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version 1.77, 2015/01/17 01:36:44	version 1.91, 2015/03/04 01:32:16
Line 92 reasonable although trailing-edge choice	Line 92 reasonable although trailing-edge choice
xenkernel42 provides Xen 4.2. This is maintained by Xen, but old as	xenkernel42 provides Xen 4.2. This is maintained by Xen, but old as
of 2014-12.	of 2014-12.

	xenkernel45 provides Xen 4.5. This is new to pkgsrc as of 2015-01 and
	not yet recommended for other than experimental/testing use.

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	Note that NetBSD support is called XEN3. It works with Xen 3 and Xen
4.2 because the hypercall interface has been stable.	4 because the hypercall interface has been stable.

Xen command program	Xen command program
-------------------	-------------------

Early Xen used a program called "xm" to manipulate the system from the	Early Xen used a program called xm to manipulate the system from the
dom0. Starting in 4.1, a replacement program with similar behavior	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	called xl is provided, but it does not work well in 4.1. In 4.2, both
the last version that has "xm".	xm and xl work fine. 4.4 is the last version that has xm. You must
	choose one or the other, because it affects which daemons you run.

NetBSD	NetBSD
------	------
Line 138 running an i386 NetBSD kernel as a domU,	Line 142 running an i386 NetBSD kernel as a domU,
(Note that emacs (at least) fails if run on i386 with PAE when built	(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.)	without, and vice versa, presumably due to bugs in the undump code.)

	Stability
	---------

	Mostly, NetBSD as a dom0 or domU is quite stable.
	However, there are some open PRs indicating problems.

	- [PR 48125](http://gnats.netbsd.org/48125)
	- [PR 47720](http://gnats.netbsd.org/47720)

	Note also that there are issues with sparse vnd(4) instances, but
	these are not about Xen.

Recommendation	Recommendation
--------------	--------------

Line 340 to configure the dom0 tools. The daemon	Line 356 to configure the dom0 tools. The daemon
with Xen version and with whether one is using xm or xl. Note that	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	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	using "xm". Do NOT enable xend if you plan on using "xl" as it will
cause problems.	cause problems. Running xl without xencommons=YES (and starting it)
	will result in a hang (so don't do that; follow the HOWTO!).

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 368 For 4.2 with xm, add to rc.conf	Line 385 For 4.2 with xm, add to rc.conf
xencommons=YES	xencommons=YES
xend=YES	xend=YES

For 4.2 with xl (preferred), add to rc.conf:	For 4.2 with xl, add to rc.conf:

	xencommons=YES
	TODO: explain if there is a xend replacement

	For 4.5 (and thus with xl), add to rc.conf:

xencommons=YES	xencommons=YES
TODO: explain if there is a xend replacement	TODO: explain if there is a xend replacement
Line 376 For 4.2 with xl (preferred), add to rc.c	Line 398 For 4.2 with xl (preferred), add to rc.c
TODO: Recommend for/against xen-watchdog.	TODO: Recommend for/against xen-watchdog.

After you have configured the daemons and either started them (in the	After you have configured the daemons and either started them (in the
order given) or rebooted, run the following (or use xl) to inspect	order given) or rebooted, use xm or xl to inspect Xen's boot messages,
Xen's boot messages, available resources, and running domains:	available resources, and running domains. An example with xm follows:

# xm dmesg	# xm dmesg
[xen's boot info]	[xen's boot info]
Line 387 Xen's boot messages, available resources	Line 409 Xen's boot messages, available resources
Name Id Mem(MB) CPU State Time(s) Console	Name Id Mem(MB) CPU State Time(s) Console
Domain-0 0 64 0 r---- 58.1	Domain-0 0 64 0 r---- 58.1

	With xl, the commands are the same, and the output may be slightly
	different. TODO: add example output for xl before the xm example,
	after confirming on 4.2 and resolving the TODO about rc.conf.

	### Issues with xencommons

	xencommons starts xenstored, which stores data on behalf of dom0 and
	domUs. It does not currently work to stop and start xenstored.
	Certainly all domUs should be shutdown first, following the sort order
	of the rc.d scripts. However, the dom0 sets up state with xenstored,
	and is not notified when xenstored exits, leading to not recreating
	the state when the new xenstored starts. Until there's a mechanism to
	make this work, one should not expect to be able to restart xenstored
	(and thus xencommons). There is currently no reason to expect that
	this will get fixed any time soon.

anita (for testing NetBSD)	anita (for testing NetBSD)
--------------------------	--------------------------

With the setup so far, one should be able to run anita (see	With the setup so far (assuming 4.2/xl), one should be able to run
pkgsrc/sysutils/py-anita) to test NetBSD releases, by doing (as root,	anita (see pkgsrc/misc/py-anita) to test NetBSD releases, by doing (as
because anita must create a domU):	root, because anita must create a domU):

anita --vmm=xm test file:///usr/obj/i386/	anita --vmm=xl test file:///usr/obj/i386/

Alternatively, one can use --vmm=xl to use xl-based domU creation instead.	Alternatively, one can use --vmm=xm to use xm-based domU creation
TODO: check this.	instead (and must, on Xen <= 4.1). TODO: confirm that anita xl really works.

Xen-specific NetBSD issues	Xen-specific NetBSD issues
--------------------------	--------------------------

Line 472 correct set of daemons. Ensure that the	Line 510 correct set of daemons. Ensure that the
for the new version.	for the new version.


	Running Xen under qemu
	----------------------

	The astute reader will note that this section is somewhat twisted.
	However, it can be useful to run Xen under qemu either because the
	version of NetBSD as a dom0 does not run on the hardware in use, or to
	generate automated test cases involving Xen.

	In 2015-01, the following combination was reported to mostly work:

	host OS: NetBSD/amd64 6.1.4
	qemu: 2.2.0 from pkgsrc
	Xen kernel: xenkernel42-4.2.5nb1 from pkgsrc
	dom0 kernel: NetBSD/amd64 6.1.5
	Xen tools: xentools42-4.2.5 from pkgsrc

	See [PR 47720](http://gnats.netbsd.org/47720) for a problem with dom0
	shutdown.

Unprivileged domains (domU)	Unprivileged domains (domU)
===========================	===========================

Line 532 domain, and see if it has finished stopp	Line 589 domain, and see if it has finished stopp
xm console foo	xm console foo
xm create -c foo	xm create -c foo
xm shutdown foo	xm shutdown foo
xm list	xm list

Typing ^] will exit the console session. Shutting down a domain is	Typing ^] will exit the console session. Shutting down a domain is
equivalent to pushing the power button; a NetBSD domU will receive a	equivalent to pushing the power button; a NetBSD domU will receive a
Line 592 create an empty 4G virtual disk, simply	Line 649 create an empty 4G virtual disk, simply

dd if=/dev/zero of=foo-xbd0 bs=1m count=4096	dd if=/dev/zero of=foo-xbd0 bs=1m count=4096

	Do not use qemu-img-xen, because this will create sparse file. There
	have been recent (2015) reports of sparse vnd(4) devices causing
	lockups, but there is apparently no PR.

With the lvm style, one creates logical devices. They are then used	With the lvm style, one creates logical devices. They are then used
similarly to vnds. TODO: Add an example with lvm.	similarly to vnds. TODO: Add an example with lvm.

Line 669 shutdown, in rc.conf add:	Line 730 shutdown, in rc.conf add:

xendomains="foo bar"	xendomains="foo bar"

TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm	Note that earlier versions of the xentools41 xendomains rc.d scripth
on 4.1. Or fix the xentools41 package to have xm	usd xl, when one should use xm with 4.1.

Creating specific unprivileged domains (domU)	Creating specific unprivileged domains (domU)
=============================================	=============================================
Line 941 TODO: add link to NetBSD amazon howto.	Line 1002 TODO: add link to NetBSD amazon howto.
Using npf	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 loaded in a
DOMU kernel.	DOMU kernel.

TODO: explain how to compile npf into a custom kernel, answering (but	TODO: explain how to compile npf into a custom kernel, answering (but

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