Provided by: xen-utils-3.3_3.3.0-1ubuntu11_i386 bug


       xm - Xen management user interface


       xm subcommand [args]


       The xm program is the main interface for managing Xen guest domains.
       The program can be used to create, pause, and shutdown domains. It can
       also be used to list current domains, enable or pin VCPUs, and attach
       or detach virtual block devices.

       The basic structure of every xm command is almost always:

         xm subcommand domain-id [OPTIONS]

       Where subcommand is one of the subcommands listed below, domain-id is
       the numeric domain id, or the domain name (which will be internally
       translated to domain id), and OPTIONS are subcommand specific options.
       There are a few exceptions to this rule in the cases where the
       subcommand in question acts on all domains, the entire machine, or
       directly on the Xen hypervisor.  Those exceptions will be clear for
       each of those subcommands.


       All xm operations rely upon the Xen control daemon, aka xend.  For any
       xm commands to run, xend must also be running.  For this reason you
       should start xend as a service when your system first boots using Xen.

       Most xm commands require root privileges to run due to the
       communications channels used to talk to the hypervisor.  Running as non
       root will return an error.

       Most xm commands act asynchronously, so just because the xm command
       returned doesn’t mean the action is complete.  This is important, as
       many operations on domains, like create and shutdown, can take
       considerable time (30 seconds or more) to bring the machine into a
       fully compliant state.  If you want to know when one of these actions
       has finished you must poll through xm list periodically.


       The following subcommands manipulate domains directly.  As stated
       previously, most commands take domain-id as the first parameter.

       console domain-id
           Attach to domain domain-id’s console.  If you’ve set up your
           domains to have a traditional log in console this will look much
           like a normal text log in screen.

           This uses the back end xenconsole service which currently only
           works for para-virtual domains.

           The attached console will perform much like a standard serial
           console, so running curses based interfaces over the console is not
           advised.  Vi tends to get very odd when using it over this

       create [-c] configfile [name=value]..
           The create sub command requires a config file and can optionally
           take a series of name value pairs that add to or override variables
           defined in the config file.  See xmdomain.cfg for full details of
           that file format, and possible options used in either the
           configfile or name=value combinations.

           configfile can either be an absolute path to a file, or a relative
           path to a file located in /etc/xen.

           Create will return as soon as the domain is started.  This does not
           mean the guest OS in the domain has actually booted, or is
           available for input.


           -c  Attache console to the domain as soon as it has started.  This
               is useful for determining issues with crashing domains.


           with config file
                 xm create Fedora4

               This creates a domain with the file /etc/xen/Fedora4, and
               returns as soon as it is run.

           without config file
                 xm create /dev/null ramdisk=initrd.img \
                    kernel=/boot/vmlinuz- \
                    name=ramdisk vif='' vcpus=1 \
                    memory=64 root=/dev/ram0

               This creates the domain without using a config file (more
               specifically using /dev/null as an empty config file), kernel
               and ramdisk as specified, setting the name of the domain to
               "ramdisk", also disabling virtual networking.  (This example
               comes from the xm-test test suite.)

       destroy domain-id
           Immediately terminate the domain domain-id.  This doesn’t give the
           domain OS any chance to react, and is the equivalent of ripping the
           power cord out on a physical machine.  In most cases you will want
           to use the shutdown command instead.

       domid domain-name
           Converts a domain name to a domain id using xend’s internal

       domname domain-id
           Converts a domain id to a domain name using xend’s internal

       help [--long]
           Displays the short help message (i.e. common commands).

           The --long option prints out the complete set of xm subcommands,
           grouped by function.

       list [--long | --label] [domain-id ...]
           Prints information about one or more domains.  If no domains are
           specified it prints out information about all domains.

           An example format for the list is as follows:

               Name                         ID Mem(MiB) VCPUs State  Time(s)
               Domain-0                      0       98     1 r-----  5068.6
               Fedora3                     164      128     1 r-----     7.6
               Fedora4                     165      128     1 ------     0.6
               Mandrake2006                166      128     1 -b----     3.6
               Mandrake10.2                167      128     1 ------     2.5
               Suse9.2                     168      100     1 ------     1.8

           Name is the name of the domain.  ID the numeric domain id.  Mem is
           the desired amount of memory to allocate to the domain (although it
           may not be the currently allocated amount).  VCPUs is the number of
           virtual CPUs allocated to the domain.  State is the run state (see
           below).  Time is the total run time of the domain as accounted for
           by Xen.


               The State field lists 6 states for a Xen domain, and which ones
               the current domain is in.

               r - running

               The domain is currently running on a CPU.

               b - blocked

               The domain is blocked, and not running or runnable.  This can
               be caused because the domain is waiting on IO (a traditional
               wait state) or has gone to sleep because there was nothing else
               for it to do.

               p - paused

               The domain has been paused, usually occurring through the
               administrator running xm pause.  When in a paused state the
               domain will still consume allocated resources like memory, but
               will not be eligible for scheduling by the Xen hypervisor.

               s - shutdown

               FIXME: Why would you ever see this state?

               c - crashed

               The domain has crashed, which is always a violent ending.
               Usually this state can only occur if the domain has been
               configured not to restart on crash.  See xmdomain.cfg for more

               d - dying

               The domain is in process of dying, but hasn’t completely
               shutdown or crashed.

               FIXME: Is this right?

           LONG OUTPUT

               If --long is specified, the output for xm list is not the table
               view shown above, but instead is an S-Expression representing
               all information known about all domains asked for.  This is
               mostly only useful for external programs to parse the data.

               Note: There is no stable guarantees on the format of this data.
               Use at your own risk.

           LABEL OUTPUT

               If --label is specified, the security labels are added to the
               output of xm list and the lines are sorted by the labels
               (ignoring case). The --long option prints the labels by default
               and cannot be combined with --label. See the ACCESS CONTROL
               SUBCOMMAND section of this man page for more information about



                   The Time column is deceptive.  Virtual IO (network and
                   block devices) used by domains requires coordination by
                   Domain0, which means that Domain0 is actually charged for
                   much of the time that a DomainU is doing IO.  Use of this
                   time value to determine relative utilizations by domains is
                   thus very suspect, as a high IO workload may show as less
                   utilized than a high CPU workload.  Consider yourself

               mem-max domain-id mem

               Specify the maximum amount of memory the domain is able to use.
               mem is specified in megabytes.

               The mem-max value may not correspond to the actual memory used
               in the domain, as it may balloon down its memory to give more
               back to the OS.

               mem-set domain-id mem

               Set the domain’s used memory using the balloon driver.

               Because this operation requires cooperation from the domain
               operating system, there is no guarantee that it will succeed.
               This command will definitely not work unless the domain has the
               required paravirt driver.

               Warning: There is no good way to know in advance how small of a
               mem-set will make a domain unstable and cause it to crash.  Be
               very careful when using this command on running domains.

               migrate domain-id host [OPTIONS]

               Migrate a domain to another host machine. Xend must be running
               on other host machine, it must be running the same version of
               Xen, it must have the migration TCP port open and accepting
               connections from the source host, and there must be sufficient
               resources for the domain to run (memory, disk, etc).

               Migration is pretty complicated, and has many security
               implications.  Please read the Xen User’s Guide to ensure you
               understand the ramifications and limitations on migration
               before attempting it in production.


               -l, --live
                   Use live migration.  This will migrate the domain between
                   hosts without shutting down the domain.  See the Xen User’s
                   Guide for more information.

               -r, --resource Mbs
                   Set maximum Mbs allowed for migrating the domain.  This
                   ensures that the network link is not saturated with
                   migration traffic while attempting to do other useful work.

               pause domain-id

               Pause a domain.  When in a paused state the domain will still
               consume allocated resources such as memory, but will not be
               eligible for scheduling by the Xen hypervisor.

               reboot [OPTIONS] domain-id

               Reboot a domain.  This acts just as if the domain had the
               reboot command run from the console.  The command returns as
               soon as it has executed the reboot action, which may be
               significantly before the domain actually reboots.

               The behavior of what happens to a domain when it reboots is set
               by the on_reboot parameter of the xmdomain.cfg file when the
               domain was created.


               -a, --all
                   Reboot all domains.

               -w, --wait
                   Wait for reboot to complete before returning.  This may
                   take a while, as all services in the domain will have to be
                   shut down cleanly.

               restore state-file

               Build a domain from an xm save state file.  See save for more

               save domain-id state-file

               Saves a running domain to a state file so that it can be
               restored later.  Once saved, the domain will no longer be
               running on the system, thus the memory allocated for the domain
               will be free for other domains to use.  xm restore restores
               from this state file.

               This is roughly equivalent to doing a hibernate on a running
               computer, with all the same limitations.  Open network
               connections may be severed upon restore, as TCP timeouts may
               have expired.

               shutdown [OPTIONS] domain-id

               Gracefully shuts down a domain.  This coordinates with the
               domain OS to perform graceful shutdown, so there is no
               guarantee that it will succeed, and may take a variable length
               of time depending on what services must be shutdown in the
               domain.  The command returns immediately after signally the
               domain unless that -w flag is used.

               The behavior of what happens to a domain when it reboots is set
               by the on_shutdown parameter of the xmdomain.cfg file when the
               domain was created.


               -a  Shutdown all domains.  Often used when doing a complete
                   shutdown of a Xen system.

               -w  Wait for the domain to complete shutdown before returning.

               sysrq domain-id letter

               Send a Magic System Request signal to the domain.  For more
               information on available magic sys req operations, see
               sysrq.txt in your Linux Kernel sources.

               unpause domain-id

               Moves a domain out of the paused state.  This will allow a
               previously paused domain to now be eligible for scheduling by
               the Xen hypervisor.

               vcpu-set domain-id vcpu-count

               Enables the vcpu-count virtual CPUs for the domain in question.
               Like mem-set, this command can only allocate up to the maximum
               virtual CPU count configured at boot for the domain.

               If the vcpu-count is smaller than the current number of active
               VCPUs, the highest number VCPUs will be hotplug removed.  This
               may be important for pinning purposes.

               Attempting to set the VCPUs to a number larger than the
               initially configured VCPU count is an error.  Trying to set
               VCPUs to < 1 will be quietly ignored.

               Because this operation requires cooperation from the domain
               operating system, there is no guarantee that it will succeed.
               This command will not work with a full virt domain.

               vcpu-list [domain-id]

               Lists VCPU information for a specific domain.  If no domain is
               specified, VCPU information for all domains will be provided.

               vcpu-pin domain-id vcpu cpus

               Pins the the VCPU to only run on the specific CPUs.  The
               keyword all can be used to apply the cpus list to all VCPUs in
               the domain.

               Normally VCPUs can float between available CPUs whenever Xen
               deems a different run state is appropriate.  Pinning can be
               used to restrict this, by ensuring certain VCPUs can only run
               on certain physical CPUs.


       dmesg [-c]
           Reads the Xen message buffer, similar to dmesg on a Linux system.
           The buffer contains informational, warning, and error messages
           created during Xen’s boot process.  If you are having problems with
           Xen, this is one of the first places to look as part of problem


           -c, --clear
               Clears Xen’s message buffer.

           Print information about the Xen host in name : value format.  When
           reporting a Xen bug, please provide this information as part of the
           bug report.

           Sample output looks as follows (lines wrapped manually to make the
           man page more readable):

            host                   : talon
            release                :
            version                : #1 Mon Nov 14 14:26:26 EST 2005
            machine                : i686
            nr_cpus                : 2
            nr_nodes               : 1
            cores_per_socket       : 1
            threads_per_core       : 1
            cpu_mhz                : 696
            hw_caps                : 0383fbff:00000000:00000000:00000040
            total_memory           : 767
            free_memory            : 37
            xen_major              : 3
            xen_minor              : 0
            xen_extra              : -devel
            xen_caps               : xen-3.0-x86_32
            xen_scheduler          : credit
            xen_pagesize           : 4096
            platform_params        : virt_start=0xfc000000
            xen_changeset          : Mon Nov 14 18:13:38 2005 +0100
            cc_compiler            : gcc version 3.4.3 (Mandrakelinux
                                     10.2 3.4.3-7mdk)
            cc_compile_by          : sdague
            cc_compile_domain      : (none)
            cc_compile_date        : Mon Nov 14 14:16:48 EST 2005
            xend_config_format     : 3


               Not all fields will be explained here, but some of the less
               obvious ones deserve explanation:


               A vector showing what hardware capabilities are supported by
               your processor.  This is equivalent to, though more cryptic,
               the flags field in /proc/cpuinfo on a normal Linux machine.


               Available memory (in MB) not allocated to Xen, or any other


               The Xen version and architecture.  Architecture values can be
               one of: x86_32, x86_32p (i.e. PAE enabled), x86_64, ia64.


               The Xen mercurial changeset id.  Very useful for determining
               exactly what version of code your Xen system was built from.

       log Print out the xend log.  This log file can be found in

       top Executes the xentop command, which provides real time monitoring of
           domains.  Xentop is a curses interface, and reasonably self


       Xen ships with a number of domain schedulers, which can be set at boot
       time with the sched= parameter on the Xen command line.  By default
       credit is used for scheduling.

       FIXME: we really need a scheduler expert to write up this section.

       sched-credit [ -d domain-id [ -w[=WEIGHT] | -c[=CAP] ] ]
           Set credit scheduler parameters.  The credit scheduler is a
           proportional fair share CPU scheduler built from the ground up to
           be work conserving on SMP hosts.

           Each domain (including Domain0) is assigned a weight and a cap.


               A domain with a weight of 512 will get twice as much CPU as a
               domain with a weight of 256 on a contended host. Legal weights
               range from 1 to 65535 and the default is 256.

           CAP The cap optionally fixes the maximum amount of CPU a domain
               will be able to consume, even if the host system has idle CPU
               cycles. The cap is expressed in percentage of one physical CPU:
               100 is 1 physical CPU, 50 is half a CPU, 400 is 4 CPUs, etc.
               The default, 0, means there is no upper cap.

       sched-sedf period slice latency-hint extratime weight
           Set Simple EDF (Earliest Deadline First) scheduler parameters.
           This scheduler provides weighted CPU sharing in an intuitive way
           and uses realtime-algorithms to ensure time guarantees.  For more
           information see docs/misc/sedf_scheduler_mini-HOWTO.txt in the Xen


               The normal EDF scheduling usage in nanoseconds

               The normal EDF scheduling usage in nanoseconds

               FIXME: these are lame, should explain more.

               Scaled period if domain is doing heavy I/O.

               Flag for allowing domain to run in extra time.

               Another way of setting CPU slice.


           normal EDF (20ms/5ms):

               xm sched-sedf <dom-id> 20000000 5000000 0 0 0

           best-effort domains (i.e. non-realtime):

               xm sched-sedf <dom-id> 20000000 0 0 1 0

           normal EDF (20ms/5ms) + share of extra-time:

               xm sched-sedf <dom-id> 20000000 5000000 0 1 0

           4 domains with weights 2:3:4:2

               xm sched-sedf <d1> 0 0 0 0 2
               xm sched-sedf <d2> 0 0 0 0 3
               xm sched-sedf <d3> 0 0 0 0 4
               xm sched-sedf <d4> 0 0 0 0 2

           1 fully-specified (10ms/3ms) domain, 3 other domains share
           available rest in 2:7:3 ratio:

               xm sched-sedf <d1> 10000000 3000000 0 0 0
               xm sched-sedf <d2> 0 0 0 0 2
               xm sched-sedf <d3> 0 0 0 0 7
               xm sched-sedf <d4> 0 0 0 0 3


       Most virtual devices can be added and removed while guests are running.
       The effect to the guest OS is much the same as any hotplug event.

       block-attach domain-id be-dev fe-dev mode [bedomain-id]
           Create a new virtual block device.  This will trigger a hotplug
           event for the guest.


               The domain id of the guest domain that the device will be
               attached to.

               The device in the backend domain (usually domain 0) to be
               exported.  This can be specified as a physical partition
               (phy:sda7) or as a file mounted as loopback

               How the device should be presented to the guest domain.  It can
               be specified as either a symbolic name, such as /dev/hdc, for
               common devices, or by device id, such as 0x1400 (/dev/hdc
               device id in hex).

               The access mode for the device from the guest domain.
               Supported modes are w (read/write) or r (read-only).

               The back end domain hosting the device.  This defaults to
               domain 0.


           Mount an ISO as a Disk
               xm block-attach guestdomain file://path/to/dsl-2.0RC2.iso
               /dev/hdc ro

               This will mount the dsl ISO as /dev/hdc in the guestdomain as a
               read only device.  This will probably not be detected as a CD-
               ROM by the guest, but mounting /dev/hdc manually will work.

       block-detach domain-id devid [--force]
           Detach a domain’s virtual block device. devid may be the symbolic
           name or the numeric device id given to the device by domain 0.  You
           will need to run xm block-list to determine that number.

           Detaching the device requires the cooperation of the domain.  If
           the domain fails to release the device (perhaps because the domain
           is hung or is still using the device), the detach will fail.  The
           --force parameter will forcefully detach the device, but may cause
           IO errors in the domain.

       block-list [-l|--long] domain-id
           List virtual block devices for a domain.  The returned output is
           formatted as a list or as an S-Expression if the --long option was

       network-attach domain-id [script=scriptname] [ip=ipaddr] [mac=macaddr]
       [bridge=bridge-name] [backend=bedomain-id]
           Creates a new network device in the domain specified by domain-id.
           It takes the following optional options:


               Use the specified script name to bring up the network.
               Defaults to the default setting in xend-config.sxp for vif-

               Passes the specified IP Address to the adapter on creation.

               FIXME: this currently appears to be broken.  I’m not sure under
               what circumstances this should actually work.

               The MAC address that the domain will see on its Ethernet
               device.  If the device is not specified it will be randomly
               generated with the 00:16:3e vendor id prefix.

               The name of the bridge to attach the vif to, in case you have
               more than one.  This defaults to xenbr0.

               The backend domain id.  By default this is domain 0.

       network-detach domain-id devid
           Removes the network device from the domain specified by domain-id.
           devid is the virtual interface device number within the domain
           (i.e. the 3 in vif22.3).

           FIXME: this is currently broken.  Network devices aren’t completely
           removed from domain 0.

       network-list [-l|--long]> domain-id
           List virtual network interfaces for a domain.  The returned output
           is formatted as a list or as an S-Expression if the --long option
           was given.

       vtpm-list [-l|--long] domain-id
           Show the virtual TPM device for a domain.  The returned output is
           formatted as a list or as an S-Expression if the --long option was


       The Virtual Network interfaces for Xen.

       FIXME: This needs a lot more explanation, or it needs to be ripped out

       vnet-list [-l|--long]
           List vnets.

       vnet-create config
           Create a vnet from a config file.

       vnet-delete vnetid
           Delete a vnet.


       Access Control in Xen consists of two components: (i) The Access
       Control Policy (ACP) defines security labels and access rules based on
       these labels. (ii) The Access Control Module (ACM) makes access control
       decisions by interpreting the policy when domains require to
       communicate or to access resources. The Xen access control has
       sufficient mechanisms in place to enforce the access decisions even
       against maliciously acting user domains (mandatory access control).

       Access rights for domains in Xen are determined by the domain security
       label only and not based on the domain Name or ID. The ACP specifies
       security labels that can then be assigned to domains and resources.
       Every domain must be assigned exactly one security label, otherwise
       access control decisions could become indeterministic. ACPs are
       distinguished by their name, which is a parameter to most of the
       subcommands described below. Currently, the ACP specifies two ways to
       interpret labels:

       (1) Simple Type Enforcement: Labels are interpreted to decide access of
       domains to communication means and virtual or physical resources.
       Communication between domains as well as access to resources are
       forbidden by default and can only take place if they are explicitly
       allowed by the security policy. The proper assignment of labels to
       domains controls the sharing of information (directly through
       communication or indirectly through shared resources) between domains.
       This interpretation allows to control the overt (intended)
       communication channels in Xen.

       (2) Chinese Wall: Labels are interpreted to decide which domains can
       co-exist (be run simultaneously) on the same system. This
       interpretation allows to prevent direct covert (unintended) channels
       and mitigates risks caused by imperfect core domain isolation (trade-
       off between security and other system requirements). For a short
       introduction to covert channels, please refer to

       The following subcommands help you to manage security policies in Xen
       and to assign security labels to domains. To enable access control
       security in Xen, you must compile Xen with ACM support enabled as
       described under "Configuring Security" below. There, you will find also
       examples of each subcommand described here.

       setpolicy ACM policy
           Makes the given ACM policy available to xend as a xend-managed
           policy.  The policy is compiled and a mapping (.map) as well as a
           binary (.bin) version of the policy is created. The policy is
           loaded and the system’s bootloader is prepared to boot the system
           with this policy the next time it is started.

               policy is a dot-separated list of names. The last part is the
               file name pre-fix for the policy XML file. The preceding name
               parts are translated into the local path pointing to the policy
               XML file relative to the global policy root directory
               (/etc/xen/acm-security/policies). For example,
               example.chwall_ste.client_v1 denotes the policy file
               example/chwall_ste/client_v1-security_policy.xml relative to
               the global policy root directory.

           Reset the system’s policy to the default state where the DEFAULT
           policy is loaded and enforced. This operation may fail if for
           example guest VMs are running and and one of them uses a different
           label than what Domain-0 does. It is best to make sure that no
           guests are running before issuing this command.

       getpolicy [--dumpxml]
           Displays information about the current xend-managed policy, such as
           name and type of the policy, the uuid xend has assigned to it on
           the local system, the version of the XML representation and the
           status of the policy, such as whether it is currently loaded into
           Xen or whether the policy is automatically loaded during system
           boot. With the --dumpxml option, the XML representation of the
           policy is displayed.

           Prints the current security policy state information of Xen.

       labels [policy] [type=dom|res|any]
           Lists all labels of a type (domain, resource, or both) that are
           defined in the policy. Unless specified, the default policy is the
           currently enforced access control policy. The default for type is
           ’dom’. The labels are arranged in alphabetical order.

       addlabel label dom configfile [policy]
       addlabel label mgt domain name [policy type:policy]
       addlabel label res resource [policy]
       addlabel label vif-idx domain name [policy type:policy]
           Adds the security label with name label to a domain configfile
           (dom), a Xend-managed domain (mgt), to the global resource label
           file for the given resource (res), or to a managed domain’s virtual
           network interface (vif) that is specified by its index. Unless
           specified, the default policy is the currently enforced access
           control policy.  This subcommand also verifies that the policy
           definition supports the specified label name.

           The only policy type that is currently supported is ACM.

       rmlabel dom configfile
       rmlabel mgt domain name
       rmlabel res resource
       rmlabel vif-idx domain name
           Works the same as the addlabel command (above), except that this
           command will remove the label from the domain configfile (dom), a
           Xend-managed domain (mgt), the global resource label file (res), or
           a managed domain’s network interface (vif).

       getlabel dom configfile
       getlabel mgt domain name
       getlabel res resource
       getlabel vif-idx domain name
           Shows the label for a domain’s configuration in the given
           configfile, a xend-managed domain (mgt), a resource, or a managed
           domain’s network interface (vif).

           Lists all resources in the global resource label file.  Each
           resource is listed with its associated label and policy name.

       dry-run configfile
           Determines if the specified configfile describes a domain with a
           valid security configuration for type enforcement. The test shows
           the policy decision made for each resource label against the domain
           label as well as the overall decision.


               In xen_source_dir/ set the following parameter:

                   XSM_ENABLE ?= y
                   ACM_SECURITY ?= y

               Then recompile and install xen and the security tools and then

                   cd xen_source_dir; make clean; make install
                   reboot into Xen


               To set the system’s security policy enforcement into its
               default state, the follow command can be issued. Make sure that
               no guests are running while doing this.

                   xm resetpolicy

               After this command has successfully completed, the system’s
               DEFAULT policy is enforced.


               This step sets the system’s policy and automatically loads it
               into Xen for enforcement.

                   xm setpolicy ACM example.client_v1


               This subcommand shows all labels that are defined and which can
               be attached to domains.

                   xm labels example.client_v1 type=dom

               will print for our example policy:



               The addlabel subcommand can attach a security label to a domain
               configuration file, here a HomeBanking label. The example
               policy ensures that this domain does not share information with
               other non-homebanking user domains (i.e., domains labeled as
               dom_Fun or dom_Boinc) and that it will not run simultaneously
               with domains labeled as dom_Fun.

               We assume that the specified myconfig.xm configuration file
               actually instantiates a domain that runs workloads related to
               home-banking, probably just a browser environment for online-

                   xm addlabel dom_HomeBanking dom myconfig.xm

               The very simple configuration file might now look as printed
               below. The addlabel subcommand added the access_control entry
               at the end of the file, consisting of a label name and the
               policy that specifies this label name:

                   kernel = "/boot/vmlinuz-2.6.16-xen"
                   memory = 164
                   name = "homebanking"
                   vif = [ '' ]
                   dhcp = "dhcp"
                   access_control = ['policy=example.chwall_ste.client_v1,

               Security labels must be assigned to domain configurations
               because these labels are essential for making access control
               decisions as early as during the configuration phase of a newly
               instantiated domain. Consequently, a security-enabled Xen
               hypervisor will only start domains that have a security label
               configured and whose security label is consistent with the
               currently enforced policy. Otherwise, starting the domain will
               fail with the error condition "operation not permitted".


               The addlabel subcommand supports labeling of domains that are
               managed by xend. This includes domains that are currently
               running, such as for example Domain-0, or those that are in a
               dormant state.  Depending on the state of the system, it is
               possible that the new label is rejected. An example for a
               reason for the rejection of the relabeling of a domain would be
               if a domain is currently allowed to access its labeled
               resources but due to the new label would be prevented from
               accessing one or more of them.

                   xm addlabel dom_Fun mgt Domain-0

               This changes the label of Domain-0 to dom_Fun under the
               condition that this new label of Domain-0 would not prevent any
               other domain from accessing its resources that are provided
               through Domain-0, such as for example network or block device


               The addlabel subcommand can also be used to attach a security
               label to a resource. Following the home banking example from
               above, we can label a disk resource (e.g., a physical partition
               or a file) to make it accessible to the home banking domain.
               The example policy provides a resource label,
               res_LogicalDiskPartition1(hda1), that is compatible with the
               HomeBanking domain label.

                   xm addlabel "res_LogicalDiskPartition1(hda1)" res phy:hda6

               After labeling this disk resource, it can be attached to the
               domain by adding a line to the domain configuration file. The
               line below attaches this disk to the domain at boot time.

                   disk = [ 'phy:hda6,sda2,w' ]

               Alternatively, the resource can be attached after booting the
               domain by using the block-attach subcommand.

                   xm block-attach homebanking phy:hda6 sda2 w

               Note that labeled resources cannot be used when security is
               turned off.  Any attempt to use labeled resources with security
               turned off will result in a failure with a corresponding error
               message.  The solution is to enable security or, if security is
               no longer desired, to remove the resource label using the
               rmlabel subcommand.


               xm create myconfig.xm

               xm list --label

                 Name         ID ...  Time(s)  Label
                 homebanking  23 ...      4.4  dom_HomeBanking
                 Domain-0      0 ...   2658.8  dom_SystemManagement


               xm resources

                       type: ACM
                     policy: example.chwall_ste.client_v1
                     label:  res_LogicalDiskPartition1(hda1)
                       type: ACM
                     policy: example.chwall_ste.client_v1
                     label:  res_LogicalDiskPartition2(hda2)


               We distinguish three representations of the Xen access control
               policy: the source XML version, its binary counterpart, and a
               mapping representation that enables the tools to
               deterministically translate back and forth between label names
               of the XML policy and label identifiers of the binary policy.
               All three versions must be kept consistent to achieve
               predictable security guarantees.

               The XML version is the version that users are supposed to
               create or change, either by manually editing the XML file or by
               using the Xen policy generation tool (xensec_gen). After
               changing the XML file, run the setpolicy subcommand to ensure
               that the new policy is available to xend. Use, for example, the
               subcommand activatepolicy to activate the changes during the
               next system reboot.

               The binary version of the policy is derived from the XML policy
               by tokenizing the specified labels and is used inside Xen only.
               It is created with the setpolicy subcommand. Essentially, the
               binary version is much more compact than the XML version and is
               easier to evaluate during access control decisions.

               The mapping version of the policy is created during the XML-to-
               binary policy translation (setpolicy) and is used by xend and
               the management tools to translate between label names used as
               input to the tools and their binary identifiers (ssidrefs) used
               inside Xen.


       xmdomain.cfg(5), xentop(1)


         Sean Dague <sean at dague dot net>
         Daniel Stekloff <dsteklof at us dot ibm dot com>
         Reiner Sailer <sailer at us dot ibm dot com>
         Stefan Berger <stefanb at us dot ibm dot com>



       Hey! The above document had some coding errors, which are explained

       Around line 167:
           You can’t have =items (as at line 172) unless the first thing after
           the =over is an =item

       Around line 224:
           You can’t have =items (as at line 247) unless the first thing after
           the =over is an =item

       Around line 420:
           You forgot a ’=back’ before ’=head1’

       Around line 480:
           You can’t have =items (as at line 485) unless the first thing after
           the =over is an =item

       Around line 701:
           You forgot a ’=back’ before ’=head2’

       Around line 703:
           ’=item’ outside of any ’=over’

       Around line 756:
           You forgot a ’=back’ before ’=head2’

       Around line 758:
           ’=item’ outside of any ’=over’

       Around line 831:
           ’=item’ outside of any ’=over’

       Around line 1158:
           You forgot a ’=back’ before ’=head1’