diff options
Diffstat (limited to 'nixos/modules/virtualisation/xen-dom0.nix')
| -rw-r--r-- | nixos/modules/virtualisation/xen-dom0.nix | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/nixos/modules/virtualisation/xen-dom0.nix b/nixos/modules/virtualisation/xen-dom0.nix new file mode 100644 index 00000000000..4c24c6a7826 --- /dev/null +++ b/nixos/modules/virtualisation/xen-dom0.nix @@ -0,0 +1,179 @@ +# Xen hypervisor (Dom0) support. + +{ config, pkgs, ... }: + +with pkgs.lib; + +let + + cfg = config.virtualisation.xen; + + xen = pkgs.xen; + + xendConfig = pkgs.writeText "xend-config.sxp" + '' + (loglevel DEBUG) + (network-script network-bridge) + (vif-script vif-bridge) + ''; + +in + +{ + ###### interface + + options = { + + virtualisation.xen.enable = + mkOption { + default = false; + description = + '' + Setting this option enables the Xen hypervisor, a + virtualisation technology that allows multiple virtual + machines, known as <emphasis>domains</emphasis>, to run + concurrently on the physical machine. NixOS runs as the + privileged <emphasis>Domain 0</emphasis>. This option + requires a reboot to take effect. + ''; + }; + + virtualisation.xen.bootParams = + mkOption { + default = ""; + description = + '' + Parameters passed to the Xen hypervisor at boot time. + ''; + }; + + virtualisation.xen.domain0MemorySize = + mkOption { + default = 0; + example = 512; + description = + '' + Amount of memory (in MiB) allocated to Domain 0 on boot. + If set to 0, all memory is assigned to Domain 0. + ''; + }; + + }; + + + ###### implementation + + config = mkIf cfg.enable { + + environment.systemPackages = [ xen ]; + + # Domain 0 requires a pvops-enabled kernel. + boot.kernelPackages = pkgs.linuxPackages_3_2_xen; + + boot.kernelModules = + [ "xen_evtchn" "xen_gntdev" "xen_blkback" "xen_netback" "xen_pciback" + "blktap" "tun" + ]; + + # The radeonfb kernel module causes the screen to go black as soon + # as it's loaded, so don't load it. + boot.blacklistedKernelModules = [ "radeonfb" ]; + + # Increase the number of loopback devices from the default (8), + # which is way too small because every VM virtual disk requires a + # loopback device. + boot.extraModprobeConfig = + '' + options loop max_loop=64 + ''; + + virtualisation.xen.bootParams = + [ "loglvl=all" "guest_loglvl=all" ] ++ + optional (cfg.domain0MemorySize != 0) "dom0_mem=${toString cfg.domain0MemorySize}M"; + + system.extraSystemBuilderCmds = + '' + ln -s ${xen}/boot/xen.gz $out/xen.gz + echo "${toString cfg.bootParams}" > $out/xen-params + ''; + + # Mount the /proc/xen pseudo-filesystem. + system.activationScripts.xen = + '' + if [ -d /proc/xen ]; then + ${pkgs.sysvtools}/bin/mountpoint -q /proc/xen || \ + ${pkgs.utillinux}/bin/mount -t xenfs none /proc/xen + fi + ''; + + jobs.xend = + { description = "Xen control daemon"; + + startOn = "stopped udevtrigger"; + + path = + [ pkgs.bridge_utils pkgs.gawk pkgs.iproute pkgs.nettools + pkgs.utillinux pkgs.bash xen pkgs.pciutils pkgs.procps + ]; + + environment.XENCONSOLED_TRACE = "hv"; + + preStart = + '' + mkdir -p /var/log/xen/console -m 0700 + + ${xen}/sbin/xend start + + # Wait until Xend is running. + for ((i = 0; i < 60; i++)); do echo "waiting for xend..."; ${xen}/sbin/xend status && break; done + + ${xen}/sbin/xend status || exit 1 + ''; + + postStop = "${xen}/sbin/xend stop"; + }; + + jobs.xendomains = + { description = "Automatically starts, saves and restores Xen domains on startup/shutdown"; + + startOn = "started xend"; + + stopOn = "starting shutdown and stopping xend"; + + restartIfChanged = false; + + path = [ pkgs.xen ]; + + environment.XENDOM_CONFIG = "${xen}/etc/sysconfig/xendomains"; + + preStart = + '' + mkdir -p /var/lock/subsys -m 755 + ${xen}/etc/init.d/xendomains start + ''; + + postStop = "${xen}/etc/init.d/xendomains stop"; + }; + + # To prevent a race between dhcpcd and xend's bridge setup script + # (which renames eth* to peth* and recreates eth* as a virtual + # device), start dhcpcd after xend. + jobs.dhcpcd.startOn = mkOverride 50 "started xend"; + + environment.etc = + [ { source = xendConfig; + target = "xen/xend-config.sxp"; + } + { source = "${xen}/etc/xen/scripts"; + target = "xen/scripts"; + } + ]; + + # Xen provides udev rules. + services.udev.packages = [ xen ]; + + services.udev.path = [ pkgs.bridge_utils pkgs.iproute ]; + + }; + +} |