def remove_PPCI(self, pci_name):
        # Update lspci info
        PciUtil.create_lspci_info()

        # Remove the PPCI
        (domain, bus, slot, func) = PciUtil.parse_pci_name(pci_name)
        ppci_ref = XendPPCI.get_by_sbdf(domain, bus, slot, func)
        XendAPIStore.get(ppci_ref, "PPCI").destroy()

        self.save_PPCIs()

    def remove_PSCSI(self, rem_HCTL):
        saved_pscsis = self.state_store.load_state('pscsi')
        if not saved_pscsis:
            return

        # Remove the PSCSI
        for pscsi_record in saved_pscsis.values():
            if rem_HCTL == pscsi_record['physical_HCTL']:
                pscsi_ref = XendPSCSI.get_by_HCTL(rem_HCTL)
                XendAPIStore.get(pscsi_ref, "PSCSI").destroy()
                self.save_PSCSIs()
                return

 def get_PSCSI_HBAs(self):
     PSCSIs = []
     uuid = self.get_uuid()
     for dscsi in XendAPIStore.get_all('DSCSI'):
         if dscsi.get_VM() == self.VM and dscsi.get_HBA() == uuid:
             PSCSIs.append(dscsi.get_PSCSI())
     PSCSI_HBAs = []
     for pscsi_uuid in PSCSIs:
         pscsi_HBA_uuid = XendAPIStore.get(pscsi_uuid, 'PSCSI').get_HBA()
         if not pscsi_HBA_uuid in PSCSI_HBAs:
             PSCSI_HBAs.append(pscsi_HBA_uuid)
     return PSCSI_HBAs

    def _init_networks(self):
        # Initialise networks
        # First configure ones off disk
        saved_networks = self.state_store.load_state('network')
        if saved_networks:
            for net_uuid, network in saved_networks.items():
                try:
                    XendNetwork.recreate(network, net_uuid)
                except CreateUnspecifiedAttributeError:
                    log.warn("Error recreating network %s", net_uuid)
                
        # Next discover any existing bridges and check
        # they are not already configured

        # 'tmpbridge' is a temporary bridge created by network-bridge script.
        # Wait a couple of seconds for it to be renamed.
        for i in xrange(20):
            bridges = Brctl.get_state().keys()
            if 'tmpbridge' in bridges:
                time.sleep(0.1)
            else:
                break
            
        configured_bridges = [XendAPIStore.get(
                                  network_uuid, "network")
                                      .get_name_label()
                              for network_uuid in XendNetwork.get_all()]
        unconfigured_bridges = [bridge
                                for bridge in bridges
                                if bridge not in configured_bridges]
        for unconfigured_bridge in unconfigured_bridges:
            if unconfigured_bridge != 'tmpbridge':
                XendNetwork.create_phy(unconfigured_bridge)

 def get_DSCSIs(self):
     DSCSIs = []
     uuid = self.get_uuid()
     for dscsi in XendAPIStore.get_all('DSCSI'):
         if dscsi.get_VM() == self.VM and dscsi.get_HBA() == uuid:
             DSCSIs.append(dscsi.get_uuid())
     return DSCSIs

 def _get_ovs_name(self):
     network_refs = XendNetwork.get_all()
     network_names = []
     for ref in network_refs:
         network = XendAPIStore.get(ref, "network")
         namelabel = network.get_name_label()
         network_names.append(namelabel)
     return network_names

 def get_by_uuid(cls, uuid):
     # Sanity check the uuid is one of us
     me = XendAPIStore.get(uuid, cls.getClass())
     if me is not None and me.getClass() == cls.getClass():
         # In OSS, ref == uuid
         return uuid
     else:
         raise "Big Error.. TODO!"

    def unplug(self):
        """Unplug the PIF from the network"""
        network = XendAPIStore.get(self.network, "network")
        bridge_name = network.get_name_label()

        from xen.util import Brctl

        Brctl.vif_bridge_rem({"bridge": bridge_name, "vif": self.get_interface_name()})

    def recreate_active_pools(cls):
        """ Read active pool config from hypervisor and create pool instances.
            - Query pool ids and assigned CPUs from hypervisor.
            - Query additional information for any pool from xenstore.
              If an entry for a pool id is missing in xenstore, it will be
              recreated with a new uuid and generic name (this is an error case)
            - Create an XendCPUPool instance for any pool id
            Function have to be called after recreation of managed pools.
        """
        log.debug('recreate_active_pools')

        for pool_rec in xc.cpupool_getinfo():
            pool = pool_rec['cpupool']

            # read pool data from xenstore
            path = XS_POOLROOT + "%s/" % pool
            uuid = xstransact.Read(path, 'uuid')
            if not uuid:
                # xenstore entry missing / invaild; create entry with new uuid
                uuid = genuuid.createString()
                name = "Pool-%s" % pool
                try:
                    inst = XendCPUPool( { 'name_label' : name }, uuid, False )
                    inst.update_XS(pool)
                except PoolError, ex:
                    # log error and skip domain
                    log.error('cannot recreate pool %s; skipping (reason: %s)' \
                        % (name, ex))
            else:
                (name, descr) = xstransact.Read(path, 'name', 'description')
                other_config = {}
                for key in xstransact.List(path + 'other_config'):
                    other_config[key] = xstransact.Read(
                        path + 'other_config/%s' % key)

                # check existance of pool instance
                inst = XendAPIStore.get(uuid, cls.getClass())
                if inst:
                    # update attributes of existing instance
                    inst.name_label = name
                    inst.name_description = descr
                    inst.other_config = other_config
                else:
                    # recreate instance
                    try:
                        inst = XendCPUPool(
                            { 'name_label' : name,
                              'name_description' : descr,
                              'other_config' : other_config,
                              'proposed_CPUs' : pool_rec['cpulist'],
                              'ncpu' : len(pool_rec['cpulist']),
                            },
                            uuid, False )
                    except PoolError, ex:
                        # log error and skip domain
                        log.error(
                            'cannot recreate pool %s; skipping (reason: %s)' \
                            % (name, ex))

    def move_domain(cls, pool_ref, domid):
        cls.pool_lock.acquire()
        try:
            pool = XendAPIStore.get(pool_ref, cls.getClass())
            pool_id = pool.query_pool_id()

            xc.cpupool_movedomain(pool_id, domid)
        finally:
            cls.pool_lock.release()

 def __init__(self):
     self.host_instance = XendNode.instance()
     self.host_cpus = self.host_instance.get_host_cpu_refs()
     
     pif_refs = self.host_instance.get_PIF_refs()
     self.host_pifs = []
     for pif_ref in pif_refs:
         pif = XendAPIStore.get(pif_ref, "PIF")
         self.host_pifs.append(pif)

    def _init_PIFs(self):
        # Initialise PIFs
        # First configure ones off disk
        saved_pifs = self.state_store.load_state('pif')
        if saved_pifs:
            for pif_uuid, pif in saved_pifs.items():
                try:
                    XendPIF.recreate(pif, pif_uuid)
                except CreateUnspecifiedAttributeError:
                    log.warn("Error recreating PIF %s", pif_uuid)
        
        # Next discover any existing PIFs and check
        # they are not already configured
        configured_pifs = [XendAPIStore.get(
                               pif_uuid, "PIF")
                                   .get_interface_name()
                           for pif_uuid in XendPIF.get_all()]
        unconfigured_pifs = [(name, mtu, mac)
                             for name, mtu, mac in linux_get_phy_ifaces()
                             if name not in configured_pifs]

        # Get a mapping from interface to bridge          
        if_to_br = dict([(i,b)
                         for (b,ifs) in Brctl.get_state().items()
                             for i in ifs])

        for name, mtu, mac in unconfigured_pifs:
            # Check PIF is on bridge
            # if not, ignore
            bridge_name = if_to_br.get(name, None)
            if bridge_name is not None:
                # Translate bridge name to network uuid
                for network_uuid in XendNetwork.get_all():
                    network = XendAPIStore.get(
                        network_uuid, 'network')
                    if network.get_name_label() == bridge_name:
                        XendPIF.create_phy(network_uuid, name,
                                           mac, mtu)
                        break
                else:
                    log.debug("Cannot find network for bridge %s "
                              "when configuring PIF %s",
                              (bridge_name, name))     

    def remove_PSCSI(self, rem_HCTL):
        saved_pscsis = self.state_store.load_state('pscsi')
        if not saved_pscsis:
            return

        # Remove the PSCSI
        for pscsi_record in saved_pscsis.values():
            if rem_HCTL == pscsi_record['physical_HCTL']:
                pscsi_ref = XendPSCSI.get_by_HCTL(rem_HCTL)
                XendAPIStore.get(pscsi_ref, "PSCSI").destroy()
                self.save_PSCSIs()

                physical_host = int(rem_HCTL.split(':')[0])
                pscsi_HBA_ref = XendPSCSI_HBA.get_by_physical_host(physical_host)
                if pscsi_HBA_ref:
                    if not XendAPIStore.get(pscsi_HBA_ref, 'PSCSI_HBA').get_PSCSIs():
                        XendAPIStore.get(pscsi_HBA_ref, 'PSCSI_HBA').destroy()
                self.save_PSCSI_HBAs()

                return

 def get_all_managed(cls):
     """ Query all managed pools.
         @return: uuids of all managed pools
         @rtype:  list of str
     """
     cls.pool_lock.acquire()
     try:
         managed_pools = [ inst.get_uuid()
                           for inst in XendAPIStore.get_all(cls.getClass())
                           if inst.is_managed() ]
     finally:
         cls.pool_lock.release()
     return managed_pools

 def get_by_name_label(cls, name_label):
     """ Query a Pool(ref) by its name.
         @return: ref of pool
         @rtype:  str
     """
     cls.pool_lock.acquire()
     try:
         return [ inst.get_uuid()
                  for inst in XendAPIStore.get_all(cls.getClass())
                  if inst.name_label == name_label
                ]
     finally:
         cls.pool_lock.release()

 def autostart_pools(cls):
     """ Start managed pools that are marked as autostart pools.
         Function is called after recreation of managed domains while
         xend restart.
     """
     cls.pool_lock.acquire()
     try:
         for inst in XendAPIStore.get_all(cls.getClass()):
             if inst.is_managed() and inst.auto_power_on and \
                inst.query_pool_id() == None:
                 inst.activate()
     finally:
         cls.pool_lock.release()

    def __init__(self, uuid, record):
        self.__uuid = uuid
        
        # First check this class implements all the correct methods:
        for attr_ro in self.getAttrRO() + self.getAttrRW():
            if not hasattr(self, "get_%s" % attr_ro):
                raise ImplementationError(self.getClass(),
                                          "get_%s" % attr_ro)

        for attr_rw in self.getAttrRW():
            if not hasattr(self, "set_%s" % attr_rw):
                raise ImplementationError(self.getClass(),
                                          "set_%s" % attr_rw)

        for method in self.getMethods():
            if not hasattr(self, method):
                raise ImplementationError(self.getClass(),
                                          method)

        for func in self.getFuncs():
            if not hasattr(self.__class__, func):
                raise ImplementationError(self.getClass(),
                                          func)

        # Next check that the class is being created with the correct
        # parameters
        if not isinstance(record, dict):
            raise CreateUnspecifiedAttributeError(
                    "record" , self.getClass())
        
        for attr_inst in self.getAttrInst():
            if attr_inst not in record:
                raise CreateUnspecifiedAttributeError(
                    attr_inst, self.getClass())
            setattr(self, attr_inst, record[attr_inst])

        # Finally register it
        XendAPIStore.register(uuid, self.getClass(), self)

    def lookup_pool(cls, id_or_name):
        """ Search XendCPUPool instance with given id_or_name.
            @param id_or_name: pool id or pool nameto search
            @type id_or_name:  [int, str]
            @return: instane or None if not found
            @rtype:  XendCPUPool
        """
        pool_uuid = None
        try:
            pool_id = int(id_or_name)
            # pool id given ?
            pool_uuid = cls.query_pool_ref(pool_id)
            if not pool_uuid:
                # not found -> search name
                pool_uuid = cls.get_by_name_label(id_or_name)
        except ValueError:
            # pool name given
            pool_uuid = cls.get_by_name_label(id_or_name)

        if len(pool_uuid) > 0:
            return XendAPIStore.get(pool_uuid[0], cls.getClass())
        else:
            return None

    def bridge_to_network(self, bridge):
        """
        Determine which network a particular bridge is attached to.

        @param bridge The name of the bridge.  If empty, the default bridge
        will be used instead (the first one in the list returned by brctl
        show); this is the behaviour of the vif-bridge script.
        @return The XendNetwork instance to which this bridge is attached.
        @raise Exception if the interface is not connected to a network.
        """
        if not bridge:
            rc, bridge = commands.getstatusoutput(
                'brctl show | cut -d "\n" -f 2 | cut -f 1')
            if rc != 0 or not bridge:
                raise Exception(
                    'Could not find default bridge, and none was specified')

        for network_uuid in XendNetwork.get_all():
            network = XendAPIStore.get(network_uuid, "network")
            if network.get_name_label() == bridge:
                return network
        else:
            raise Exception('Cannot find network for bridge %s' % bridge)

    def create(self, dpci_struct):

        # Check if VM is valid
        xendom = XendDomain.instance()
        if not xendom.is_valid_vm(dpci_struct['VM']):
            raise InvalidHandleError('VM', dpci_struct['VM'])
        dom = xendom.get_vm_by_uuid(dpci_struct['VM'])

        # Check if PPCI is valid
        xennode = XendNode.instance()
        ppci_uuid = xennode.get_ppci_by_uuid(dpci_struct['PPCI'])
        if not ppci_uuid:
            raise InvalidHandleError('PPCI', dpci_struct['PPCI'])
        for existing_dpci in XendAPIStore.get_all('DPCI'):
            if ppci_uuid == existing_dpci.get_PPCI():
                raise DirectPCIError("Device is in use")

        # Assign PPCI to VM
        try:
            dpci_ref = XendTask.log_progress(0, 100, dom.create_dpci,
                                             dpci_struct)
        except XendError, e:
            raise DirectPCIError("Failed to assign device")