vmix.nix/nixos/vms/config.nix
Git Sagar 4226f6fdfd add spice.vgamem option for QXL video memory
When spice.vgamem is set (e.g. 64), uses -device qxl-vga,vgamem_mb=N
instead of -vga qxl (which defaults to 16MB). When null (default),
uses -vga qxl for backwards compatibility.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-06-08 13:53:00 +05:30

272 lines
14 KiB
Nix

{ config, pkgs, lib, vmixLib, ... }:
with lib;
with vmixLib.network;
let
vmixCfg = config.vmix;
mkShortIfaceName = prefix: seed: "${prefix}-${builtins.substring 0 8 (builtins.hashString "sha256" seed)}";
mkServices4aVMInNamespace = spaceName: vmName: cfg:
let
vmCfg = cfg // { name = vmName; };
netCfg = vmCfg.networks;
mkTap4aLan = lanName: tapCfg:
let
tapInterfaceName = mkShortIfaceName "vt" "${spaceName}-${vmCfg.name}-${lanName}";
lanInterfaceName = "brx-${lanName}";
in
{
name = lanName;
iface = tapInterfaceName;
mac = tapCfg.mac;
create = ''
ip tuntap add dev ${tapInterfaceName} mode tap
ip link set dev ${tapInterfaceName} up
ip link set dev ${tapInterfaceName} master ${lanInterfaceName}
'' + lib.optionalString (tapCfg.ip != null) ''
# Make the static ip somehow part of the script so nixOs thinks the service has changed when the IP changes, which will trigger a VM restart.
# So whenever IP changes, VM will restart automatically
# The IP is actually bein assigned to VM by dnsmasq, when VM requests it via DHCP
# Static IP - ${tapCfg.ip}
'';
delete = ''
ip link del ${tapInterfaceName}
'';
};
mkMacvtap = macvtapName: macvtapVmCfg:
let
macvtapNetworkCfg = config.vmix.namespaces.${spaceName}.networks.macvtaps.${macvtapName};
macvtapInterfaceName = mkShortIfaceName "mt" "${spaceName}-${vmCfg.name}-${macvtapNetworkCfg.uplink.iface}-${macvtapName}";
uplinkNamespaceArg = lib.optionalString (macvtapNetworkCfg.uplink.namespace != null) "-n ${macvtapNetworkCfg.uplink.namespace}";
in
{
name = macvtapName;
iface = macvtapInterfaceName;
mac = macvtapVmCfg.mac;
create = ''
ip ${uplinkNamespaceArg} link add link ${macvtapNetworkCfg.uplink.iface} name ${macvtapInterfaceName} type macvtap mode bridge
${lib.optionalString (macvtapVmCfg.mac != null) "ip ${uplinkNamespaceArg} link set dev ${macvtapInterfaceName} address ${macvtapVmCfg.mac}"}
ip ${uplinkNamespaceArg} link set ${macvtapInterfaceName} netns ${spaceName}.vmix
ip -n ${spaceName}.vmix link set dev ${macvtapInterfaceName} up
'';
delete = ''
ip -n ${spaceName}.vmix link del ${macvtapInterfaceName}
'';
};
allTaps = (mapAttrsToList mkTap4aLan netCfg.lans);
allMacvtaps = (mapAttrsToList mkMacvtap netCfg.macvtaps);
createTapsforLansScript = pkgs.writeShellScript "${vmCfg.name}-taps-vmix" (
concatStringsSep "\n" (builtins.map (tap: tap.create) allTaps)
);
deleteTapsforLansScript = pkgs.writeShellScript "${vmCfg.name}-taps-vmix" (
concatStringsSep "\n" (builtins.map (tap: tap.delete) allTaps)
);
createMacvTapsScript = pkgs.writeShellScript "${vmCfg.name}-taps-vmix" (
concatStringsSep "\n" (builtins.map (macvtap: macvtap.create) allMacvtaps)
);
deleteMacvTapsScript = pkgs.writeShellScript "${vmCfg.name}-taps-vmix" (
concatStringsSep "\n" (builtins.map (macvtap: macvtap.delete) allMacvtaps)
);
hasOsDisk = vmCfg.disks.os.file != null;
# Auto-detect Windows from _vmixOsType marker on the disk image
isWindows = vmCfg.windows.enable || (hasOsDisk && (vmCfg.disks.os.file._vmixOsType or "linux") == "windows");
# Linux VMs: apply customizeImage with 9p fstab and machine-id setup
linuxOsImage = vmixLib.linux.customizeImage vmCfg.disks.os.file {
name = vmCfg.name;
commands = ''
truncate /etc/machine-id
run-command systemd-machine-id-setup
run-command ssh-keygen -A
run ${vmixLib.linux.scriptsNFiles.add-9p-mounts-to-fstab vmCfg.shares}
'';
};
# Windows VMs: use disk image as-is (customization done at image build time)
storeImage = if !hasOsDisk then null
else if isWindows then vmCfg.disks.os.file
else linuxOsImage;
# When persist = true, QEMU needs a mutable disk outside /nix/store.
# The store image is copied to persistPath on first boot.
osDiskPath = if !hasOsDisk then null
else if vmCfg.disks.os.persist then vmCfg.disks.os.persistPath
else toString storeImage;
# Script to seed the persistent disk from the store image on first boot
seedPersistentDiskScript = pkgs.writeShellScript "${vmCfg.name}-seed-disk-vmix" ''
PERSIST_PATH="${vmCfg.disks.os.persistPath}"
if [ ! -f "$PERSIST_PATH" ]; then
echo "Seeding persistent disk from store image..."
mkdir -p "$(dirname "$PERSIST_PATH")"
cp --no-preserve=mode "${toString storeImage}" "$PERSIST_PATH"
chmod 600 "$PERSIST_PATH"
fi
'';
persistExecStartPre = lib.optional (hasOsDisk && vmCfg.disks.os.persist) seedPersistentDiskScript;
# QEMU expects single-letter boot codes (e.g. c,d,n), while vmix uses readable names.
bootOrderQemu =
let
bootDeviceAliases = {
os = "c";
iso = "d";
net = "n";
floppy = "a";
};
in
concatStrings (builtins.map (device: bootDeviceAliases.${device}) vmCfg.boot.order);
spiceUsbRedirArgs =
if vmCfg.spice.enable && vmCfg.spice.usbRedir.enable then
concatStringsSep " \\\n " ([
"-device qemu-xhci,id=spice-usb-xhci"
] ++ (concatMap (i: [
"-chardev spicevmc,name=usbredir,id=spice-usbredirchardev${toString i}"
"-device usb-redir,chardev=spice-usbredirchardev${toString i},id=spice-usbredirdev${toString i}"
]) (range 1 vmCfg.spice.usbRedir.channels)))
else
"";
vncArgs = concatStringsSep "," (
[
"${vmCfg.vnc.addr}:${toString (vmCfg.vnc.port - 5900)}"
"share=${vmCfg.vnc.sharePolicy}"
]
++ optional (vmCfg.vnc.websocketPort != null) "websocket=${toString vmCfg.vnc.websocketPort}"
++ optional (vmCfg.vnc.passwordFile != null) "password-secret=vnc-pass-${vmCfg.name}"
);
qemuStartVMScript = pkgs.writeShellScript "${vmCfg.name}-qemu-vmix" ''
${optionalString vmCfg.vnc.enable ''
${optionalString (vmCfg.vnc.passwordFile != null) ''
if [ ! -r ${escapeShellArg vmCfg.vnc.passwordFile} ]; then
echo "VNC password file is not readable: ${vmCfg.vnc.passwordFile}" >&2
exit 1
fi
if [ ! -s ${escapeShellArg vmCfg.vnc.passwordFile} ]; then
echo "VNC password file is empty: ${vmCfg.vnc.passwordFile}" >&2
exit 1
fi
''}
''}
${optionalString vmCfg.spice.enable ''
${optionalString (vmCfg.spice.passwordFile != null) ''
if [ ! -r ${escapeShellArg vmCfg.spice.passwordFile} ]; then
echo "SPICE password file is not readable: ${vmCfg.spice.passwordFile}" >&2
exit 1
fi
if [ ! -s ${escapeShellArg vmCfg.spice.passwordFile} ]; then
echo "SPICE password file is empty: ${vmCfg.spice.passwordFile}" >&2
exit 1
fi
''}
''}
exec qemu-system-${vmCfg.arch} \
${if vmCfg.nographic && vmCfg.pci.passthrough != [] then "-display none -vga none" else optionalString vmCfg.nographic "-nographic"} \
${optionalString (vmCfg.vnc.enable && vmCfg.vnc.passwordFile != null) "-object secret,id=vnc-pass-${vmCfg.name},file=${escapeShellArg vmCfg.vnc.passwordFile}"} \
${optionalString vmCfg.vnc.enable "-vnc ${vncArgs}"} \
${optionalString (vmCfg.spice.enable && vmCfg.spice.passwordFile != null) "-object secret,id=spice-pass-${vmCfg.name},file=${escapeShellArg vmCfg.spice.passwordFile}"} \
${optionalString vmCfg.spice.enable "-spice addr=${vmCfg.spice.addr},port=${toString vmCfg.spice.port}${optionalString (vmCfg.spice.passwordFile == null) ",disable-ticketing=on"}${optionalString (vmCfg.spice.passwordFile != null) ",password-secret=spice-pass-${vmCfg.name}"}"} \
${optionalString vmCfg.spice.enable (if vmCfg.spice.displayDevice == "qxl" && vmCfg.spice.vgamem != null then "-vga none -device qxl-vga,vgamem_mb=${toString vmCfg.spice.vgamem}" else "-vga ${vmCfg.spice.displayDevice}")} \
${optionalString (vmCfg.spice.enable && vmCfg.spice.agent.enable) "-device virtio-serial-pci -chardev spicevmc,id=vdagent,debug=0,name=vdagent -device virtserialport,chardev=vdagent,name=com.redhat.spice.0"} \
${# Guest agent channel — prevents qemu-ga from spinning when virtio-win guest tools are installed
optionalString isWindows "${optionalString (!vmCfg.spice.enable || !vmCfg.spice.agent.enable) "-device virtio-serial-pci"} -chardev socket,path=/tmp/qga-${vmCfg.name}.sock,server=on,wait=off,id=qga0 -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0"} \
${spiceUsbRedirArgs} \
${optionalString vmCfg.kvm "-accel kvm"} \
-name ${vmCfg.name} \
-m ${toString vmCfg.mem.size} \
${optionalString vmCfg.mem.balloon "-device virtio-balloon-pci"} \
-smp cores=${toString vmCfg.cpu.cores} \
-cpu ${vmCfg.cpu.model}${optionalString vmCfg.cpu.hideVirtualized ",kvm=off,hv_vendor_id=1234567890ab,-hypervisor"} \
-machine type=${vmCfg.pc.type}${optionalString vmCfg.cpu.hideVirtualized ",kernel_irqchip=on"} \
${optionalString vmCfg.bios.efi "-bios ${pkgs.OVMF.fd}/FV/OVMF.fd"} \
${optionalString vmCfg.bios.tpm "-chardev socket,id=chrtpm,path=/tmp/mytpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0"} \
${# Windows: localtime RTC, USB tablet for mouse, disable S3/S4 sleep
optionalString isWindows ''
-rtc base=localtime,clock=host \
-device qemu-xhci -device usb-tablet \
-global ICH9-LMB.disable_s3=1 -global ICH9-LMB.disable_s4=1 \
''} \
${optionalString hasOsDisk "-drive file=${osDiskPath},format=qcow2,if=virtio${optionalString (vmCfg.disks.os.persist == false) ",snapshot=on"}"} \
${optionalString (vmCfg.disks.iso.file != null) "-drive file=${toString vmCfg.disks.iso.file},media=cdrom,readonly=on"} \
${concatMapStrings (diskCfg: ''
-drive file=${toString diskCfg.file},format=${diskCfg.format},if=${vmCfg.disks.bus} \
'') (attrValues vmCfg.disks.add)} \
${concatStrings (mapAttrsToList (shareName: shareCfg: ''
-virtfs local,path=${toString shareCfg.source},security_model=passthrough,mount_tag=${shareName} \
'') vmCfg.shares)} \
${optionalString cfg.networks.user.enable "
-netdev user,id=user \
-device virtio-net-pci,netdev=user \
"} \
${concatMapStrings (tapCfg: ''
-device virtio-net-pci,netdev=lan-${tapCfg.name},mac=${tapCfg.mac} \
-netdev tap,id=lan-${tapCfg.name},ifname=${tapCfg.iface},script=no,downscript=no \
'') allTaps} \
${concatStrings (imap1 (i: macvtap: ''
-device virtio-net-pci,netdev=macvtap-${macvtap.name},mac=$(ip l show ${macvtap.iface} | awk '/link\/ether/{print $2}') \
-netdev tap,id=macvtap-${macvtap.name},fd=${toString (i+2)} ${toString (i+2)}<>/dev/tap$(ip l show ${macvtap.iface} | awk -F':' '/${macvtap.iface}/{print $1}') \
'') allMacvtaps)} \
${concatStrings (imap1 (i: pciAddr: ''
-device pcie-root-port,id=pci-passthrough${toString i},chassis=${toString i},slot=${toString i} \
-device vfio-pci,host=${pciAddr},bus=pci-passthrough${toString i}${optionalString (i == 1) ",x-vga=on${optionalString (vmCfg.pci.romFile != null) ",romfile=${vmCfg.pci.romFile}"}"} \
'') vmCfg.pci.passthrough)} \
${concatMapStrings (usbDev: ''
-device usb-host,vendorid=0x${usbDev.vendorId},productid=0x${usbDev.productId} \
'') vmCfg.usb.hostDevices} \
${optionalString (vmCfg.boot.menu == true) "-boot menu=on"} \
${optionalString (length vmCfg.boot.order > 0) "-boot order=${bootOrderQemu}"} \
'';
in
lib.optionalAttrs (cfg.enable) {
"vm.vmix@${vmCfg.name}" = rec {
bindsTo = [ "net.vmix@${spaceName}.target" ] ++ lib.optional (allMacvtaps != []) "macvtaps.vm.vmix@${vmCfg.name}.service";
unitConfig.JoinsNamespaceOf = "ns.net.vmix@${spaceName}.service";
after = bindsTo;
path = with pkgs; [ iproute2 qemu gawk coreutils ];
serviceConfig = {
ExecStartPre = persistExecStartPre ++ [ createTapsforLansScript ];
ExecStart = qemuStartVMScript;
ExecStopPost = deleteTapsforLansScript;
PrivateTmp = true;
ProtectSystem = true;
ProtectHome = true;
PrivateNetwork = true;
} // lib.optionalAttrs (vmCfg.pci.passthrough != []) {
# VFIO passthrough needs raw device access — relax sandboxing
ProtectSystem = lib.mkForce false;
SupplementaryGroups = [ "kvm" ];
};
wantedBy = lib.mkIf vmCfg.autostart [ "multi-user.target" ];
};
} // lib.optionalAttrs (allMacvtaps != []) {
"macvtaps.vm.vmix@${vmCfg.name}" = rec {
bindsTo = [ "net.vmix@${spaceName}.target" ];
after = bindsTo;
partOf = [ "vm.vmix@${vmCfg.name}.service" ];
path = with pkgs; [ iproute2 ];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
ExecStart = createMacvTapsScript;
ExecStop = deleteMacvTapsScript;
};
};
};
vmServices = concatMapAttrs (spaceName: namespaceCfg: (concatMapAttrs (mkServices4aVMInNamespace spaceName) namespaceCfg.vms)) vmixCfg.namespaces;
in
{
config.systemd.services = vmServices;
}