526 lines
18 KiB
Nix
526 lines
18 KiB
Nix
# This module creates a virtual machine from the NixOS configuration.
|
|
# Building the `config.system.build.vm' attribute gives you a command
|
|
# that starts a KVM/QEMU VM running the NixOS configuration defined in
|
|
# `config'. The Nix store is shared read-only with the host, which
|
|
# makes (re)building VMs very efficient. However, it also means you
|
|
# can't reconfigure the guest inside the guest - you need to rebuild
|
|
# the VM in the host. On the other hand, the root filesystem is a
|
|
# read/writable disk image persistent across VM reboots.
|
|
|
|
{ config, lib, pkgs, ... }:
|
|
|
|
with lib;
|
|
|
|
let
|
|
|
|
qemu = config.system.build.qemu or pkgs.qemu_test;
|
|
|
|
vmName =
|
|
if config.networking.hostName == ""
|
|
then "noname"
|
|
else config.networking.hostName;
|
|
|
|
cfg = config.virtualisation;
|
|
|
|
qemuGraphics = if cfg.graphics then "" else "-nographic";
|
|
kernelConsole = if cfg.graphics then "" else "console=ttyS0";
|
|
ttys = [ "tty1" "tty2" "tty3" "tty4" "tty5" "tty6" ];
|
|
|
|
# Shell script to start the VM.
|
|
startVM =
|
|
''
|
|
#! ${pkgs.stdenv.shell}
|
|
|
|
NIX_DISK_IMAGE=$(readlink -f ''${NIX_DISK_IMAGE:-${config.virtualisation.diskImage}})
|
|
|
|
if ! test -e "$NIX_DISK_IMAGE"; then
|
|
${qemu}/bin/qemu-img create -f qcow2 "$NIX_DISK_IMAGE" \
|
|
${toString config.virtualisation.diskSize}M || exit 1
|
|
fi
|
|
|
|
# Create a directory for storing temporary data of the running VM.
|
|
if [ -z "$TMPDIR" -o -z "$USE_TMPDIR" ]; then
|
|
TMPDIR=$(mktemp -d nix-vm.XXXXXXXXXX --tmpdir)
|
|
fi
|
|
|
|
# Create a directory for exchanging data with the VM.
|
|
mkdir -p $TMPDIR/xchg
|
|
|
|
${if cfg.useBootLoader then ''
|
|
# Create a writable copy/snapshot of the boot disk.
|
|
# A writable boot disk can be booted from automatically.
|
|
${qemu}/bin/qemu-img create -f qcow2 -b ${bootDisk}/disk.img $TMPDIR/disk.img || exit 1
|
|
|
|
${if cfg.useEFIBoot then ''
|
|
# VM needs a writable flash BIOS.
|
|
cp ${bootDisk}/bios.bin $TMPDIR || exit 1
|
|
chmod 0644 $TMPDIR/bios.bin || exit 1
|
|
'' else ''
|
|
''}
|
|
'' else ''
|
|
''}
|
|
|
|
cd $TMPDIR
|
|
idx=2
|
|
extraDisks=""
|
|
${flip concatMapStrings cfg.emptyDiskImages (size: ''
|
|
if ! test -e "empty$idx.qcow2"; then
|
|
${qemu}/bin/qemu-img create -f qcow2 "empty$idx.qcow2" "${toString size}M"
|
|
fi
|
|
extraDisks="$extraDisks -drive index=$idx,file=$(pwd)/empty$idx.qcow2,if=${cfg.qemu.diskInterface},werror=report"
|
|
idx=$((idx + 1))
|
|
'')}
|
|
|
|
# Start QEMU.
|
|
exec ${qemu}/bin/qemu-kvm \
|
|
-name ${vmName} \
|
|
-m ${toString config.virtualisation.memorySize} \
|
|
${optionalString (pkgs.stdenv.system == "x86_64-linux") "-cpu kvm64"} \
|
|
${concatStringsSep " " config.virtualisation.qemu.networkingOptions} \
|
|
-virtfs local,path=/nix/store,security_model=none,mount_tag=store \
|
|
-virtfs local,path=$TMPDIR/xchg,security_model=none,mount_tag=xchg \
|
|
-virtfs local,path=''${SHARED_DIR:-$TMPDIR/xchg},security_model=none,mount_tag=shared \
|
|
${if cfg.useBootLoader then ''
|
|
-drive index=0,id=drive1,file=$NIX_DISK_IMAGE,if=${cfg.qemu.diskInterface},cache=writeback,werror=report \
|
|
-drive index=1,id=drive2,file=$TMPDIR/disk.img,media=disk \
|
|
${if cfg.useEFIBoot then ''
|
|
-pflash $TMPDIR/bios.bin \
|
|
'' else ''
|
|
''}
|
|
'' else ''
|
|
-drive index=0,id=drive1,file=$NIX_DISK_IMAGE,if=${cfg.qemu.diskInterface},cache=writeback,werror=report \
|
|
-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} ${kernelConsole} $QEMU_KERNEL_PARAMS" \
|
|
''} \
|
|
$extraDisks \
|
|
${qemuGraphics} \
|
|
${toString config.virtualisation.qemu.options} \
|
|
$QEMU_OPTS \
|
|
$@
|
|
'';
|
|
|
|
|
|
regInfo = pkgs.runCommand "reginfo"
|
|
{ exportReferencesGraph =
|
|
map (x: [("closure-" + baseNameOf x) x]) config.virtualisation.pathsInNixDB;
|
|
buildInputs = [ pkgs.perl ];
|
|
preferLocalBuild = true;
|
|
}
|
|
''
|
|
printRegistration=1 perl ${pkgs.pathsFromGraph} closure-* > $out
|
|
'';
|
|
|
|
|
|
# Generate a hard disk image containing a /boot partition and GRUB
|
|
# in the MBR. Used when the `useBootLoader' option is set.
|
|
# FIXME: use nixos/lib/make-disk-image.nix.
|
|
bootDisk =
|
|
pkgs.vmTools.runInLinuxVM (
|
|
pkgs.runCommand "nixos-boot-disk"
|
|
{ preVM =
|
|
''
|
|
mkdir $out
|
|
diskImage=$out/disk.img
|
|
bootFlash=$out/bios.bin
|
|
${qemu}/bin/qemu-img create -f qcow2 $diskImage "40M"
|
|
${if cfg.useEFIBoot then ''
|
|
cp ${pkgs.OVMF-CSM}/FV/OVMF.fd $bootFlash
|
|
chmod 0644 $bootFlash
|
|
'' else ''
|
|
''}
|
|
'';
|
|
buildInputs = [ pkgs.utillinux ];
|
|
QEMU_OPTS = if cfg.useEFIBoot
|
|
then "-pflash $out/bios.bin -nographic -serial pty"
|
|
else "-nographic -serial pty";
|
|
}
|
|
''
|
|
# Create a /boot EFI partition with 40M
|
|
${pkgs.gptfdisk}/bin/sgdisk -G /dev/vda
|
|
${pkgs.gptfdisk}/bin/sgdisk -a 1 -n 1:34:2047 -c 1:"BIOS Boot Partition" -t 1:ef02 /dev/vda
|
|
${pkgs.gptfdisk}/bin/sgdisk -a 512 -N 2 -c 2:"EFI System" -t 2:ef00 /dev/vda
|
|
${pkgs.gptfdisk}/bin/sgdisk -A 1:set:1 /dev/vda
|
|
${pkgs.gptfdisk}/bin/sgdisk -A 2:set:2 /dev/vda
|
|
${pkgs.gptfdisk}/bin/sgdisk -h 2 /dev/vda
|
|
${pkgs.gptfdisk}/bin/sgdisk -C /dev/vda
|
|
${pkgs.utillinux}/bin/sfdisk /dev/vda -A 2
|
|
. /sys/class/block/vda2/uevent
|
|
mknod /dev/vda2 b $MAJOR $MINOR
|
|
. /sys/class/block/vda/uevent
|
|
${pkgs.dosfstools}/bin/mkfs.fat -F16 /dev/vda2
|
|
export MTOOLS_SKIP_CHECK=1
|
|
${pkgs.mtools}/bin/mlabel -i /dev/vda2 ::boot
|
|
|
|
# Mount /boot; load necessary modules first.
|
|
${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/nls/nls_cp437.ko.xz || true
|
|
${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/nls/nls_iso8859-1.ko.xz || true
|
|
${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/fat/fat.ko.xz || true
|
|
${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/fat/vfat.ko.xz || true
|
|
${pkgs.kmod}/bin/insmod ${pkgs.linux}/lib/modules/*/kernel/fs/efivarfs/efivarfs.ko.xz || true
|
|
mkdir /boot
|
|
mount /dev/vda2 /boot
|
|
|
|
# This is needed for GRUB 0.97, which doesn't know about virtio devices.
|
|
mkdir /boot/grub
|
|
echo '(hd0) /dev/vda' > /boot/grub/device.map
|
|
|
|
# Install GRUB and generate the GRUB boot menu.
|
|
touch /etc/NIXOS
|
|
mkdir -p /nix/var/nix/profiles
|
|
${config.system.build.toplevel}/bin/switch-to-configuration boot
|
|
|
|
umount /boot
|
|
'' # */
|
|
);
|
|
|
|
in
|
|
|
|
{
|
|
imports = [ ../profiles/qemu-guest.nix ];
|
|
|
|
options = {
|
|
|
|
virtualisation.memorySize =
|
|
mkOption {
|
|
default = 384;
|
|
description =
|
|
''
|
|
Memory size (M) of virtual machine.
|
|
'';
|
|
};
|
|
|
|
virtualisation.diskSize =
|
|
mkOption {
|
|
default = 512;
|
|
description =
|
|
''
|
|
Disk size (M) of virtual machine.
|
|
'';
|
|
};
|
|
|
|
virtualisation.diskImage =
|
|
mkOption {
|
|
default = "./${vmName}.qcow2";
|
|
description =
|
|
''
|
|
Path to the disk image containing the root filesystem.
|
|
The image will be created on startup if it does not
|
|
exist.
|
|
'';
|
|
};
|
|
|
|
virtualisation.bootDevice =
|
|
mkOption {
|
|
type = types.str;
|
|
example = "/dev/vda";
|
|
description =
|
|
''
|
|
The disk to be used for the root filesystem.
|
|
'';
|
|
};
|
|
|
|
virtualisation.emptyDiskImages =
|
|
mkOption {
|
|
default = [];
|
|
type = types.listOf types.int;
|
|
description =
|
|
''
|
|
Additional disk images to provide to the VM. The value is
|
|
a list of size in megabytes of each disk. These disks are
|
|
writeable by the VM.
|
|
'';
|
|
};
|
|
|
|
virtualisation.graphics =
|
|
mkOption {
|
|
default = true;
|
|
description =
|
|
''
|
|
Whether to run QEMU with a graphics window, or access
|
|
the guest computer serial port through the host tty.
|
|
'';
|
|
};
|
|
|
|
virtualisation.pathsInNixDB =
|
|
mkOption {
|
|
default = [];
|
|
description =
|
|
''
|
|
The list of paths whose closure is registered in the Nix
|
|
database in the VM. All other paths in the host Nix store
|
|
appear in the guest Nix store as well, but are considered
|
|
garbage (because they are not registered in the Nix
|
|
database in the guest).
|
|
'';
|
|
};
|
|
|
|
virtualisation.vlans =
|
|
mkOption {
|
|
default = [ 1 ];
|
|
example = [ 1 2 ];
|
|
description =
|
|
''
|
|
Virtual networks to which the VM is connected. Each
|
|
number <replaceable>N</replaceable> 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
|
|
<literal>192.168.<replaceable>N</replaceable>.<replaceable>M</replaceable></literal>,
|
|
where <replaceable>M</replaceable> is the index of this VM
|
|
in the list of VMs.
|
|
'';
|
|
};
|
|
|
|
virtualisation.writableStore =
|
|
mkOption {
|
|
default = true; # FIXME
|
|
description =
|
|
''
|
|
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 {
|
|
default = true;
|
|
description =
|
|
''
|
|
Use a tmpfs for the writable store instead of writing to the VM's
|
|
own filesystem.
|
|
'';
|
|
};
|
|
|
|
networking.primaryIPAddress =
|
|
mkOption {
|
|
default = "";
|
|
internal = true;
|
|
description = "Primary IP address used in /etc/hosts.";
|
|
};
|
|
|
|
virtualisation.qemu = {
|
|
options =
|
|
mkOption {
|
|
type = types.listOf types.unspecified;
|
|
default = [];
|
|
example = [ "-vga std" ];
|
|
description = "Options passed to QEMU.";
|
|
};
|
|
|
|
networkingOptions =
|
|
mkOption {
|
|
default = [
|
|
"-net nic,vlan=0,model=virtio"
|
|
"-net user,vlan=0\${QEMU_NET_OPTS:+,$QEMU_NET_OPTS}"
|
|
];
|
|
type = types.listOf types.str;
|
|
description = ''
|
|
Networking-related command-line options that should be passed to qemu.
|
|
The default is to use userspace networking (slirp).
|
|
|
|
If you override this option, be advised to keep
|
|
''${QEMU_NET_OPTS:+,$QEMU_NET_OPTS} (as seen in the default)
|
|
to keep the default runtime behaviour.
|
|
'';
|
|
};
|
|
|
|
diskInterface =
|
|
mkOption {
|
|
default = "virtio";
|
|
example = "scsi";
|
|
type = types.str;
|
|
description = ''
|
|
The interface used for the virtual hard disks
|
|
(<literal>virtio</literal> or <literal>scsi</literal>).
|
|
'';
|
|
};
|
|
};
|
|
|
|
virtualisation.useBootLoader =
|
|
mkOption {
|
|
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 {
|
|
default = false;
|
|
description =
|
|
''
|
|
If enabled, the virtual machine will provide a EFI boot
|
|
manager.
|
|
useEFIBoot is ignored if useBootLoader == false.
|
|
'';
|
|
};
|
|
|
|
};
|
|
|
|
config = {
|
|
|
|
boot.loader.grub.device = mkVMOverride cfg.bootDevice;
|
|
|
|
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 (if cfg.qemu.diskInterface == "scsi" then "/dev/sda" else "/dev/vda");
|
|
|
|
virtualisation.pathsInNixDB = [ config.system.build.toplevel ];
|
|
|
|
virtualisation.qemu.options = [ "-vga std" "-usbdevice tablet" ];
|
|
|
|
# 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 = mkVMOverride (
|
|
{ "/".device = cfg.bootDevice;
|
|
${if cfg.writableStore then "/nix/.ro-store" else "/nix/store"} =
|
|
{ device = "store";
|
|
fsType = "9p";
|
|
options = [ "trans=virtio" "version=9p2000.L" "veryloose" ];
|
|
neededForBoot = true;
|
|
};
|
|
"/tmp/xchg" =
|
|
{ device = "xchg";
|
|
fsType = "9p";
|
|
options = [ "trans=virtio" "version=9p2000.L" "veryloose" ];
|
|
neededForBoot = true;
|
|
};
|
|
"/tmp/shared" =
|
|
{ device = "shared";
|
|
fsType = "9p";
|
|
options = [ "trans=virtio" "version=9p2000.L" ];
|
|
neededForBoot = true;
|
|
};
|
|
} // optionalAttrs (cfg.writableStore && cfg.writableStoreUseTmpfs)
|
|
{ "/nix/.rw-store" =
|
|
{ fsType = "tmpfs";
|
|
options = [ "mode=0755" ];
|
|
neededForBoot = true;
|
|
};
|
|
} // optionalAttrs cfg.useBootLoader
|
|
{ "/boot" =
|
|
{ device = "/dev/vdb2";
|
|
fsType = "vfat";
|
|
options = [ "ro" ];
|
|
noCheck = true; # fsck fails on a r/o filesystem
|
|
};
|
|
});
|
|
|
|
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;
|
|
|
|
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} $out/bin/run-${vmName}-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 [ { x = 1024; y = 768; } ];
|
|
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;
|
|
networking.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")
|
|
(isYes "BLK_DEV")
|
|
(isYes "PCI")
|
|
(isYes "EXPERIMENTAL")
|
|
(isYes "NETDEVICES")
|
|
(isYes "NET_CORE")
|
|
(isYes "INET")
|
|
(isYes "NETWORK_FILESYSTEMS")
|
|
] ++ optional (!cfg.graphics) [
|
|
(isYes "SERIAL_8250_CONSOLE")
|
|
(isYes "SERIAL_8250")
|
|
];
|
|
|
|
};
|
|
}
|