940 lines
31 KiB
Nix
940 lines
31 KiB
Nix
# This module creates a virtual machine from the NixOS configuration.
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# Building the `config.system.build.vm' attribute gives you a command
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# that starts a KVM/QEMU VM running the NixOS configuration defined in
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# `config'. The Nix store is shared read-only with the host, which
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# makes (re)building VMs very efficient. However, it also means you
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# can't reconfigure the guest inside the guest - you need to rebuild
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# the VM in the host. On the other hand, the root filesystem is a
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# read/writable disk image persistent across VM reboots.
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{ config, lib, pkgs, options, ... }:
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with lib;
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let
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qemu-common = import ../../lib/qemu-common.nix { inherit lib pkgs; };
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cfg = config.virtualisation;
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qemu = cfg.qemu.package;
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consoles = lib.concatMapStringsSep " " (c: "console=${c}") cfg.qemu.consoles;
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driveOpts = { ... }: {
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options = {
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file = mkOption {
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type = types.str;
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description = "The file image used for this drive.";
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};
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driveExtraOpts = mkOption {
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type = types.attrsOf types.str;
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default = {};
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description = "Extra options passed to drive flag.";
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};
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deviceExtraOpts = mkOption {
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type = types.attrsOf types.str;
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default = {};
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description = "Extra options passed to device flag.";
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};
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name = mkOption {
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type = types.nullOr types.str;
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default = null;
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description =
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"A name for the drive. Must be unique in the drives list. Not passed to qemu.";
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};
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};
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};
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driveCmdline = idx: { file, driveExtraOpts, deviceExtraOpts, ... }:
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let
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drvId = "drive${toString idx}";
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mkKeyValue = generators.mkKeyValueDefault {} "=";
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mkOpts = opts: concatStringsSep "," (mapAttrsToList mkKeyValue opts);
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driveOpts = mkOpts (driveExtraOpts // {
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index = idx;
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id = drvId;
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"if" = "none";
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inherit file;
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});
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deviceOpts = mkOpts (deviceExtraOpts // {
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drive = drvId;
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});
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device =
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if cfg.qemu.diskInterface == "scsi" then
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"-device lsi53c895a -device scsi-hd,${deviceOpts}"
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else
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"-device virtio-blk-pci,${deviceOpts}";
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in
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"-drive ${driveOpts} ${device}";
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drivesCmdLine = drives: concatStringsSep "\\\n " (imap1 driveCmdline drives);
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# Creates a device name from a 1-based a numerical index, e.g.
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# * `driveDeviceName 1` -> `/dev/vda`
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# * `driveDeviceName 2` -> `/dev/vdb`
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driveDeviceName = idx:
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let letter = elemAt lowerChars (idx - 1);
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in if cfg.qemu.diskInterface == "scsi" then
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"/dev/sd${letter}"
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else
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"/dev/vd${letter}";
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lookupDriveDeviceName = driveName: driveList:
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(findSingle (drive: drive.name == driveName)
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(throw "Drive ${driveName} not found")
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(throw "Multiple drives named ${driveName}") driveList).device;
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addDeviceNames =
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imap1 (idx: drive: drive // { device = driveDeviceName idx; });
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efiPrefix =
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if (pkgs.stdenv.isi686 || pkgs.stdenv.isx86_64) then "${pkgs.OVMF.fd}/FV/OVMF"
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else if pkgs.stdenv.isAarch64 then "${pkgs.OVMF.fd}/FV/AAVMF"
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else throw "No EFI firmware available for platform";
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efiFirmware = "${efiPrefix}_CODE.fd";
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efiVarsDefault = "${efiPrefix}_VARS.fd";
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# Shell script to start the VM.
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startVM =
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''
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#! ${pkgs.runtimeShell}
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set -e
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NIX_DISK_IMAGE=$(readlink -f "''${NIX_DISK_IMAGE:-${config.virtualisation.diskImage}}")
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if ! test -e "$NIX_DISK_IMAGE"; then
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${qemu}/bin/qemu-img create -f qcow2 "$NIX_DISK_IMAGE" \
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${toString config.virtualisation.diskSize}M
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fi
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# Create a directory for storing temporary data of the running VM.
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if [ -z "$TMPDIR" ] || [ -z "$USE_TMPDIR" ]; then
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TMPDIR=$(mktemp -d nix-vm.XXXXXXXXXX --tmpdir)
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fi
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# Create a directory for exchanging data with the VM.
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mkdir -p "$TMPDIR/xchg"
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${lib.optionalString cfg.useBootLoader
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''
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# Create a writable copy/snapshot of the boot disk.
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# A writable boot disk can be booted from automatically.
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${qemu}/bin/qemu-img create -f qcow2 -F qcow2 -b ${bootDisk}/disk.img "$TMPDIR/disk.img"
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NIX_EFI_VARS=$(readlink -f "''${NIX_EFI_VARS:-${cfg.efiVars}}")
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${lib.optionalString cfg.useEFIBoot
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''
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# VM needs writable EFI vars
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if ! test -e "$NIX_EFI_VARS"; then
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cp ${bootDisk}/efi-vars.fd "$NIX_EFI_VARS"
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chmod 0644 "$NIX_EFI_VARS"
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fi
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''}
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''}
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cd "$TMPDIR"
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${lib.optionalString (cfg.emptyDiskImages != []) "idx=0"}
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${flip concatMapStrings cfg.emptyDiskImages (size: ''
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if ! test -e "empty$idx.qcow2"; then
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${qemu}/bin/qemu-img create -f qcow2 "empty$idx.qcow2" "${toString size}M"
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fi
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idx=$((idx + 1))
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'')}
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# Start QEMU.
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exec ${qemu-common.qemuBinary qemu} \
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-name ${config.system.name} \
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-m ${toString config.virtualisation.memorySize} \
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-smp ${toString config.virtualisation.cores} \
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-device virtio-rng-pci \
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${concatStringsSep " " config.virtualisation.qemu.networkingOptions} \
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${concatStringsSep " \\\n "
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(mapAttrsToList
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(tag: share: "-virtfs local,path=${share.source},security_model=none,mount_tag=${tag}")
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config.virtualisation.sharedDirectories)} \
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${drivesCmdLine config.virtualisation.qemu.drives} \
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${concatStringsSep " \\\n " config.virtualisation.qemu.options} \
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$QEMU_OPTS \
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"$@"
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'';
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regInfo = pkgs.closureInfo { rootPaths = config.virtualisation.pathsInNixDB; };
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# Generate a hard disk image containing a /boot partition and GRUB
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# in the MBR. Used when the `useBootLoader' option is set.
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# Uses `runInLinuxVM` to create the image in a throwaway VM.
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# See note [Disk layout with `useBootLoader`].
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# FIXME: use nixos/lib/make-disk-image.nix.
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bootDisk =
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pkgs.vmTools.runInLinuxVM (
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pkgs.runCommand "nixos-boot-disk"
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{ preVM =
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''
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mkdir $out
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diskImage=$out/disk.img
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${qemu}/bin/qemu-img create -f qcow2 $diskImage "60M"
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${if cfg.useEFIBoot then ''
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efiVars=$out/efi-vars.fd
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cp ${efiVarsDefault} $efiVars
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chmod 0644 $efiVars
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'' else ""}
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'';
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buildInputs = [ pkgs.util-linux ];
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QEMU_OPTS = "-nographic -serial stdio -monitor none"
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+ lib.optionalString cfg.useEFIBoot (
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" -drive if=pflash,format=raw,unit=0,readonly=on,file=${efiFirmware}"
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+ " -drive if=pflash,format=raw,unit=1,file=$efiVars");
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}
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''
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# Create a /boot EFI partition with 60M and arbitrary but fixed GUIDs for reproducibility
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${pkgs.gptfdisk}/bin/sgdisk \
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--set-alignment=1 --new=1:34:2047 --change-name=1:BIOSBootPartition --typecode=1:ef02 \
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--set-alignment=512 --largest-new=2 --change-name=2:EFISystem --typecode=2:ef00 \
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--attributes=1:set:1 \
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--attributes=2:set:2 \
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--disk-guid=97FD5997-D90B-4AA3-8D16-C1723AEA73C1 \
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--partition-guid=1:1C06F03B-704E-4657-B9CD-681A087A2FDC \
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--partition-guid=2:970C694F-AFD0-4B99-B750-CDB7A329AB6F \
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--hybrid 2 \
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--recompute-chs /dev/vda
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${optionalString (config.boot.loader.grub.device != "/dev/vda")
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# In this throwaway VM, we only have the /dev/vda disk, but the
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# actual VM described by `config` (used by `switch-to-configuration`
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# below) may set `boot.loader.grub.device` to a different device
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# that's nonexistent in the throwaway VM.
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# Create a symlink for that device, so that the `grub-install`
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# by `switch-to-configuration` will hit /dev/vda anyway.
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''
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ln -s /dev/vda ${config.boot.loader.grub.device}
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''
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}
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${pkgs.dosfstools}/bin/mkfs.fat -F16 /dev/vda2
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export MTOOLS_SKIP_CHECK=1
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${pkgs.mtools}/bin/mlabel -i /dev/vda2 ::boot
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# Mount /boot; load necessary modules first.
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${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/nls/nls_cp437.ko.xz || true
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${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/nls/nls_iso8859-1.ko.xz || true
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${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/fat/fat.ko.xz || true
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${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/fat/vfat.ko.xz || true
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${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/efivarfs/efivarfs.ko.xz || true
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mkdir /boot
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mount /dev/vda2 /boot
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${optionalString config.boot.loader.efi.canTouchEfiVariables ''
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mount -t efivarfs efivarfs /sys/firmware/efi/efivars
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''}
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# This is needed for GRUB 0.97, which doesn't know about virtio devices.
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mkdir /boot/grub
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echo '(hd0) /dev/vda' > /boot/grub/device.map
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# This is needed for systemd-boot to find ESP, and udev is not available here to create this
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mkdir -p /dev/block
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ln -s /dev/vda2 /dev/block/254:2
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# Set up system profile (normally done by nixos-rebuild / nix-env --set)
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mkdir -p /nix/var/nix/profiles
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ln -s ${config.system.build.toplevel} /nix/var/nix/profiles/system-1-link
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ln -s /nix/var/nix/profiles/system-1-link /nix/var/nix/profiles/system
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# Install bootloader
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touch /etc/NIXOS
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export NIXOS_INSTALL_BOOTLOADER=1
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${config.system.build.toplevel}/bin/switch-to-configuration boot
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umount /boot
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'' # */
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);
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in
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{
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imports = [
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../profiles/qemu-guest.nix
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];
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options = {
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virtualisation.fileSystems = options.fileSystems;
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virtualisation.memorySize =
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mkOption {
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type = types.ints.positive;
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default = 384;
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description =
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''
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The memory size in megabytes of the virtual machine.
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'';
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};
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virtualisation.msize =
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mkOption {
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type = types.ints.positive;
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default = 16384;
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description =
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''
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The msize (maximum packet size) option passed to 9p file systems, in
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bytes. Increasing this should increase performance significantly,
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at the cost of higher RAM usage.
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'';
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};
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virtualisation.diskSize =
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mkOption {
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type = types.nullOr types.ints.positive;
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default = 512;
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description =
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''
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The disk size in megabytes of the virtual machine.
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'';
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};
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virtualisation.diskImage =
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mkOption {
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type = types.str;
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default = "./${config.system.name}.qcow2";
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description =
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''
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Path to the disk image containing the root filesystem.
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The image will be created on startup if it does not
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exist.
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'';
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};
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virtualisation.bootDevice =
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mkOption {
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type = types.path;
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example = "/dev/vda";
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description =
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''
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The disk to be used for the root filesystem.
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'';
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};
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virtualisation.emptyDiskImages =
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mkOption {
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type = types.listOf types.ints.positive;
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default = [];
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description =
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''
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Additional disk images to provide to the VM. The value is
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a list of size in megabytes of each disk. These disks are
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writeable by the VM.
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'';
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};
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virtualisation.graphics =
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mkOption {
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type = types.bool;
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default = true;
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description =
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''
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Whether to run QEMU with a graphics window, or in nographic mode.
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Serial console will be enabled on both settings, but this will
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change the preferred console.
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'';
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};
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virtualisation.resolution =
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mkOption {
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type = options.services.xserver.resolutions.type.nestedTypes.elemType;
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default = { x = 1024; y = 768; };
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description =
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''
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The resolution of the virtual machine display.
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'';
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};
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virtualisation.cores =
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mkOption {
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type = types.ints.positive;
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default = 1;
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description =
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''
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Specify the number of cores the guest is permitted to use.
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The number can be higher than the available cores on the
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host system.
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'';
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};
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virtualisation.sharedDirectories =
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mkOption {
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type = types.attrsOf
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(types.submodule {
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options.source = mkOption {
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type = types.str;
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description = "The path of the directory to share, can be a shell variable";
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};
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options.target = mkOption {
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type = types.path;
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description = "The mount point of the directory inside the virtual machine";
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};
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});
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default = { };
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example = {
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my-share = { source = "/path/to/be/shared"; target = "/mnt/shared"; };
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};
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description =
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''
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An attributes set of directories that will be shared with the
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virtual machine using VirtFS (9P filesystem over VirtIO).
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The attribute name will be used as the 9P mount tag.
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'';
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};
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virtualisation.pathsInNixDB =
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mkOption {
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type = types.listOf types.path;
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default = [];
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description =
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''
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The list of paths whose closure is registered in the Nix
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database in the VM. All other paths in the host Nix store
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appear in the guest Nix store as well, but are considered
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garbage (because they are not registered in the Nix
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database in the guest).
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'';
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};
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virtualisation.forwardPorts = mkOption {
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type = types.listOf
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(types.submodule {
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options.from = mkOption {
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type = types.enum [ "host" "guest" ];
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default = "host";
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description =
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''
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Controls the direction in which the ports are mapped:
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- <literal>"host"</literal> means traffic from the host ports
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is forwarded to the given guest port.
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- <literal>"guest"</literal> means traffic from the guest ports
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is forwarded to the given host port.
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'';
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};
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options.proto = mkOption {
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type = types.enum [ "tcp" "udp" ];
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default = "tcp";
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description = "The protocol to forward.";
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};
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options.host.address = mkOption {
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type = types.str;
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default = "";
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description = "The IPv4 address of the host.";
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};
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options.host.port = mkOption {
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type = types.port;
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description = "The host port to be mapped.";
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};
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options.guest.address = mkOption {
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type = types.str;
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default = "";
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description = "The IPv4 address on the guest VLAN.";
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};
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options.guest.port = mkOption {
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type = types.port;
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description = "The guest port to be mapped.";
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};
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});
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default = [];
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example = lib.literalExpression
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''
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[ # forward local port 2222 -> 22, to ssh into the VM
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{ from = "host"; host.port = 2222; guest.port = 22; }
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# forward local port 80 -> 10.0.2.10:80 in the VLAN
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{ from = "guest";
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guest.address = "10.0.2.10"; guest.port = 80;
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host.address = "127.0.0.1"; host.port = 80;
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}
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]
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'';
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description =
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''
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When using the SLiRP user networking (default), this option allows to
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forward ports to/from the host/guest.
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<warning><para>
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If the NixOS firewall on the virtual machine is enabled, you also
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have to open the guest ports to enable the traffic between host and
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guest.
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</para></warning>
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<note><para>Currently QEMU supports only IPv4 forwarding.</para></note>
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'';
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};
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virtualisation.vlans =
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mkOption {
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type = types.listOf types.ints.unsigned;
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default = [ 1 ];
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example = [ 1 2 ];
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description =
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''
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Virtual networks to which the VM is connected. Each
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number <replaceable>N</replaceable> in this list causes
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the VM to have a virtual Ethernet interface attached to a
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separate virtual network on which it will be assigned IP
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address
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<literal>192.168.<replaceable>N</replaceable>.<replaceable>M</replaceable></literal>,
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where <replaceable>M</replaceable> is the index of this VM
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in the list of VMs.
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'';
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};
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virtualisation.writableStore =
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mkOption {
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type = types.bool;
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default = true; # FIXME
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description =
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''
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If enabled, the Nix store in the VM is made writable by
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layering an overlay filesystem on top of the host's Nix
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store.
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'';
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};
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|
|
virtualisation.writableStoreUseTmpfs =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = true;
|
|
description =
|
|
''
|
|
Use a tmpfs for the writable store instead of writing to the VM's
|
|
own filesystem.
|
|
'';
|
|
};
|
|
|
|
networking.primaryIPAddress =
|
|
mkOption {
|
|
type = types.str;
|
|
default = "";
|
|
internal = true;
|
|
description = "Primary IP address used in /etc/hosts.";
|
|
};
|
|
|
|
virtualisation.qemu = {
|
|
package =
|
|
mkOption {
|
|
type = types.package;
|
|
default = pkgs.qemu;
|
|
example = "pkgs.qemu_test";
|
|
description = "QEMU package to use.";
|
|
};
|
|
|
|
options =
|
|
mkOption {
|
|
type = types.listOf types.str;
|
|
default = [];
|
|
example = [ "-vga std" ];
|
|
description = "Options passed to QEMU.";
|
|
};
|
|
|
|
consoles = mkOption {
|
|
type = types.listOf types.str;
|
|
default = let
|
|
consoles = [ "${qemu-common.qemuSerialDevice},115200n8" "tty0" ];
|
|
in if cfg.graphics then consoles else reverseList consoles;
|
|
example = [ "console=tty1" ];
|
|
description = ''
|
|
The output console devices to pass to the kernel command line via the
|
|
<literal>console</literal> parameter, the primary console is the last
|
|
item of this list.
|
|
|
|
By default it enables both serial console and
|
|
<literal>tty0</literal>. The preferred console (last one) is based on
|
|
the value of <option>virtualisation.graphics</option>.
|
|
'';
|
|
};
|
|
|
|
networkingOptions =
|
|
mkOption {
|
|
type = types.listOf types.str;
|
|
default = [ ];
|
|
example = [
|
|
"-net nic,netdev=user.0,model=virtio"
|
|
"-netdev user,id=user.0,\${QEMU_NET_OPTS:+,$QEMU_NET_OPTS}"
|
|
];
|
|
description = ''
|
|
Networking-related command-line options that should be passed to qemu.
|
|
The default is to use userspace networking (SLiRP).
|
|
|
|
If you override this option, be advised to keep
|
|
''${QEMU_NET_OPTS:+,$QEMU_NET_OPTS} (as seen in the example)
|
|
to keep the default runtime behaviour.
|
|
'';
|
|
};
|
|
|
|
drives =
|
|
mkOption {
|
|
type = types.listOf (types.submodule driveOpts);
|
|
description = "Drives passed to qemu.";
|
|
apply = addDeviceNames;
|
|
};
|
|
|
|
diskInterface =
|
|
mkOption {
|
|
type = types.enum [ "virtio" "scsi" "ide" ];
|
|
default = "virtio";
|
|
example = "scsi";
|
|
description = "The interface used for the virtual hard disks.";
|
|
};
|
|
|
|
guestAgent.enable =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = true;
|
|
description = ''
|
|
Enable the Qemu guest agent.
|
|
'';
|
|
};
|
|
};
|
|
|
|
virtualisation.useBootLoader =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = false;
|
|
description =
|
|
''
|
|
If enabled, the virtual machine will be booted using the
|
|
regular boot loader (i.e., GRUB 1 or 2). This allows
|
|
testing of the boot loader. If
|
|
disabled (the default), the VM directly boots the NixOS
|
|
kernel and initial ramdisk, bypassing the boot loader
|
|
altogether.
|
|
'';
|
|
};
|
|
|
|
virtualisation.useEFIBoot =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = false;
|
|
description =
|
|
''
|
|
If enabled, the virtual machine will provide a EFI boot
|
|
manager.
|
|
useEFIBoot is ignored if useBootLoader == false.
|
|
'';
|
|
};
|
|
|
|
virtualisation.efiVars =
|
|
mkOption {
|
|
type = types.str;
|
|
default = "./${config.system.name}-efi-vars.fd";
|
|
description =
|
|
''
|
|
Path to nvram image containing UEFI variables. The will be created
|
|
on startup if it does not exist.
|
|
'';
|
|
};
|
|
|
|
virtualisation.bios =
|
|
mkOption {
|
|
type = types.nullOr types.package;
|
|
default = null;
|
|
description =
|
|
''
|
|
An alternate BIOS (such as <package>qboot</package>) with which to start the VM.
|
|
Should contain a file named <literal>bios.bin</literal>.
|
|
If <literal>null</literal>, QEMU's builtin SeaBIOS will be used.
|
|
'';
|
|
};
|
|
|
|
};
|
|
|
|
config = {
|
|
|
|
assertions =
|
|
lib.concatLists (lib.flip lib.imap cfg.forwardPorts (i: rule:
|
|
[
|
|
{ assertion = rule.from == "guest" -> rule.proto == "tcp";
|
|
message =
|
|
''
|
|
Invalid virtualisation.forwardPorts.<entry ${toString i}>.proto:
|
|
Guest forwarding supports only TCP connections.
|
|
'';
|
|
}
|
|
{ assertion = rule.from == "guest" -> lib.hasPrefix "10.0.2." rule.guest.address;
|
|
message =
|
|
''
|
|
Invalid virtualisation.forwardPorts.<entry ${toString i}>.guest.address:
|
|
The address must be in the default VLAN (10.0.2.0/24).
|
|
'';
|
|
}
|
|
]));
|
|
|
|
# Note [Disk layout with `useBootLoader`]
|
|
#
|
|
# If `useBootLoader = true`, we configure 2 drives:
|
|
# `/dev/?da` for the root disk, and `/dev/?db` for the boot disk
|
|
# which has the `/boot` partition and the boot loader.
|
|
# Concretely:
|
|
#
|
|
# * The second drive's image `disk.img` is created in `bootDisk = ...`
|
|
# using a throwaway VM. Note that there the disk is always `/dev/vda`,
|
|
# even though in the final VM it will be at `/dev/*b`.
|
|
# * The disks are attached in `virtualisation.qemu.drives`.
|
|
# Their order makes them appear as devices `a`, `b`, etc.
|
|
# * `fileSystems."/boot"` is adjusted to be on device `b`.
|
|
|
|
# If `useBootLoader`, GRUB goes to the second disk, see
|
|
# note [Disk layout with `useBootLoader`].
|
|
boot.loader.grub.device = mkVMOverride (
|
|
if cfg.useBootLoader
|
|
then driveDeviceName 2 # second disk
|
|
else cfg.bootDevice
|
|
);
|
|
boot.loader.grub.gfxmodeBios = with cfg.resolution; "${toString x}x${toString y}";
|
|
|
|
boot.initrd.extraUtilsCommands =
|
|
''
|
|
# We need mke2fs in the initrd.
|
|
copy_bin_and_libs ${pkgs.e2fsprogs}/bin/mke2fs
|
|
'';
|
|
|
|
boot.initrd.postDeviceCommands =
|
|
''
|
|
# If the disk image appears to be empty, run mke2fs to
|
|
# initialise.
|
|
FSTYPE=$(blkid -o value -s TYPE ${cfg.bootDevice} || true)
|
|
if test -z "$FSTYPE"; then
|
|
mke2fs -t ext4 ${cfg.bootDevice}
|
|
fi
|
|
'';
|
|
|
|
boot.initrd.postMountCommands =
|
|
''
|
|
# Mark this as a NixOS machine.
|
|
mkdir -p $targetRoot/etc
|
|
echo -n > $targetRoot/etc/NIXOS
|
|
|
|
# Fix the permissions on /tmp.
|
|
chmod 1777 $targetRoot/tmp
|
|
|
|
mkdir -p $targetRoot/boot
|
|
|
|
${optionalString cfg.writableStore ''
|
|
echo "mounting overlay filesystem on /nix/store..."
|
|
mkdir -p 0755 $targetRoot/nix/.rw-store/store $targetRoot/nix/.rw-store/work $targetRoot/nix/store
|
|
mount -t overlay overlay $targetRoot/nix/store \
|
|
-o lowerdir=$targetRoot/nix/.ro-store,upperdir=$targetRoot/nix/.rw-store/store,workdir=$targetRoot/nix/.rw-store/work || fail
|
|
''}
|
|
'';
|
|
|
|
# After booting, register the closure of the paths in
|
|
# `virtualisation.pathsInNixDB' in the Nix database in the VM. This
|
|
# allows Nix operations to work in the VM. The path to the
|
|
# registration file is passed through the kernel command line to
|
|
# allow `system.build.toplevel' to be included. (If we had a direct
|
|
# reference to ${regInfo} here, then we would get a cyclic
|
|
# dependency.)
|
|
boot.postBootCommands =
|
|
''
|
|
if [[ "$(cat /proc/cmdline)" =~ regInfo=([^ ]*) ]]; then
|
|
${config.nix.package.out}/bin/nix-store --load-db < ''${BASH_REMATCH[1]}
|
|
fi
|
|
'';
|
|
|
|
boot.initrd.availableKernelModules =
|
|
optional cfg.writableStore "overlay"
|
|
++ optional (cfg.qemu.diskInterface == "scsi") "sym53c8xx";
|
|
|
|
virtualisation.bootDevice = mkDefault (driveDeviceName 1);
|
|
|
|
virtualisation.pathsInNixDB = [ config.system.build.toplevel ];
|
|
|
|
virtualisation.sharedDirectories = {
|
|
nix-store = { source = "/nix/store"; target = "/nix/store"; };
|
|
xchg = { source = ''"$TMPDIR"/xchg''; target = "/tmp/xchg"; };
|
|
shared = { source = ''"''${SHARED_DIR:-$TMPDIR/xchg}"''; target = "/tmp/shared"; };
|
|
};
|
|
|
|
virtualisation.qemu.networkingOptions =
|
|
let
|
|
forwardingOptions = flip concatMapStrings cfg.forwardPorts
|
|
({ proto, from, host, guest }:
|
|
if from == "host"
|
|
then "hostfwd=${proto}:${host.address}:${toString host.port}-" +
|
|
"${guest.address}:${toString guest.port},"
|
|
else "'guestfwd=${proto}:${guest.address}:${toString guest.port}-" +
|
|
"cmd:${pkgs.netcat}/bin/nc ${host.address} ${toString host.port}',"
|
|
);
|
|
in
|
|
[
|
|
"-net nic,netdev=user.0,model=virtio"
|
|
"-netdev user,id=user.0,${forwardingOptions}\"$QEMU_NET_OPTS\""
|
|
];
|
|
|
|
# FIXME: Consolidate this one day.
|
|
virtualisation.qemu.options = mkMerge [
|
|
(mkIf (pkgs.stdenv.isi686 || pkgs.stdenv.isx86_64) [
|
|
"-usb" "-device usb-tablet,bus=usb-bus.0"
|
|
])
|
|
(mkIf (pkgs.stdenv.isAarch32 || pkgs.stdenv.isAarch64) [
|
|
"-device virtio-gpu-pci" "-device usb-ehci,id=usb0" "-device usb-kbd" "-device usb-tablet"
|
|
])
|
|
(mkIf (!cfg.useBootLoader) [
|
|
"-kernel ${config.system.build.toplevel}/kernel"
|
|
"-initrd ${config.system.build.toplevel}/initrd"
|
|
''-append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.toplevel}/init regInfo=${regInfo}/registration ${consoles} $QEMU_KERNEL_PARAMS"''
|
|
])
|
|
(mkIf cfg.useEFIBoot [
|
|
"-drive if=pflash,format=raw,unit=0,readonly,file=${efiFirmware}"
|
|
"-drive if=pflash,format=raw,unit=1,file=$NIX_EFI_VARS"
|
|
])
|
|
(mkIf (cfg.bios != null) [
|
|
"-bios ${cfg.bios}/bios.bin"
|
|
])
|
|
(mkIf (!cfg.graphics) [
|
|
"-nographic"
|
|
])
|
|
];
|
|
|
|
virtualisation.qemu.drives = mkMerge [
|
|
[{
|
|
name = "root";
|
|
file = ''"$NIX_DISK_IMAGE"'';
|
|
driveExtraOpts.cache = "writeback";
|
|
driveExtraOpts.werror = "report";
|
|
}]
|
|
(mkIf cfg.useBootLoader [
|
|
# The order of this list determines the device names, see
|
|
# note [Disk layout with `useBootLoader`].
|
|
{
|
|
name = "boot";
|
|
file = ''"$TMPDIR"/disk.img'';
|
|
driveExtraOpts.media = "disk";
|
|
deviceExtraOpts.bootindex = "1";
|
|
}
|
|
])
|
|
(imap0 (idx: _: {
|
|
file = "$(pwd)/empty${toString idx}.qcow2";
|
|
driveExtraOpts.werror = "report";
|
|
}) cfg.emptyDiskImages)
|
|
];
|
|
|
|
# Mount the host filesystem via 9P, and bind-mount the Nix store
|
|
# of the host into our own filesystem. We use mkVMOverride to
|
|
# allow this module to be applied to "normal" NixOS system
|
|
# configuration, where the regular value for the `fileSystems'
|
|
# attribute should be disregarded for the purpose of building a VM
|
|
# test image (since those filesystems don't exist in the VM).
|
|
fileSystems =
|
|
let
|
|
mkSharedDir = tag: share:
|
|
{
|
|
name =
|
|
if tag == "nix-store" && cfg.writableStore
|
|
then "/nix/.ro-store"
|
|
else share.target;
|
|
value.device = tag;
|
|
value.fsType = "9p";
|
|
value.neededForBoot = true;
|
|
value.options =
|
|
[ "trans=virtio" "version=9p2000.L" "msize=${toString cfg.msize}" ]
|
|
++ lib.optional (tag == "nix-store") "cache=loose";
|
|
};
|
|
in
|
|
mkVMOverride (cfg.fileSystems //
|
|
{
|
|
"/".device = cfg.bootDevice;
|
|
|
|
"/tmp" = mkIf config.boot.tmpOnTmpfs
|
|
{ device = "tmpfs";
|
|
fsType = "tmpfs";
|
|
neededForBoot = true;
|
|
# Sync with systemd's tmp.mount;
|
|
options = [ "mode=1777" "strictatime" "nosuid" "nodev" "size=${toString config.boot.tmpOnTmpfsSize}" ];
|
|
};
|
|
|
|
"/nix/.rw-store" = mkIf (cfg.writableStore && cfg.writableStoreUseTmpfs)
|
|
{ fsType = "tmpfs";
|
|
options = [ "mode=0755" ];
|
|
neededForBoot = true;
|
|
};
|
|
|
|
"/boot" = mkIf cfg.useBootLoader
|
|
# see note [Disk layout with `useBootLoader`]
|
|
{ device = "${lookupDriveDeviceName "boot" cfg.qemu.drives}2"; # 2 for e.g. `vdb2`, as created in `bootDisk`
|
|
fsType = "vfat";
|
|
noCheck = true; # fsck fails on a r/o filesystem
|
|
};
|
|
} // lib.mapAttrs' mkSharedDir cfg.sharedDirectories);
|
|
|
|
swapDevices = mkVMOverride [ ];
|
|
boot.initrd.luks.devices = mkVMOverride {};
|
|
|
|
# Don't run ntpd in the guest. It should get the correct time from KVM.
|
|
services.timesyncd.enable = false;
|
|
|
|
services.qemuGuest.enable = cfg.qemu.guestAgent.enable;
|
|
|
|
system.build.vm = pkgs.runCommand "nixos-vm" { preferLocalBuild = true; }
|
|
''
|
|
mkdir -p $out/bin
|
|
ln -s ${config.system.build.toplevel} $out/system
|
|
ln -s ${pkgs.writeScript "run-nixos-vm" startVM} $out/bin/run-${config.system.name}-vm
|
|
'';
|
|
|
|
# When building a regular system configuration, override whatever
|
|
# video driver the host uses.
|
|
services.xserver.videoDrivers = mkVMOverride [ "modesetting" ];
|
|
services.xserver.defaultDepth = mkVMOverride 0;
|
|
services.xserver.resolutions = mkVMOverride [ cfg.resolution ];
|
|
services.xserver.monitorSection =
|
|
''
|
|
# Set a higher refresh rate so that resolutions > 800x600 work.
|
|
HorizSync 30-140
|
|
VertRefresh 50-160
|
|
'';
|
|
|
|
# Wireless won't work in the VM.
|
|
networking.wireless.enable = mkVMOverride false;
|
|
services.connman.enable = mkVMOverride false;
|
|
|
|
# Speed up booting by not waiting for ARP.
|
|
networking.dhcpcd.extraConfig = "noarp";
|
|
|
|
networking.usePredictableInterfaceNames = false;
|
|
|
|
system.requiredKernelConfig = with config.lib.kernelConfig;
|
|
[ (isEnabled "VIRTIO_BLK")
|
|
(isEnabled "VIRTIO_PCI")
|
|
(isEnabled "VIRTIO_NET")
|
|
(isEnabled "EXT4_FS")
|
|
(isEnabled "NET_9P_VIRTIO")
|
|
(isEnabled "9P_FS")
|
|
(isYes "BLK_DEV")
|
|
(isYes "PCI")
|
|
(isYes "NETDEVICES")
|
|
(isYes "NET_CORE")
|
|
(isYes "INET")
|
|
(isYes "NETWORK_FILESYSTEMS")
|
|
] ++ optionals (!cfg.graphics) [
|
|
(isYes "SERIAL_8250_CONSOLE")
|
|
(isYes "SERIAL_8250")
|
|
] ++ optionals (cfg.writableStore) [
|
|
(isEnabled "OVERLAY_FS")
|
|
];
|
|
|
|
};
|
|
}
|