NAME
    xl.cfg - XL Domain Configuration File Syntax

SYNOPSIS
     /etc/xen/xldomain

DESCRIPTION
    To create a VM (a domain in Xen terminology, sometimes called a guest)
    with xl requires the provision of a domain config file. Typically these
    live in `/etc/xen/DOMAIN.cfg` where DOMAIN is the name of the domain.

SYNTAX
    A domain config file consists of a series of "KEY=VALUE" pairs.

    Some "KEY"s are mandatory, others are global options which apply to any
    guest type while others relate only to specific guest types (e.g. PV or
    HVM guests).

    A value "VALUE" is one of:

    "STRING"
        A string, surrounded by either single or double quotes.

    NUMBER
        A number, in either decimal, octal (using a 0 prefix) or hexadecimal
        (using an "0x" prefix).

    BOOLEAN
        A "NUMBER" interpreted as "False" (0) or "True" (any other value).

    [ VALUE, VALUE, ... ]
        A list of "VALUES" of the above types. Lists are homogeneous and are
        not nested.

    The semantics of each "KEY" defines which form of "VALUE" is required.

OPTIONS
  Mandatory Configuration Items
    The following key is mandatory for any guest type:

    name="NAME"
        Specifies the name of the domain. Names of domains existing on a
        single host must be unique.

  Selecting Guest Type
    builder="generic"
        Specifies that this is to be a PV domain. This is the default.

    builder="hvm"
        Specifies that this is to be an HVM domain. That is, a fully
        virtualised computer with emulated BIOS, disk and network
        peripherals, etc. The default is a PV domain, suitable for hosting
        Xen-aware guest operating systems.

  Global Options
    The following options apply to guests of any type.

    uuid="UUID"
        Specifies the UUID of the domain. If not specified, a fresh unique
        UUID will be generated.

    vncviewer=BOOLEAN
        Automatically spawn a vncviewer when creating/restoring a guest

    pool="CPUPOOLNAME"
        Put the guest's vcpus into the named cpu pool.

    vcpus=N
        Start the guest with N vcpus initially online.

    maxvcpus=M
        Allow the guest to bring up a maximum of M vcpus. At start of day if
        `vcpus=N` is less than `maxvcpus=M` then the first `N` vcpus will be
        created online and the remainder will be offline.

    cpus="CPU-LIST"
        List of which cpus the guest is allowed to use. By default xl will
        pick some cpus on its own (see below). A "CPU-LIST" may be specified
        as follows:

        "all"
            To allow all the vcpus of the guest to run on all the cpus on
            the host.

        "0-3,5,^1"
            To allow all the vcpus of the guest to run on cpus 0,2,3,5.

        ["2", "3"] (or [2, 3])
            To ask for specific vcpu mapping. That means (in this example),
            vcpu #0 of the guest will run on cpu #2 of the host and vcpu #1
            of the guest will run on cpu #3 of the host.

        If this option is not specified, libxl automatically tries to place
        the new domain on the host's NUMA nodes (provided the host has more
        than one NUMA node) by pinning it to the cpus of those nodes. A
        heuristic approach is utilized with the goals of maximizing
        performance for the domain and, at the same time, achieving
        efficient utilization of the host's CPUs and RAM.

    cpu_weight=WEIGHT
        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. Honoured by the credit, credit2 and
        sedf schedulers.

    cap=N
        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. Honoured by the credit and credit2
        schedulers.

    period=NANOSECONDS
        The normal EDF scheduling usage in nanoseconds. This means every
        period the domain gets cpu time defined in slice. Honoured by the
        sedf scheduler.

    slice=NANOSECONDS
        The normal EDF scheduling usage in nanoseconds. it defines the time
        a domain get every period time. Honoured by the sedf scheduler.

    latency=N
        Scaled period if domain is doing heavy I/O. Honoured by the sedf
        scheduler.

    extratime=BOOLEAN
        Flag for allowing domain to run in extra time. Honoured by the sedf
        scheduler.

    memory=MBYTES
        Start the guest with MBYTES megabytes of RAM.

    maxmem=MBYTES
        Specifies the maximum amount of memory a guest can ever see. The
        value of maxmem= must be equal or greater than memory=.

        In combination with memory= it will start the guest "pre-ballooned",
        if the values of memory= and maxmem= differ. A "pre-ballooned" HVM
        guest needs a balloon driver, without a balloon driver it will
        crash.

    on_poweroff="ACTION"
        Specifies what should be done with the domain if it shuts itself
        down. The "ACTION"s are:

        destroy
            destroy the domain

        restart
            destroy the domain and immediately create a new domain with the
            same configuration

        rename-restart
            rename the domain which terminated, and then immediately create
            a new domain with the same configuration as the original

        preserve
            keep the domain. It can be examined, and later destroyed with
            `xl destroy`.

        coredump-destroy
            write a "coredump" of the domain to /var/xen/dump/NAME and then
            destroy the domain.

        coredump-restart
            write a "coredump" of the domain to /var/xen/dump/NAME and then
            restart the domain.

        The default for "on_poweroff" is "destroy".

    on_reboot="ACTION"
        Action to take if the domain shuts down with a reason code
        requesting a reboot. Default is "restart".

    on_watchdog="ACTION"
        Action to take if the domain shuts down due to a Xen watchdog
        timeout. Default is "destroy".

    on_crash="ACTION"
        Action to take if the domain crashes. Default is "destroy".

    seclabel="LABEL"
        Assign an XSM security label to this domain.

  Devices
    The following options define the paravirtual, emulated and physical
    devices which the guest will contain.

    disk=[ "DISK_SPEC_STRING", "DISK_SPEC_STRING", ...]
        Specifies the disks (both emulated disks and Xen virtual block
        devices) which are to be provided to the guest, and what objects on
        the they should map to. See docs/misc/xl-disk-configuration.txt.

    vif=[ "NET_SPEC_STRING", "NET_SPEC_STRING", ...]
        Specifies the networking provision (both emulated network adapters,
        and Xen virtual interfaces) to provided to the guest. See
        docs/misc/xl-network-configuration.markdown.

    vfb=[ "VFB_SPEC_STRING", "VFB_SPEC_STRING", ...]
        Specifies the paravirtual framebuffer devices which should be
        supplied to the domain.

        This options does not control the emulated graphics card presented
        to an HVM guest. See "Emulated VGA Graphics Device" below for how to
        configure the emulated device.

        Each VFB_SPEC_STRING is a comma-separated list of "KEY=VALUE"
        settings, from the following list:

        "vnc=BOOLEAN"
            Allow access to the display via the VNC protocol. This enables
            the other VNC-related settings. The default is to enable this.

        "vnclisten="ADDRESS[:DISPLAYNUM]""
            Specifies the IP address, and optionally VNC display number, to
            use.

        "vncdisplay=DISPLAYNUM"
            Specifies the VNC display number to use. The actual TCP port
            number will be DISPLAYNUM+5900.

        "vncunused=BOOLEAN"
            Requests that the VNC display setup search for a free TCP port
            to use. The actual display used can be accessed with "xl
            vncviewer".

        "vncpasswd="PASSWORD""
            Specifies the password for the VNC server.

        "sdl=BOOLEAN"
            Specifies that the display should be presented via an X window
            (using Simple DirectMedia Layer). The default is to not enable
            this mode

        "opengl=BOOLEAN"
            Enable OpenGL acceleration of the SDL display. Only effects
            machines using "device_model_version="qemu-xen-traditional"" and
            only if the device-model was compiled with OpenGL support.
            Disabled by default.

        "keymap="LANG""
            Configure the keymap to use for the keyboard associated with
            this display. If the input method does not easily support raw
            keycodes (e.g. this is often the case when using VNC) then this
            allows us to correctly map the input keys into keycodes seen by
            the guest. The specific values which are accepted are defined by
            the version of the device-model which you are using. See Keymaps
            below or consult the qemu(1) manpage. The default is en-us.

        "display=XXX"
            XXX written to xenstore backend for vfb but does not appear to
            be used anywhere?

        "authority=XXX"
            XXX written to xenstore backend for vfb but does not appear to
            be used anywhere?

    pci=[ "PCI_SPEC_STRING", "PCI_SPEC_STRING", ... ]
        Specifies the host PCI devices to passthrough to this guest. Each
        PCI_SPEC_STRING has the form
        "[DDDD:]BB:DD.F[@VSLOT],KEY=VALUE,KEY=VALUE,..." where:

        DDDD:BB:DD.F
            identifies the PCI device from the host perspective in domain
            (DDDD), Bus (BB), Device (DD) and Function (F) syntax. This is
            the same scheme as used in the output of "lspci" for the device
            in question. Note: By default "lspci" will omit the domain
            (DDDD) if it is zero and it is optional here also. You may
            specify the function (F) as * to indicate all functions.

        @VSLOT
            specifies the virtual device where the guest will see this
            device. This is equivalent to the DD which the guest sees. In a
            guest DDDD and BB are "0000:00". XXX how does this really work?

        KEY=VALUE
            Possible KEYs are:

            msitranslate=BOOLEAN
                XXX

            power_mgmt=BOOLEAN
                XXX

            permissive=BOOLEAN
                (PV only) By default pciback only allows PV guests to write
                "known safe" values into PCI config space. But many devices
                require writes to other areas of config space in order to
                operate properly. This tells the pciback driver to allow all
                writes to PCI config space of this device by this domain.
                This option should be enabled with caution: it gives the
                guest much more control over the device, which may have
                security or stability implications. It is recommended to
                enable this option only for trusted VMs under administrator
                control.

    pci_permissive=BOOLEAN
        (PV only) Changes the default value of 'permissive' for all PCI
        devices for this VM. This can still be overridden on a per-device
        basis. This option should be enabled with caution: it gives the
        guest much more control over the device, which may have security or
        stability implications. It is recommended to enable this option only
        for trusted VMs under administrator control. See the "pci=" section
        for more information on the "permissive" flag.

    ioports=[ "IOPORT_RANGE", "IOPORT_RANGE", ... ]

            Allow guest to access specific legacy I/O ports. Each
            IOPORT_RANGE is given in hexadecimal and may either a span e.g.
            "2f8-2ff" (inclusive) or a single I/O port "2f8".

            It is recommended to use this option only for trusted VMs under
            administrator control.

    irqs=[ NUMBER, NUMBER, ... ]

            Allow a guest to access specific physical IRQs.

            It is recommended to use this option only for trusted VMs under
            administrator control.

  Paravirtualised (PV) Guest Specific Options
    The following options apply only to Paravirtual guests.

    kernel="PATHNAME"
        Load the specified file as the kernel image. Either kernel or
        bootloader must be specified for PV guests.

    ramdisk="PATHNAME"
        Load the specified file as the ramdisk.

    bootloader="PROGRAM"
        Run "PROGRAM" to find the kernel image and ramdisk to use. Normally
        "PROGRAM" would be "pygrub", which is an emulation of
        grub/grub2/syslinux.

    bootloader_args=[ "ARG", "ARG", ...]
        Append ARGs to the arguments to the bootloader program.
        Alternatively if the argument is a simple string then it will be
        split into words at whitespace (this second option is deprecated).

    root="STRING"
        Append root="STRING" to the kernel command line (Note: it is guest
        specific what meaning this has).

    extra="STRING"
        Append STRING to the kernel command line. Note: it is guest specific
        what meaning this has).

    e820_host=BOOLEAN
        Selects whether to expose the host e820 (memory map) to the guest
        via the virtual e820. When this option is false the guest
        pseudo-physical address space consists of a single contiguous RAM
        region. When this option is specified the virtual e820 instead
        reflects the host e820 and contains the same PCI holes. The total
        amount of RAM represented by the memory map is always the same, this
        option configures only how it is layed out.

        Exposing the host e820 to the guest gives the guest kernel the
        opportunity to set aside the required part of its pseudo-physical
        address space in order to provide address space to map passedthrough
        PCI devices. It is guest Operating System dependant whether this
        option is required, specifically it is required when using a
        mainline Linux ("pvops") kernel. This option defaults to true if any
        PCI passthrough devices are configured and false otherwise. If you
        do not configure any passthrough devices at domain creation time but
        expect to hotplug devices later then you should set this option.
        Conversely if your particular guest kernel does not require this
        behaviour then it is safe to allow this to be enabled but you may
        wish to disable it anyway.

  Fully-virtualised (HVM) Guest Specific Options
    The following options apply only to HVM guests.

   Boot Device
    boot=[c|d|n]
        Selects the emulated virtual device to boot from. Options are hard
        disk (c), cd-rom (d) or network/PXE (n). Multiple options can be
        given and will be attempted in the order they are given. e.g. to
        boot from cd-rom but fallback to the hard disk you can give dc. The
        default is cd.

   Paging
    The following options control the mechanisms used to virtualise guest
    memory. The defaults are selected to give the best results for the
    common case and so you should normally leave these options unspecified.

    hap=BOOLEAN
        Turns "hardware assisted paging" (the use of the hardware nested
        page table feature) on or off. This feature is called EPT (Extended
        Page Tables) by Intel and NPT (Nested Page Tables) or RVI (Rapid
        Virtualisation Indexing) by AMD. Affects HVM guests only. If turned
        off, Xen will run the guest in "shadow page table" mode where the
        guest's page table updates and/or TLB flushes etc. will be emulated.
        Use of HAP is the default when available.

    oos=BOOLEAN
        Turns "out of sync pagetables" on or off. When running in shadow
        page table mode, the guest's page table updates may be deferred as
        specified in the Intel/AMD architecture manuals. However this may
        expose unexpected bugs in the guest, or find bugs in Xen, so it is
        possible to disable this feature. Use of out of sync page tables,
        when Xen thinks it appropriate, is the default.

    shadow_memory=MBYTES
        Number of megabytes to set aside for shadowing guest pagetable pages
        (effectively acting as a cache of translated pages) or to use for
        HAP state. By default this is 1MB per guest vcpu plus 8KB per MB of
        guest RAM. You should not normally need to adjust this value.
        However if you are not using hardware assisted paging (i.e. you are
        using shadow mode) and your guest workload consists of a a very
        large number of similar processes then increasing this value may
        improve performance.

   Processor and Platform Features
    The following options allow various processor and platform level
    features to be hidden or exposed from the guest's point of view. This
    can be useful when running older guest Operating Systems which may
    misbehave when faced with more modern features. In general you should
    accept the defaults for these options wherever possible.

    bios="STRING"
        Select the virtual firmware that is exposed to the guest. By
        default, a guess is made based on the device model, but sometimes it
        may be useful to request a different one, like UEFI.

        rombios
            Loads ROMBIOS, a 16-bit x86 compatible BIOS. This is used by
            default when device_model_version=qemu-xen-traditional. This is
            the only BIOS option supported when
            device_model_version=qemu-xen-traditional. This is the BIOS used
            by all previous Xen versions.

        seabios
            Loads SeaBIOS, a 16-bit x86 compatible BIOS. This is used by
            default with device_model_version=qemu-xen.

        ovmf
            Loads OVMF, a standard UEFI firmware by Tianocore project.
            Requires device_model_version=qemu-xen.

    pae=BOOLEAN
        Hide or expose the IA32 Physical Address Extensions. These
        extensions make it possible for a 32 bit guest Operating System to
        access more than 4GB of RAM. Enabling PAE also enabled other
        features such as NX. PAE is required if you wish to run a 64-bit
        guest Operating System. In general you should leave this enabled and
        allow the guest Operating System to choose whether or not to use
        PAE. (X86 only)

    acpi=BOOLEAN
        Expose ACPI (Advanced Configuration and Power Interface) tables from
        the virtual firmware to the guest Operating System. ACPI is required
        by most modern guest Operating Systems. This option is enabled by
        default and usually you should omit it. However it may be necessary
        to disable ACPI for compatibility with some guest Operating Systems.

    apic=BOOLEAN
        Include information regarding APIC (Advanced Programmable Interrupt
        Controller) in the firmware/BIOS tables on a single processor guest.
        This causes the MP (multiprocessor) and PIR (PCI Interrupt Routing)
        tables to be exported by the virtual firmware. This option has no
        effect on a guest with multiple virtual CPUS as they must always
        include these tables. This option is enabled by default and you
        should usually omit it but it may be necessary to disable these
        firmware tables when using certain older guest Operating Systems.
        These tables have been superseded by newer constructs within the
        ACPI tables. (X86 only)

    nx=BOOLEAN
        Hides or exposes the No-eXecute capability. This allows a guest
        Operating system to map pages such that they cannot be executed
        which can enhance security. This options requires that PAE also be
        enabled. (X86 only)

    hpet=BOOLEAN
        Enables or disables HPET (High Precision Event Timer). This option
        is enabled by default and you should usually omit it. It may be
        necessary to disable the HPET in order to improve compatibility with
        guest Operating Systems (X86 only)

    nestedhvm=BOOLEAN
        Enable or disables guest access to hardware virtualisation features,
        e.g. it allows a guest Operating System to also function as a
        hypervisor. This option is disabled by default. You may want this
        option if you want to run another hypervisor (including another copy
        of Xen) within a Xen guest or to support a guest Operating System
        which uses hardware virtualisation extensions (e.g. Windows XP
        compatibility mode on more modern Windows OS).

   Guest Virtual Time Controls
    tsc_mode="MODE"
        Specifies how the TSC (Time Stamp Counter) should be provided to the
        guest (X86 only). Specifying this option as a number is deprecated.
        Options are:

        "default"
            Guest rdtsc/p executed natively when monotonicity can be
            guaranteed and emulated otherwise (with frequency scaled if
            necessary).

        "always_emulate"
            Guest rdtsc/p always emulated at 1GHz (kernel and user). Guest
            rdtsc/p always emulated and the virtual TSC will appear to
            increment (kernel and user) at a fixed 1GHz rate, regardless of
            the PCPU HZ rate or power state; Although there is an overhead
            associated with emulation this will NOT affect underlying CPU
            performance.

        "native"
            Guest rdtsc always executed natively (no monotonicity/frequency
            guarantees); guest rdtscp emulated at native frequency if
            unsupported by h/w, else executed natively.

        "native_paravirt"
            Same as native, except xen manages TSC_AUX register so guest can
            determine when a restore/migration has occurred and assumes
            guest obtains/uses pvclock-like mechanism to adjust for
            monotonicity and frequency changes.

    Please see docs/misc/tscmode.txt for more information on this option.

    localtime=BOOLEAN
        Set the real time clock to local time or to UTC. 0 by default, i.e.
        set to UTC.

    rtc_timeoffset=SECONDS
        Set the real time clock offset in seconds. 0 by default.

   Support for Paravirtualisation of HVM Guests
    The following options allow Paravirtualised features (such as devices)
    to be exposed to the guest Operating System in an HVM guest. Utilising
    these features requires specific guest support but when available they
    will result in improved performance.

    xen_platform_pci=BOOLEAN
        Enable or disable the Xen platform PCI device. The presence of this
        virtual device enables a guest Operating System (subject to the
        availability of suitable drivers) to make use of paravirtualisation
        features such as disk and network devices etc. Enabling these
        drivers improves performance and is strongly recommended when
        available. PV drivers are available for various Operating Systems
        including HVM Linux
        <http://wiki.xen.org/wiki/XenLinuxPVonHVMdrivers> and Microsoft
        Windows <http://wiki.xen.org/wiki/XenWindowsGplPv>.

    viridian=BOOLEAN
        Turns on or off the exposure of MicroSoft Hyper-V (AKA viridian)
        compatible enlightenments to the guest. These can improve
        performance of Microsoft Windows guests from Windows Vista and
        Windows 2008 onwards and setting this option for such guests is
        strongly recommended. This option should be harmless for other
        versions of Windows (although it won't give any benefit) and the
        majority of other non-Windows OSes. However it is known to be
        incompatible with some other Operating Systems and in some
        circumstance can prevent Xen's own paravirtualisation interfaces for
        HVM guests from being used.

   Emulated VGA Graphics Device
    The following options control the features of the emulated graphics
    device. Many of these options behave similarly to the equivalent key in
    the VFB_SPEC_STRING for configuring virtual frame buffer devices (see
    above).

    videoram=MBYTES
        Sets the amount of RAM which the emulated video card will contain,
        which in turn limits the resolutions and bit depths which will be
        available. This option is only available when using the stdvga
        option (see below). The default amount of video ram for stdvga is
        8MB which is sufficient for e.g. 1600x1200 at 32bpp.

        When using the emulated Cirrus graphics card (stdvga=0) the amount
        of video ram is fixed at 4MB which is sufficient for 1024x768 at 32
        bpp.

        videoram option is currently only available when using the
        qemu-xen-traditional device-model. Upstream qemu-xen device-model
        currently doesn't support changing the amount of video memory for
        the emulated graphics device.

    stdvga=BOOLEAN
        Select a standard VGA card with VBE (VESA BIOS Extensions) as the
        emulated graphics device. The default is false which means to
        emulate a Cirrus Logic GD5446 VGA card. If your guest supports VBE
        2.0 or later (e.g. Windows XP onwards) then you should enable this.
        stdvga supports more video ram and bigger resolutions than Cirrus.

    vnc=BOOLEAN
        Allow access to the display via the VNC protocol. This enables the
        other VNC-related settings. The default is to enable this.

    vnclisten="ADDRESS[:DISPLAYNUM]"
        Specifies the IP address, and optionally VNC display number, to use.

    vncdisplay=DISPLAYNUM
        Specifies the VNC display number to use. The actual TCP port number
        will be DISPLAYNUM+5900.

    vncunused=BOOLEAN
        Requests that the VNC display setup search for a free TCP port to
        use. The actual display used can be accessed with "xl vncviewer".

    vncpasswd="PASSWORD"
        Specifies the password for the VNC server.

    keymap="LANG"
        Configure the keymap to use for the keyboard associated with this
        display. If the input method does not easily support raw keycodes
        (e.g. this is often the case when using VNC) then this allows us to
        correctly map the input keys into keycodes seen by the guest. The
        specific values which are accepted are defined by the version of the
        device-model which you are using. See Keymaps below of consult the
        qemu(1) manpage. The default is en-us.

    sdl=BOOLEAN
        Specifies that the display should be presented via an X window
        (using Simple DirectMedia Layer). The default is not to enable this
        mode.

    opengl=BOOLEAN
        Enable OpenGL acceleration of the SDL display. Only effects machines
        using device_model_version="qemu-xen-traditional" and only if the
        device-model was compiled with OpenGL support. Disabled by default.

    nographic=BOOLEAN
        Enable or disable the virtual graphics device. The default is to
        provide a VGA graphics device but this option can be used to disable
        it.

   Spice Graphics Support
    The following options control the features of SPICE.

    spice=BOOLEAN
        Allow access to the display via the SPICE protocol. This enables the
        other SPICE-related settings.

    spicehost="ADDRESS"
        Specify the interface address to listen on if given, otherwise any
        interface.

    spiceport=NUMBER
        Specify the port to listen on by the SPICE server if the SPICE is
        enabled.

    spicetls_port=NUMBER
        Specify the secure port to listen on by the SPICE server if the
        SPICE is enabled. At least one of the spiceport or spicetls_port
        must be given if SPICE is enabled. NB. the options depending on
        spicetls_port have not been supported.

    spicedisable_ticketing=BOOLEAN
        Enable client connection without password. The default is false. If
        it's false (set to 0), spicepasswd must be set.

    spicepasswd="PASSWORD"
        Specify the ticket password which is used by a client for
        connection.

    spiceagent_mouse=BOOLEAN
        Whether SPICE agent is used for client mouse mode. The default is
        true (turn on)

   Miscellaneous Emulated Hardware
    serial=DEVICE
        Redirect the virtual serial port to DEVICE. Please see the -serial
        option in the qemu(1) manpage for details of the valid DEVICE
        options. Default is vc when in graphical mode and stdio if
        nographics=1 is used.

    soundhw=DEVICE
        Select the virtual sound card to expose to the guest. The valid
        devices are defined by the device model configuration, please see
        the qemu(1) manpage for details. The default is not to export any
        sound device.

    usb=BOOLEAN
        Enables or disables a USB bus in the guest.

    usbdevice=DEVICE
        Adds DEVICE to the USB bus. The USB bus must also be enabled using
        usb=1. The most common use for this option is usbdevice=tablet which
        adds pointer device using absolute coordinates. Such devices
        function better than relative coordinate devices (such as a standard
        mouse) since many methods of exporting guest graphics (such as VNC)
        work better in this mode. Note that this is independent of the
        actual pointer device you are using on the host/client side. XXX
        should/could be a list of devices.

   Unclassified HVM Specific Options
    These HVM specific options have not yet been documented or classified.
    They almost certainly belong in a more appropriate section.

    vpt_align=BOOLEAN
        Align the Virtual Platform Timer ??? XXX Reduces interrupts?

    timer_mode=NUMBER
        Set mode for Virtual Timers XXX ??? should be an enum of particular
        values. See "HVM_PARAM_TIMER_MODE" in
        xen/include/public/hvm/params.h.

  Device-Model Options
    The following options control the selection of the device-model. This is
    the component which provides emulation of the virtual devices to an HVM
    guest. For a PV guest a device-model is sometimes used to provide
    backends for certain PV devices (most usually a virtual framebuffer
    device).

    device_model_version="DEVICE-MODEL"
        Selects which variant of the device-model should be used for this
        guest. Valid values are:

        qemu-xen-traditional
            Use the device-model based upon the historical Xen fork of Qemu.
            This device-model is currently the default.

        qemu-xen
            use the device-model merged into the upstream Qemu project. This
            device-model will become the default in a future version of Xen.

        It is recommended to accept the default value for new guests. If you
        have existing guests then, depending on the nature of the guest
        Operating System, you may wish to force them to use the device model
        which they were installed with.

    device_model_override="PATH"
        Override the path to the binary to be used as the device-model. The
        binary provided here MUST be consistent with the
        `device_model_version` which you have specified. You should not
        normally need to specify this option.

    device_model_stubdomain_override=BOOLEAN
        Override the use of stubdomain based device-model. Normally this
        will be automatically selected based upon the other features and
        options you have selected.

    device_model_stubdomain_seclabel="LABEL"
        Assign an XSM security label to the device-model stubdomain.

    device_model_args=[ "ARG", "ARG", ...]
        Pass additional arbitrary options on the device-model command line.
        Each element in the list is passed as an option to the device-model.

    device_model_args_pv=[ "ARG", "ARG", ...]
        Pass additional arbitrary options on the device-model command line
        for a PV device model only. Each element in the list is passed as an
        option to the device-model.

    device_model_args_hvm=[ "ARG", "ARG", ...]
        Pass additional arbitrary options on the device-model command line
        for an HVM device model only. Each element in the list is passed as
        an option to the device-model.

  Unclassified General Options
    These have not yet been fully documented or classified. They almost
    certainly belong in a more appropriate section.

    gfx_passthru=BOOLEAN
        Enable graphics device PCI passthrough. This option makes the
        passthru graphics card become primary graphics card in the VM, so
        the Qemu emulated graphics adapter is disabled, and the VNC console
        for the VM won't have any graphics output. All graphics output,
        including boot time Qemu BIOS messages from the VM, will go to the
        physical outputs of the passed thru physical graphics card.

        Graphics card PCI device to passthru is chosen with pci option,
        exactly in the same way as normal Xen PCI device passthru/assignment
        is done. Note that gfx_passthru doesn't do any kind of sharing of
        the GPU, so you can only assign the GPU to one single VM at a time.

        gfx_passthru also enables various legacy VGA memory ranges, BARs,
        MMIOs, and ioports to be passed thru to the VM, since those are
        required for correct operation of things like VGA BIOS, text mode,
        VBE, etc.

        Enabling gfx_passthru option also copies the physical graphics card
        video BIOS to the guest memory, and executes the VBIOS in the guest
        to get the graphics card initialized.

        Most graphics adapters require vendor specific tweaks for properly
        working graphics passthru. See the XenVGAPassthroughTestedAdapters
        <http://wiki.xen.org/wiki/XenVGAPassthroughTestedAdapters> wiki page
        for currently supported graphics cards for gfx_passthru.

        gfx_passthru is currently only supported with the
        qemu-xen-traditional device-model. Upstream qemu-xen device-model
        currently doesn't have support for gfx_passthru.

        Note that some graphics adapters (AMD/ATI cards, for example) don't
        necessarily require gfx_passthru option, so you can use the normal
        Xen PCI passthru to assign the graphics card as a secondary graphics
        card to the VM. Qemu emulated graphics card stays as the primary
        graphics card, and you get VNC output from the Qemu-emulated primary
        adapter.

        More information about Xen gfx_passthru feature is available on the
        XenVGAPassthrough <http://wiki.xen.org/wiki/XenVGAPassthrough> wiki
        page.

    nomigrate=BOOLEAN
        Disable migration of this domain. This enables certain other
        features which are incompatible with migration (currently certain
        TSC modes XXX ?).

    pci_msitranslate=BOOLEAN
        XXX

    pci_power_mgmt=BOOLEAN
        XXX

    cpuid="LIBXL_STRING" or cpuid=[ "XEND_STRING", "XEND_STRING" ]
        Configure the value returned when a guest executes CPUID
        instruction. Two versions of config syntax are recognized: libxl and
        xend.

        The libxl syntax is a comma separated list of key=value pairs,
        preceded by the word "host". A few keys take a numerical value, all
        others take a single character which describes what to do with the
        feature bit.

        Possible values for a single feature bit: '1' -> force the
        corresponding bit to 1 '0' -> force to 0 'x' -> Get a safe value
        (pass through and mask with the default policy) 'k' -> pass through
        the host bit value 's' -> as 'k' but preserve across save/restore
        and migration (not implemented)

        List of keys taking a value: apicidsize brandid clflush family
        localapicid maxleaf model nc proccount procpkg stepping

        List of keys taking a character: 3dnow 3dnowext 3dnowprefetch abm
        acpi aes altmovcr8 apic avx clfsh cmov cmplegacy cmpxchg16 cmpxchg8
        cntxid dca de ds dscpl dtes64 est extapic f16c ffxsr fma4 fpu fxsr
        htt hypervisor ia64 ibs lahfsahf lm lwp mca mce misalignsse mmx
        mmxext monitor movbe msr mtrr nodeid nx osvw osxsave pae page1gb pat
        pbe pclmulqdq pdcm pge popcnt pse pse36 psn rdtscp skinit smx ss sse
        sse2 sse3 sse4.1 sse4.2 sse4a ssse3 svm svm_decode svm_lbrv svm_npt
        svm_nrips svm_pausefilt svm_tscrate svm_vmcbclean syscall sysenter
        tbm tm tm2 topoext tsc vme vmx wdt x2apic xop xsave xtpr

        The xend syntax is a list of values in the form of
        'leafnum:register=bitstring,register=bitstring' "leafnum" is the
        requested function, "register" is the response register to modify
        "bitstring" represents all bits in the register, its length must be
        32 chars. Each successive character represent a lesser-significant
        bit, possible values are listed above in the libxl section.

        Example to hide two features from the guest: 'tm', which is bit #29
        in EDX, and 'pni' (SSE3), which is bit #0 in ECX:

        xend: [
        '1:ecx=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx0,edx=xx0xxxxxxxxxxxxxxxxxxxxx
        xxxxxxxx' ]

        libxl: 'host,tm=0,sse3=0'

        More info about the CPUID instruction can be found in the processor
        manuals, and in Wikipedia: <http://en.wikipedia.org/wiki/CPUID>

    acpi_s3=BOOLEAN
        XXX

    acpi_s3=BOOLEAN
        XXX

    nodes=XXX
        XXX

    sched=XXX
        XXX

    device_model=XXX
        XXX deprecated

    vif2=XXX
        XXX deprecated

  Keymaps
    The keymaps available are defined by the device-model which you are
    using. Commonly this includes:

            ar  de-ch  es  fo     fr-ca  hu  ja  mk     no  pt-br  sv
            da  en-gb  et  fr     fr-ch  is  lt  nl     pl  ru     th
            de  en-us  fi  fr-be  hr     it  lv  nl-be  pt  sl     tr

    The default is en-us.

    See qemu(1) for more information.

SEE ALSO
    xl(1)
    xl-disk-configuration
    xl-network-configuration

FILES
    /etc/xen/NAME.cfg /var/xen/dump/NAME docs/misc/tscmode.txt

BUGS
    This document is a work in progress and contains items which require
    further documentation and which are generally incomplete (marked with
    XXX). However all options are included here whether or not they are
    fully documented.

    Patches to improve incomplete items (or any other item) would be
    gratefully received on the xen-devel@lists.xen.org mailing list. Please
    see <http://wiki.xen.org/wiki/SubmittingXenPatches> for information on
    how to submit a patch to Xen.

POD ERRORS
    Hey! The above document had some coding errors, which are explained
    below:

    Around line 405:
        '=item' outside of any '=over'

    Around line 429:
        You forgot a '=back' before '=head2'

    Around line 687:
        '=item' outside of any '=over'

    Around line 695:
        You forgot a '=back' before '=head3'

