU = yes; SQUASHFS_XATTR = yes; SQUASHFS_ZLIB = yes; SQUASHFS_LZO = yes; SQUASHFS_XZ = yes; SQUASHFS_LZ4 = yes; # Native Language Support modules, needed by some filesystems NLS = yes; NLS_DEFAULT = "utf8"; NLS_UTF8 = module; NLS_CODEPAGE_437 = module; # VFAT default for the codepage = mount option NLS_ISO8859_1 = module; # VFAT default for the iocharset= mount option DEVTMPFS = yes; }; security = { # Detect writes to read-only module pages DEBUG_SET_MODULE_RONX = option (whenOlder "4.11" yes); RANDOMIZE_BASE = option yes; STRICT_DEVMEM = option yes; # Filter access to /dev/mem SECURITY_SELINUX_BOOTPARAM_VALUE = "0"; # Disable SELinux by default # Prevent processes from ptracing non-children processes SECURITY_YAMA = option yes; DEVKMEM = when (!features.grsecurity) no; # Disable /dev/kmem USER_NS = yes; # Support for user namespaces SECURITY_APPARMOR = yes; DEFAULT_SECURITY_APPARMOR = yes; } // optionalAttrs (!stdenv.hostPlatform.isAarch32) { # Detect buffer overflows on the stack CC_STACKPROTECTOR_REGULAR = option (whenOlder "4.18" yes); }; microcode = { MICROCODE = yes; MICROCODE_INTEL = yes; MICROCODE_AMD = yes; MICROCODE_EARLY = whenOlder "4.4" yes; MICROCODE_INTEL_EARLY = whenOlder "4.4" yes; MICROCODE_AMD_EARLY = whenOlder "4.4" yes; } // optionalAttrs (versionAtLeast version "4.10") { # Write Back Throttling # https://lwn.net/Articles/682582/ # https://bugzilla.kernel.org/show_bug.cgi?id=12309#c655 BLK_WBT = yes; BLK_WBT_SQ = yes; BLK_WBT_MQ = yes; }; container = { NAMESPACES = option yes; # Required by 'unshare' used by 'nixos-install' RT_GROUP_SCHED = no; CGROUP_DEVICE = option yes; MEMCG = yes; MEMCG_SWAP = yes; DEVPTS_MULTIPLE_INSTANCES = whenOlder "4.7" yes; BLK_DEV_THROTTLING = yes; CFQ_GROUP_IOSCHED = yes; CGROUP_PIDS = whenAtLeast "4.3" yes; }; staging = { # Enable staging drivers. These are somewhat experimental, but # they generally don't hurt. STAGING = yes; }; proc-events = { # PROC_EVENTS requires that the netlink connector is not built # as a module. This is required by libcgroup's cgrulesengd. CONNECTOR = yes; PROC_EVENTS = yes; }; tracing = { FTRACE = yes; KPROBES = yes; FUNCTION_TRACER = yes; FTRACE_SYSCALLS = yes; SCHED_TRACER = yes; STACK_TRACER = yes; UPROBE_EVENT = option (whenOlder "4.11" yes); UPROBE_EVENTS = option (whenAtLeast "4.11" yes); BPF_SYSCALL = whenAtLeast "4.4" yes; BPF_EVENTS = whenAtLeast "4.4" yes; FUNCTION_PROFILER = yes; RING_BUFFER_BENCHMARK = no; }; virtualisation = { PARAVIRT = option yes; HYPERVISOR_GUEST = when (!features.grsecurity) yes; PARAVIRT_SPINLOCKS = option yes; KVM_APIC_ARCHITECTURE = whenOlder "4.8" yes; KVM_ASYNC_PF = yes; KVM_COMPAT = option (whenBetween "4.0" "4.12" yes); KVM_DEVICE_ASSIGNMENT = option (whenBetween "3.10" "4.12" yes); KVM_GENERIC_DIRTYLOG_READ_PROTECT = whenAtLeast "4.0" yes; KVM_GUEST = when (!features.grsecurity) yes; KVM_MMIO = yes; KVM_VFIO = yes; KSM = yes; VIRT_DRIVERS = yes; # We nneed 64 GB (PAE) support for Xen guest support HIGHMEM64G = option (when (!stdenv.is64bit) yes); VFIO_PCI_VGA = when stdenv.is64bit yes; } // optionalAttrs (stdenv.isx86_64 || stdenv.isi686) ({ XEN = option yes; # XXX: why isn't this in the xen-dom0 conditional section below? XEN_DOM0 = option yes; } // optionalAttrs features.xen_dom0 { PCI_XEN = option yes; HVC_XEN = option yes; HVC_XEN_FRONTEND = option yes; XEN_SYS_HYPERVISOR = option yes; SWIOTLB_XEN = option yes; XEN_BACKEND = option yes; XEN_BALLOON = option yes; XEN_BALLOON_MEMORY_HOTPLUG = option yes; XEN_EFI = option yes; XEN_HAVE_PVMMU = option yes; XEN_MCE_LOG = option yes; XEN_PVH = option yes; XEN_PVHVM = option yes; XEN_SAVE_RESTORE = option yes; XEN_SCRUB_PAGES = option yes; XEN_SELFBALLOONING = option yes; XEN_STUB = option yes; XEN_TMEM = option yes; }); media = { MEDIA_DIGITAL_TV_SUPPORT = yes; MEDIA_CAMERA_SUPPORT = yes; MEDIA_RC_SUPPORT = whenOlder "4.14" yes; MEDIA_CONTROLLER = yes; MEDIA_PCI_SUPPORT = yes; MEDIA_USB_SUPPORT = yes; MEDIA_ANALOG_TV_SUPPORT = yes; VIDEO_STK1160_COMMON = module; VIDEO_STK1160_AC97 = whenOlder "4.11" yes; }; "9p" = { # Enable the 9P cache to speed up NixOS VM tests. "9P_FSCACHE" = option yes; "9P_FS_POSIX_ACL" = option yes; }; huge-page = { TRANSPARENT_HUGEPAGE = option yes; TRANSPARENT_HUGEPAGE_ALWAYS = option no; TRANSPARENT_HUGEPAGE_MADVISE = option yes; }; zram = { ZRAM = module; ZSWAP = option yes; ZBUD = option yes; ZSMALLOC = module; }; brcmfmac = { # Enable PCIe and USB for the brcmfmac driver BRCMFMAC_USB = option yes; BRCMFMAC_PCIE = option yes; }; # Support x2APIC (which requires IRQ remapping) x2apic = optionalAttrs (stdenv.system == "x86_64-linux") { X86_X2APIC = yes; IRQ_REMAP = yes; }; # For older kernels, painstakingly disable each symbol. tests = { # Disable various self-test modules that have no use in a production system # This menu disables all/most of them on >= 4.16 RUNTIME_TESTING_MENU = option no; } // optionalAttrs (versionOlder version "4.16") { ARM_KPROBES_TEST = option no; ASYNC_RAID6_TEST = option no; ATOMIC64_SELFTEST = option no; BACKTRACE_SELF_TEST = option no; INTERVAL_TREE_TEST = option no; PERCPU_TEST = option no; RBTREE_TEST = option no; TEST_BITMAP = option no; TEST_BPF = option no; TEST_FIRMWARE = option no; TEST_HASH = option no; TEST_HEXDUMP = option no; TEST_KMOD = option no; TEST_KSTRTOX = option no; TEST_LIST_SORT = option no; TEST_LKM = option no; TEST_PARMAN = option no; TEST_PRINTF = option no; TEST_RHASHTABLE = option no; TEST_SORT = option no; TEST_STATIC_KEYS = option no; TEST_STRING_HELPERS = option no; TEST_UDELAY = option no; TEST_USER_COPY = option no; TEST_UUID = option no; } // { CRC32_SELFTEST = option no; CRYPTO_TEST = option no; EFI_TEST = option no; GLOB_SELFTEST = option no; DRM_DEBUG_MM_SELFTEST = option (whenOlder "4.18" no); LNET_SELFTEST = option (whenOlder "4.18" no); LOCK_TORTURE_TEST = option no; MTD_TESTS = option no; NOTIFIER_ERROR_INJECTION = option no; RCU_PERF_TEST = option no; RCU_TORTURE_TEST = option no; TEST_ASYNC_DRIVER_PROBE = option no; WW_MUTEX_SELFTEST = option no; XZ_DEC_TEST = option no; } // optionalAttrs (features.criu or false) ({ EXPERT = yes; CHECKPOINT_RESTORE = yes; } // optionalAttrs (features.criu_revert_expert or true) { RFKILL_INPUT = option yes; HID_PICOLCD_FB = option yes; HID_PICOLCD_BACKLIGHT = option yes; HID_PICOLCD_LCD = option yes; HID_PICOLCD_LEDS = option yes; HID_PICOLCD_CIR = option yes; DEBUG_MEMORY_INIT = option yes; }); misc = { MODULE_COMPRESS = yes; MODULE_COMPRESS_XZ = yes; KERNEL_XZ = yes; UNIX = yes; # Unix domain sockets. MD = yes; # Device mapper (RAID, LVM, etc.) # Enable initrd support. BLK_DEV_RAM = yes; BLK_DEV_INITRD = yes; PM_TRACE_RTC = no; # Disable some expensive (?) features. ACCESSIBILITY = yes; # Accessibility support AUXDISPLAY = yes; # Auxiliary Display support DONGLE = whenOlder "4.17" yes; # Serial dongle support HIPPI = yes; MTD_COMPLEX_MAPPINGS = yes; # needed for many devices SCSI_LOWLEVEL = yes; # enable lots of SCSI devices SCSI_LOWLEVEL_PCMCIA = yes; SCSI_SAS_ATA = yes; # added to enable detection of hard drive SPI = yes; # needed for many devices SPI_MASTER = yes; "8139TOO_8129" = yes; "8139TOO_PIO" = no; # PIO is slower AIC79XX_DEBUG_ENABLE = no; AIC7XXX_DEBUG_ENABLE = no; AIC94XX_DEBUG = no; B43_PCMCIA = option (whenOlder "4.4" yes); BLK_DEV_INTEGRITY = yes; BSD_PROCESS_ACCT_V3 = yes; BT_HCIUART_BCSP = option yes; BT_HCIUART_H4 = option yes; # UART (H4) protocol support BT_HCIUART_LL = option yes; BT_RFCOMM_TTY = option yes; # RFCOMM TTY support CLEANCACHE = option yes; CRASH_DUMP = option no; DVB_DYNAMIC_MINORS = option yes; # we use udev EFI_STUB = yes; # EFI bootloader in the bzImage itself CGROUPS = yes; # used by systemd FHANDLE = yes; # used by systemd SECCOMP = yes; # used by systemd >= 231 SECCOMP_FILTER = yes; # ditto POSIX_MQUEUE = yes; FRONTSWAP = yes; FUSION = yes; # Fusion MPT device support IDE = no; # deprecated IDE support IDLE_PAGE_TRACKING = yes; IRDA_ULTRA = whenOlder "4.17" yes; # Ultra (connectionless) protocol JOYSTICK_IFORCE_232 = option yes; # I-Force Serial joysticks and wheels JOYSTICK_IFORCE_USB = option yes; # I-Force USB joysticks and wheels JOYSTICK_XPAD_FF = option yes; # X-Box gamepad rumble support JOYSTICK_XPAD_LEDS = option yes; # LED Support for Xbox360 controller 'BigX' LED KEXEC_FILE = option yes; KEXEC_JUMP = option yes; # Windows Logical Disk Manager (Dynamic Disk) support LDM_PARTITION = yes; LOGIRUMBLEPAD2_FF = yes; # Logitech Rumblepad 2 force feedback LOGO = no; # not needed MEDIA_ATTACH = yes; MEGARAID_NEWGEN = yes; MLX4_EN_VXLAN = whenOlder "4.8" yes; MODVERSIONS = whenOlder "4.9" yes; MOUSE_PS2_ELANTECH = yes; # Elantech PS/2 protocol extension MTRR_SANITIZER = yes; NET_FC = yes; # Fibre Channel driver support # GPIO on Intel Bay Trail, for some Chromebook internal eMMC disks PINCTRL_BAYTRAIL = yes; # 8 is default. Modern gpt tables on eMMC may go far beyond 8. MMC_BLOCK_MINORS = "32"; REGULATOR = yes; # Voltage and Current Regulator Support RC_DEVICES = option yes; # Enable IR devices RT2800USB_RT53XX = yes; RT2800USB_RT55XX = yes; SCHED_AUTOGROUP = yes; CFS_BANDWIDTH = yes; SCSI_LOGGING = yes; # SCSI logging facility SERIAL_8250 = yes; # 8250/16550 and compatible serial support SLIP_COMPRESSED = yes; # CSLIP compressed headers SLIP_SMART = yes; HWMON = yes; THERMAL_HWMON = yes; # Hardware monitoring support UEVENT_HELPER = no; USERFAULTFD = yes; X86_CHECK_BIOS_CORRUPTION = yes; X86_MCE = yes; # Our initrd init uses shebang scripts, so can't be modular. BINFMT_SCRIPT = yes; # For systemd-binfmt BINFMT_MISC = option yes; # Disable the firmware helper fallback, udev doesn't implement it any more FW_LOADER_USER_HELPER_FALLBACK = option no; HOTPLUG_PCI_ACPI = yes; # PCI hotplug using ACPI HOTPLUG_PCI_PCIE = yes; # PCI-Expresscard hotplug support } // optionalAttrs (stdenv.hostPlatform.system == "x86_64-linux" || stdenv.hostPlatform.system == "aarch64-linux") { # Bump the maximum number of CPUs to support systems like EC2 x1.* # instances and Xeon Phi. NR_CPUS = "384"; }; }; in (generateNixKConf ((flattenKConf options) // structuredExtraConfig) mkValueOverride) + extraConfig