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 NetBSD/xen Howto  Introduction
 ================  ============
   
 [![BSD  
 daemon](../../images/BSD-daemon.jpg)](../../about/disclaimer.html#bsd-daemon)  
   
 Table Of Contents  
 -----------------  
   
 -   [Introduction](#introduction)  [![[Xen
 -   [Installing NetBSD as privileged domain (Dom0)](#netbsd-dom0)  screenshot]](http://www.netbsd.org/gallery/in-Action/hubertf-xens.png)](../../gallery/in-Action/hubertf-xen.png)
 -   [Creating an unprivileged NetBSD domain (DomU)](#netbsd-domU)  
 -   [Creating an unprivileged Linux domain (DomU)](#linux-domU)  
 -   [Creating an unprivileged Solaris domain (DomU)](#solaris-domU)  
 -   [Using PCI devices in guest domains](#pci-pass-through)  
 -   [Links and further information](#links-and-more)  
   
 * * * * *  
   
 ### Introduction  Xen is a virtual machine monitor or hypervisor for x86 hardware
   (i686-class or higher), which supports running multiple guest
   operating systems on a single physical machine.  With Xen, one uses
   the Xen kernel to control the CPU, memory and console, a dom0
   operating system which mediates access to other hardware (e.g., disks,
   network, USB), and one or more domU operating systems which operate in
   an unprivileged virtualized environment.  IO requests from the domU
   systems are forwarded by the hypervisor (Xen) to the dom0 to be
   fulfilled.
   
   Xen supports two styles of guests.  The original is Para-Virtualized
   (PV) which means that the guest OS does not attempt to access hardware
   directly, but instead makes hypercalls to the hypervisor.  This is
   analogous to a user-space program making system calls.  (The dom0
   operating system uses PV calls for some functions, such as updating
   memory mapping page tables, but has direct hardware access for disk
   and network.)   PV guests must be specifically coded for Xen.
   
   The more recent style is HVM, which means that the guest does not have
   code for Xen and need not be aware that it is running under Xen.
   Attempts to access hardware registers are trapped and emulated.  This
   style is less efficient but can run unmodified guests.
   
   Generally any amd64 machine will work with Xen and PV guests.  In
   theory i386 computers without amd64 support can be used for Xen <=
   4.2, but we have no recent reports of this working (this is a hint).
   For HVM guests, the VT or VMX cpu feature (Intel) or SVM/HVM/VT
   (amd64) is needed; "cpuctl identify 0" will show this.  TODO: Clean up
   and check the above features.
   
   At boot, the dom0 kernel is loaded as a module with Xen as the kernel.
   The dom0 can start one or more domUs.  (Booting is explained in detail
   in the dom0 section.)
   
   NetBSD supports Xen in that it can serve as dom0, be used as a domU,
   and that Xen kernels and tools are available in pkgsrc.  This HOWTO
   attempts to address both the case of running a NetBSD dom0 on hardware
   and running domUs under it (NetBSD and other), and also running NetBSD
   as a domU in a VPS.
   
   Some versions of Xen support "PCI passthrough", which means that
   specific PCI devices can be made available to a specific domU instead
   of the dom0.  This can be useful to let a domU run X11, or access some
   network interface or other peripheral.
   
   Prerequisites
   -------------
   
   Installing NetBSD/Xen is not extremely difficult, but it is more
   complex than a normal installation of NetBSD.
   In general, this HOWTO is occasionally overly restrictive about how
   things must be done, guiding the reader to stay on the established
   path when there are no known good reasons to stray.
   
   This HOWTO presumes a basic familiarity with the Xen system
   architecture.  This HOWTO presumes familiarity with installing NetBSD
   on i386/amd64 hardware and installing software from pkgsrc.
   See also the [Xen website](http://www.xenproject.org/).
   
   History
   -------
   
   NetBSD used to support Xen2; this has been removed.
   
   Before NetBSD's native bootloader could support Xen, the use of
   grub was recommended.  If necessary, see the
   [old grub information](/ports/xen/howto-grub/).
   
   Versions of Xen and NetBSD
   ==========================
   
   Most of the installation concepts and instructions are independent
   of Xen version and NetBSD version.  This section gives advice on
   which version to choose.  Versions not in pkgsrc and older unsupported
   versions of NetBSD are intentionally ignored.
   
   Xen
   ---
   
   In NetBSD, xen is provided in pkgsrc, via matching pairs of packages
   xenkernel and xentools.  We will refer only to the kernel versions,
   but note that both packages must be installed together and must have
   matching versions.
   
   xenkernel3 and xenkernel33 provide Xen 3.1 and 3.3.  These no longer
   receive security patches and should not be used.  Xen 3.1 supports PCI
   passthrough.  Xen 3.1 supports non-PAE on i386.
   
   xenkernel41 provides Xen 4.1.  This is no longer maintained by Xen,
   but as of 2014-12 receives backported security patches.  It is a
   reasonable although trailing-edge choice.
   
   xenkernel42 provides Xen 4.2.  This is maintained by Xen, but old as
   of 2014-12.
   
   Ideally newer versions of Xen will be added to pkgsrc.
   
   Note that NetBSD support is called XEN3.  It works with 3.1 through
   4.2 because the hypercall interface has been stable.
   
   Xen command program
   -------------------
   
   Early Xen used a program called "xm" to manipulate the system from the
   dom0.  Starting in 4.1, a replacement program with similar behavior
   called "xl" is provided.  In 4.2 and later, "xl" is preferred.  4.4 is
   the last version that has "xm".
   
   NetBSD
   ------
   
   The netbsd-5, netbsd-6, netbsd-7, and -current branches are all
   reasonable choices, with more or less the same considerations for
   non-Xen use.  Therefore, netbsd-6 is recommended as the stable version
   of the most recent release for production use.  For those wanting to
   learn Xen or without production stability concerns, netbsd-7 is likely
   most appropriate.
   
   As of NetBSD 6, a NetBSD domU will support multiple vcpus.  There is
   no SMP support for NetBSD as dom0.  (The dom0 itself doesn't really
   need SMP; the lack of support is really a problem when using a dom0 as
   a normal computer.)
   
   Architecture
   ------------
   
   Xen itself can run on i386 or amd64 machines.  (Practically, almost
   any computer where one would want to run Xen supports amd64.)  If
   using an i386 NetBSD kernel for the dom0, PAE is required (PAE
   versions are built by default).  While i386 dom0 works fine, amd64 is
   recommended as more normal.
   
   Xen 4.2 is the last version to support i386 as a host.  TODO: Clarify
   if this is about the CPU having to be amd64, or about the dom0 kernel
   having to be amd64.
   
   One can then run i386 domUs and amd64 domUs, in any combination.  If
   running an i386 NetBSD kernel as a domU, the PAE version is required.
   (Note that emacs (at least) fails if run on i386 with PAE when built
   without, and vice versa, presumably due to bugs in the undump code.)
   
   Recommendation
   --------------
   
   Therefore, this HOWTO recommends running xenkernel42 (and xentools42),
   xl, the NetBSD 6 stable branch, and to use an amd64 kernel as the
   dom0.  Either the i386 or amd64 of NetBSD may be used as domUs.
   
   Build problems
   --------------
   
   Ideally, all versions of Xen in pkgsrc would build on all versions of
   NetBSD on both i386 and amd64.  However, that isn't the case.  Besides
   aging code and aging compilers, qemu (included in xentools for HVM
   support) is difficult to build.  The following are known to fail:
   
           xenkernel3 netbsd-6 i386
           xentools42 netbsd-6 i386 
   
   The following are known to work:
   
           xenkernel41 netbsd-5 amd64
           xentools41 netbsd-5 amd64
           xenkernel41 netbsd-6 i386
           xentools41 netbsd-6 i386
   
 [![[Xen  NetBSD as a dom0
 screenshot]](../../gallery/in-Action/hubertf-xens.png)](../../gallery/in-Action/hubertf-xen.png)  ================
   
 Xen is a virtual machine monitor for x86 hardware (requires i686-class  NetBSD can be used as a dom0 and works very well.  The following
 CPUs), which supports running multiple guest operating systems on a  sections address installation, updating NetBSD, and updating Xen.
 single machine. Guest OSes (also called <E2><80><9C>domains<E2><80><9D>) require a modified  Note that it doesn't make sense to talk about installing a dom0 OS
 kernel which supports Xen hypercalls in replacement to access to the  without also installing Xen itself.  We first address installing
 physical hardware. At boot, the Xen kernel (also known as the Xen  NetBSD, which is not yet a dom0, and then adding Xen, pivoting the
 hypervisor) is loaded (via the bootloader) along with the guest kernel  NetBSD install to a dom0 install by just changing the kernel and boot
 for the first domain (called *domain0*). The Xen kernel has to be loaded  configuration.
 using the multiboot protocol. You would use the NetBSD boot loader for  
 this, or alternatively the **grub** boot loader (**grub** has some  For experimenting with Xen, a machine with as little as 1G of RAM and
 limitations, detailed below). *domain0* has special privileges to access  100G of disk can work.  For running many domUs in productions, far
 the physical hardware (PCI and ISA devices), administrate other domains  more will be needed.
 and provide virtual devices (disks and network) to other domains that  
 lack those privileges. For more details, see  Styles of dom0 operation
 [http://www.xen.org/](http://www.xen.org/).  ------------------------
   
 NetBSD can be used for both *domain0 (Dom0)* and further, unprivileged  There are two basic ways to use Xen.  The traditional method is for
 (DomU) domains. (Actually there can be multiple privileged domains  the dom0 to do absolutely nothing other than providing support to some
 accessing different parts of the hardware, all providing virtual devices  number of domUs.  Such a system was probably installed for the sole
 to unprivileged domains. We will only talk about the case of a single  purpose of hosting domUs, and sits in a server room on a UPS.
 privileged domain, *domain0*). *domain0* will see physical devices much  
 like a regular i386 or amd64 kernel, and will own the physical console  The other way is to put Xen under a normal-usage computer, so that the
 (VGA or serial). Unprivileged domains will only see a character-only  dom0 is what the computer would have been without Xen, perhaps a
 virtual console, virtual disks (`xbd`{.code}) and virtual network  desktop or laptop.  Then, one can run domUs at will.  Purists will
 interfaces (`xennet`{.code}) provided by a privileged domain (usually  deride this as less secure than the previous approach, and for a
 *domain0*). xbd devices are connected to a block device (i.e., a  computer whose purpose is to run domUs, they are right.  But Xen and a
 partition of a disk, raid, ccd, ... device) in the privileged domain.  dom0 (without domUs) is not meaingfully less secure than the same
 xennet devices are connected to virtual devices in the privileged  things running without Xen.  One can boot Xen or boot regular NetBSD
 domain, named xvif\<domain number\>.\<if number for this domain\>, e.g.,  alternately with little problems, simply refraining from starting the
 xvif1.0. Both xennet and xvif devices are seen as regular Ethernet  Xen daemons when not running Xen.
 devices (they can be seen as a crossover cable between 2 PCs) and can be  
 assigned addresses (and be routed or NATed, filtered using IPF, etc ...)  Note that NetBSD as dom0 does not support multiple CPUs.  This will
 or be added as part of a bridge.  limit the performance of the Xen/dom0 workstation approach.
   
 * * * * *  Installation of NetBSD
 ### Installing NetBSD as privileged domain (Dom0)  ----------------------
   
 First do a NetBSD/i386 or NetBSD/amd64  First,
 [installation](../../docs/guide/en/chap-inst.html) of the 5.1 release  [install NetBSD/amd64](/guide/inst/)
 (or newer) as you usually do on x86 hardware. The binary releases are  just as you would if you were not using Xen.
 available from  However, the partitioning approach is very important.
 [ftp://ftp.NetBSD.org/pub/NetBSD/](ftp://ftp.NetBSD.org/pub/NetBSD/).  
 Binary snapshots for current and the stable branches are available on  If you want to use RAIDframe for the dom0, there are no special issues
 [daily autobuilds](http://nyftp.NetBSD.org/pub/NetBSD-daily/). If you  for Xen.  Typically one provides RAID storage for the dom0, and the
 plan to use the **grub** boot loader, when partitioning the disk you  domU systems are unaware of RAID.  The 2nd-stage loader bootxx_* skips
 have to make the root partition smaller than 512Mb, and formatted as  over a RAID1 header to find /boot from a filesystem within a RAID
 FFSv1 with 8k block/1k fragments. If the partition is larger than this,  partition; this is no different when booting Xen.
 uses FFSv2 or has different block/fragment sizes, grub may fail to load  
 some files. Also keep in mind that you'll probably want to provide  There are 4 styles of providing backing storage for the virtual disks
 virtual disks to other domains, so reserve some partitions for these  used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN,
 virtual disks. Alternatively, you can create large files in the file  
 system, map them to vnd(4) devices and export theses vnd devices to  With raw partitions, one has a disklabel (or gpt) partition sized for
 other domains.  each virtual disk to be used by the domU.  (If you are able to predict
   how domU usage will evolve, please add an explanation to the HOWTO.
 Next step is to install the Xen packages via pkgsrc or from binary  Seriously, needs tend to change over time.)
 packages. See [the pkgsrc  
 documentation](http://www.NetBSD.org/docs/pkgsrc/) if you are unfamiliar  One can use [lvm(8)](/guide/lvm/) to create logical devices to use
 with pkgsrc and/or handling of binary packages. Xen 3.1, 3.3, 4.1 and  for domU disks.  This is almost as efficient as raw disk partitions
 4.2 are available. 3.1 supports PCI pass-through while other versions do  and more flexible.  Hence raw disk partitions should typically not
 not. You'll need either  be used.
 [`sysutils/xentools3`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xentools3/README.html)  
 and  One can use files in the dom0 filesystem, typically created by dd'ing
 [`sysutils/xenkernel3`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xenkernel3/README.html)  /dev/zero to create a specific size.  This is somewhat less efficient,
 for Xen 3.1,  but very convenient, as one can cp the files for backup, or move them
 [`sysutils/xentools33`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xentools33/README.html)  between dom0 hosts.
 and  
 [`sysutils/xenkernel33`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xenkernel33/README.html)  Finally, in theory one can place the files backing the domU disks in a
 for Xen 3.3,  SAN.  (This is an invitation for someone who has done this to add a
 [`sysutils/xentools41`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xentools41/README.html)  HOWTO page.)
 and  
 [`sysutils/xenkernel41`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xenkernel41/README.html)  Installation of Xen
 for Xen 4.1. or  -------------------
 [`sysutils/xentools42`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xentools42/README.html)  
 and  In the dom0, install sysutils/xenkernel42 and sysutils/xentools42 from
 [`sysutils/xenkernel42`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xenkernel42/README.html)  pkgsrc (or another matching pair).
 for Xen 4.2. You'll also need  See [the pkgsrc
 [`sysutils/grub`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/grub/README.html)  documentation](http://www.NetBSD.org/docs/pkgsrc/) for help with pkgsrc.
 if you plan do use the grub boot loader. If using Xen 3.1, you may also  
 want to install  For Xen 3.1, support for HVM guests is in sysutils/xentool3-hvm.  More
 [`sysutils/xentools3-hvm`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xentools3-hvm/README.html)  recent versions have HVM support integrated in the main xentools
 which contains the utilities to run unmodified guests OSes using the  package.  It is entirely reasonable to run only PV guests.
 *HVM* support (for later versions this is included in  
 [`sysutils/xentools`{.filename}](http://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/sysutils/xentools/README.html)).  Next you need to install the selected Xen kernel itself, which is
 Note that your CPU needs to support this. Intel CPUs must have the 'VT'  installed by pkgsrc as "/usr/pkg/xen*-kernel/xen.gz".  Copy it to /.
 instruction, AMD CPUs the 'SVM' instruction. You can easily find out if  For debugging, one may copy xen-debug.gz; this is conceptually similar
 your CPU support HVM by using NetBSD's cpuctl command:  to DIAGNOSTIC and DEBUG in NetBSD.  xen-debug.gz is basically only
   useful with a serial console.  Then, place a NetBSD XEN3_DOM0 kernel
 ~~~ {.programlisting}  in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
 # cpuctl identify 0  of a NetBSD build.  Both xen and NetBSD may be left compressed.  (If
 cpu0: Intel Core 2 (Merom) (686-class), id 0x6f6  using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)
 cpu0: features 0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>  
 cpu0: features 0xbfebfbff<PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX>  In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
 cpu0: features 0xbfebfbff<FXSR,SSE,SSE2,SS,HTT,TM,SBF>  kernel, so ensure that /kern is in fstab.
 cpu0: features2 0x4e33d<SSE3,DTES64,MONITOR,DS-CPL,VMX,TM2,SSSE3,CX16,xTPR,PDCM,DCA>  
 cpu0: features3 0x20100800<SYSCALL/SYSRET,XD,EM64T>  Because you already installed NetBSD, you have a working boot setup
 cpu0: "Intel(R) Xeon(R) CPU            5130  @ 2.00GHz"  with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
 cpu0: I-cache 32KB 64B/line 8-way, D-cache 32KB 64B/line 8-way  beginning of your root filesystem, /boot present, and likely
 cpu0: L2 cache 4MB 64B/line 16-way  /boot.cfg.  (If not, fix before continuing!)
 cpu0: ITLB 128 4KB entries 4-way  
 cpu0: DTLB 256 4KB entries 4-way, 32 4MB entries 4-way  See boot.cfg(5) for an example.  The basic line is
 cpu0: Initial APIC ID 0  
 cpu0: Cluster/Package ID 0          menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M
 cpu0: Core ID 0  
 cpu0: family 06 model 0f extfamily 00 extmodel 00  which specifies that the dom0 should have 256M, leaving the rest to be
 ~~~  allocated for domUs.  In an attempt to add performance, one can also
   add
 Depending on your CPU, the feature you are looking for is called HVM,  
 SVM or VMX.          dom0_max_vcpus=1 dom0_vcpus_pin
   
 Next you need to copy the selected Xen kernel itself. pkgsrc installed  to force only one vcpu to be provided (since NetBSD dom0 can't use
 them under `/usr/pkg/xen*-kernel/`{.filename}. The file you're looking  more) and to pin that vcpu to a physical cpu.  TODO: benchmark this.
 for is `xen.gz`{.filename}. Copy it to your root file system.  
 `xen-debug.gz`{.filename} is a kernel with more consistency checks and  As with non-Xen systems, you should have a line to boot /netbsd (a
 more details printed on the serial console. It is useful for debugging  kernel that works without Xen) and fallback versions of the non-Xen
 crashing guests if you use a serial console. It is not useful with a VGA  kernel, Xen, and the dom0 kernel.
 console.  
   The [HowTo on Installing into
   RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
   explains how to set up booting a dom0 with Xen using grub with
   NetBSD's RAIDframe.  (This is obsolete with the use of NetBSD's native
   boot.)
   
   Configuring Xen
   ---------------
   
   Now, you have a system that will boot Xen and the dom0 kernel, and
   just run the dom0 kernel.  There will be no domUs, and none can be
   started because you still have to configure the dom0 tools.  The
   daemons which should be run vary with Xen version and with whether one
   is using xm or xl.  Note that xend is for supporting "xm", and should
   only be used if you plan on using "xm".  Do NOT enable xend if you
   plan on using "xl" as it will cause problems.
   
   The installation of NetBSD should already have created devices for xen
   (xencons, xenevt), but if they are not present, create them:
   
           cd /dev && sh MAKEDEV xen
   
   TODO: Give 3.1 advice (or remove it from pkgsrc).
   
   For 3.3 (and thus xm), add to rc.conf (but note that you should have
   installed 4.1 or 4.2):
   
           xend=YES
           xenbackendd=YES
   
   For 4.1 (and thus xm; xl is believed not to work well), add to rc.conf:
   
           xend=YES
           xencommons=YES
   
   TODO: Explain why if xm is preferred on 4.1, rc.d/xendomains has xl.
   Or fix the package.
   
   For 4.2 with xm, add to rc.conf
   
           xend=YES
           xencommons=YES
   
   For 4.2 with xl (preferred), add to rc.conf:
   
           TODO: explain if there is a xend replacement
           xencommons=YES
   
   TODO: Recommend for/against xen-watchdog.
   
   After you have configured the daemons and either started them or
   rebooted, run the following (or use xl) to inspect Xen's boot
   messages, available resources, and running domains:
   
           # xm dmesg
           [xen's boot info]
           # xm info
           [available memory, etc.]
           # xm list
           Name              Id  Mem(MB)  CPU  State  Time(s)  Console
           Domain-0           0       64    0  r----     58.1
   
   anita (for testing NetBSD)
   --------------------------
   
   With the setup so far, one should be able to run anita (see
   pkgsrc/sysutils/py-anita) to test NetBSD releases, by doing (as root,
   because anita must create a domU):
   
           anita --vmm=xm test file:///usr/obj/i386/
   
   Alternatively, one can use --vmm=xl to use xl-based domU creation instead.
   TODO: check this.
   
   Xen-specific NetBSD issues
   --------------------------
   
   There are (at least) two additional things different about NetBSD as a
   dom0 kernel compared to hardware.
   
   One is that modules are not usable in DOM0 kernels, so one must
   compile in what's needed.  It's not really that modules cannot work,
   but that modules must be built for XEN3_DOM0 because some of the
   defines change and the normal module builds don't do this.  Basically,
   enabling Xen changes the kernel ABI, and the module build system
   doesn't cope with this.
   
   The other difference is that XEN3_DOM0 does not have exactly the same
   options as GENERIC.  While it is debatable whether or not this is a
   bug, users should be aware of this and can simply add missing config
   items if desired.
   
   Updating NetBSD in a dom0
   -------------------------
   
   This is just like updating NetBSD on bare hardware, assuming the new
   version supports the version of Xen you are running.  Generally, one
   replaces the kernel and reboots, and then overlays userland binaries
   and adjusts /etc.
   
   Note that one must update both the non-Xen kernel typically used for
   rescue purposes and the DOM0 kernel used with Xen.
   
   To convert from grub to /boot, install an mbr bootblock with fdisk,
   bootxx_ with installboot, /boot and /boot.cfg.  This really should be
   no different than completely reinstalling boot blocks on a non-Xen
   system.
   
   Updating Xen versions
   ---------------------
   
   Updating Xen is conceptually not difficult, but can run into all the
   issues found when installing Xen.  Assuming migration from 4.1 to 4.2,
   remove the xenkernel41 and xentools41 packages and install the
   xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.
   
   Ensure that the contents of /etc/rc.d/xen* are correct.  Enable the
   correct set of daemons.  Ensure that the domU config files are valid
   for the new version.
   
   
   Unprivileged domains (domU)
   ===========================
   
   This section describes general concepts about domUs.  It does not
   address specific domU operating systems or how to install them.  The
   config files for domUs are typically in /usr/pkg/etc/xen, and are
   typically named so that the file anme, domU name and the domU's host
   name match.
   
   The domU is provided with cpu and memory by Xen, configured by the
   dom0.  The domU is provided with disk and network by the dom0,
   mediated by Xen, and configured in the dom0.
   
   Entropy in domUs can be an issue; physical disks and network are on
   the dom0.  NetBSD's /dev/random system works, but is often challenged.
   
   Config files
   ------------
   
   There is no good order to present config files and the concepts
   surrounding what is being configured.  We first show an example config
   file, and then in the various sections give details.
   
   See (at least in xentools41) /usr/pkg/share/examples/xen/xmexample*,
   for a large number of well-commented examples, mostly for running
   GNU/Linux.
   
   The following is an example minimal domain configuration file
   "/usr/pkg/etc/xen/foo".  It is (with only a name change) an actual
   known working config file on Xen 4.1 (NetBSD 5 amd64 dom0 and NetBSD 5
   i386 domU).  The domU serves as a network file server.
   
           # -*- mode: python; -*-
   
           kernel = "/netbsd-XEN3PAE_DOMU-i386-foo.gz"
           memory = 1024
           vif = [ 'mac=aa:00:00:d1:00:09,bridge=bridge0' ]
           disk = [ 'file:/n0/xen/foo-wd0,0x0,w',
                    'file:/n0/xen/foo-wd1,0x1,w' ]
   
   The domain will have the same name as the file.  The kernel has the
   host/domU name in it, so that on the dom0 one can update the various
   domUs independently.  The vif line causes an interface to be provided,
   with a specific mac address (do not reuse MAC addresses!), in bridge
   mode.  Two disks are provided, and they are both writable; the bits
   are stored in files and Xen attaches them to a vnd(4) device in the
   dom0 on domain creation.  The system treates xbd0 as the boot device
   without needing explicit configuration.
   
   By default xm looks for domain config files in /usr/pkg/etc/xen.  Note
   that "xm create" takes the name of a config file, while other commands
   take the name of a domain.  To create the domain, connect to the
   console, create the domain while attaching the console, shutdown the
   domain, and see if it has finished stopping, do (or xl with Xen >=
   4.2):
   
           xm create foo
           xm console foo
           xm create -c foo
           xm shutdown foo
           xm list
   
   Typing ^] will exit the console session.  Shutting down a domain is
   equivalent to pushing the power button; a NetBSD domU will receive a
   power-press event and do a clean shutdown.  Shutting down the dom0
   will trigger controlled shutdowns of all configured domUs.
   
   domU kernels
   ------------
   
   On a physical computer, the BIOS reads sector 0, and a chain of boot
   loaders finds and loads a kernel.  Normally this comes from the root
   filesystem.  With Xen domUs, the process is totally different.  The
   normal path is for the domU kernel to be a file in the dom0's
   filesystem.  At the request of the dom0, Xen loads that kernel into a
   new domU instance and starts execution.  While domU kernels can be
   anyplace, reasonable places to store domU kernels on the dom0 are in /
   (so they are near the dom0 kernel), in /usr/pkg/etc/xen (near the
   config files), or in /u0/xen (where the vdisks are).
   
   See the VPS section near the end for discussion of alternate ways to
   obtain domU kernels.
   
   CPU and memory
   --------------
   
   A domain is provided with some number of vcpus, less than the number
   of cpus seen by the hypervisor.  (For a dom0, this is controlled by
   the boot argument "dom0_max_vcpus=1".)  For a domU, it is controlled
   from the config file by the "vcpus = N" directive.
   
   A domain is provided with memory; this is controlled in the config
   file by "memory = N" (in megabytes).  In the straightforward case, the
   sum of the the memory allocated to the dom0 and all domUs must be less
   than the available memory.
   
   Xen also provides a "balloon" driver, which can be used to let domains
   use more memory temporarily.  TODO: Explain better, and explain how
   well it works with NetBSD.
   
   Virtual disks
   -------------
   
   With the file/vnd style, typically one creates a directory,
   e.g. /u0/xen, on a disk large enough to hold virtual disks for all
   domUs.  Then, for each domU disk, one writes zeros to a file that then
   serves to hold the virtual disk's bits; a suggested name is foo-xbd0
   for the first virtual disk for the domU called foo.  Writing zeros to
   the file serves two purposes.  One is that preallocating the contents
   improves performance.  The other is that vnd on sparse files has
   failed to work.  TODO: give working/notworking NetBSD versions for
   sparse vnd.  Note that the use of file/vnd for Xen is not really
   different than creating a file-backed virtual disk for some other
   purpose, except that xentools handles the vnconfig commands.  To
   create an empty 4G virtual disk, simply do
   
           dd if=/dev/zero of=foo-xbd0 bs=1m count=4096
   
   With the lvm style, one creates logical devices.  They are then used
   similarly to vnds.  TODO: Add an example with lvm.
   
   In domU config files, the disks are defined as a sequence of 3-tuples.
   The first element is "method:/path/to/disk".  Common methods are
   "file:" for file-backed vnd. and "phy:" for something that is already
   a (TODO: character or block) device.
   
   The second element is an artifact of how virtual disks are passed to
   Linux, and a source of confusion with NetBSD Xen usage.  Linux domUs
   are given a device name to associate with the disk, and values like
   "hda1" or "sda1" are common.  In a NetBSD domU, the first disk appears
   as xbd0, the second as xbd1, and so on.  However, xm/xl demand a
   second argument.  The name given is converted to a major/minor by
   consulting /dev and this is passed to the domU (TODO: check this).  In
   the general case, the dom0 and domU can be different operating
   systems, and it is an unwarranted assumption that they have consistent
   numbering in /dev, or even that the dom0 OS has a /dev.  With NetBSD
   as both dom0 and domU, using values of 0x0 for the first disk and 0x1
   for the second works fine and avoids this issue.
   
   The third element is "w" for writable disks, and "r" for read-only
   disks.
   
   Virtual Networking
   ------------------
   
   Xen provides virtual ethernets, each of which connects the dom0 and a
   domU.  For each virtual network, there is an interface "xvifN.M" in
   the dom0, and in domU index N, a matching interface xennetM (NetBSD
   name).  The interfaces behave as if there is an Ethernet with two
   adaptors connected.  From this primitive, one can construct various
   configurations.  We focus on two common and useful cases for which
   there are existing scripts: bridging and NAT.
   
   With bridging (in the example above), the domU perceives itself to be
   on the same network as the dom0.  For server virtualization, this is
   usually best.  Bridging is accomplished by creating a bridge(4) device
   and adding the dom0's physical interface and the various xvifN.0
   interfaces to the bridge.  One specifies "bridge=bridge0" in the domU
   config file.  The bridge must be set up already in the dom0; an
   example /etc/ifconfig.bridge0 is:
   
           create
           up
           !brconfig bridge0 add wm0
   
   With NAT, the domU perceives itself to be behind a NAT running on the
   dom0.  This is often appropriate when running Xen on a workstation.
   TODO: NAT appears to be configured by "vif = [ '' ]".
   
   Sizing domains
   --------------
   
   Modern x86 hardware has vast amounts of resources.  However, many
   virtual servers can function just fine on far less.  A system with
   256M of RAM and a 4G disk can be a reasonable choice.  Note that it is
   far easier to adjust virtual resources than physical ones.  For
   memory, it's just a config file edit and a reboot.  For disk, one can
   create a new file and vnconfig it (or lvm), and then dump/restore,
   just like updating physical disks, but without having to be there and
   without those pesky connectors.
   
   Starting domains automatically
   ------------------------------
   
   To start domains foo at bar at boot and shut them down cleanly on dom0
   shutdown, in rc.conf add:
   
           xendomains="foo bar"
   
   TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm
   on 4.1.  Or fix the xentools41 package to have xm
   
   Creating specific unprivileged domains (domU)
   =============================================
   
   Creating domUs is almost entirely independent of operating system.  We
   first explain NetBSD, and then differences for Linux and Solaris.
   Note that you must have already completed the dom0 setup so that "xm
   list" (or "xl list") works.
   
 You'll then need a NetBSD/Xen kernel for *domain0* on your root file  Creating an unprivileged NetBSD domain (domU)
 system. The XEN3PAE\_DOM0 kernel or XEN3\_DOM0 provided as part of the  ---------------------------------------------
 i386 or amd64 binaries is suitable for this, but you may want to  
 customize it. Keep your native kernel around, as it can be useful for  
 recovery. *Note:* the *domain0* kernel must support KERNFS and  
 `/kern`{.filename} must be mounted because *xend* needs access to  
 `/kern/xen/privcmd`{.filename}.  
   
 Next you need to get a bootloader to load the `xen.gz`{.filename}  
 kernel, and the NetBSD *domain0* kernel as a module. This can be  
 **grub** or NetBSD's boot loader. Below is a detailled example for grub,  
 see the boot.cfg(5) manual page for an example using the latter.  
   
 This is also where you'll specify the memory allocated to *domain0*, the  
 console to use, etc ...  
   
 Here is a commented `/grub/menu.lst`{.filename} file:  
   
 ~~~ {.programlisting}  
 #Grub config file for NetBSD/xen. Copy as /grub/menu.lst and run  
 # grub-install /dev/rwd0d (assuming your boot device is wd0).  
 #  
 # The default entry to load will be the first one  
 default=0  
   
 # boot the default entry after 10s if the user didn't hit keyboard  
 timeout=10  
   
 # Configure serial port to use as console. Ignore if you'll use VGA only  
 serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1  
   
 # Let the user select which console to use (serial or VGA), default  
 # to serial after 10s  
 terminal --timeout=10 serial console  
   
 # An entry for NetBSD/xen, using /netbsd as the domain0 kernel, and serial  
 # console. Domain0 will have 64MB RAM allocated.  
 # Assume NetBSD is installed in the first MBR partition.  
 title Xen 3 / NetBSD (hda0, serial)  
   root(hd0,0)  
   kernel (hd0,a)/xen.gz dom0_mem=65536 com1=115200,8n1  
   module (hd0,a)/netbsd bootdev=wd0a ro console=ttyS0  
   
 # Same as above, but using VGA console  
 # We can use console=tty0 (Linux syntax) or console=pc (NetBSD syntax)  
 title Xen 3 / NetBSD (hda0, vga)  
   root(hd0,0)  
   kernel (hd0,a)/xen.gz dom0_mem=65536  
   module (hd0,a)/netbsd bootdev=wd0a ro console=tty0  
   
 # NetBSD/xen using a backup domain0 kernel (in case you installed a  
 # nonworking kernel as /netbsd  
 title Xen 3 / NetBSD (hda0, backup, serial)  
   root(hd0,0)  
   kernel (hd0,a)/xen.gz dom0_mem=65536 com1=115200,8n1  
   module (hd0,a)/netbsd.backup bootdev=wd0a ro console=ttyS0  
 title Xen 3 / NetBSD (hda0, backup, VGA)  
   root(hd0,0)  
   kernel (hd0,a)/xen.gz dom0_mem=65536  
   module (hd0,a)/netbsd.backup bootdev=wd0a ro console=tty0  
   
 #Load a regular NetBSD/i386 kernel. Can be useful if you end up with a  
 #nonworking /xen.gz  
 title NetBSD 5.1  
   root (hd0,a)  
   kernel --type=netbsd /netbsd-GENERIC  
   
 #Load the NetBSD bootloader, letting it load the NetBSD/i386 kernel.  
 #May be better than the above, as grub can't pass all required infos  
 #to the NetBSD/i386 kernel (e.g. console, root device, ...)  
 title NetBSD chain  
   root        (hd0,0)  
   chainloader +1  
   
 ## end of grub config file.  
         
 ~~~  
   
 Install grub with the following command:  
   
 ~~~ {.programlisting}  
 # grub --no-floppy  
   
 grub> root (hd0,a)  
  Filesystem type is ffs, partition type 0xa9  
   
 grub> setup (hd0)  
  Checking if "/boot/grub/stage1" exists... no  
  Checking if "/grub/stage1" exists... yes  
  Checking if "/grub/stage2" exists... yes  
  Checking if "/grub/ffs_stage1_5" exists... yes  
  Running "embed /grub/ffs_stage1_5 (hd0)"...  14 sectors are embedded.  
 succeeded  
  Running "install /grub/stage1 (hd0) (hd0)1+14 p (hd0,0,a)/grub/stage2 /grub/menu.lst"...  
  succeeded  
 Done.  
         
 ~~~  
   
 * * * * *  
   
 ### Creating an unprivileged NetBSD domain (DomU)  
   
 Once you have *domain0* running, you need to start the xen tool daemon  
 (**/usr/pkg/share/examples/rc.d/xend start**) and the xen backend daemon  
 (**/usr/pkg/share/examples/rc.d/xenbackendd start** for Xen3\*,  
 **/usr/pkg/share/examples/rc.d/xencommons start** for Xen4.\*). Make  
 sure that `/dev/xencons`{.filename} and `/dev/xenevt`{.filename} exist  
 before starting **xend**. You can create them with this command:  
   
 ~~~ {.programlisting}  
 # cd /dev && sh MAKEDEV xen  
 ~~~  
   
 xend will write logs to `/var/log/xend.log`{.filename} and  
 `/var/log/xend-debug.log`{.filename}. You can then control xen with the  
 xm tool. 'xm list' will show something like:  
   
 ~~~ {.programlisting}  
 # xm list  
 Name              Id  Mem(MB)  CPU  State  Time(s)  Console  
 Domain-0           0       64    0  r----     58.1  
 ~~~  
   
 'xm create' allows you to create a new domain. It uses a config file in  'xm create' allows you to create a new domain. It uses a config file in
 PKG\_SYSCONFDIR for its parameters. By default, this file will be in  PKG\_SYSCONFDIR for its parameters. By default, this file will be in
 `/usr/pkg/etc/xen/`{.filename}. On creation, a kernel has to be  `/usr/pkg/etc/xen/`. On creation, a kernel has to be specified, which
 specified, which will be executed in the new domain (this kernel is in  will be executed in the new domain (this kernel is in the *domain0* file
 the *domain0* file system, not on the new domain virtual disk; but  system, not on the new domain virtual disk; but please note, you should
 please note, you should install the same kernel into *domainU* as  install the same kernel into *domainU* as `/netbsd` in order to make
 `/netbsd`{.filename} in order to make your system tools, like  your system tools, like savecore(8), work). A suitable kernel is
 [savecore(8)](http://netbsd.gw.com/cgi-bin/man-cgi?savecore+8+NetBSD-6.0+i386),  provided as part of the i386 and amd64 binary sets: XEN3\_DOMU.
 work). A suitable kernel is provided as part of the i386 and amd64  
 binary sets: XEN3\_DOMU.  
   
 Here is an /usr/pkg/etc/xen/nbsd example config file:  Here is an /usr/pkg/etc/xen/nbsd example config file:
   
 ~~~ {.programlisting}      #  -*- mode: python; -*-
 #  -*- mode: python; -*-      #============================================================================
 #============================================================================      # Python defaults setup for 'xm create'.
 # Python defaults setup for 'xm create'.      # Edit this file to reflect the configuration of your system.
 # Edit this file to reflect the configuration of your system.      #============================================================================
 #============================================================================  
       #----------------------------------------------------------------------------
 #----------------------------------------------------------------------------      # Kernel image file. This kernel will be loaded in the new domain.
 # Kernel image file. This kernel will be loaded in the new domain.      kernel = "/home/bouyer/netbsd-XEN3_DOMU"
 kernel = "/home/bouyer/netbsd-XEN3_DOMU"      #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
 #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"  
       # Memory allocation (in megabytes) for the new domain.
 # Memory allocation (in megabytes) for the new domain.      memory = 128
 memory = 128  
       # A handy name for your new domain. This will appear in 'xm list',
 # A handy name for your new domain. This will appear in 'xm list',      # and you can use this as parameters for xm in place of the domain
 # and you can use this as parameters for xm in place of the domain      # number. All domains must have different names.
 # number. All domains must have different names.      #
 #      name = "nbsd"
 name = "nbsd"  
       # The number of virtual CPUs this domain has.
 # The number of virtual CPUs this domain has.      #
 #      vcpus = 1
 vcpus = 1  
       #----------------------------------------------------------------------------
 #----------------------------------------------------------------------------      # Define network interfaces for the new domain.
 # Define network interfaces for the new domain.  
       # Number of network interfaces (must be at least 1). Default is 1.
 # Number of network interfaces (must be at least 1). Default is 1.      nics = 1
 nics = 1  
       # Define MAC and/or bridge for the network interfaces.
 # Define MAC and/or bridge for the network interfaces.      #
 #      # The MAC address specified in ``mac'' is the one used for the interface
 # The MAC address specified in ``mac'' is the one used for the interface      # in the new domain. The interface in domain0 will use this address XOR'd
 # in the new domain. The interface in domain0 will use this address XOR'd      # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random
 # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random      # MACs are assigned if not given.
 # MACs are assigned if not given.      #
 #      # ``bridge'' is a required parameter, which will be passed to the
 # ``bridge'' is a required parameter, which will be passed to the      # vif-script called by xend(8) when a new domain is created to configure
 # vif-script called by xend(8) when a new domain is created to configure      # the new xvif interface in domain0.
 # the new xvif interface in domain0.      #
 #      # In this example, the xvif is added to bridge0, which should have been
 # In this example, the xvif is added to bridge0, which should have been      # set up prior to the new domain being created -- either in the
 # set up prior to the new domain being created -- either in the      # ``network'' script or using a /etc/ifconfig.bridge0 file.
 # ``network'' script or using a /etc/ifconfig.bridge0 file.      #
 #      vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]
 vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]  
       #----------------------------------------------------------------------------
 #----------------------------------------------------------------------------      # Define the disk devices you want the domain to have access to, and
 # Define the disk devices you want the domain to have access to, and      # what you want them accessible as.
 # what you want them accessible as.      #
 #      # Each disk entry is of the form:
 # Each disk entry is of the form:      #
 #      #   phy:DEV,VDEV,MODE
 #       phy:DEV,VDEV,MODE      #
 #      # where DEV is the device, VDEV is the device name the domain will see,
 # where DEV is the device, VDEV is the device name the domain will see,      # and MODE is r for read-only, w for read-write.  You can also create
 # and MODE is r for read-only, w for read-write.  You can also create      # file-backed domains using disk entries of the form:
 # file-backed domains using disk entries of the form:      #
 #      #   file:PATH,VDEV,MODE
 #       file:PATH,VDEV,MODE      #
 #      # where PATH is the path to the file used as the virtual disk, and VDEV
 # where PATH is the path to the file used as the virtual disk, and VDEV      # and MODE have the same meaning as for ``phy'' devices.
 # and MODE have the same meaning as for ``phy'' devices.      #
 #      # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),
 # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),      # but it does for Linux.
 # but it does for Linux.      # Worse, the device has to exist in /dev/ of domain0, because xm will
 # Worse, the device has to exist in /dev/ of domain0, because xm will      # try to stat() it. This means that in order to load a Linux guest OS
 # try to stat() it. This means that in order to load a Linux guest OS      # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...
 # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...      # on domain0, with the major/minor from Linux :(
 # on domain0, with the major/minor from Linux :(      # Alternatively it's possible to specify the device number in hex,
 # Alternatively it's possible to specify the device number in hex,      # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...
 # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...  
       disk = [ 'phy:/dev/wd0e,0x1,w' ]
 disk = [ 'phy:/dev/wd0e,0x1,w' ]      #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]
 #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]      #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]
 #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]  
       #----------------------------------------------------------------------------
 #----------------------------------------------------------------------------      # Set the kernel command line for the new domain.
 # Set the kernel command line for the new domain.  
       # Set root device. This one does matter for NetBSD
 # Set root device. This one does matter for NetBSD      root = "xbd0"
 root = "xbd0"      # extra parameters passed to the kernel
 # extra parameters passed to the kernel      # this is where you can set boot flags like -s, -a, etc ...
 # this is where you can set boot flags like -s, -a, etc ...      #extra = ""
 #extra = ""  
       #----------------------------------------------------------------------------
 #----------------------------------------------------------------------------      # Set according to whether you want the domain restarted when it exits.
 # Set according to whether you want the domain restarted when it exits.      # The default is False.
 # The default is False.      #autorestart = True
 #autorestart = True  
   
 # end of nbsd config file ====================================================      # end of nbsd config file ====================================================
 ~~~  
   
 When a new domain is created, xen calls the  When a new domain is created, xen calls the
 `/usr/pkg/etc/xen/vif-bridge`{.filename} script for each virtual network  `/usr/pkg/etc/xen/vif-bridge` script for each virtual network interface
 interface created in *domain0*. This can be used to automatically  created in *domain0*. This can be used to automatically configure the
 configure the xvif?.? interfaces in *domain0*. In our example, these  xvif?.? interfaces in *domain0*. In our example, these will be bridged
 will be bridged with the bridge0 device in *domain0*, but the bridge has  with the bridge0 device in *domain0*, but the bridge has to exist first.
 to exist first. To do this, create the file  To do this, create the file `/etc/ifconfig.bridge0` and make it look
 `/etc/ifconfig.bridge0`{.filename} and make it look like this:  like this:
   
 ~~~ {.programlisting}      create
 create      !brconfig $int add ex0 up
 !brconfig $int add ex0 up  
 ~~~  (replace `ex0` with the name of your physical interface). Then bridge0
   will be created on boot. See the bridge(4) man page for details.
 (replace `ex0`{.literal} with the name of your physical interface). Then  
 bridge0 will be created on boot. See the  So, here is a suitable `/usr/pkg/etc/xen/vif-bridge` for xvif?.? (a
 [bridge(4)](http://netbsd.gw.com/cgi-bin/man-cgi?bridge+4+NetBSD-6.0+i386)  working vif-bridge is also provided with xentools20) configuring:
 man page for details.  
       #!/bin/sh
 So, here is a suitable `/usr/pkg/etc/xen/vif-bridge`{.filename} for      #============================================================================
 xvif?.? (a working vif-bridge is also provided with xentools20)      # $NetBSD: howto.mdwn,v 1.47 2014/12/26 18:35:45 gdt Exp $
 configuring:      #
       # /usr/pkg/etc/xen/vif-bridge
       #
 ~~~ {.programlisting}      # Script for configuring a vif in bridged mode with a dom0 interface.
 #!/bin/sh      # The xend(8) daemon calls a vif script when bringing a vif up or down.
 #============================================================================      # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp
 # $NetBSD: vif-bridge-nbsd,v 1.3 2005/11/08 00:47:35 jlam Exp $      # in the ``vif-script'' field.
 #      #
 # /usr/pkg/etc/xen/vif-bridge      # Usage: vif-bridge up|down [var=value ...]
 #      #
 # Script for configuring a vif in bridged mode with a dom0 interface.      # Actions:
 # The xend(8) daemon calls a vif script when bringing a vif up or down.      #    up     Adds the vif interface to the bridge.
 # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp      #    down   Removes the vif interface from the bridge.
 # in the ``vif-script'' field.      #
 #      # Variables:
 # Usage: vif-bridge up|down [var=value ...]      #    domain name of the domain the interface is on (required).
 #      #    vifq   vif interface name (required).
 # Actions:      #    mac    vif MAC address (required).
 #    up         Adds the vif interface to the bridge.      #    bridge bridge to add the vif to (required).
 #    down       Removes the vif interface from the bridge.      #
 #      # Example invocation:
 # Variables:      #
 #    domain     name of the domain the interface is on (required).      # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0
 #    vifq       vif interface name (required).      #
 #    mac        vif MAC address (required).      #============================================================================
 #    bridge     bridge to add the vif to (required).  
 #      # Exit if anything goes wrong
 # Example invocation:      set -e
 #  
 # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0      echo "vif-bridge $*"
 #  
 #============================================================================      # Operation name.
       OP=$1; shift
 # Exit if anything goes wrong  
 set -e      # Pull variables in args into environment
       for arg ; do export "${arg}" ; done
 echo "vif-bridge $*"  
       # Required parameters. Fail if not set.
 # Operation name.      domain=${domain:?}
 OP=$1; shift      vif=${vif:?}
       mac=${mac:?}
 # Pull variables in args into environment      bridge=${bridge:?}
 for arg ; do export "${arg}" ; done  
       # Optional parameters. Set defaults.
 # Required parameters. Fail if not set.      ip=${ip:-''}   # default to null (do nothing)
 domain=${domain:?}  
 vif=${vif:?}      # Are we going up or down?
 mac=${mac:?}      case $OP in
 bridge=${bridge:?}      up) brcmd='add' ;;
       down)   brcmd='delete' ;;
 # Optional parameters. Set defaults.      *)
 ip=${ip:-''}   # default to null (do nothing)  
   
 # Are we going up or down?  
 case $OP in  
 up)     brcmd='add' ;;  
 down)   brcmd='delete' ;;  
 *)  
         echo 'Invalid command: ' $OP          echo 'Invalid command: ' $OP
         echo 'Valid commands are: up, down'          echo 'Valid commands are: up, down'
         exit 1          exit 1
         ;;          ;;
 esac      esac
   
 # Don't do anything if the bridge is "null".      # Don't do anything if the bridge is "null".
 if [ "${bridge}" = "null" ] ; then      if [ "${bridge}" = "null" ] ; then
         exit          exit
 fi      fi
   
 # Don't do anything if the bridge doesn't exist.      # Don't do anything if the bridge doesn't exist.
 if ! ifconfig -l | grep "${bridge}" >/dev/null; then      if ! ifconfig -l | grep "${bridge}" >/dev/null; then
         exit          exit
 fi      fi
   
 # Add/remove vif to/from bridge.      # Add/remove vif to/from bridge.
 ifconfig x${vif} $OP      ifconfig x${vif} $OP
 brconfig ${bridge} ${brcmd} x${vif}      brconfig ${bridge} ${brcmd} x${vif}
 ~~~  
   
 Now, running  Now, running
   
 ~~~ {.programlisting}      xm create -c /usr/pkg/etc/xen/nbsd
 xm create -c /usr/pkg/etc/xen/nbsd  
 ~~~  should create a domain and load a NetBSD kernel in it. (Note: `-c`
   causes xm to connect to the domain's console once created.) The kernel
 should create a domain and load a NetBSD kernel in it. (Note:  will try to find its root file system on xbd0 (i.e., wd0e) which hasn't
 `-c`{.code} causes xm to connect to the domain's console once created.)  been created yet. wd0e will be seen as a disk device in the new domain,
 The kernel will try to find its root file system on xbd0 (i.e., wd0e)  so it will be 'sub-partitioned'. We could attach a ccd to wd0e in
 which hasn't been created yet. wd0e will be seen as a disk device in the  *domain0* and partition it, newfs and extract the NetBSD/i386 or amd64
 new domain, so it will be 'sub-partitioned'. We could attach a ccd to  tarballs there, but there's an easier way: load the
 wd0e in *domain0* and partition it, newfs and extract the NetBSD/i386 or  `netbsd-INSTALL_XEN3_DOMU` kernel provided in the NetBSD binary sets.
 amd64 tarballs there, but there's an easier way: load the  Like other install kernels, it contains a ramdisk with sysinst, so you
 `netbsd-INSTALL_XEN3_DOMU`{.filename} kernel provided in the NetBSD  can install NetBSD using sysinst on your new domain.
 binary sets. Like other install kernels, it contains a ramdisk with  
 sysinst, so you can install NetBSD using sysinst on your new domain.  
   
 If you want to install NetBSD/Xen with a CDROM image, the following line  If you want to install NetBSD/Xen with a CDROM image, the following line
 should be used in the `/usr/pkg/etc/xen/nbsd`{.filename} file:  should be used in the `/usr/pkg/etc/xen/nbsd` file:
   
 ~~~ {.programlisting}      disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
 disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]  
 ~~~  
   
 After booting the domain, the option to install via CDROM may be  After booting the domain, the option to install via CDROM may be
 selected. The CDROM device should be changed to **xbd1d**.  selected. The CDROM device should be changed to `xbd1d`.
   
 Once done installing, **halt -p** the new domain (don't reboot or halt,  Once done installing, `halt -p` the new domain (don't reboot or halt, it
 it would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the  would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the
 config file), switch the config file back to the XEN3\_DOMU kernel, and  config file), switch the config file back to the XEN3\_DOMU kernel, and
 start the new domain again. Now it should be able to use **root on  start the new domain again. Now it should be able to use `root on xbd0a`
 xbd0a** and you should have a second, functional NetBSD system on your  and you should have a second, functional NetBSD system on your xen
 xen installation.  installation.
   
 When the new domain is booting you'll see some warnings about *wscons*  When the new domain is booting you'll see some warnings about *wscons*
 and the pseudo-terminals. These can be fixed by editing the files  and the pseudo-terminals. These can be fixed by editing the files
 `/etc/ttys`{.filename} and `/etc/wscons.conf`{.filename}. You must  `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
 disable all terminals in `/etc/ttys`{.filename}, except *console*, like  `/etc/ttys`, except *console*, like this:
 this:  
   
 ~~~ {.programlisting}  
 console "/usr/libexec/getty Pc"         vt100   on secure  
 ttyE0   "/usr/libexec/getty Pc"         vt220   off secure  
 ttyE1   "/usr/libexec/getty Pc"         vt220   off secure  
 ttyE2   "/usr/libexec/getty Pc"         vt220   off secure  
 ttyE3   "/usr/libexec/getty Pc"         vt220   off secure  
 ~~~  
   
 Finally, all screens must be commented out from      console "/usr/libexec/getty Pc"         vt100   on secure
 `/etc/wscons.conf`{.filename}.      ttyE0   "/usr/libexec/getty Pc"         vt220   off secure
       ttyE1   "/usr/libexec/getty Pc"         vt220   off secure
       ttyE2   "/usr/libexec/getty Pc"         vt220   off secure
       ttyE3   "/usr/libexec/getty Pc"         vt220   off secure
   
   Finally, all screens must be commented out from `/etc/wscons.conf`.
   
 It is also desirable to add  It is also desirable to add
   
 ~~~ {.programlisting}      powerd=YES
 powerd=YES  
 ~~~  
   
 in rc.conf. This way, the domain will be properly shut down if **xm  in rc.conf. This way, the domain will be properly shut down if
 shutdown -R** or **xm shutdown -H** is used on the domain0.  `xm shutdown -R` or `xm shutdown -H` is used on the domain0.
   
 Your domain should be now ready to work, enjoy.  Your domain should be now ready to work, enjoy.
   
 * * * * *  Creating an unprivileged Linux domain (domU)
   --------------------------------------------
 ### Creating an unprivileged Linux domain (DomU)  
   
 Creating unprivileged Linux domains isn't much different from  Creating unprivileged Linux domains isn't much different from
 unprivileged NetBSD domains, but there are some details to know.  unprivileged NetBSD domains, but there are some details to know.
Line 541  unprivileged NetBSD domains, but there a Line 868  unprivileged NetBSD domains, but there a
 First, the second parameter passed to the disk declaration (the '0x1' in  First, the second parameter passed to the disk declaration (the '0x1' in
 the example below)  the example below)
   
 ~~~ {.programlisting}      disk = [ 'phy:/dev/wd0e,0x1,w' ]
 disk = [ 'phy:/dev/wd0e,0x1,w' ]  
 ~~~  
   
 does matter to Linux. It wants a Linux device number here (e.g. 0x300  does matter to Linux. It wants a Linux device number here (e.g. 0x300
 for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,  for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,
Line 552  number 0x301. Alternatively, devices nam Line 877  number 0x301. Alternatively, devices nam
 as xentools has a table to map these names to devices numbers. To export  as xentools has a table to map these names to devices numbers. To export
 a partition to a Linux guest we can use:  a partition to a Linux guest we can use:
   
 ~~~ {.programlisting}      disk = [ 'phy:/dev/wd0e,0x300,w' ]
 disk = [ 'phy:/dev/wd0e,0x300,w' ]      root = "/dev/hda1 ro"
 root = "/dev/hda1 ro"  
 ~~~  
   
 and it will appear as /dev/hda on the Linux system, and be used as root  and it will appear as /dev/hda on the Linux system, and be used as root
 partition.  partition.
Line 564  To install the Linux system on the parti Line 887  To install the Linux system on the parti
 domain, the following method can be used: install sysutils/e2fsprogs  domain, the following method can be used: install sysutils/e2fsprogs
 from pkgsrc. Use mke2fs to format the partition that will be the root  from pkgsrc. Use mke2fs to format the partition that will be the root
 partition of your Linux domain, and mount it. Then copy the files from a  partition of your Linux domain, and mount it. Then copy the files from a
 working Linux system, make adjustments in `/etc`{.filename} (fstab,  working Linux system, make adjustments in `/etc` (fstab, network
 network config). It should also be possible to extract binary packages  config). It should also be possible to extract binary packages such as
 such as .rpm or .deb directly to the mounted partition using the  .rpm or .deb directly to the mounted partition using the appropriate
 appropriate tool, possibly running under NetBSD's Linux emulation. Once  tool, possibly running under NetBSD's Linux emulation. Once the
 the filesystem has been populated, umount it. If desirable, the  filesystem has been populated, umount it. If desirable, the filesystem
 filesystem can be converted to ext3 using tune2fs -j. It should now be  can be converted to ext3 using tune2fs -j. It should now be possible to
 possible to boot the Linux guest domain, using one of the  boot the Linux guest domain, using one of the vmlinuz-\*-xenU kernels
 vmlinuz-\*-xenU kernels available in the Xen binary distribution.  available in the Xen binary distribution.
   
 To get the linux console right, you need to add:  To get the linux console right, you need to add:
   
 ~~~ {.programlisting}      extra = "xencons=tty1"
 extra = "xencons=tty1"  
 ~~~  
   
 to your configuration since not all linux distributions auto-attach a  to your configuration since not all linux distributions auto-attach a
 tty to the xen console.  tty to the xen console.
   
 * * * * *  Creating an unprivileged Solaris domain (domU)
   ----------------------------------------------
 ### Creating an unprivileged Solaris domain (DomU)  
   
 Download an Opensolaris [release](http://opensolaris.org/os/downloads/)  Download an Opensolaris [release](http://opensolaris.org/os/downloads/)
 or [development snapshot](http://genunix.org/) DVD image. Attach the DVD  or [development snapshot](http://genunix.org/) DVD image. Attach the DVD
 image to a  image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem
 [vnd(4)](http://netbsd.gw.com/cgi-bin/man-cgi?vnd+4+NetBSD-6.0+i386)  image to your dom0 filesystem.
 device. Copy the kernel and ramdisk filesystem image to your dom0  
 filesystem.      dom0# mkdir /root/solaris
       dom0# vnconfig vnd0 osol-1002-124-x86.iso
 ~~~ {.programlisting}      dom0# mount /dev/vnd0a /mnt
 dom0# mkdir /root/solaris  
 dom0# vnconfig vnd0 osol-1002-124-x86.iso      ## for a 64-bit guest
 dom0# mount /dev/vnd0a /mnt      dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris
       dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris
 ## for a 64-bit guest  
 dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris      ## for a 32-bit guest
 dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris      dom0# cp /mnt/boot/x86.microroot /root/solaris
       dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris
 ## for a 32-bit guest  
 dom0# cp /mnt/boot/x86.microroot /root/solaris      dom0# umount /mnt
 dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris            
   
 dom0# umount /mnt  Keep the MAN.VND.4 configured. For some reason the boot process stalls
         unless the DVD image is attached to the guest as a "phy" device. Create
 ~~~  an initial configuration file with the following contents. Substitute
   */dev/wd0k* with an empty partition at least 8 GB large.
 Keep the  
 [vnd(4)](http://netbsd.gw.com/cgi-bin/man-cgi?vnd+4+NetBSD-6.0+i386)      memory = 640
 configured. For some reason the boot process stalls unless the DVD image      name = 'solaris'
 is attached to the guest as a "phy" device. Create an initial      disk = [ 'phy:/dev/wd0k,0,w' ]
 configuration file with the following contents. Substitute */dev/wd0k*      disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]
 with an empty partition at least 8 GB large.      vif = [ 'bridge=bridge0' ]
       kernel = '/root/solaris/unix'
 ~~~ {.programlisting}      ramdisk = '/root/solaris/x86.microroot'
 memory = 640      # for a 64-bit guest
 name = 'solaris'      extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'
 disk = [ 'phy:/dev/wd0k,0,w' ]      # for a 32-bit guest
 disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]      #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'
 vif = [ 'bridge=bridge0' ]            
 kernel = '/root/solaris/unix'  
 ramdisk = '/root/solaris/x86.microroot'  
 # for a 64-bit guest  
 extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'  
 # for a 32-bit guest  
 #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'  
         
 ~~~  
   
 Start the guest.  Start the guest.
   
 ~~~ {.programlisting}      dom0# xm create -c solaris.cfg
 dom0# xm create -c solaris.cfg      Started domain solaris
 Started domain solaris                            v3.3.2 chgset 'unavailable'
                       v3.3.2 chgset 'unavailable'      SunOS Release 5.11 Version snv_124 64-bit
 SunOS Release 5.11 Version snv_124 64-bit      Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
 Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.      Use is subject to license terms.
 Use is subject to license terms.      Hostname: opensolaris
 Hostname: opensolaris      Remounting root read/write
 Remounting root read/write      Probing for device nodes ...
 Probing for device nodes ...      WARNING: emlxs: ddi_modopen drv/fct failed: err 2
 WARNING: emlxs: ddi_modopen drv/fct failed: err 2      Preparing live image for use
 Preparing live image for use      Done mounting Live image
 Done mounting Live image            
         
 ~~~  
   
 Make sure the network is configured. Note that it can take a minute for  Make sure the network is configured. Note that it can take a minute for
 the xnf0 interface to appear.  the xnf0 interface to appear.
   
 ~~~ {.programlisting}      opensolaris console login: jack
 opensolaris console login: jack      Password: jack
 Password: jack      Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008
 Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008      jack@opensolaris:~$ pfexec sh
 jack@opensolaris:~$ pfexec sh      sh-3.2# ifconfig -a
 sh-3.2# ifconfig -a      sh-3.2# exit
 sh-3.2# exit            
         
 ~~~  
   
 Set a password for VNC and start the VNC server which provides the X11  Set a password for VNC and start the VNC server which provides the X11
 display where the installation program runs.  display where the installation program runs.
   
 ~~~ {.programlisting}      jack@opensolaris:~$ vncpasswd
 jack@opensolaris:~$ vncpasswd      Password: solaris
 Password: solaris      Verify: solaris
 Verify: solaris      jack@opensolaris:~$ cp .Xclients .vnc/xstartup
 jack@opensolaris:~$ cp .Xclients .vnc/xstartup      jack@opensolaris:~$ vncserver :1
 jack@opensolaris:~$ vncserver :1            
         
 ~~~  From a remote machine connect to the VNC server. Use `ifconfig xnf0` on
   the guest to find the correct IP address to use.
 From a remote machine connect to the VNC server. Use **ifconfig xnf0**  
 on the guest to find the correct IP address to use.      remote$ vncviewer 172.18.2.99:1
             
 ~~~ {.programlisting}  
 remote$ vncviewer 172.18.2.99:1  
         
 ~~~  
   
 It is also possible to launch the installation on a remote X11 display.  It is also possible to launch the installation on a remote X11 display.
   
 ~~~ {.programlisting}      jack@opensolaris:~$ export DISPLAY=172.18.1.1:0
 jack@opensolaris:~$ export DISPLAY=172.18.1.1:0      jack@opensolaris:~$ pfexec gui-install
 jack@opensolaris:~$ pfexec gui-install             
          
 ~~~  
   
 After the GUI installation is complete you will be asked to reboot.  After the GUI installation is complete you will be asked to reboot.
 Before that you need to determine the ZFS ID for the new boot filesystem  Before that you need to determine the ZFS ID for the new boot filesystem
 and update the configuration file accordingly. Return to the guest  and update the configuration file accordingly. Return to the guest
 console.  console.
   
 ~~~ {.programlisting}      jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs
 jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs                      bootfs = 43
                 bootfs = 43      ^C
 ^C      jack@opensolaris:~$
 jack@opensolaris:~$             
          
 ~~~  
   
 The final configuration file should look like this. Note in particular  The final configuration file should look like this. Note in particular
 the last line.  the last line.
   
       memory = 640
 ~~~ {.programlisting}      name = 'solaris'
 memory = 640      disk = [ 'phy:/dev/wd0k,0,w' ]
 name = 'solaris'      vif = [ 'bridge=bridge0' ]
 disk = [ 'phy:/dev/wd0k,0,w' ]      kernel = '/root/solaris/unix'
 vif = [ 'bridge=bridge0' ]      ramdisk = '/root/solaris/x86.microroot'
 kernel = '/root/solaris/unix'      extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'
 ramdisk = '/root/solaris/x86.microroot'             
 extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'  
          
 ~~~  
   
 Restart the guest to verify it works correctly.  Restart the guest to verify it works correctly.
   
 ~~~ {.programlisting}      dom0# xm destroy solaris
 dom0# xm destroy solaris      dom0# xm create -c solaris.cfg
 dom0# xm create -c solaris.cfg      Using config file "./solaris.cfg".
 Using config file "./solaris.cfg".      v3.3.2 chgset 'unavailable'
 v3.3.2 chgset 'unavailable'      Started domain solaris
 Started domain solaris      SunOS Release 5.11 Version snv_124 64-bit
 SunOS Release 5.11 Version snv_124 64-bit      Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
 Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.      Use is subject to license terms.
 Use is subject to license terms.      WARNING: emlxs: ddi_modopen drv/fct failed: err 2
 WARNING: emlxs: ddi_modopen drv/fct failed: err 2      Hostname: osol
 Hostname: osol      Configuring devices.
 Configuring devices.      Loading smf(5) service descriptions: 160/160
 Loading smf(5) service descriptions: 160/160      svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .
 svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .      Reading ZFS config: done.
 Reading ZFS config: done.      Mounting ZFS filesystems: (6/6)
 Mounting ZFS filesystems: (6/6)      Creating new rsa public/private host key pair
 Creating new rsa public/private host key pair      Creating new dsa public/private host key pair
 Creating new dsa public/private host key pair  
       osol console login:
 osol console login:             
          
 ~~~  
   
 Using PCI devices in guest domains  Using PCI devices in guest domains
 ----------------------------------  ----------------------------------
Line 762  and domU. If the domain0 is NetBSD, it h Line 1057  and domU. If the domain0 is NetBSD, it h
 support has not been ported to later versions at this time.  support has not been ported to later versions at this time.
   
 For a PCI device to be exported to a domU, is has to be attached to the  For a PCI device to be exported to a domU, is has to be attached to the
 `pciback`{.literal} driver in domain0. Devices passed to the domain0 via  `pciback` driver in domain0. Devices passed to the domain0 via the
 the pciback.hide boot parameter will attach to `pciback`{.literal}  pciback.hide boot parameter will attach to `pciback` instead of the
 instead of the usual driver. The list of devices is specified as  usual driver. The list of devices is specified as `(bus:dev.func)`,
 `(bus:dev.func)`{.literal}, where bus and dev are 2-digit hexadecimal  where bus and dev are 2-digit hexadecimal numbers, and func a
 numbers, and func a single-digit number:  single-digit number:
   
 ~~~ {.programlisting}      pciback.hide=(00:0a.0)(00:06.0)
 pciback.hide=(00:0a.0)(00:06.0)  
 ~~~  
   
 pciback devices should show up in the domain0's boot messages, and the  pciback devices should show up in the domain0's boot messages, and the
 devices should be listed in the `/kern/xen/pci`{.filename} directory.  devices should be listed in the `/kern/xen/pci` directory.
   
   PCI devices to be exported to a domU are listed in the `pci` array of
   the domU's config file, with the format `'0000:bus:dev.func'`
   
       pci = [ '0000:00:06.0', '0000:00:0a.0' ]
   
   In the domU an `xpci` device will show up, to which one or more pci
   busses will attach. Then the PCI drivers will attach to PCI busses as
   usual. Note that the default NetBSD DOMU kernels do not have `xpci` or
   any PCI drivers built in by default; you have to build your own kernel
   to use PCI devices in a domU. Here's a kernel config example:
   
       include         "arch/i386/conf/XEN3_DOMU"
       #include         "arch/i386/conf/XENU"           # in NetBSD 3.0
   
       # Add support for PCI busses to the XEN3_DOMU kernel
       xpci* at xenbus ?
       pci* at xpci ?
   
       # Now add PCI and related devices to be used by this domain
       # USB Controller and Devices
   
       # PCI USB controllers
       uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)
   
       # USB bus support
       usb*    at uhci?
   
       # USB Hubs
       uhub*   at usb?
       uhub*   at uhub? port ? configuration ? interface ?
   
       # USB Mass Storage
       umass*  at uhub? port ? configuration ? interface ?
       wd*     at umass?
       # SCSI controllers
       ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI
   
       # SCSI bus support (for both ahc and umass)
       scsibus* at scsi?
   
       # SCSI devices
       sd*     at scsibus? target ? lun ?      # SCSI disk drives
       cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
   
   
   NetBSD as a domU in a VPS
   =========================
   
   The bulk of the HOWTO is about using NetBSD as a dom0 on your own
   hardware.  This section explains how to deal with Xen in a domU as a
   virtual private server where you do not control or have access to the
   dom0.
   
   TODO: Perhaps reference panix, prmgr, amazon as interesting examples.
   
   TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel
   from the domU filesystem.
   
 PCI devices to be exported to a domU are listed in the `pci`{.literal}  Using npf
 array of the domU's config file, with the format  ---------
 `'0000:bus:dev.func'`{.literal}  
   
 ~~~ {.programlisting}  
 pci = [ '0000:00:06.0', '0000:00:0a.0' ]  
 ~~~  
   
 In the domU an `xpci`{.literal} device will show up, to which one or  
 more pci busses will attach. Then the PCI drivers will attach to PCI  
 busses as usual. Note that the default NetBSD DOMU kernels do not have  
 `xpci`{.literal} or any PCI drivers built in by default; you have to  
 build your own kernel to use PCI devices in a domU. Here's a kernel  
 config example:  
   
 ~~~ {.programlisting}  
 include         "arch/i386/conf/XEN3_DOMU"  
 #include         "arch/i386/conf/XENU"           # in NetBSD 3.0  
   
 # Add support for PCI busses to the XEN3_DOMU kernel  
 xpci* at xenbus ?  
 pci* at xpci ?  
   
 # Now add PCI and related devices to be used by this domain  
 # USB Controller and Devices  
   
 # PCI USB controllers  
 uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)  
   
 # USB bus support  
 usb*    at uhci?  
   
 # USB Hubs  
 uhub*   at usb?  
 uhub*   at uhub? port ? configuration ? interface ?  
   
 # USB Mass Storage  
 umass*  at uhub? port ? configuration ? interface ?  
 wd*     at umass?  
 # SCSI controllers  
 ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI  
   
 # SCSI bus support (for both ahc and umass)  
 scsibus* at scsi?  
   
 # SCSI devices  
 sd*     at scsibus? target ? lun ?      # SCSI disk drives  
 cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives  
 ~~~  
   
 Links and further information  
 -----------------------------  
   
 -   The HowTo on [Installing into  
     RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)  
     gives some hints on using Xen (grub) with NetBSD's RAIDframe  
 -   Harold Gutch wrote documentation on [setting up a Linux DomU with a  
     NetBSD Dom0](http://www.gutch.de/NetBSD/docs/xen.html)  
 -   An example of how to use NetBSD's native bootloader to load  
     NetBSD/Xen instead of Grub can be found in the i386/amd64  
     [boot(8)](http://netbsd.gw.com/cgi-bin/man-cgi?boot+8+NetBSD-6.0+i386)  
     and  
     [boot.cfg(5)](http://netbsd.gw.com/cgi-bin/man-cgi?boot.cfg+5+NetBSD-6.0+i386)  
     manpages.  
   
   In standard kernels, npf is a module, and thus cannot be loadeed in a
   DOMU kernel.
   
   TODO: explain how to compile npf into a custom kernel, answering:
   http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html
Removed from v.1.1  
changed lines
  Added in v.1.48

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