HOWTO: QEMU on FreeBSD

[vermaden]

I wrote short qemu howto install/usage on FreeBSD as host os, and in this example with Win2000 as guest os.

changelog:

1. removed useless /etc/qemu-ifup script [it was used in older versions of qemu with tap/bridge interfaces]
2. added info about sound emumation inside qemu OS.
3. removed HACKS_CIRRUS from options [thx to scottro sugestion], reason here: http://forums.bsdnexus.com/viewtopic...d=14036#p14036
4. sometimes OS installation requires unload of kqemu. short: install without kqemu and the use with kqemu

Install qemu with options showed below:

# cd /usr/ports/emulators/qemu && make install clean

Options for qemu:
 [X] KQEMU          Build with (alpha!) accelerator module
 [ ] HACKS_CIRRUS   Large display speedup (buggy!)
 [ ] RTL8139_TIMER  allow use of re(4) nic with FreeBSD guests
 [ ] SAMBA          samba dependency (for -smb)
 [X] SDL            SDL/X dependency (graphical output)
 [X] CDROM_DMA      IDE CDROM DMA

install and configure sudo:

# cd /usr/ports/security/sudo && make install clean

sudo config:

# cat > /usr/local/etc/sudoers << EOF
root            ALL=(ALL) ALL
username        ALL=(ALL) NOPASSWD: ALL
EOF

username is YOU.

load needed modules:

# sudo kldload aio
# sudo kldload kqemu

create Windows2000 install CD image, use cat or dd:

% cat /dev/acd0 > ~/qemu/win2k.iso
% dd bs=2048 if=/dev/acd0 of=~/qemu/win2k.iso

create qemu image for new OS:

% qemu-img create -f qcow2 ~/qemu/win2000.img 4G

install new os, Windows2000 in our example:

% qemu -boot d -hda ~/qemu/win2000.img -m 128 -cdrom ~/qemu/win2k.iso -win2k-hack -localtime

if You have any problems while installing the OS then unload kqemu module and install again, then after install, load the kqemu module again:

% sudo kldunload kqemu
% qemu -boot d -hda ~/qemu/win2000.img -m 128 -cdrom ~/qemu/win2k.iso -win2k-hack -localtime
% sudo kldload kqemu

typical usage of OS under qemu:

% qemu -hda ~/qemu/win2000.img -m 256 -localtime

typical usage of OS under qemu in snapshot mode [to commit made changes hit left_CTRL+left_ALT+2 and type commit]:

% qemu -hda ~/qemu/win2000.img -m 256 -localtime -snapshot

1. to switch focus between qemu mouse focus and X11 mouse focus use: left_CTRL+left_ALT
2. to ensure that You use kqemu kernel module in user mode hit left_CTRL+left_ALT+2 and type info kqemu, if everything is ok You will see:

kqemu support: enabled for user code

if not You will see:

kqemu support: disabled

if disabled it will work, but terribly slow, You will be running at Pentium 75 speed at host with CPU AthlonXP 1.66GHz.
3. to switch between qemu console and qemu os emualtion use left_CTRL+left_ALT+2 to go to console and left_CTRL+left_ALT+1 to back to emulation.
4. enabling network on emulated os, use DHCP configuration inside emulated os to get automatic IP adress 10.x.x.x

after You quit You os inside emulated os, or by qemu console left_CTRL+left_ALT+2 and type quit use this command to launch again Your emulated OS:

% qemu -hda ~/qemu/win2000.img -m 256 -localtime

How to have sound in qemu OS, You just need to launch qemu the way I listed above, only with -soundhw sb16 or -soundhw es1370 to emulate Sound Blaster 16, or Sound Blaster 128. You can also enable standart annoying BEEP with -soundhw pcspk. You can also enable all three of them like that: -soundhw sb16,es1370,pcspk, or just BEEP + one of them: -soundhw es1370,pcspk, examples

% qemu -hda ~/qemu/win2000.img -m 256 -localtime -soundhw pcspk

% qemu -hda ~/qemu/win2000.img -m 256 -localtime -soundhw es1370,pcspk

% qemu -hda ~/qemu/win2000.img -m 256 -localtime -soundhw es1370,pcspk,sb16

fluxbox add-on:
in ~/.fluxbox/apps:

# qemu
[app] (class=SDL_App)
  [Workspace]  {2}
  [Deco]       {BORDER}
[end]

resources:

man qemu-img
man qemu
man aio
man dd
man cat
http://kidsquid.com/cgi-bin/moin.cgi/QuickStartGuide
http://qemu-forum.ipi.fi/qemu-snapshots/
http://qemu-forum.ipi.fi/
http://qemu.org/user-doc.html
http://en.wikipedia.org/wiki/QEMU


The same schema works for Solaris 10 and WindowsXP, You only do not use -win2k-hack.

feel free to point errors, typo and Your hints/suggestions here.

[Bitweiler]

Hey can I setup qemu up on NetBSD this way as well? I never emulation software before so I'm green ;-)

[Oko]

Originally Posted by Bitweiler

Hey can I setup qemu up on NetBSD this way as well? I never emulation software before so I'm green ;-)

Of course. The real qestion is why would you want to use Qemu on NetBSD when you have Xen? NetBSD has by a mile best support as a host OS for virtualization of any BSD.

[Bitweiler]

Originally Posted by Oko

Of course. The real qestion is why would you want to use Qemu on NetBSD when you have Xen? NetBSD has by a mile best support as a host OS for virtualization of any BSD.

Because I don't know or understand the hardware requirements to run Xen.
Are their any memory requirements? I have only 256MB on my machine so would
Xen run on my machine?

[TerryP]

If you only have 256MB for both NetBSD/X, adding QEMU is probably not a great idea.

[Bitweiler]

what about xen then

[Bitweiler]

Originally Posted by TerryP

If you only have 256MB for both NetBSD/X, adding QEMU is probably not a great idea.

Why is that? I use a very light window manager known as stumpwm

[TerryP]

Ok, here is an example:

Windows XP requires a minimal of 64MB of RAM; 128MB is recommended (although how anyone could live with that on XP, is beyond me). So let us say, QEMU will be allowed 96MB of memory for running an Windows XP image. Let us further postulate, that between stumpwm and QEMU itself, a further 4MB of memory is consumed (fair enough? This will probably be a bit worse, depending on the size of the disk image used with QEMU).

This leaves 156MB of memory free, not deducting memory space used by the Kernel, hardware resources, or incurred by file system related operations (a background fsck perhaps?).


You will have to be running the X Windows System. A standard X.Org installation I believe, maps part or all of the gfx cards memory into it's own address space where possible; so memory usage on X.Org should be less then most things could ever report; I'm not familiar with NetBSDs X setup, but assume it would be similiar to normal X.Org/Xenocara. So, let us say at least 20MB of system memory for X. If your graphics card uses shared memory, like several (cheaper) ATI Xpress and Intel GMA cards do; that will increase the drain on system memory. X also should be caching image data used by programs, so that out to keep its memory usage lower....


So in reality, you've got closer to < 2/3 your memory to run other applications in. The exact memory used by programs is very hard to gauge, and the figures I've given are for the sake of *example* only. Needless to say, running things like OpenOffice, MS Office, Flash player, Mozilla, running a 3D game, encoding/decoding video, or building anything from ports or with GCC -- will further reduce your memory closer to swap space by a 'nice chunk'. In short: it helps drains system resources, which depending on your needs could someday become a problem sooner then later. FreeBSD is pretty efficient with it's usage of memory IMHO, but not always wise to push it to low memory situations. That is why I said, 'If you only have 256MB for both NetBSD/X, adding QEMU is probably not a great idea.' If one wants to run multiple OSes at once.... oy: much higher chance of getting into SWAP.


Running Windows in QEMU with 96MB of RAM available to it, plus MS Office and IE6; alone would probably push XP into using SWAP file on the disk image. Most Linux or BSD systems, you'd want at least 64MB for QEMU... but ya get my point.

You should really test it out before you commit to it, if you have a real need for using it in such a configuration; rather then a passing fancy.



--> That is my 2 cents.

[phoenix]

Originally Posted by Bitweiler

Because I don't know or understand the hardware requirements to run Xen.
Are their any memory requirements? I have only 256MB on my machine so would
Xen run on my machine?

You need at least 128 M to run the Xen dom0 (the management domain). If you want to run Windows, you also need a CPU that supports hardware virtualisation (Intel VT or AMD SVM). Then you need however much RAM the virtual OS requires (256 MB at least for Windows XP).

You really should not run any kind of VM software on a system with less than 512 MB of RAM.

Personally, I recommend 1 GHz of CPU power and 1 GB of RAM per VM as a starting point.

[vermaden]

Originally Posted by phoenix

You need at least 128 M to run the Xen dom0 (the management domain).

Official NetBSD Xen HOWTO states that 64MB for dom0 is ok:
http://www.netbsd.org/ports/xen/howto.html

(...)
# 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 3.0 / 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
(...)

... but IMHO 512-1024MB will be a good start point for virtualization.

[Mr-Biscuit]

Add for x86_64/amd64 hosts.

# kldload kqemu aio if_tap if_bridge
# sysctl net.link.tap.user_open=1
# ifconfig tap0 create
# ifconfig bridge0 create

## example from my computer##
vi /etc/devfs.rules

#BiscuitBox Rules
#
[biscuitbox_rules=100]
add path 'acd*' mode 666
#add path 'cd*' mode 666
#own tap0 moleque:moleque <-- remove the # from this line to where it looks like this:
vi /etc/devfs.rules

#BiscuitBox Rules
#
[biscuitbox_rules=100]
add path 'acd*' mode 666
#add path 'cd*' mode 666
own tap0 moleque:moleque-->
Save changes and exit.

Jurgen suggested
" Or if you really want to run qemu as root use something like kdesu to
allow root to access your X display, or just do the following `hack':
ln -sf ~yourlogin/.Xauthority ~
(as root.)"

Use the qcow2 format for images.