Diff for /wikisrc/ports/xen/howto.mdwn between versions 1.49 and 1.76

version 1.49, 2014/12/26 20:25:19 version 1.76, 2015/01/17 01:34:29
Line 2  Introduction Line 2  Introduction
 ============  ============
   
 [![[Xen  [![[Xen
 screenshot]](http://www.netbsd.org/gallery/in-Action/hubertf-xens.png)](../../gallery/in-Action/hubertf-xen.png)  screenshot]](http://www.netbsd.org/gallery/in-Action/hubertf-xens.png)](http://www.netbsd.org/gallery/in-Action/hubertf-xen.png)
   
 Xen is a virtual machine monitor or hypervisor for x86 hardware  Xen is a hypervisor (or virtual machine monitor) for x86 hardware
 (i686-class or higher), which supports running multiple guest  (i686-class or higher), which supports running multiple guest
 operating systems on a single physical machine.  With Xen, one uses  operating systems on a single physical machine.  Xen is a Type 1 or
 the Xen kernel to control the CPU, memory and console, a dom0  bare-metal hypervisor; one uses the Xen kernel to control the CPU,
 operating system which mediates access to other hardware (e.g., disks,  memory and console, a dom0 operating system which mediates access to
 network, USB), and one or more domU operating systems which operate in  other hardware (e.g., disks, network, USB), and one or more domU
 an unprivileged virtualized environment.  IO requests from the domU  operating systems which operate in an unprivileged virtualized
 systems are forwarded by the hypervisor (Xen) to the dom0 to be  environment.  IO requests from the domU systems are forwarded by the
 fulfilled.  hypervisor (Xen) to the dom0 to be fulfilled.
   
 Xen supports two styles of guests.  The original is Para-Virtualized  Xen supports two styles of guests.  The original is Para-Virtualized
 (PV) which means that the guest OS does not attempt to access hardware  (PV) which means that the guest OS does not attempt to access hardware
Line 49  specific PCI devices can be made availab Line 49  specific PCI devices can be made availab
 of the dom0.  This can be useful to let a domU run X11, or access some  of the dom0.  This can be useful to let a domU run X11, or access some
 network interface or other peripheral.  network interface or other peripheral.
   
   NetBSD used to support Xen2; this has been removed.
   
 Prerequisites  Prerequisites
 -------------  -------------
   
Line 63  architecture.  This HOWTO presumes famil Line 65  architecture.  This HOWTO presumes famil
 on i386/amd64 hardware and installing software from pkgsrc.  on i386/amd64 hardware and installing software from pkgsrc.
 See also the [Xen website](http://www.xenproject.org/).  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  Versions of Xen and NetBSD
 ==========================  ==========================
   
Line 158  Build problems Line 151  Build problems
 Ideally, all versions of Xen in pkgsrc would build on all versions of  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  NetBSD on both i386 and amd64.  However, that isn't the case.  Besides
 aging code and aging compilers, qemu (included in xentools for HVM  aging code and aging compilers, qemu (included in xentools for HVM
 support) is difficult to build.  The following are known to fail:  support) is difficult to build.  The following are known to work or FAIL:
   
         xenkernel3 netbsd-6 i386  
         xentools42 netbsd-6 i386   
   
 The following are known to work:  
   
           xenkernel3 netbsd-5 amd64
           xentools3 netbsd-5 amd64
           xentools3=hvm netbsd-5 amd64 ????
           xenkernel33 netbsd-5 amd64
           xentools33 netbsd-5 amd64
         xenkernel41 netbsd-5 amd64          xenkernel41 netbsd-5 amd64
         xentools41 netbsd-5 amd64          xentools41 netbsd-5 amd64
           xenkernel42 netbsd-5 amd64
           xentools42 netbsd-5 amd64
   
           xenkernel3 netbsd-6 i386 FAIL
           xentools3 netbsd-6 i386
           xentools3-hvm netbsd-6 i386 FAIL (dependencies fail)
           xenkernel33 netbsd-6 i386
           xentools33 netbsd-6 i386
         xenkernel41 netbsd-6 i386          xenkernel41 netbsd-6 i386
         xentools41 netbsd-6 i386          xentools41 netbsd-6 i386
           xenkernel42 netbsd-6 i386
           xentools42 netbsd-6 i386 *MIXED
   
           (all 3 and 33 seem to FAIL)
           xenkernel41 netbsd-7 i386
           xentools41 netbsd-7 i386
           xenkernel42 netbsd-7 i386
           xentools42 netbsd-7 i386 ??FAIL
   
   (*On netbsd-6 i386, there is a xentools42 in the 2014Q3 official builds,
   but it does not build for gdt.)
   
 NetBSD as a dom0  NetBSD as a dom0
 ================  ================
Line 204  alternately with little problems, simply Line 216  alternately with little problems, simply
 Xen daemons when not running Xen.  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.  In theory
   the only issue is that the "backend drivers" are not yet MPSAFE:
     http://mail-index.netbsd.org/netbsd-users/2014/08/29/msg015195.html
   
 Installation of NetBSD  Installation of NetBSD
 ----------------------  ----------------------
Line 260  For debugging, one may copy xen-debug.gz Line 274  For debugging, one may copy xen-debug.gz
 to DIAGNOSTIC and DEBUG in NetBSD.  xen-debug.gz is basically only  to DIAGNOSTIC and DEBUG in NetBSD.  xen-debug.gz is basically only
 useful with a serial console.  Then, place a NetBSD XEN3_DOM0 kernel  useful with a serial console.  Then, place a NetBSD XEN3_DOM0 kernel
 in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz  in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
 of a NetBSD build.  Both xen and NetBSD may be left compressed.  (If  of a NetBSD build.  If using i386, use
 using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)  releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.  (If using Xen
   3.1 and i386, you may use XEN3_DOM0 with the non-PAE Xen.  But you
 With Xen as the kernel, you must provide a dom0 NetBSD kernel to be  should not use Xen 3.1.)  Both xen and the NetBSD kernel may be (and
 used as a module; place this in /.  Suitable kernels are provided in  typically are) left compressed.
 releasedir/binary/kernel:  
   In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
         i386 XEN3_DOM0  kernel, so ensure that /kern is in fstab.  TODO: Say this is default,
         i386 XEN3PAE_DOM0  or file a PR and give a reference.
         amd64 XEN3_DOM0  
   
 The first one is only for use with Xen 3.1 and i386-mode Xen (and you  
 should not do this).  Current Xen always uses PAE on i386, but you  
 should generally use amd64 for the dom0.  In a dom0 kernel, kernfs is  
 mandatory for xend to comunicate with the kernel, so ensure that /kern  
 is in fstab.  TODO: Say this is default, or file a PR and give a  
 reference.  
   
 Because you already installed NetBSD, you have a working boot setup  Because you already installed NetBSD, you have a working boot setup
 with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the  with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
 beginning of your root filesystem, /boot present, and likely  beginning of your root filesystem, /boot present, and likely
 /boot.cfg.  (If not, fix before continuing!)  /boot.cfg.  (If not, fix before continuing!)
   
 See boot.cfg(5) for an example.  The basic line is  Add a line to to /boot.cfg to boot Xen.  See boot.cfg(5) for an
   example.  The basic line is
   
         menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M          menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M
   
 which specifies that the dom0 should have 256M, leaving the rest to be  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  allocated for domUs.  To use In an attempt to add performance, one can
 add  also add
   
         dom0_max_vcpus=1 dom0_vcpus_pin          dom0_max_vcpus=1 dom0_vcpus_pin
   
Line 300  As with non-Xen systems, you should have Line 307  As with non-Xen systems, you should have
 kernel that works without Xen) and fallback versions of the non-Xen  kernel that works without Xen) and fallback versions of the non-Xen
 kernel, Xen, and the dom0 kernel.  kernel, Xen, and the dom0 kernel.
   
   Now, reboot so that you are running a DOM0 kernel under Xen, rather
   than GENERIC without Xen.
   
   Using grub (historic)
   ---------------------
   
   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/).
   
 The [HowTo on Installing into  The [HowTo on Installing into
 RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)  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  explains how to set up booting a dom0 with Xen using grub with
Line 309  boot.) Line 326  boot.)
 Configuring Xen  Configuring Xen
 ---------------  ---------------
   
 Now, you have a system that will boot Xen and the dom0 kernel, and  Xen logs will be in /var/log/xen.
 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  Now, you have a system that will boot Xen and the dom0 kernel, but not
 daemons which should be run vary with Xen version and with whether one  do anything else special.  Make sure that you have rebooted into Xen.
 is using xm or xl.  Note that xend is for supporting "xm", and should  There will be no domUs, and none can be started because you still have
 only be used if you plan on using "xm".  Do NOT enable xend if you  to configure the dom0 tools.  The daemons which should be run vary
 plan on using "xl" as it will cause problems.  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  The installation of NetBSD should already have created devices for xen
 (xencons, xenevt), but if they are not present, create them:  (xencons, xenevt), but if they are not present, create them:
Line 332  installed 4.1 or 4.2): Line 352  installed 4.1 or 4.2):
   
 For 4.1 (and thus xm; xl is believed not to work well), add to rc.conf:  For 4.1 (and thus xm; xl is believed not to work well), add to rc.conf:
   
         xend=YES  
         xencommons=YES          xencommons=YES
           xend=YES
   
 TODO: Explain why if xm is preferred on 4.1, rc.d/xendomains has xl.  (If you are using xentools41 from before 2014-12-26, change
 Or fix the package.  rc.d/xendomains to use xm rather than xl.)
   
 For 4.2 with xm, add to rc.conf  For 4.2 with xm, add to rc.conf
   
         xend=YES  
         xencommons=YES          xencommons=YES
           xend=YES
   
 For 4.2 with xl (preferred), add to rc.conf:  For 4.2 with xl (preferred), add to rc.conf:
   
         TODO: explain if there is a xend replacement  
         xencommons=YES          xencommons=YES
           TODO: explain if there is a xend replacement
   
 TODO: Recommend for/against xen-watchdog.  TODO: Recommend for/against xen-watchdog.
   
 After you have configured the daemons and either started them or  After you have configured the daemons and either started them (in the
 rebooted, run the following (or use xl) to inspect Xen's boot  order given) or rebooted, run the following (or use xl) to inspect
 messages, available resources, and running domains:  Xen's boot messages, available resources, and running domains:
   
         # xm dmesg          # xm dmesg
         [xen's boot info]          [xen's boot info]
Line 403  and adjusts /etc. Line 423  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,  Converting from grub to /boot
 bootxx_ with installboot, /boot and /boot.cfg.  This really should be  -----------------------------
 no different than completely reinstalling boot blocks on a non-Xen  
 system.  These instructions were [TODO: will be] used to convert a system from
   grub to /boot.  The system was originally installed in February of
   2006 with a RAID1 setup and grub to boot Xen 2, and has been updated
   over time.  Before these commands, it was running NetBSD 6 i386, Xen
   4.1 and grub, much like the message linked earlier in the grub
   section.
   
           # Install mbr bootblocks on both disks. 
           fdisk -i /dev/rwd0d
           fdisk -i /dev/rwd1d
           # Install NetBSD primary boot loader (/ is FFSv1) into RAID1 components.
           installboot -v /dev/rwd0d /usr/mdec/bootxx_ffsv1
           installboot -v /dev/rwd1d /usr/mdec/bootxx_ffsv1
           # Install secondary boot loader
           cp -p /usr/mdec/boot /
           # Create boog.cfg following earlier guidance:
           menu=Xen:load /netbsd-XEN3PAE_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M
           menu=Xen.ok:load /netbsd-XEN3PAE_DOM0.ok.gz console=pc;multiboot /xen.ok.gz dom0_mem=256M
           menu=GENERIC:boot
           menu=GENERIC single-user:boot -s
           menu=GENERIC.ok:boot netbsd.ok
           menu=GENERIC.ok single-user:boot netbsd.ok -s
           menu=Drop to boot prompt:prompt
           default=1
           timeout=30
   
   TODO: actually do this and fix it if necessary.
   
 Updating Xen versions  Updating Xen versions
 ---------------------  ---------------------
Line 427  Unprivileged domains (domU) Line 473  Unprivileged domains (domU)
 This section describes general concepts about domUs.  It does not  This section describes general concepts about domUs.  It does not
 address specific domU operating systems or how to install them.  The  address specific domU operating systems or how to install them.  The
 config files for domUs are typically in /usr/pkg/etc/xen, and are  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  typically named so that the file name, domU name and the domU's host
 name match.  name match.
   
 The domU is provided with cpu and memory by Xen, configured by the  The domU is provided with cpu and memory by Xen, configured by the
Line 501  anyplace, reasonable places to store dom Line 547  anyplace, reasonable places to store dom
 (so they are near the dom0 kernel), in /usr/pkg/etc/xen (near the  (so they are near the dom0 kernel), in /usr/pkg/etc/xen (near the
 config files), or in /u0/xen (where the vdisks are).  config files), or in /u0/xen (where the vdisks are).
   
   Note that loading the domU kernel from the dom0 implies that boot
   blocks, /boot, /boot.cfg, and so on are all ignored in the domU.
 See the VPS section near the end for discussion of alternate ways to  See the VPS section near the end for discussion of alternate ways to
 obtain domU kernels.  obtain domU kernels.
   
Line 593  dom0.  This is often appropriate when ru Line 641  dom0.  This is often appropriate when ru
 TODO: NAT appears to be configured by "vif = [ '' ]".  TODO: NAT appears to be configured by "vif = [ '' ]".
   
 The MAC address specified is the one used for the interface in the new  The MAC address specified is the one used for the interface in the new
 domain.  The interface in domain0 will use this address XOR'd with  domain.  The interface in dom0 will use this address XOR'd with
 00:00:00:01:00:00.  Random MAC addresses are assigned if not given.  00:00:00:01:00:00.  Random MAC addresses are assigned if not given.
   
 Sizing domains  Sizing domains
Line 693  It is also desirable to add Line 741  It is also desirable to add
         powerd=YES          powerd=YES
   
 in rc.conf. This way, the domain will be properly shut down if  in rc.conf. This way, the domain will be properly shut down if
 `xm shutdown -R` or `xm shutdown -H` is used on the domain0.  `xm shutdown -R` or `xm shutdown -H` is used on the dom0.
   
 Your domain should be now ready to work, enjoy.  Your domain should be now ready to work, enjoy.
   
Line 744  tty to the xen console. Line 792  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/)  See possibly outdated
 or [development snapshot](http://genunix.org/) DVD image. Attach the DVD  [Solaris domU instructions](/ports/xen/howto-solaris/).
 image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem  
 image to your dom0 filesystem.  
   
     dom0# mkdir /root/solaris  
     dom0# vnconfig vnd0 osol-1002-124-x86.iso  
     dom0# mount /dev/vnd0a /mnt  
   
     ## for a 64-bit guest  
     dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris  
     dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris  
   
     ## for a 32-bit guest  
     dom0# cp /mnt/boot/x86.microroot /root/solaris  
     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.  
   
     memory = 640  
     name = 'solaris'  
     disk = [ 'phy:/dev/wd0k,0,w' ]  
     disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]  
     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.  
   
     dom0# xm create -c solaris.cfg  
     Started domain solaris  
                           v3.3.2 chgset 'unavailable'  
     SunOS Release 5.11 Version snv_124 64-bit  
     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.  
     Use is subject to license terms.  
     Hostname: opensolaris  
     Remounting root read/write  
     Probing for device nodes ...  
     WARNING: emlxs: ddi_modopen drv/fct failed: err 2  
     Preparing live image for use  
     Done mounting Live image  
             
   
 Make sure the network is configured. Note that it can take a minute for  
 the xnf0 interface to appear.  
   
     opensolaris console login: jack  
     Password: jack  
     Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008  
     jack@opensolaris:~$ pfexec sh  
     sh-3.2# ifconfig -a  
     sh-3.2# exit  
             
   
 Set a password for VNC and start the VNC server which provides the X11  
 display where the installation program runs.  
   
     jack@opensolaris:~$ vncpasswd  
     Password: solaris  
     Verify: solaris  
     jack@opensolaris:~$ cp .Xclients .vnc/xstartup  
     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.  
   
     remote$ vncviewer 172.18.2.99:1  
             
   
 It is also possible to launch the installation on a remote X11 display.  
   
     jack@opensolaris:~$ export DISPLAY=172.18.1.1:0  
     jack@opensolaris:~$ pfexec gui-install  
              
   
 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  
 and update the configuration file accordingly. Return to the guest  
 console.  
   
     jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs  
                     bootfs = 43  
     ^C  
     jack@opensolaris:~$  
              
   
 The final configuration file should look like this. Note in particular  
 the last line.  
   
     memory = 640  
     name = 'solaris'  
     disk = [ 'phy:/dev/wd0k,0,w' ]  
     vif = [ 'bridge=bridge0' ]  
     kernel = '/root/solaris/unix'  
     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.  
   
     dom0# xm destroy solaris  
     dom0# xm create -c solaris.cfg  
     Using config file "./solaris.cfg".  
     v3.3.2 chgset 'unavailable'  
     Started domain solaris  
     SunOS Release 5.11 Version snv_124 64-bit  
     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.  
     Use is subject to license terms.  
     WARNING: emlxs: ddi_modopen drv/fct failed: err 2  
     Hostname: osol  
     Configuring devices.  
     Loading smf(5) service descriptions: 160/160  
     svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .  
     Reading ZFS config: done.  
     Mounting ZFS filesystems: (6/6)  
     Creating new rsa public/private host key pair  
     Creating new dsa public/private host key pair  
   
     osol console login:  
              
   
 Using PCI devices in guest domains  
 ----------------------------------  
   
 The domain0 can give other domains access to selected PCI devices. This  
 can allow, for example, a non-privileged domain to have access to a  
 physical network interface or disk controller. However, keep in mind  
 that giving a domain access to a PCI device most likely will give the  
 domain read/write access to the whole physical memory, as PCs don't have  
 an IOMMU to restrict memory access to DMA-capable device. Also, it's not  
 possible to export ISA devices to non-domain0 domains (which means that  
 the primary VGA adapter can't be exported. A guest domain trying to  
 access the VGA registers will panic).  
   
 This functionality is only available in NetBSD-5.1 (and later) domain0  
 and domU. If the domain0 is NetBSD, it has to be running Xen 3.1, as  
 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  
 `pciback` driver in domain0. Devices passed to the domain0 via the  
 pciback.hide boot parameter will attach to `pciback` instead of the  
 usual driver. The list of devices is specified as `(bus:dev.func)`,  
 where bus and dev are 2-digit hexadecimal numbers, and func a  
 single-digit number:  
   
     pciback.hide=(00:0a.0)(00:06.0)  
   
 pciback devices should show up in the domain0's boot messages, and the  
 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  PCI passthrough: Using PCI devices in guest domains
     # USB Controller and Devices  ---------------------------------------------------
   
     # PCI USB controllers  The dom0 can give other domains access to selected PCI
     uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)  devices. This can allow, for example, a non-privileged domain to have
   access to a physical network interface or disk controller.  However,
   keep in mind that giving a domain access to a PCI device most likely
   will give the domain read/write access to the whole physical memory,
   as PCs don't have an IOMMU to restrict memory access to DMA-capable
   device.  Also, it's not possible to export ISA devices to non-dom0
   domains, which means that the primary VGA adapter can't be exported.
   A guest domain trying to access the VGA registers will panic.
   
   If the dom0 is NetBSD, it has to be running Xen 3.1, as 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 "pciback" driver in dom0.  Devices passed to the dom0 via the
   pciback.hide boot parameter will attach to "pciback" instead of the
   usual driver.  The list of devices is specified as "(bus:dev.func)",
   where bus and dev are 2-digit hexadecimal numbers, and func a
   single-digit number:
   
     # USB bus support          pciback.hide=(00:0a.0)(00:06.0)
     usb*    at uhci?  
   
     # USB Hubs  pciback devices should show up in the dom0's boot messages, and the
     uhub*   at usb?  devices should be listed in the `/kern/xen/pci` directory.
     uhub*   at uhub? port ? configuration ? interface ?  
   
     # USB Mass Storage  PCI devices to be exported to a domU are listed in the "pci" array of
     umass*  at uhub? port ? configuration ? interface ?  the domU's config file, with the format "0000:bus:dev.func".
     wd*     at umass?  
     # SCSI controllers  
     ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI  
   
     # SCSI bus support (for both ahc and umass)          pci = [ '0000:00:06.0', '0000:00:0a.0' ]
     scsibus* at scsi?  
   
     # SCSI devices  In the domU an "xpci" device will show up, to which one or more pci
     sd*     at scsibus? target ? lun ?      # SCSI disk drives  busses will attach.  Then the PCI drivers will attach to PCI busses as
     cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives  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;
   note that only the "xpci" lines are unusual.
   
           include         "arch/i386/conf/XEN3_DOMU"
   
           # Add support for PCI busses to the XEN3_DOMU kernel
           xpci* at xenbus ?
           pci* at xpci ?
   
           # 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  NetBSD as a domU in a VPS
Line 957  NetBSD as a domU in a VPS Line 872  NetBSD as a domU in a VPS
 The bulk of the HOWTO is about using NetBSD as a dom0 on your own  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  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  virtual private server where you do not control or have access to the
 dom0.  dom0.  This is not intended to be an exhaustive list of VPS providers;
   only a few are mentioned that specifically support NetBSD.
   
 TODO: Perhaps reference panix, prmgr, amazon as interesting examples.  VPS operators provide varying degrees of access and mechanisms for
   configuration.  The big issue is usually how one controls which kernel
   is booted, because the kernel is nominally in the dom0 filesystem (to
   which VPS users do not normally have acesss).  A second issue is how
   to install NetBSD.
   A VPS user may want to compile a kernel for security updates, to run
   npf, run IPsec, or any other reason why someone would want to change
   their kernel.
   
   One approach is to have an adminstrative interface to upload a kernel,
   or to select from a prepopulated list.  Other approaches are pygrub
   (deprecated) and pvgrub, which are ways to have a bootloader obtain a
   kernel from the domU filesystem.  This is closer to a regular physical
   computer, where someone who controls a machine can replace the kernel.
   
   A second issue is multiple CPUs.  With NetBSD 6, domUs support
   multiple vcpus, and it is typical for VPS providers to enable multiple
   CPUs for NetBSD domUs.
   
 TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel  pygrub
 from the domU filesystem.  -------
   
   pygrub runs in the dom0 and looks into the domU filesystem.  This
   implies that the domU must have a kernel in a filesystem in a format
   known to pygrub.  As of 2014, pygrub seems to be of mostly historical
   interest.
   
   pvgrub
   ------
   
   pvgrub is a version of grub that uses PV operations instead of BIOS
   calls.  It is booted from the dom0 as the domU kernel, and then reads
   /grub/menu.lst and loads a kernel from the domU filesystem.
   
   [Panix](http://www.panix.com/) lets users use pvgrub.  Panix reports
   that pvgrub works with FFsv2 with 16K/2K and 32K/4K block/frag sizes
   (and hence with defaults from "newfs -O 2").  See [Panix's pvgrub
   page](http://www.panix.com/v-colo/grub.html), which describes only
   Linux but should be updated to cover NetBSD :-).
   
   [prgmr.com](http://prgmr.com/) also lets users with pvgrub to boot
   their own kernel.  See then [prgmr.com NetBSD
   HOWTO](http://wiki.prgmr.com/mediawiki/index.php/NetBSD_as_a_DomU)
   (which is in need of updating).
   
   It appears that [grub's FFS
   code](http://xenbits.xensource.com/hg/xen-unstable.hg/file/bca284f67702/tools/libfsimage/ufs/fsys_ufs.c)
   does not support all aspects of modern FFS, but there are also reports
   that FFSv2 works fine.  At prgmr, typically one has an ext2 or FAT
   partition for the kernel with the intent that grub can understand it,
   which leads to /netbsd not being the actual kernel.  One must remember
   to update the special boot partiion.
   
   Amazon
   ------
   
   TODO: add link to NetBSD amazon howto.
   
 Using npf  Using npf
 ---------  ---------
Line 970  Using npf Line 939  Using npf
 In standard kernels, npf is a module, and thus cannot be loadeed in a  In standard kernels, npf is a module, and thus cannot be loadeed in a
 DOMU kernel.  DOMU kernel.
   
 TODO: explain how to compile npf into a custom kernel, answering:  TODO: explain how to compile npf into a custom kernel, answering (but
   note that the problem was caused by not booting the right kernel):
 http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html  http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html
   
   TODO items for improving NetBSD/xen
   ===================================
   
   * Package Xen 4.4.
   * Get PCI passthrough working on Xen 4.2 (or 4.4).
   * Get pvgrub into pkgsrc, either via xentools or separately.
   * grub
     * Check/add support to pkgsrc grub2 for UFS2 and arbitrary
       fragsize/blocksize (UFS2 support may be present; the point is to
       make it so that with any UFS1/UFS2 filesystem setup that works
       with NetBSD grub will also work).
       See [pkg/40258](http://gnats.netbsd.org/40258).
     * Push patches upstream.
     * Get UFS2 patches into pvgrub.
   * Add support for PV ops to a version of /boot, and make it usable as
     a kernel in Xen, similar to pvgrub.

Removed from v.1.49  
changed lines
  Added in v.1.76


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