Move all of NixOS to nixos/ in preparation of the repository merge

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 000000000000..4c24c6a7826a
--- /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 ];
+
+  };
+
+}