forked from mirrors/nixpkgs
e039cb9d97
This adds an option to the qemu virtualisation module to isolate the guest's from the host's and outside networks. This is particularly useful for development sandboxes for example. The option is disabled by default to preserve the current behaviour.
1165 lines
40 KiB
Nix
1165 lines
40 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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opt = options.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 = lib.mdDoc "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 = lib.mdDoc "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 = lib.mdDoc "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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lib.mdDoc "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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# Shell script to start the VM.
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startVM =
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''
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#! ${cfg.host.pkgs.runtimeShell}
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export PATH=${makeBinPath [ cfg.host.pkgs.coreutils ]}''${PATH:+:}$PATH
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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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${lib.optionalString (cfg.useNixStoreImage)
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(if cfg.writableStore
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then ''
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# Create a writable copy/snapshot of the store image.
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${qemu}/bin/qemu-img create -f qcow2 -F qcow2 -b ${storeImage}/nixos.qcow2 "$TMPDIR"/store.img
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''
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else ''
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(
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cd ${builtins.storeDir}
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${pkgs.erofs-utils}/bin/mkfs.erofs \
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--force-uid=0 \
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--force-gid=0 \
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-U eb176051-bd15-49b7-9e6b-462e0b467019 \
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-T 0 \
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--exclude-regex="$(
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<${pkgs.closureInfo { rootPaths = [ config.system.build.toplevel regInfo ]; }}/store-paths \
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sed -e 's^.*/^^g' \
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| cut -c -10 \
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| ${pkgs.python3}/bin/python ${./includes-to-excludes.py} )" \
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"$TMPDIR"/store.img \
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. \
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</dev/null >/dev/null
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)
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''
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)
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}
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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.additionalPaths; };
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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 ${cfg.efi.variables} $efiVars
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chmod 0644 $efiVars
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'' else ""}
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'';
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buildInputs = [ pkgs.util-linux ];
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QEMU_OPTS = "-nographic -serial stdio -monitor none"
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+ lib.optionalString cfg.useEFIBoot (
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" -drive if=pflash,format=raw,unit=0,readonly=on,file=${cfg.efi.firmware}"
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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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storeImage = import ../../lib/make-disk-image.nix {
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inherit pkgs config lib;
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additionalPaths = [ regInfo ];
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format = "qcow2";
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onlyNixStore = true;
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partitionTableType = "none";
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installBootLoader = false;
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diskSize = "auto";
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additionalSpace = "0M";
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copyChannel = false;
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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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(mkRenamedOptionModule [ "virtualisation" "pathsInNixDB" ] [ "virtualisation" "additionalPaths" ])
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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 = 1024;
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description =
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lib.mdDoc ''
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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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lib.mdDoc ''
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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 = 1024;
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description =
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lib.mdDoc ''
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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 = "./${config.system.name}.qcow2";
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defaultText = literalExpression ''"./''${config.system.name}.qcow2"'';
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description =
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lib.mdDoc ''
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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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lib.mdDoc ''
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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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lib.mdDoc ''
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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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lib.mdDoc ''
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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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lib.mdDoc ''
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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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lib.mdDoc ''
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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 = lib.mdDoc "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 = lib.mdDoc "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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lib.mdDoc ''
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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.additionalPaths =
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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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lib.mdDoc ''
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A list of paths whose closure should be made available to
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the VM.
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When 9p is used, the 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 of the guest).
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When {option}`virtualisation.useNixStoreImage` is
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set, the closure is copied to the Nix store image.
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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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lib.mdDoc ''
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Controls the direction in which the ports are mapped:
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- `"host"` means traffic from the host ports
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is forwarded to the given guest port.
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- `"guest"` 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 = lib.mdDoc "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 = lib.mdDoc "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 = lib.mdDoc "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 = lib.mdDoc "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 = lib.mdDoc "The guest port to be mapped.";
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};
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});
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default = [];
|
|
example = lib.literalExpression
|
|
''
|
|
[ # forward local port 2222 -> 22, to ssh into the VM
|
|
{ from = "host"; host.port = 2222; guest.port = 22; }
|
|
|
|
# forward local port 80 -> 10.0.2.10:80 in the VLAN
|
|
{ from = "guest";
|
|
guest.address = "10.0.2.10"; guest.port = 80;
|
|
host.address = "127.0.0.1"; host.port = 80;
|
|
}
|
|
]
|
|
'';
|
|
description =
|
|
lib.mdDoc ''
|
|
When using the SLiRP user networking (default), this option allows to
|
|
forward ports to/from the host/guest.
|
|
|
|
::: {.warning}
|
|
If the NixOS firewall on the virtual machine is enabled, you also
|
|
have to open the guest ports to enable the traffic between host and
|
|
guest.
|
|
:::
|
|
|
|
::: {.note}
|
|
Currently QEMU supports only IPv4 forwarding.
|
|
:::
|
|
'';
|
|
};
|
|
|
|
virtualisation.restrictNetwork =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = false;
|
|
example = true;
|
|
description =
|
|
lib.mdDoc ''
|
|
If this option is enabled, the guest will be isolated, i.e. it will
|
|
not be able to contact the host and no guest IP packets will be
|
|
routed over the host to the outside. This option does not affect
|
|
any explicitly set forwarding rules.
|
|
'';
|
|
};
|
|
|
|
virtualisation.vlans =
|
|
mkOption {
|
|
type = types.listOf types.ints.unsigned;
|
|
default = [ 1 ];
|
|
example = [ 1 2 ];
|
|
description =
|
|
lib.mdDoc ''
|
|
Virtual networks to which the VM is connected. Each
|
|
number «N» in this list causes
|
|
the VM to have a virtual Ethernet interface attached to a
|
|
separate virtual network on which it will be assigned IP
|
|
address
|
|
`192.168.«N».«M»`,
|
|
where «M» is the index of this VM
|
|
in the list of VMs.
|
|
'';
|
|
};
|
|
|
|
virtualisation.writableStore =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = true; # FIXME
|
|
description =
|
|
lib.mdDoc ''
|
|
If enabled, the Nix store in the VM is made writable by
|
|
layering an overlay filesystem on top of the host's Nix
|
|
store.
|
|
'';
|
|
};
|
|
|
|
virtualisation.writableStoreUseTmpfs =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = true;
|
|
description =
|
|
lib.mdDoc ''
|
|
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 = lib.mdDoc "Primary IP address used in /etc/hosts.";
|
|
};
|
|
|
|
virtualisation.host.pkgs = mkOption {
|
|
type = options.nixpkgs.pkgs.type;
|
|
default = pkgs;
|
|
defaultText = "pkgs";
|
|
example = literalExpression ''
|
|
import pkgs.path { system = "x86_64-darwin"; }
|
|
'';
|
|
description = lib.mdDoc ''
|
|
pkgs set to use for the host-specific packages of the vm runner.
|
|
Changing this to e.g. a Darwin package set allows running NixOS VMs on Darwin.
|
|
'';
|
|
};
|
|
|
|
virtualisation.qemu = {
|
|
package =
|
|
mkOption {
|
|
type = types.package;
|
|
default = cfg.host.pkgs.qemu_kvm;
|
|
example = "pkgs.qemu_test";
|
|
description = lib.mdDoc "QEMU package to use.";
|
|
};
|
|
|
|
options =
|
|
mkOption {
|
|
type = types.listOf types.str;
|
|
default = [];
|
|
example = [ "-vga std" ];
|
|
description = lib.mdDoc "Options passed to QEMU.";
|
|
};
|
|
|
|
consoles = mkOption {
|
|
type = types.listOf types.str;
|
|
default = let
|
|
consoles = [ "${qemu-common.qemuSerialDevice},115200n8" "tty0" ];
|
|
in if cfg.graphics then consoles else reverseList consoles;
|
|
example = [ "console=tty1" ];
|
|
description = lib.mdDoc ''
|
|
The output console devices to pass to the kernel command line via the
|
|
`console` parameter, the primary console is the last
|
|
item of this list.
|
|
|
|
By default it enables both serial console and
|
|
`tty0`. The preferred console (last one) is based on
|
|
the value of {option}`virtualisation.graphics`.
|
|
'';
|
|
};
|
|
|
|
networkingOptions =
|
|
mkOption {
|
|
type = types.listOf types.str;
|
|
default = [ ];
|
|
example = [
|
|
"-net nic,netdev=user.0,model=virtio"
|
|
"-netdev user,id=user.0,\${QEMU_NET_OPTS:+,$QEMU_NET_OPTS}"
|
|
];
|
|
description = lib.mdDoc ''
|
|
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 = lib.mdDoc "Drives passed to qemu.";
|
|
apply = addDeviceNames;
|
|
};
|
|
|
|
diskInterface =
|
|
mkOption {
|
|
type = types.enum [ "virtio" "scsi" "ide" ];
|
|
default = "virtio";
|
|
example = "scsi";
|
|
description = lib.mdDoc "The interface used for the virtual hard disks.";
|
|
};
|
|
|
|
guestAgent.enable =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = true;
|
|
description = lib.mdDoc ''
|
|
Enable the Qemu guest agent.
|
|
'';
|
|
};
|
|
|
|
virtioKeyboard =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = true;
|
|
description = lib.mdDoc ''
|
|
Enable the virtio-keyboard device.
|
|
'';
|
|
};
|
|
};
|
|
|
|
virtualisation.useNixStoreImage =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = false;
|
|
description = lib.mdDoc ''
|
|
Build and use a disk image for the Nix store, instead of
|
|
accessing the host's one through 9p.
|
|
|
|
For applications which do a lot of reads from the store,
|
|
this can drastically improve performance, but at the cost of
|
|
disk space and image build time.
|
|
'';
|
|
};
|
|
|
|
virtualisation.useBootLoader =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = false;
|
|
description =
|
|
lib.mdDoc ''
|
|
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 =
|
|
lib.mdDoc ''
|
|
If enabled, the virtual machine will provide a EFI boot
|
|
manager.
|
|
useEFIBoot is ignored if useBootLoader == false.
|
|
'';
|
|
};
|
|
|
|
virtualisation.efi = {
|
|
firmware = mkOption {
|
|
type = types.path;
|
|
default = pkgs.OVMF.firmware;
|
|
defaultText = "pkgs.OVMF.firmware";
|
|
description =
|
|
lib.mdDoc ''
|
|
Firmware binary for EFI implementation, defaults to OVMF.
|
|
'';
|
|
};
|
|
|
|
variables = mkOption {
|
|
type = types.path;
|
|
default = pkgs.OVMF.variables;
|
|
defaultText = "pkgs.OVMF.variables";
|
|
description =
|
|
lib.mdDoc ''
|
|
Platform-specific flash binary for EFI variables, implementation-dependent to the EFI firmware.
|
|
Defaults to OVMF.
|
|
'';
|
|
};
|
|
};
|
|
|
|
virtualisation.useDefaultFilesystems =
|
|
mkOption {
|
|
type = types.bool;
|
|
default = true;
|
|
description =
|
|
lib.mdDoc ''
|
|
If enabled, the boot disk of the virtual machine will be
|
|
formatted and mounted with the default filesystems for
|
|
testing. Swap devices and LUKS will be disabled.
|
|
|
|
If disabled, a root filesystem has to be specified and
|
|
formatted (for example in the initial ramdisk).
|
|
'';
|
|
};
|
|
|
|
virtualisation.efiVars =
|
|
mkOption {
|
|
type = types.str;
|
|
default = "./${config.system.name}-efi-vars.fd";
|
|
defaultText = literalExpression ''"./''${config.system.name}-efi-vars.fd"'';
|
|
description =
|
|
lib.mdDoc ''
|
|
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 =
|
|
lib.mdDoc ''
|
|
An alternate BIOS (such as `qboot`) with which to start the VM.
|
|
Should contain a file named `bios.bin`.
|
|
If `null`, 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).
|
|
'';
|
|
}
|
|
]));
|
|
|
|
warnings =
|
|
optional (
|
|
cfg.writableStore &&
|
|
cfg.useNixStoreImage &&
|
|
opt.writableStore.highestPrio > lib.modules.defaultPriority)
|
|
''
|
|
You have enabled ${opt.useNixStoreImage} = true,
|
|
without setting ${opt.writableStore} = false.
|
|
|
|
This causes a store image to be written to the store, which is
|
|
costly, especially for the binary cache, and because of the need
|
|
for more frequent garbage collection.
|
|
|
|
If you really need this combination, you can set ${opt.writableStore}
|
|
explicitly to true, incur the cost and make this warning go away.
|
|
Otherwise, we recommend
|
|
|
|
${opt.writableStore} = false;
|
|
'';
|
|
|
|
# Note [Disk layout with `useBootLoader`]
|
|
#
|
|
# If `useBootLoader = true`, we configure 2 drives:
|
|
# `/dev/?da` for the root disk, and `/dev/?db` for the boot disk
|
|
# which has the `/boot` partition and the boot loader.
|
|
# Concretely:
|
|
#
|
|
# * The second drive's image `disk.img` is created in `bootDisk = ...`
|
|
# using a throwaway VM. Note that there the disk is always `/dev/vda`,
|
|
# even though in the final VM it will be at `/dev/*b`.
|
|
# * The disks are attached in `virtualisation.qemu.drives`.
|
|
# Their order makes them appear as devices `a`, `b`, etc.
|
|
# * `fileSystems."/boot"` is adjusted to be on device `b`.
|
|
|
|
# If `useBootLoader`, GRUB goes to the second disk, see
|
|
# note [Disk layout with `useBootLoader`].
|
|
boot.loader.grub.device = mkVMOverride (
|
|
if cfg.useBootLoader
|
|
then driveDeviceName 2 # second disk
|
|
else cfg.bootDevice
|
|
);
|
|
boot.loader.grub.gfxmodeBios = with cfg.resolution; "${toString x}x${toString y}";
|
|
|
|
boot.initrd.kernelModules = optionals (cfg.useNixStoreImage && !cfg.writableStore) [ "erofs" ];
|
|
|
|
boot.initrd.extraUtilsCommands = lib.mkIf (cfg.useDefaultFilesystems && !config.boot.initrd.systemd.enable)
|
|
''
|
|
# We need mke2fs in the initrd.
|
|
copy_bin_and_libs ${pkgs.e2fsprogs}/bin/mke2fs
|
|
'';
|
|
|
|
boot.initrd.postDeviceCommands = lib.mkIf (cfg.useDefaultFilesystems && !config.boot.initrd.systemd.enable)
|
|
''
|
|
# If the disk image appears to be empty, run mke2fs to
|
|
# initialise.
|
|
FSTYPE=$(blkid -o value -s TYPE ${cfg.bootDevice} || true)
|
|
if test -z "$FSTYPE"; then
|
|
mke2fs -t ext4 ${cfg.bootDevice}
|
|
fi
|
|
'';
|
|
|
|
boot.initrd.postMountCommands = lib.mkIf (!config.boot.initrd.systemd.enable)
|
|
''
|
|
# 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
|
|
''}
|
|
'';
|
|
|
|
systemd.tmpfiles.rules = lib.mkIf config.boot.initrd.systemd.enable [
|
|
"f /etc/NIXOS 0644 root root -"
|
|
"d /boot 0644 root root -"
|
|
];
|
|
|
|
# After booting, register the closure of the paths in
|
|
# `virtualisation.additionalPaths' 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 ${regInfo} here, then we would get a cyclic
|
|
# dependency.)
|
|
boot.postBootCommands = lib.mkIf config.nix.enable
|
|
''
|
|
if [[ "$(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.additionalPaths = [ config.system.build.toplevel ];
|
|
|
|
virtualisation.sharedDirectories = {
|
|
nix-store = mkIf (!cfg.useNixStoreImage) {
|
|
source = builtins.storeDir;
|
|
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} ${toString host.port}',"
|
|
);
|
|
restrictNetworkOption = lib.optionalString cfg.restrictNetwork "restrict=on,";
|
|
in
|
|
[
|
|
"-net nic,netdev=user.0,model=virtio"
|
|
"-netdev user,id=user.0,${forwardingOptions}${restrictNetworkOption}\"$QEMU_NET_OPTS\""
|
|
];
|
|
|
|
# FIXME: Consolidate this one day.
|
|
virtualisation.qemu.options = mkMerge [
|
|
(mkIf cfg.qemu.virtioKeyboard [
|
|
"-device virtio-keyboard"
|
|
])
|
|
(mkIf pkgs.stdenv.hostPlatform.isx86 [
|
|
"-usb" "-device usb-tablet,bus=usb-bus.0"
|
|
])
|
|
(mkIf pkgs.stdenv.hostPlatform.isAarch [
|
|
"-device virtio-gpu-pci" "-device usb-ehci,id=usb0" "-device usb-kbd" "-device usb-tablet"
|
|
])
|
|
(let
|
|
alphaNumericChars = lowerChars ++ upperChars ++ (map toString (range 0 9));
|
|
# Replace all non-alphanumeric characters with underscores
|
|
sanitizeShellIdent = s: concatMapStrings (c: if builtins.elem c alphaNumericChars then c else "_") (stringToCharacters s);
|
|
in mkIf (!cfg.useBootLoader) [
|
|
"-kernel \${NIXPKGS_QEMU_KERNEL_${sanitizeShellIdent config.system.name}:-${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} $QEMU_KERNEL_PARAMS"''
|
|
])
|
|
(mkIf cfg.useEFIBoot [
|
|
"-drive if=pflash,format=raw,unit=0,readonly=on,file=${cfg.efi.firmware}"
|
|
"-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.useNixStoreImage [{
|
|
name = "nix-store";
|
|
file = ''"$TMPDIR"/store.img'';
|
|
deviceExtraOpts.bootindex = if cfg.useBootLoader then "3" else "2";
|
|
driveExtraOpts.format = if cfg.writableStore then "qcow2" else "raw";
|
|
}])
|
|
(mkIf cfg.useBootLoader [
|
|
# The order of this list determines the device names, see
|
|
# note [Disk layout with `useBootLoader`].
|
|
{
|
|
name = "boot";
|
|
file = ''"$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=${toString cfg.msize}" ]
|
|
++ lib.optional (tag == "nix-store") "cache=loose";
|
|
};
|
|
in
|
|
mkVMOverride (cfg.fileSystems //
|
|
optionalAttrs cfg.useDefaultFilesystems {
|
|
"/".device = cfg.bootDevice;
|
|
"/".fsType = "ext4";
|
|
"/".autoFormat = true;
|
|
} //
|
|
optionalAttrs config.boot.tmpOnTmpfs {
|
|
"/tmp" = {
|
|
device = "tmpfs";
|
|
fsType = "tmpfs";
|
|
neededForBoot = true;
|
|
# Sync with systemd's tmp.mount;
|
|
options = [ "mode=1777" "strictatime" "nosuid" "nodev" "size=${toString config.boot.tmpOnTmpfsSize}" ];
|
|
};
|
|
} //
|
|
optionalAttrs cfg.useNixStoreImage {
|
|
"/nix/${if cfg.writableStore then ".ro-store" else "store"}" = {
|
|
device = "${lookupDriveDeviceName "nix-store" cfg.qemu.drives}";
|
|
neededForBoot = true;
|
|
options = [ "ro" ];
|
|
};
|
|
} //
|
|
optionalAttrs (cfg.writableStore && cfg.writableStoreUseTmpfs) {
|
|
"/nix/.rw-store" = {
|
|
fsType = "tmpfs";
|
|
options = [ "mode=0755" ];
|
|
neededForBoot = true;
|
|
};
|
|
} //
|
|
optionalAttrs cfg.useBootLoader {
|
|
# see note [Disk layout with `useBootLoader`]
|
|
"/boot" = {
|
|
device = "${lookupDriveDeviceName "boot" cfg.qemu.drives}2"; # 2 for e.g. `vdb2`, as created in `bootDisk`
|
|
fsType = "vfat";
|
|
noCheck = true; # fsck fails on a r/o filesystem
|
|
};
|
|
} // lib.mapAttrs' mkSharedDir cfg.sharedDirectories);
|
|
|
|
boot.initrd.systemd = lib.mkIf (config.boot.initrd.systemd.enable && cfg.writableStore) {
|
|
mounts = [{
|
|
where = "/sysroot/nix/store";
|
|
what = "overlay";
|
|
type = "overlay";
|
|
options = "lowerdir=/sysroot/nix/.ro-store,upperdir=/sysroot/nix/.rw-store/store,workdir=/sysroot/nix/.rw-store/work";
|
|
wantedBy = ["local-fs.target"];
|
|
before = ["local-fs.target"];
|
|
requires = ["sysroot-nix-.ro\\x2dstore.mount" "sysroot-nix-.rw\\x2dstore.mount" "rw-store.service"];
|
|
after = ["sysroot-nix-.ro\\x2dstore.mount" "sysroot-nix-.rw\\x2dstore.mount" "rw-store.service"];
|
|
unitConfig.IgnoreOnIsolate = true;
|
|
}];
|
|
services.rw-store = {
|
|
after = ["sysroot-nix-.rw\\x2dstore.mount"];
|
|
unitConfig.DefaultDependencies = false;
|
|
serviceConfig = {
|
|
Type = "oneshot";
|
|
ExecStart = "/bin/mkdir -p 0755 /sysroot/nix/.rw-store/store /sysroot/nix/.rw-store/work /sysroot/nix/store";
|
|
};
|
|
};
|
|
};
|
|
|
|
swapDevices = (if cfg.useDefaultFilesystems then mkVMOverride else mkDefault) [ ];
|
|
boot.initrd.luks.devices = (if cfg.useDefaultFilesystems then mkVMOverride else mkDefault) {};
|
|
|
|
# Don't run ntpd in the guest. It should get the correct time from KVM.
|
|
services.timesyncd.enable = false;
|
|
|
|
services.qemuGuest.enable = cfg.qemu.guestAgent.enable;
|
|
|
|
system.build.vm = cfg.host.pkgs.runCommand "nixos-vm" {
|
|
preferLocalBuild = true;
|
|
meta.mainProgram = "run-${config.system.name}-vm";
|
|
}
|
|
''
|
|
mkdir -p $out/bin
|
|
ln -s ${config.system.build.toplevel} $out/system
|
|
ln -s ${cfg.host.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")
|
|
];
|
|
|
|
};
|
|
|
|
# uses types of services/x11/xserver.nix
|
|
meta.buildDocsInSandbox = false;
|
|
}
|