Diff for /wikisrc/ports/xen/howto.mdwn between versions 1.188 and 1.197

version 1.188, 2020/11/15 15:36:35 version 1.197, 2021/03/03 23:17:59
Line 107  NetBSD 8 and up support PV and HVM modes Line 107  NetBSD 8 and up support PV and HVM modes
   
 Support for PVHVM and PVH is available only in NetBSD-current.  Support for PVHVM and PVH is available only in NetBSD-current.
   
 NetBSD as a dom0 does not run SMP, because some drivers are not yet  NetBSD up to and including NetBSD 9 as a dom0 does not run SMP,
 safe for this.  \todo Link to more information about what needs work.  because some drivers are not yet safe for this.  NetBSD-current
   supports SMP in dom0.
   
 NetBSD, when run as a domU, can and does typically run SMP.  NetBSD, when run as a domU, can and does typically run SMP.
   
 Note: NetBSD support is called XEN3.  However, it does support Xen 4,  Note that while Xen 4.13 is current, the kernel support is still
 because the hypercall interface has remained identical.  called XEN3, because the hypercall interface has not changed
   significantly.
   
 # Creating a NetBSD dom0  # Creating a NetBSD dom0
   
 In order to install a NetBSD as a dom0, one must first install a normal  In order to install a NetBSD as a dom0, one first installs a normal
 NetBSD system, and then pivot the install to a dom0 install by changing  NetBSD system, and then pivot the install to a dom0 install by
 the kernel and boot configuration.  changing the kernel and boot configuration.
   
 In 2018-05, trouble booting a dom0 was reported with 256M of RAM: with  In 2018-05, trouble booting a dom0 was reported with 256M of RAM: with
 512M it worked reliably.  This does not make sense, but if you see  512M it worked reliably.  This does not make sense, but if you see
Line 127  In 2018-05, trouble booting a dom0 was r Line 129  In 2018-05, trouble booting a dom0 was r
   
 ## Installation of NetBSD  ## Installation of NetBSD
   
 [Install NetBSD/amd64](/guide/inst/)  [Install NetBSD/amd64](/guide/inst/) just as you would if you were not
 just as you would if you were not using Xen.  using Xen.  Therefore, use the most recent release, or a build from
 Therefore, use the most recent release, or a build from the most recent stable branch.  the most recent stable branch.  Alternatively, use -current, being
   mindful of all the usual caveats of lower stability of current, and
   likely a bit more so.
   
 ## Installation of Xen  ## Installation of Xen
   
   ### Building Xen
   
 Use the most recent version of Xen in pkgsrc, unless the DESCR says that it is not suitable.  Use the most recent version of Xen in pkgsrc, unless the DESCR says that it is not suitable.
 Therefore, choose 4.13.  Therefore, choose 4.13.
 In the dom0, install xenkernel413 and xentools413 from pkgsrc.  In the dom0, install xenkernel413 and xentools413 from pkgsrc.
Line 144  where the boot process will be able to f Line 150  where the boot process will be able to f
 # cp -p /usr/pkg/xen413-kernel/xen.gz /  # cp -p /usr/pkg/xen413-kernel/xen.gz /
 """]]  """]]
   
 Then, place a NetBSD XEN3_DOM0 kernel in the `/` directory. Such kernel  Then, place a NetBSD XEN3_DOM0 kernel in the `/` directory. Such
 can either be compiled manually, or downloaded from the NetBSD FTP, for  kernel can either be taken from a local release build.sh run, compiled
 example at:  manually, or downloaded from the NetBSD FTP, for example at:
   
 [[!template id=programlisting text="""  [[!template id=programlisting text="""
 ftp.netbsd.org/pub/NetBSD/NetBSD-9.1/amd64/binary/kernel/netbsd-XEN3_DOM0.gz  ftp.netbsd.org/pub/NetBSD/NetBSD-9.1/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
 """]]  """]]
   
 Add a line to /boot.cfg to boot Xen:  ### Configuring booting
   
   Read boot.cfg(8) carefully.  Add lines to /boot.cfg to boot Xen:
   
 [[!template id=filecontent name="/boot.cfg" text="""  [[!template id=filecontent name="/boot.cfg" text="""
 menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=512M  menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=512M
   menu=Xen single user:load /netbsd-XEN3_DOM0.gz console=pc -s;multiboot /xen.gz dom0_mem=512M
 """]]  """]]
   
 This specifies that the dom0 should have 512MB of ram, leaving the rest  This specifies that the dom0 should have 512MB of ram, leaving the rest
 to be allocated for domUs.  to be allocated for domUs.
   
 NB: This says add, not replace, so that you will be able to boot a  NB: This says add, not replace, so that you will be able to more
 NetBSD kernel without Xen.  Once Xen boots ok, you may want to set it  easily boot a NetBSD kernel without Xen.  Once Xen boots ok, you may
 as default.  want to set it as default.  It is highly likely that you will have
   trouble at some point, and keeping an up-to-date GENERIC for use in
 To use a serial console, add settings as follows:  fixing problems is the standard prudent approach.
   
   \todo Explain why rndseed is not set with Xen as part of the dom0
   subconfiguration.
   
   Beware that userconf statements must be attached to the dom0 load, and
   may not be at top-level, because then they would try to configure the
   hypervisor, if there is a way to pass them via multiboot .  It appears
   that adding `userconf=pckbc` to `/boot.cfg` causes Xen to crash very
   early with a heap overflow.
   
   ### Console selection
   
   See boot_console(8).  Understand that you should start from a place of
   having console setup correct for booting GENERIC before trying to
   configure Xen.
   
   Generally for GENERIC, one sets the console in bootxx_ffsv1 or
   equivalent, and this is passed on to /boot (where one typically does
   not set the console).  This configuration of bootxx_ffsv1 should also
   be in place for Xen systems, to allow seeing messages from /boot and
   use of a keyboard to select a line from the menu.  And, one should
   have a working boot path to GENERIC for rescue situations.
   
   With GENERIC, the boot options are passed on to /netbsd, but there is
   currently no mechanism to pass these via multiboot to the hypervisor.
   Thus, in addition to configuring the console in the boot blocks, one
   must also configure it for Xen.
   
   By default, the hypervisor (Xen itself) will use some sort of vga
   device as the console, much like GENERIC uses by default.  The vga
   console is relinquished at the conclusion of hypervisor boot, before
   the dom0 is started.  Xen when using a vga console does not process
   console input.
   
   The hypervisor can be configured to use a serial port console, e.g.
 [[!template id=filecontent name="/boot.cfg" text="""  [[!template id=filecontent name="/boot.cfg" text="""
 menu=Xen:load /netbsd-XEN3_DOM0.gz;multiboot /xen.gz dom0_mem=512M console=com1 com1=9600,8n1  menu=Xen:losad /netbsd-XEN3_DOM0.gz console=com0;multiboot /xen.gz dom0_mem=512M console=com1 com1=9600,8n1
 """]]  """]]
   This example uses the first serial port (Xen counts from 1; this is
   what NetBSD would call com0), and sets speed and parity.  (The dom0 is
   then configured to use the same serial port in this example.)
   
   With the hypervisor configured for a serial console, it can get input,
   and there is a notion of passing this input to the dom0.  \todo
   Explain why, if Xen has a serial console, the dom0 console is
   typically also configured to open that same serial port, instead of
   getting the passthrough input via the xen console.
   
   One also configures the console for the dom0.  While one might expect
   console=pc to be default, following behavior of GENERIC, a hasty read
   of the code suggests there is no default and booting without a
   selected console might lead to a panic.  Also, there is merit in
   explicit configuration.  Therefore the standard approach is to place
   console=pc as part of the load statement for the dom0 kernel, or
   alternatively console=com0.
   
   The NetBSD dom0 kernel will attach xencons(4) (the man page does not
   exist), but this is not used as a console.  It is used to obtain the
   messages from the hypervisor's console; run `xl dmesg` to see them.
   
 which will use the first serial port for Xen (which counts starting  ### Tuning
 from 1, unlike NetBSD which counts starting from 0), forcing  
 speed/parity.  Because the NetBSD command line lacks a  
 "console=pc" argument, it will use the default "xencons" console device,  
 which directs the console I/O through Xen to the same console device Xen  
 itself uses (in this case, the serial port).  
   
 In an attempt to add performance, one can also add `dom0_max_vcpus=1 dom0_vcpus_pin`,  In an attempt to add performance, one can also add `dom0_max_vcpus=1 dom0_vcpus_pin`,
 to force only one vcpu to be provided (since NetBSD dom0 can't use  to force only one vcpu to be provided (since NetBSD dom0 can't use
Line 184  more) and to pin that vcpu to a physical Line 243  more) and to pin that vcpu to a physical
 [many boot options](http://xenbits.xenproject.org/docs/4.13-testing/misc/xen-command-line.html),  [many boot options](http://xenbits.xenproject.org/docs/4.13-testing/misc/xen-command-line.html),
 and other than dom0 memory and max_vcpus, they are generally not  and other than dom0 memory and max_vcpus, they are generally not
 necessary.  necessary.
   \todo Revisit this advice with current.
   \todo Explain if anyone has ever actually measured that this helps.
   
   ### rc.conf
   
 Ensure that the boot scripts installed in  Ensure that the boot scripts installed in
 `/usr/pkg/share/examples/rc.d` are in `/etc/rc.d`, either because you  `/usr/pkg/share/examples/rc.d` are in `/etc/rc.d`, either because you
Line 198  xencommons=YES Line 261  xencommons=YES
   
 \todo Recommend for/against xen-watchdog.  \todo Recommend for/against xen-watchdog.
   
   ### Testing
   
 Now, reboot so that you are running a DOM0 kernel under Xen, rather  Now, reboot so that you are running a DOM0 kernel under Xen, rather
 than GENERIC without Xen.  than GENERIC without Xen.
   
Line 234  this will get fixed any time soon. Line 299  this will get fixed any time soon.
 There are (at least) two additional things different about NetBSD as a  There are (at least) two additional things different about NetBSD as a
 dom0 kernel compared to hardware.  dom0 kernel compared to hardware.
   
 One is that the module ABI is different because some of the #defines  One is that through NetBSD 9 the module ABI is different because some
 change, so one must build modules for Xen.  As of netbsd-7, the build  of the #defines change, so there are separate sets of modules in
 system does this automatically.  /stand.  In NetBSD-current, there is only one set of modules.
   
 The other difference is that XEN3_DOM0 does not have exactly the same  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  options as GENERIC.  While it is debatable whether or not this is a
Line 260  version supports the version of Xen you  Line 325  version supports the version of Xen you 
 replaces the kernel and reboots, and then overlays userland binaries  replaces the kernel and reboots, and then overlays userland binaries
 and adjusts `/etc`.  and adjusts `/etc`.
   
 Note that one must update both the non-Xen kernel typically used for  Note that one should update both the non-Xen kernel typically used for
 rescue purposes and the DOM0 kernel used with Xen.  rescue purposes, as well as the DOM0 kernel used with Xen.
   
 ## anita (for testing NetBSD)  ## anita (for testing NetBSD)
   
Line 273  root, because anita must create a domU): Line 338  root, because anita must create a domU):
 anita --vmm=xl test file:///usr/obj/i386/  anita --vmm=xl test file:///usr/obj/i386/
 """]]  """]]
   
 ## Converting from grub to /boot (historical note)  
   
 These instructions are provided only to help people using grub, which  
 used to be the normal approach.  
   
 These instructions were 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.  
   
 [[!template id=programlisting text="""  
 # 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 boot.cfg following earlier guidance:  
 menu=Xen:load /netbsd-XEN3PAE_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=512M  
 menu=Xen.ok:load /netbsd-XEN3PAE_DOM0.ok.gz console=pc;multiboot /xen.ok.gz dom0_mem=512M  
 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  
 """]]  
   
 # Unprivileged domains (domU)  # Unprivileged domains (domU)
   
 This section describes general concepts about domUs.  It does not  This section describes general concepts about domUs.  It does not
Line 380  file by "memory = N" (in megabytes).  In Line 412  file by "memory = N" (in megabytes).  In
 sum of the the memory allocated to the dom0 and all domUs must be less  sum of the the memory allocated to the dom0 and all domUs must be less
 than the available memory.  than the available memory.
   
 Xen also provides a "balloon" driver, which can be used to let domains  ## Balloon driver
 use more memory temporarily.  
   Xen provides a `balloon` driver, which can be used to let domains use
   more memory temporarily.
   
   \todo Explain how to set up a aystem to use the balloon scheme in a
   useful manner.
   
 ## Virtual disks  ## Virtual disks
   
Line 522  and the pseudo-terminals. These can be f Line 559  and the pseudo-terminals. These can be f
   
 Finally, all screens must be commented out from `/etc/wscons.conf`.  Finally, all screens must be commented out from `/etc/wscons.conf`.
   
 It is also desirable to add  One should also run `powerd` in a domU, but this should not need
   configuring.  With powerd, the domain will run a controlled shutdown
         powerd=YES  if `xl shutdown -R` or `xl shutdown -H` is used on the dom0, via
   receiving a synthetic `power button pressed` signal.  In 9 and
 in rc.conf. This way, the domain will be properly shut down if  current, `powerd` is run by default under Xen kernels (or if ACPI is
 `xl shutdown -R` or `xl shutdown -H` is used on the dom0.  present), and it can be added to rc.conf if not.
 \todo Check the translation to xl.  
   
 It is not strictly necessary to have a kernel (as /netbsd) in the domU  It is not strictly necessary to have a kernel (as /netbsd) in the domU
 file system.  However, various programs (e.g. netstat) will use that  file system.  However, various programs (e.g. netstat) will use that
Line 541  missing with Xen.) Line 577  missing with Xen.)
 Note that NetBSD by default creates only xbd[0123].  If you need more  Note that NetBSD by default creates only xbd[0123].  If you need more
 virtual disks in a domU, run e.g. "./MAKEDEV xbd4" in the domU.  virtual disks in a domU, run e.g. "./MAKEDEV xbd4" in the domU.
   
 ## Creating a Linux domU  ## Creating a Linux PV 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 586  tty to the xen console. Line 622  tty to the xen console.
   
 ## Creating a NetBSD HVM domU  ## Creating a NetBSD HVM domU
   
 Use type='hmv', probably.  Use a GENERIC kernel within the disk image.  Use type='hvm', probably.  Use a GENERIC kernel within the disk image.
   
 ## Creating a NetBSD PVH domU  ## Creating a NetBSD PVH domU
   
 Use type='pvh'.  This only works with a current kernel in the domU.
   
   Use type='pvh'.  Probably, use a GENERIC kernel within the disk image,
   which in current has PV support.
   
 \todo Explain where the kernel comes from.  \todo Verify.
   
   \todo Verify if one can have current PVH domU on a 9 dom0.
   
 ## Creating a Solaris domU  ## Creating a Solaris domU
   
 See possibly outdated  See possibly outdated
 [Solaris domU instructions](/ports/xen/howto-solaris/).  [Solaris domU instructions](/ports/xen/howto-solaris/).
   
   
 ## PCI passthrough: Using PCI devices in guest domains  ## PCI passthrough: Using PCI devices in guest domains
   
 NB: PCI passthrough only works on some Xen versions and as of 2020 it  NB: PCI passthrough only works on some Xen versions and as of 2020 it
 is not clear that it works on any version in pkgsrc.  Reports  is not clear that it works on any version in pkgsrc.  \todo Reports
 confirming or denying this notion should be sent to port-xen@.  confirming or denying this notion should be sent to port-xen@.
   
 The dom0 can give other domains access to selected PCI  The dom0 can give other domains access to selected PCI
Line 674  note that only the "xpci" lines are unus Line 713  note that only the "xpci" lines are unus
         cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives          cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
   
   
 # Specific Issues  # Miscellaneous Information
   
   ## Nesting under Linux KVM
   
   It is possible to run a Xen and a NetBSD dom0 under Linux KVM.  One
   can enable virtio in the dom0 for greater speed.
   
   ## Other nesting
   
   In theory, any full emulation should be able to run Xen and a NetBSD
   dom0.  The HOWTO does not currently have information about Xen XVM
   mode, nvmm, qemu, Virtualbox, etc.
   
 ## domU  ## NetBSD 5 as domU
   
 [NetBSD 5 is known to panic.](http://mail-index.netbsd.org/port-xen/2018/04/17/msg009181.html)  [NetBSD 5 is known to panic.](http://mail-index.netbsd.org/port-xen/2018/04/17/msg009181.html)
 (However, NetBSD 5 systems should be updated to a supported version.)  (However, NetBSD 5 systems should be updated to a supported version.)

Removed from v.1.188  
changed lines
  Added in v.1.197


CVSweb for NetBSD wikisrc <wikimaster@NetBSD.org> software: FreeBSD-CVSweb