diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index c41ae69c1ace..a19f49387abc 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -432,5 +432,5 @@
   ./virtualisation/openvswitch.nix
   ./virtualisation/parallels-guest.nix
   ./virtualisation/virtualbox-guest.nix
-  #./virtualisation/xen-dom0.nix
+  ./virtualisation/xen-dom0.nix
 ]
diff --git a/nixos/modules/virtualisation/xen-dom0.nix b/nixos/modules/virtualisation/xen-dom0.nix
index f3a24c5cf25b..157da76d752d 100644
--- a/nixos/modules/virtualisation/xen-dom0.nix
+++ b/nixos/modules/virtualisation/xen-dom0.nix
@@ -5,18 +5,8 @@
 with 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
 
 {
@@ -58,23 +48,60 @@ in
           '';
       };
 
+    virtualisation.xen.bridge =
+      mkOption {
+        default = "xenbr0";
+        description =
+          ''
+            Create a bridge for the Xen domUs to connect to.
+          '';
+      };
+
+    virtualisation.xen.stored =
+      mkOption {
+        default = "${pkgs.xen}/bin/oxenstored";
+        description =
+          ''
+            Xen Store daemon to use.
+          '';
+      };
+
+    virtualisation.xen.trace =
+      mkOption {
+        default = false;
+        description =
+          ''
+            Enable Xen tracing.
+          '';
+      };
   };
 
 
   ###### implementation
 
   config = mkIf cfg.enable {
+    assertions = [ {
+      assertion = pkgs.stdenv.isx86_64;
+      message = "Xen currently not supported on ${pkgs.stdenv.system}";
+    } {
+      assertion = config.boot.loader.grub.enable && (config.boot.loader.grub.efiSupport == false);
+      message = "Xen currently does not support EFI boot";
+    } ];
 
     environment.systemPackages = [ xen ];
 
-    # Domain 0 requires a pvops-enabled kernel.
-    boot.kernelPackages = pkgs.linuxPackages_3_2_xen;
+    # Make sure Domain 0 gets the required configuration
+    #boot.kernelPackages = pkgs.boot.kernelPackages.override { features={xen_dom0=true;}; };
 
     boot.kernelModules =
-      [ "xen_evtchn" "xen_gntdev" "xen_blkback" "xen_netback" "xen_pciback"
-        "blktap" "tun"
+      [ "xen-evtchn" "xen-gntdev" "xen-gntalloc" "xen-blkback" "xen-netback"
+        "xen-pciback" "evtchn" "gntdev" "netbk" "blkbk" "xen-scsibk"
+        "usbbk" "pciback" "xen-acpi-processor" "blktap2" "tun" "netxen_nic"
+        "xen_wdt" "xen-acpi-processor" "xen-privcmd" "xen-scsiback"
+        "xenfs"
       ];
 
+
     # The radeonfb kernel module causes the screen to go black as soon
     # as it's loaded, so don't load it.
     boot.blacklistedKernelModules = [ "radeonfb" ];
@@ -87,8 +114,8 @@ in
         options loop max_loop=64
       '';
 
-    virtualisation.xen.bootParams =
-      [ "loglvl=all" "guest_loglvl=all" ] ++
+    virtualisation.xen.bootParams = [] ++
+      optionals cfg.trace [ "loglvl=all" "guest_loglvl=all" ] ++
       optional (cfg.domain0MemorySize != 0) "dom0_mem=${toString cfg.domain0MemorySize}M";
 
     system.extraSystemBuilderCmds =
@@ -101,71 +128,36 @@ in
     system.activationScripts.xen =
       ''
         if [ -d /proc/xen ]; then
-            ${pkgs.sysvtools}/bin/mountpoint -q /proc/xen || \
+            ${pkgs.kmod}/bin/modprobe xenfs 2> /dev/null
+            ${pkgs.utillinux}/bin/mountpoint -q /proc/xen || \
                 ${pkgs.utillinux}/bin/mount -t xenfs none /proc/xen
         fi
       '';
 
-    jobs.xend =
-      { description = "Xen Control Daemon";
+    # Domain 0 requires a pvops-enabled kernel.
+    system.requiredKernelConfig = with config.lib.kernelConfig;
+      [ (isYes "XEN")
+        (isYes "X86_IO_APIC")
+        (isYes "ACPI")
+        (isYes "XEN_DOM0")
+        (isYes "PCI_XEN")
+        (isYes "XEN_DEV_EVTCHN")
+        (isYes "XENFS")
+        (isYes "XEN_COMPAT_XENFS")
+        (isYes "XEN_SYS_HYPERVISOR")
+        (isYes "XEN_GNTDEV")
+        (isYes "XEN_BACKEND")
+        (isModule "XEN_NETDEV_BACKEND")
+        (isModule "XEN_BLKDEV_BACKEND")
+        (isModule "XEN_PCIDEV_BACKEND")
+        (isYes "XEN_BALLOON")
+        (isYes "XEN_SCRUB_PAGES")
+      ];
 
-        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 = "${xen}/etc/xen/scripts";
-          target = "xen/scripts";
+      [ { source = "${xen}/etc/xen/xl.conf";
+          target = "xen/xl.conf";
         }
       ];
 
@@ -174,6 +166,125 @@ in
 
     services.udev.path = [ pkgs.bridge-utils pkgs.iproute ];
 
+    systemd.services.xen-store = {
+      description = "Xen Store Daemon";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" "xen-store.socket" ];
+      requires = [ "xen-store.socket" ];
+      preStart = ''
+        export XENSTORED_ROOTDIR="/var/lib/xenstored"
+        rm -f "$XENSTORED_ROOTDIR"/tdb* &>/dev/null
+
+        mkdir -p /var/run
+        ${optionalString cfg.trace "mkdir -p /var/log/xen"}
+        grep -q control_d /proc/xen/capabilities
+        '';
+      serviceConfig.ExecStart = ''
+        ${cfg.stored}${optionalString cfg.trace " -T /var/log/xen/xenstored-trace.log"} --no-fork
+        '';
+      postStart = ''
+        time=0
+        timeout=30
+        # Wait for xenstored to actually come up, timing out after 30 seconds
+        while [ $time -lt $timeout ] && ! `${pkgs.xen}/bin/xenstore-read -s / >/dev/null 2>&1` ; do
+            time=$(($time+1))
+            sleep 1
+        done
+
+        # Exit if we timed out
+        if ! [ $time -lt $timeout ] ; then
+            echo "Could not start Xenstore Daemon"
+            exit 1
+        fi
+
+        ${pkgs.xen}/bin/xenstore-write "/local/domain/0/name" "Domain-0"
+        ${pkgs.xen}/bin/xenstore-write "/local/domain/0/domid" 0
+        '';
+    };
+
+    systemd.sockets.xen-store = {
+      description = "XenStore Socket for userspace API";
+      wantedBy = [ "sockets.target" ];
+      socketConfig = {
+        ListenStream = [ "/var/run/xenstored/socket" "/var/run/xenstored/socket_ro" ];
+        SocketMode = "0660";
+        SocketUser = "root";
+        SocketGroup = "root";
+      };
+    };
+
+
+    systemd.services.xen-console = {
+      description = "Xen Console Daemon";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "xen-store.service" ];
+      preStart = ''
+        mkdir -p /var/run/xen
+        ${optionalString cfg.trace "mkdir -p /var/log/xen"}
+        grep -q control_d /proc/xen/capabilities
+        '';
+      serviceConfig = {
+        ExecStart = ''
+          ${pkgs.xen}/bin/xenconsoled${optionalString cfg.trace " --log=all --log-dir=/var/log/xen"}
+          '';
+      };
+    };
+
+
+    systemd.services.xen-qemu = {
+      description = "Xen Qemu Daemon";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "xen-console.service" ];
+      serviceConfig.ExecStart = ''
+        ${pkgs.xen}/lib/xen/bin/qemu-system-i386 -xen-domid 0 -xen-attach -name dom0 -nographic -M xenpv \
+           -monitor /dev/null -serial /dev/null -parallel /dev/null
+        '';
+    };
+
+
+    systemd.services.xen-watchdog = {
+      description = "Xen Watchdog Daemon";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "xen-qemu.service" ];
+      serviceConfig.ExecStart = "${pkgs.xen}/bin/xenwatchdogd 30 15";
+      serviceConfig.Type = "forking";
+      serviceConfig.RestartSec = "1";
+      serviceConfig.Restart = "on-failure";
+    };
+
+
+    systemd.services.xen-bridge = {
+      description = "Xen bridge";
+      wantedBy = [ "multi-user.target" ];
+      before = [ "xen-domains.service" ];
+      serviceConfig.RemainAfterExit = "yes";
+      serviceConfig.ExecStart = ''
+        ${pkgs.bridge-utils}/bin/brctl addbr ${cfg.bridge}
+        ${pkgs.inetutils}/bin/ifconfig ${cfg.bridge} up
+        '';
+      serviceConfig.ExecStop = ''
+        ${pkgs.inetutils}/bin/ifconfig ${cfg.bridge} down
+        ${pkgs.bridge-utils}/bin/brctl delbr ${cfg.bridge}
+        '';
+    };
+
+    systemd.services.xen-domains = {
+      description = "Xen domains - automatically starts, saves and restores Xen domains";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "xen-bridge.service" "xen-qemu.service" ];
+      ## To prevent a race between dhcpcd and xend's bridge setup script
+      ## (which renames eth* to peth* and recreates eth* as a virtual
+      ## device), start dhcpcd after xend.
+      before = [ "dhcpd.service" ];
+      restartIfChanged = false;
+      serviceConfig.RemainAfterExit = "yes";
+      path = [ pkgs.xen ];
+      environment.XENDOM_CONFIG = "${pkgs.xen}/etc/sysconfig/xendomains";
+      preStart = "mkdir -p /var/lock/subsys -m 755";
+      serviceConfig.ExecStart = "${pkgs.xen}/etc/init.d/xendomains start";
+      serviceConfig.ExecStop = "${pkgs.xen}/etc/init.d/xendomains stop";
+    };
+
   };
 
 }
diff --git a/nixos/modules/virtualisation/xen-domU.nix b/nixos/modules/virtualisation/xen-domU.nix
index 483589669345..2db3190ad139 100644
--- a/nixos/modules/virtualisation/xen-domU.nix
+++ b/nixos/modules/virtualisation/xen-domU.nix
@@ -9,7 +9,10 @@
   boot.loader.grub.device = "nodev";
   boot.loader.grub.extraPerEntryConfig = "root (hd0)";
 
-  boot.initrd.kernelModules = [ "xen-blkfront" ];
+  boot.initrd.kernelModules =
+    [ "xen-blkfront" "xen-tpmfront" "xen-kbdfront" "xen-fbfront"
+      "xen-netfront" "xen-pcifront" "xen-scsifront"
+    ];
 
   # Send syslog messages to the Xen console.
   services.syslogd.tty = "hvc0";
diff --git a/pkgs/applications/virtualization/xen/4.4.1.nix b/pkgs/applications/virtualization/xen/4.4.1.nix
new file mode 100644
index 000000000000..a13a51a1d4ef
--- /dev/null
+++ b/pkgs/applications/virtualization/xen/4.4.1.nix
@@ -0,0 +1,46 @@
+{ callPackage, fetchurl, ... } @ args:
+
+let
+  # Xen 4.4.1
+  xenConfig = {
+    name = "xen-4.4.1";
+    version = "4.4.1";
+
+    src = fetchurl {
+      url = "http://bits.xensource.com/oss-xen/release/4.4.1/xen-4.4.1.tar.gz";
+      sha256 = "09gaqydqmy64s5pqnwgjyzhd3wc61xyghpqjfl97kmvm8ly9vd2m";
+    };
+
+    # Sources needed to build the xen tools and tools/firmware.
+    toolsGits =
+      [ # tag qemu-xen-4.4.1
+        { name = "qemu-xen";
+          url = git://xenbits.xen.org/qemu-upstream-4.4-testing.git;
+          rev = "65fc9b78ba3d868a26952db0d8e51cecf01d47b4";
+          sha256 = "e24fb58f773fd9134c5aae6d3ca7e9f754dc9822de92b1eb2cedc76faf911f18";
+        }
+        # tag xen-4.4.1
+        {  name = "qemu-xen-traditional";
+          url = git://xenbits.xen.org/qemu-xen-4.4-testing.git;
+          rev = "6ae4e588081620b141071eb010ec40aca7e12876";
+          sha256 = "b1ed1feb92fbe658273a8d6d38d6ea60b79c1658413dd93979d6d128d8554ded";
+        }
+      ];
+
+    firmwareGits =
+      [ # tag 1.7.3.1
+        { name = "seabios";
+          url = git://xenbits.xen.org/seabios.git;
+          rev = "7d9cbe613694924921ed1a6f8947d711c5832eee";
+          sha256 = "c071282bbcb1dd0d98536ef90cd1410f5d8da19648138e0e3863bc540d954a87";
+        }
+        { name = "ovmf";
+          url = git://xenbits.xen.org/ovmf.git;
+          rev = "447d264115c476142f884af0be287622cd244423";
+          sha256 = "7086f882495a8be1497d881074e8f1005dc283a5e1686aec06c1913c76a6319b";
+        }
+      ];
+
+  };
+
+in callPackage ./generic.nix (args // { xenConfig=xenConfig; })
diff --git a/pkgs/applications/virtualization/xen/4.5.0.nix b/pkgs/applications/virtualization/xen/4.5.0.nix
new file mode 100644
index 000000000000..176e15ea2c75
--- /dev/null
+++ b/pkgs/applications/virtualization/xen/4.5.0.nix
@@ -0,0 +1,58 @@
+{ callPackage, fetchurl, fetchgit, ... } @ args:
+
+let
+  # Xen 4.5.0
+  xenConfig = {
+    name = "xen-4.5.0";
+    version = "4.5.0";
+
+    src = fetchurl {
+      url = "http://bits.xensource.com/oss-xen/release/4.5.0/xen-4.5.0.tar.gz";
+      sha256 = "0fvg00d596gh6cfm51xr8kj2mghcyivrf6np3dafnbldnbi41nsv";
+    };
+
+    # Sources needed to build the xen tools and tools/firmware.
+    firmwareGits =
+      [ # tag 1.7.5
+        { name = "seabios";
+          url = git://xenbits.xen.org/seabios.git;
+          rev = "e51488c5f8800a52ac5c8da7a31b85cca5cc95d2";
+          sha256 = "b96a0b9f31cab0f3993d007dcbe5f1bd69ad02b0a23eb2dc8a3ed1aafe7985cb";
+        }
+        { name = "ovmf";
+          url = git://xenbits.xen.org/ovmf.git;
+          rev = "447d264115c476142f884af0be287622cd244423";
+          sha256 = "7086f882495a8be1497d881074e8f1005dc283a5e1686aec06c1913c76a6319b";
+        }
+      ];
+
+    toolsGits =
+      [ # tag qemu-xen-4.5.0
+        { name = "qemu-xen";
+          url = git://xenbits.xen.org/qemu-upstream-4.5-testing.git;
+          rev = "1ebb75b1fee779621b63e84fefa7b07354c43a99";
+          sha256 = "1j312q2mqvkvby9adkkxf7f1pn3nz85g5mr9nbg4qpf2y9cg122z";
+        }
+        # tag xen-4.5.0
+        { name = "qemu-xen-traditional";
+          url = git://xenbits.xen.org/qemu-xen-4.5-testing.git;
+          rev = "b0d42741f8e9a00854c3b3faca1da84bfc69bf22";
+          sha256 = "ce52b5108936c30ab85ec0c9554f88d5e7b34896f3acb666d56765b49c86f2af";
+        }
+      ];
+
+    xenserverPatches = let
+      patches = {
+        url = https://github.com/ts468/xen-4.5.pg.git;
+        rev = "3442b65b490f43c817cbc53369220d0b1ab9b785";
+        sha256 = "31436c15def0a300b3ea1a63b2208c4a3bcbb143db5c6488d4db370b3ceeb845";
+      };
+      in ''
+        cp -r ${fetchgit patches}/master patches
+        quilt push -a
+        substituteInPlace tools/xenguest/Makefile --replace "_BSD_SOURCE" "_DEFAULT_SOURCE"
+        '';
+  };
+
+in callPackage ./generic.nix (args // { xenConfig=xenConfig; })
+
diff --git a/pkgs/applications/virtualization/xen/default.nix b/pkgs/applications/virtualization/xen/generic.nix
similarity index 73%
rename from pkgs/applications/virtualization/xen/default.nix
rename to pkgs/applications/virtualization/xen/generic.nix
index e6ad49f20351..da33af525f9d 100644
--- a/pkgs/applications/virtualization/xen/default.nix
+++ b/pkgs/applications/virtualization/xen/generic.nix
@@ -3,46 +3,20 @@
 , lvm2, utillinux, procps, texinfo, perl, pythonPackages
 , glib, bridge-utils, xlibs, pixman, iproute, udev, bison
 , flex, cmake, ocaml, ocamlPackages, figlet, libaio, yajl
-, checkpolicy, transfig, glusterfs, fetchgit, xz }:
+, checkpolicy, transfig, glusterfs, fetchgit, xz, spice
+, spice_protocol, usbredir, alsaLib, quilt
+, coreutils, gawk, gnused, gnugrep, diffutils, multipath_tools
+, inetutils, iptables, openvswitch, nbd, drbd, xenConfig
+, xenserverPatched ? false, ... }:
 
 with stdenv.lib;
 
 let
-  version = "4.4.1";
 
   libDir = if stdenv.is64bit then "lib64" else "lib";
 
-  # Sources needed to build the xen tools and tools/firmware.
-  toolsGits =
-    [ # tag qemu-xen-4.4.1
-      #{ name = "qemu-xen";
-      #  url = git://xenbits.xen.org/qemu-upstream-4.4-testing.git;
-      #  rev = "65fc9b78ba3d868a26952db0d8e51cecf01d47b4";
-      #  sha256 = "e7abaf0e927f7a2bba4c59b6dad6ae19e77c92689c94fa0384e2c41742f8cdb6";
-      #}
-      # tag xen-4.4.1
-      {  name = "qemu-xen-traditional";
-        url = git://xenbits.xen.org/qemu-xen-4.4-testing.git;
-        rev = "6ae4e588081620b141071eb010ec40aca7e12876";
-        sha256 = "b1ed1feb92fbe658273a8d6d38d6ea60b79c1658413dd93979d6d128d8554ded";
-      }
-    ];
-  firmwareGits =
-    [ # tag 1.7.3.1
-      { name = "seabios";
-        url = git://xenbits.xen.org/seabios.git;
-        rev = "7d9cbe613694924921ed1a6f8947d711c5832eee";
-        sha256 = "c071282bbcb1dd0d98536ef90cd1410f5d8da19648138e0e3863bc540d954a87";
-      }
-      { name = "ovmf";
-        url = git://xenbits.xen.org/ovmf.git;
-        rev = "447d264115c476142f884af0be287622cd244423";
-        sha256 = "7086f882495a8be1497d881074e8f1005dc283a5e1686aec06c1913c76a6319b";
-      }
-    ];
-
-
   # Sources needed to build the stubdoms and tools
+  # These sources are already rather old and probably do not change frequently
   xenExtfiles = [
       { url = http://xenbits.xensource.com/xen-extfiles/lwip-1.3.0.tar.gz;
         sha256 = "13wlr85s1hnvia6a698qpryyy12lvmqw0a05xmjnd0h71ralsbkp";
@@ -76,15 +50,15 @@ let
       }
     ];
 
+  scriptEnvPath = stdenv.lib.concatStrings (stdenv.lib.intersperse ":" (map (x: "${x}/bin")
+    [ coreutils gawk gnused gnugrep which perl diffutils utillinux multipath_tools
+      iproute inetutils iptables bridge_utils openvswitch nbd drbd ]));
 in
 
-stdenv.mkDerivation {
-  name = "xen-${version}";
 
-  src = fetchurl {
-    url = "http://bits.xensource.com/oss-xen/release/${version}/xen-${version}.tar.gz";
-    sha256 = "09gaqydqmy64s5pqnwgjyzhd3wc61xyghpqjfl97kmvm8ly9vd2m";
-  };
+
+stdenv.mkDerivation {
+  inherit (xenConfig) name version src;
 
   dontUseCmakeConfigure = true;
 
@@ -95,11 +69,15 @@ stdenv.mkDerivation {
       glib bridge-utils pixman iproute udev bison xlibs.libX11
       flex ocaml ocamlPackages.findlib figlet libaio
       checkpolicy pythonPackages.markdown transfig
-      glusterfs cmake
+      glusterfs cmake spice spice_protocol usbredir
+      alsaLib quilt
     ];
 
   pythonPath = [ pythonPackages.curses ];
 
+  patchPhase = if ((xenserverPatched == true) && (builtins.hasAttr "xenserverPatches" xenConfig))
+    then xenConfig.xenserverPatches
+    else "";
 
   preConfigure = ''
     # Fake wget: copy prefetched downloads instead
@@ -111,6 +89,13 @@ stdenv.mkDerivation {
     export PATH=$PATH:$PWD/wget
   '';
 
+  # TODO: If multiple arguments are given with with-extra-qemuu,
+  #       then the configuration aborts; the reason is unclear.
+  #       If you know how to fix it, please let me know! :)
+  #configureFlags = "--with-extra-qemuu-configure-args='--enable-spice --enable-usb-redir --enable-linux-aio'";
+
+  # TODO: Flask needs more testing before enabling it by default.
+  #makeFlags = "XSM_ENABLE=y FLASK_ENABLE=y PREFIX=$(out) CONFIG_DIR=/etc XEN_EXTFILES_URL=\\$(XEN_ROOT)/xen_ext_files ";
   makeFlags = "PREFIX=$(out) CONFIG_DIR=/etc XEN_EXTFILES_URL=\\$(XEN_ROOT)/xen_ext_files ";
 
   buildFlags = "xen tools stubdom";
@@ -136,6 +121,12 @@ stdenv.mkDerivation {
       substituteInPlace tools/ioemu-qemu-xen/xen-hooks.mak \
         --replace /usr/include/pci ${pciutils}/include/pci
 
+      substituteInPlace tools/hotplug/Linux/xen-backend.rules \
+        --replace /etc/xen/scripts $out/etc/xen/scripts
+
+      # blktap is not provided by xen, but by xapi
+      sed -i '/blktap/d' tools/hotplug/Linux/xen-backend.rules
+
       # Work around a bug in our GCC wrapper: `gcc -MF foo -v' doesn't
       # print the GCC version number properly.
       substituteInPlace xen/Makefile \
@@ -157,15 +148,17 @@ stdenv.mkDerivation {
       # overriden at runtime.
       substituteInPlace tools/hotplug/Linux/init.d/xendomains \
         --replace 'XENDOM_CONFIG=/etc/sysconfig/xendomains' "" \
+        --replace 'XENDOM_CONFIG=/etc/default/xendomains' "" \
+        --replace /etc/xen/scripts/hotplugpath.sh $out/etc/xen/scripts/hotplugpath.sh \
         --replace /bin/ls ls
 
       # Xen's tools and firmares need various git repositories that it
       # usually checks out at time using git.  We can't have that.
-      ${flip concatMapStrings toolsGits (x: let src = fetchgit x; in ''
+      ${flip concatMapStrings xenConfig.toolsGits (x: let src = fetchgit x; in ''
         cp -r ${src} tools/${src.name}-dir-remote
         chmod +w tools/${src.name}-dir-remote
       '')}
-      ${flip concatMapStrings firmwareGits (x: let src = fetchgit x; in ''
+      ${flip concatMapStrings xenConfig.firmwareGits (x: let src = fetchgit x; in ''
         cp -r ${src} tools/firmware/${src.name}-dir-remote
         chmod +w tools/firmware/${src.name}-dir-remote
       '')}
@@ -189,13 +182,19 @@ stdenv.mkDerivation {
 
   installPhase =
     ''
-      mkdir -p $out
+      mkdir -p $out $out/share
       cp -prvd dist/install/nix/store/*/* $out/
       cp -prvd dist/install/boot $out/boot
-      cp -prvd dist/install/etc $out/etc
+      cp -prvd dist/install/etc $out
       cp -dR docs/man1 docs/man5 $out/share/man/
       wrapPythonPrograms
-    ''; # */
+      substituteInPlace $out/etc/xen/scripts/hotplugpath.sh --replace SBINDIR=\"$out/sbin\" SBINDIR=\"$out/bin\"
+
+      shopt -s extglob
+      for i in $out/etc/xen/scripts/!(*.sh); do
+        sed -i '2s@^@export PATH=$out/bin:${scriptEnvPath}@' $i
+      done
+    '';
 
   meta = {
     homepage = http://www.xen.org/;
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 4dea95572d6e..f33f8c230db1 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -12008,9 +12008,10 @@ let
 
   xdotool = callPackage ../tools/X11/xdotool { };
 
-  xen = callPackage ../applications/virtualization/xen {
-    stdenv = overrideCC stdenv gcc45;
-  };
+  xen_4_4_1 = callPackage ../applications/virtualization/xen/4.4.1.nix { };
+  xen_4_5_0 = callPackage ../applications/virtualization/xen/4.5.0.nix { };
+  xen_xenServer = callPackage ../applications/virtualization/xen/4.5.0.nix { xenserverPatched = true; };
+  xen = xen_4_5_0;
 
   xfe = callPackage ../applications/misc/xfe {
     fox = fox_1_6;