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 KEYs 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 ACTIONs 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

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", ... ]
irqs=[ NUMBER, NUMBER, ... ]

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. The default amount of video ram for stdvga is 8MB which is sufficient for e.g. 1600x1200 at 32bpp and videoram option is currently working only when using the qemu-xen-traditional device-model.

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 and videoram option is currently working only when using the upstream qemu-xen device-model.

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=xx0xxxxxxxxxxxxxxxxxxxxxxxxxxxxx' ]

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'