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version 1.15, 2014/12/24 00:04:47 version 1.22, 2014/12/24 01:27:36
Line 27  code for Xen and need not be aware that  Line 27  code for Xen and need not be aware that 
 Attempts to access hardware registers are trapped and emulated.  This  Attempts to access hardware registers are trapped and emulated.  This
 style is less efficient but can run unmodified guests.  style is less efficient but can run unmodified guests.
   
   Generally any amd64 machine will work with Xen and PV guests.  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.  TODO: Explain if i386 (non-amd64) machines can
   still be used - I think that witthe requirement to use PAE kernels is
   about the hypervisor being amd64 only.
   
 At boot, the dom0 kernel is loaded as module with Xen as the kernel.  At boot, the dom0 kernel is loaded as module with Xen as the kernel.
 The dom0 can start one or more domUs.  (Booting is explained in detail  The dom0 can start one or more domUs.  (Booting is explained in detail
 in the dom0 section.)  in the dom0 section.)
Line 36  and that Xen kernels and tools are avail Line 43  and that Xen kernels and tools are avail
 attempts to address both the case of running a NetBSD dom0 on hardware  attempts to address both the case of running a NetBSD dom0 on hardware
 and running NetBSD as a domU in a VPS.  and 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  Prerequisites
 -------------  -------------
   
Line 46  things must be done, guiding the reader  Line 58  things must be done, guiding the reader 
 path when there are no known good reasons to stray.  path when there are no known good reasons to stray.
   
 This HOWTO presumes a basic familiarity with the Xen system  This HOWTO presumes a basic familiarity with the Xen system
 architecture.  architecture.  This HOWTO presumes familiarity with installing NetBSD
   on i386/amd64 hardware and installing software from pkgsrc.
 This HOWTO presumes familiarity with installing NetBSD on i386/amd64  See also the [Xen website](http://www.xen.org/).
 hardware and installing software from pkgsrc.  
   History
 For more details on Xen, see [](http://www.xen.org/).  -------
   
   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](/xen/howto-grub/).
   
 Versions of Xen and NetBSD  Versions of Xen and NetBSD
 ==========================  ==========================
Line 70  but note that both packages must be inst Line 88  but note that both packages must be inst
 matching versions.  matching versions.
   
 xenkernel3 and xenkernel33 provide Xen 3.1 and 3.3.  These no longer  xenkernel3 and xenkernel33 provide Xen 3.1 and 3.3.  These no longer
 receive security patches and should not be used.  receive security patches and should not be used.  Xen 3.1 supports PCI
   passthrough.
   
 xenkernel41 provides Xen 4.1.  This is no longer maintained by Xen,  xenkernel41 provides Xen 4.1.  This is no longer maintained by Xen,
 but as of 2014-12 receives backported security patches.  It is a  but as of 2014-12 receives backported security patches.  It is a
Line 81  of 2014-12. Line 100  of 2014-12.
   
 Ideally newer versions of Xen will be added to pkgsrc.  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, "xm" is no longer available.
   
 NetBSD  NetBSD
 ------  ------
   
Line 94  no SMP support for NetBSD as dom0.  (The Line 123  no SMP support for NetBSD as dom0.  (The
 need SMP; the lack of support is really a problem when using a dom0 as  need SMP; the lack of support is really a problem when using a dom0 as
 a normal computer.)  a normal computer.)
   
   Architecture
   ------------
   
   Xen is basically amd64 only at this point.  One can either run i386
   domains or amd64 domains.  If running i386, PAE versions are required,
   for both dom0 and domU.  These versions are built by default in NetBSD
   releases.  While i386 dom0 works fine, amd64 is recommended as more
   normal.  (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  Recommendation
 --------------  --------------
   
 Therefore, this HOWTO recommends running xenkernel42 (and xentools42)  Therefore, this HOWTO recommends running xenkernel42 (and xentools42),
 and NetBSD 6 stable branch.  xl, the NetBSD 6 stable branch, and to use amd64 as the dom0.  Either
   the i386 or amd64 of NetBSD may be used as domUs.
   
 NetBSD as a dom0  NetBSD as a dom0
 ================  ================
   
 NetBSD can be used as a dom0 and works very well.  The following  NetBSD can be used as a dom0 and works very well.  The following
 sections address installation, updating NetBSD, and updating Xen.  sections address installation, updating NetBSD, and updating Xen.
   Note that it doesn't make sense to talk about installing a dom0 OS
   without also installing Xen itself.  We first address installing
   NetBSD, which is not yet a dom0, and then adding Xen, pivoting the
   NetBSD install to a dom0 install by just changing the kernel and boot
   configuration.
   
 Styles of dom0 operation  Styles of dom0 operation
 ------------------------  ------------------------
Line 127  Xen daemons when not running Xen. Line 173  Xen daemons when not running Xen.
 Note that NetBSD as dom0 does not support multiple CPUs.  This will  Note that NetBSD as dom0 does not support multiple CPUs.  This will
 limit the performance of the Xen/dom0 workstation approach.  limit the performance of the Xen/dom0 workstation approach.
   
 Installation of NetBSD and Xen  Installation of NetBSD
 ------------------------------  ----------------------
   
 Note that it doesn't make sense to talk about installing a dom0 OS  First,
 without also installing Xen itself.  [install NetBSD/amd64](../../docs/guide/en/chap-inst.html)
   just as you would if you were not using Xen.
 First do a NetBSD/i386 or NetBSD/amd64  However, the partitioning approach is very important.
 [installation](../../docs/guide/en/chap-inst.html) of the 5.1 release  
 (or newer) as you usually do on x86 hardware. The binary releases are  If you want to use RAIDframe for the dom0, there are no special issues
 available from [](ftp://ftp.NetBSD.org/pub/NetBSD/). Binary snapshots  for Xen.  Typically one provides RAID storage for the dom0, and the
 for current and the stable branches are available on daily autobuilds.  domU systems are unaware of RAID.  The 2nd-stage loader bootxx_* skips
 If you plan to use the `grub` boot loader, when partitioning the disk  over a RAID1 header to find /boot from a filesystem within a RAID
 you have to make the root partition smaller than 512Mb, and formatted as  partition; this is no different when booting Xen.
 FFSv1 with 8k block/1k fragments. If the partition is larger than this,  
 uses FFSv2 or has different block/fragment sizes, grub may fail to load  There are 4 styles of providing backing storage for the virtual disks
 some files. Also keep in mind that you'll probably want to provide  used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN,
 virtual disks to other domains, so reserve some partitions for these  
 virtual disks. Alternatively, you can create large files in the file  With raw partitions, one has a disklabel (or gpt) partition sized for
 system, map them to vnd(4) devices and export theses vnd devices to  each virtual disk to be used by the domU.  (If you are able to predict
 other domains.  how domU usage will evolve, please add an explanation to the HOWTO.
   Seriously, needs tend to change over time.)
 Next step is to install the Xen packages via pkgsrc or from binary  
 packages. See [the pkgsrc  One can use lvm(8) to create logical devices to use for domU disks.
 documentation](http://www.NetBSD.org/docs/pkgsrc/) if you are unfamiliar  This is almost as efficient sa raw disk partitions and more flexible.
 with pkgsrc and/or handling of binary packages. Xen 3.1, 3.3, 4.1 and  Hence raw disk partitions should typically not be used.
 4.2 are available. 3.1 supports PCI pass-through while other versions do  
 not. You'll need either `sysutils/xentools3` and `sysutils/xenkernel3`  One can use files in the dom0 filesystem, typically created by dd'ing
 for Xen 3.1, `sysutils/xentools33` and `sysutils/xenkernel33` for Xen  /dev/zero to create a specific size.  This is somewhat less efficient,
 3.3, `sysutils/xentools41` and `sysutils/xenkernel41` for Xen 4.1. or  but very convenient, as one can cp the files for backup, or move them
 `sysutils/xentools42` and `sysutils/xenkernel42` for Xen 4.2. You'll  between dom0 hosts.
 also need `sysutils/grub` if you plan do use the grub boot loader. If  
 using Xen 3.1, you may also want to install `sysutils/xentools3-hvm`  Finally, in theory one can place the files backing the domU disks in a
 which contains the utilities to run unmodified guests OSes using the  SAN.  (This is an invitation for someone who has done this to add a
 *HVM* support (for later versions this is included in  HOWTO page.)
 `sysutils/xentools`). Note that your CPU needs to support this. Intel  
 CPUs must have the 'VT' instruction, AMD CPUs the 'SVM' instruction. You  Installation of Xen
 can easily find out if your CPU support HVM by using NetBSD's cpuctl  -------------------
 command:  
   In the dom0, install sysutils/xenkernel42 and sysutils/xentools42 from
     # cpuctl identify 0  pkgsrc (or another matching pair).
     cpu0: Intel Core 2 (Merom) (686-class), id 0x6f6  See [the pkgsrc
     cpu0: features 0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>  documentation](http://www.NetBSD.org/docs/pkgsrc/) for help with pkgsrc.
     cpu0: features 0xbfebfbff<PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX>  
     cpu0: features 0xbfebfbff<FXSR,SSE,SSE2,SS,HTT,TM,SBF>  For Xen 3.1, support for HVM guests is in sysutils/xentool3-hvm.  More
     cpu0: features2 0x4e33d<SSE3,DTES64,MONITOR,DS-CPL,,TM2,SSSE3,CX16,xTPR,PDCM,DCA>  recent versions have HVM support integrated in the main xentools
     cpu0: features3 0x20100800<SYSCALL/SYSRET,XD,EM64T>  package.  It is entirely reasonable to run only PV guests.
     cpu0: "Intel(R) Xeon(R) CPU            5130  @ 2.00GHz"  
     cpu0: I-cache 32KB 64B/line 8-way, D-cache 32KB 64B/line 8-way  Next you need to install the selected Xen kernel itself, which is
     cpu0: L2 cache 4MB 64B/line 16-way  installed by pkgsrc as "/usr/pkg/xen*-kernel/xen.gz".  Copy it to /.
     cpu0: ITLB 128 4KB entries 4-way  For debugging, one may copy xen-debug.gz; this is conceptually similar
     cpu0: DTLB 256 4KB entries 4-way, 32 4MB entries 4-way  to DIAGNOSTIC and DEBUG in NetBSD.  xen-debug.gz is basically only
     cpu0: Initial APIC ID 0  useful with a serial console.  Then, place a NetBSD XEN3_DOM0 kernel
     cpu0: Cluster/Package ID 0  in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
     cpu0: Core ID 0  of a NetBSD build.  Both xen and NetBSD may be left compressed.  (If
     cpu0: family 06 model 0f extfamily 00 extmodel 00  using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)
   
 Depending on your CPU, the feature you are looking for is called HVM,  In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
 SVM or VMX.  kernel, so ensure that /kern is in fstab.
   
 Next you need to copy the selected Xen kernel itself. pkgsrc installed  Because you already installed NetBSD, you have a working boot setup
 them under `/usr/pkg/xen*-kernel/`. The file you're looking for is  with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
 `xen.gz`. Copy it to your root file system. `xen-debug.gz` is a kernel  beginning of your root filesystem, /boot present, and likely
 with more consistency checks and more details printed on the serial  /boot.cfg.  (If not, fix before continuing!)
 console. It is useful for debugging crashing guests if you use a serial  
 console. It is not useful with a VGA console.  See boot.cfg(5) for an example.  The basic line is
   
 You'll then need a NetBSD/Xen kernel for *domain0* on your root file  "menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M"
 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  which specifies that the dom0 should have 256M, leaving the rest to be
 customize it. Keep your native kernel around, as it can be useful for  allocated for domUs.
 recovery. *Note:* the *domain0* kernel must support KERNFS and `/kern`  
 must be mounted because *xend* needs access to `/kern/xen/privcmd`.  As with non-Xen systems, you should have a line to boot /netbsd (a
   kernel that works without Xen) and fallback versions of the non-Xen
 Next you need to get a bootloader to load the `xen.gz` kernel, and the  kernel, Xen, and the dom0 kernel.
 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)  Configuring Xen
 manual page for an example using the latter.  ---------------
   
 This is also where you'll specify the memory allocated to *domain0*, the  Now, you have a system that will boot Xen and the dom0 kernel, and
 console to use, etc ...  just run the dom0 kernel.  There will be no domUs, and none can be
   started because you still have to configure the dom0 tools.
 Here is a commented `/grub/menu.lst` file:  
   For 3.3 (and probably 3.1), add to rc.conf (but note that you should
     #Grub config file for NetBSD/xen. Copy as /grub/menu.lst and run  have installed 4.2):
     # grub-install /dev/rwd0d (assuming your boot device is wd0).    xend=YES
     #    xenbackendd=YES
     # The default entry to load will be the first one  
     default=0  For 4.1 and 4.2, add to rc.conf:
     xend=YES
     # boot the default entry after 10s if the user didn't hit keyboard    xencommons=YES
     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:  
   
     # 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.  
             
   
 Updating NetBSD in a dom0  Updating NetBSD in a dom0
 -------------------------  -------------------------
Line 298  and adjusts /etc. Line 275  and adjusts /etc.
 Note that one must update both the non-Xen kernel typically used for  Note that one must update both the non-Xen kernel typically used for
 rescue purposes and the DOM0 kernel used with Xen.  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 versions
 ---------------------  ---------------------
   
 TODO: write  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.
   
 Creating unprivileged domains (domU)  Creating unprivileged domains (domU)
 ====================================  ====================================
Line 452  working vif-bridge is also provided with Line 441  working vif-bridge is also provided with
   
     #!/bin/sh      #!/bin/sh
     #============================================================================      #============================================================================
     # $NetBSD: howto.mdwn,v 1.14 2014/12/23 23:43:27 gdt Exp $      # $NetBSD: howto.mdwn,v 1.21 2014/12/24 01:12:49 gdt Exp $
     #      #
     # /usr/pkg/etc/xen/vif-bridge      # /usr/pkg/etc/xen/vif-bridge
     #      #
Removed from v.1.15  
changed lines
  Added in v.1.22

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