docs/127923: Please mention qemu in the FreeBSD Handbook
Juergen Lock
nox at jelal.kn-bremen.de
Sun Dec 21 17:20:34 UTC 2008
In article <200812171626.mBHGQL0K035212 at freefall.freebsd.org> you write:
>loader <loader at freebsdmall.com> wrote:
>
>>> http://www.freebsd.org/cgi/query-pr.cgi?pr=127923
>
>And I reworded some parts of Juergen's patch
>with the help of murray at .
>
A few minor nits:
>Index: chapter.sgml
>===================================================================
>RCS file: /home/ncvs/doc/en_US.ISO8859-1/books/handbook/virtualization/chapter.sgml,v
>retrieving revision 1.17
>diff -u -r1.17 chapter.sgml
>--- chapter.sgml 28 Jul 2008 14:33:51 -0000 1.17
>+++ chapter.sgml 17 Dec 2008 16:13:40 -0000
>@@ -54,6 +54,11 @@
> virtualization.</para>
> </listitem>
>
>+ <listitem>
>+ <para>How to run FreeBSD as guest in <application>qemu</application>
>+ and as a qemu host.</para>
>+ </listitem>
>+
> </itemizedlist>
>
> <para>Before reading this chapter, you should:</para>
>@@ -969,6 +974,327 @@
> Work is also ongoing in getting <application>&xen;</application> to
> work as a host environment on FreeBSD.</para>
>
>+ <sect2 id="virtualization-host-qemu">
>+ <sect2info>
>+ <authorgroup>
>+ <author>
>+ <firstname>Juergen</firstname>
>+ <surname>Lock</surname>
>+ <contrib>Contributed by </contrib>
>+ </author>
>+ </authorgroup>
>+ </sect2info>
>+ <title><application>QEMU</application> on &os; as Host</title>
>+
>+ <para><ulink url="http://bellard.org/qemu/">QEMU</ulink>
>+ is a generic processor emulator using dynamic binary translation
>+ to achieve a reasonable emulation speed.</para>
>+
>+ <sect3 id="virtualization-host-qemu-installation">
>+ <title>Installation</title>
>+
>+ <para>There are two <application>QEMU</application> ports in the &os;
>+ Ports tree at the moment:
>+ <filename role="package">emulators/qemu</filename>
>+ is usually the latest release, and
>+ <filename role="package">emulators/qemu-devel</filename>.
>+ is an svn snapshot. For best results try the latest version
>+ available as a &os; package, or alternatively try the
>+ <filename role="package">emulators/qemu-devel</filename>.</para>
>+
>+ <para>Install <filename role="package">emulators/qemu-devel</filename>
>+ with the following commands:</para>
>+
>+ <screen>&prompt.root; <userinput>cd /usr/ports/emulators/qemu-devel</userinput>
>+&prompt.root; <userinput>make install clean</userinput></screen>
>+
>+ <para>If the <application>QEMU</application> port is built with the
>+ kqemu knob enabled, load the kqemu kernel module:</para>
>+
>+ <screen>&prompt.root; <userinput>kldload kqemu</userinput></screen>
>+
>+ <para>And kqemu can be loaded automatically at boot by adding
>+ the following line to <filename>/etc/rc.conf</filename>:</para>
>+
>+ <programlisting>kqemu_enable="YES"</programlisting>
>+
>+ <para>Please make sure the <filename>kqemu.ko</filename> is always in sync
>+ with the kernel like with any kld installed outside of the base. Rebuild
>+ the port <filename role="package">emulators/kqemu-kmod</filename> or
>+ <filename role="package">emulators/kqemu-kmod-devel</filename>
>+ whenever you update the kernel.</para>
>+
>+ <para><application>QEMU</application> now uses &man.aio.4; at least
>+ for IDE DMA, otherwise <application>QEMU</application> crashes
>+ with <quote>Invalid system call</quote>:</para>
>+
>+ <screen>&prompt.root; <userinput>kldload aio</userinput></screen>
>+
>+ <note>
>+ <para>If you want to run <application>QEMU</application> with
>+ <option>-m</option> 512 or larger on &os; 6.3 i386 hosts,
This most likely also applies to 6.4.
>+ <varname>kern.maxdsiz</varname> needs to be increased in
>+ <filename>/boot/loader.conf</filename> since the default
>+ value is 512 MB, and <application>QEMU</application> needs
>+ memory for itself also. &os; 7.0 and up use jemalloc which uses
>+ &man.mmap.2; and isn't affected by
>+ <varname>kern.maxdsiz</varname> anymore.</para>
>+ </note>
>+ </sect3>
>+
>+ <sect3 id="virtualization-host-qemu-fbsdguest">
>+ <title>An example of installing &os; 7.0 as a
>+ <application>QEMU</application> guest</title>
>+
>+ <para>First, create an empty raw 5 GB image:</para>
>+
>+ <screen>&prompt.user; <userinput>qemu-img create 7.0.img 5G</userinput></screen>
>+
>+ <note>
>+ <para>qcow2 is the <application>QEMU</application> image format,
>+ use the <option>-f</option> qcow2 option to avoid sparse files
>+ on the host. Some backup applications like &man.bsdtar.1; don't
>+ support them properly, others like <application>gtar</application>
>+ or <application>star</application> do if passed appropriate flags,
>+ qcow2 format might be slower than raw format.</para>
>+ </note>
>+
>+ <para>Next, boot sysinstall with the image:</para>
>+
>+ <screen>&prompt.user; <userinput>qemu -m 256 -cdrom 7.0-RELEASE-i386-disc1.iso -hda 7.0.img -boot d -monitor stdio</userinput></screen>
>+
>+ <note>
>+ <para>You need to run <command>qemu-system-x86_64</command>
>+ if you want to emulate a amd64 guest.</para>
..an amd64 guest?
>+ </note>
>+
>+ <para>Now follow the instructions in <xref linkend="install"> like
>+ as if you would install a real machine using CD media.
>+ Click into the guest window to access the guest mouse pointer
>+ and hit <keycombo action="simul"><keycap>Alt</keycap>
>+ <keycap>Ctrl</keycap></keycombo> to leave the guest window
>+ mouse grab. If you use the default usermode networking (aka slirp)
>+ like in the above example the guest should have network if you
>+ configure it to use DHCP, so if you want you could probably
>+ also use a bootonly iso instead of disc1 and do a network install.
>+ (&man.ping.8; doesn't work with slirp though.)</para>
>+
>+ <para>When finished, select <quote>exit install</quote> in sysinstall to reboot,
>+ and when the guest booting the ISO again, type
>+ <command>q</command> in <application>QEMU</application>'s monitor or
>+ <command>killall</command> qemu on another host shell if you are
... <command>killall qemu</command> ... ?
>+ using <option>-curses</option>, like when you have no X11 on the
>+ host.</para>
>+
>+ <para>Now, boot the installed image:</para>
>+
>+ <screen>&prompt.user; <userinput>qemu -m 256 -cdrom 7.0-RELEASE-i386-disc1.iso -hda 7.0.img -boot c -monitor stdio</userinput></screen>
>+
>+ <para>Now you should see a normal boot like on a freshly installed
>+ box, all the way up to your first login prompt. If you plan to
>+ use this guest with <option>-nographic</option> later on,
>+ now is the time to configure it for a serial console in the guest:</para>
>+
>+ <screen>&prompt.root; <userinput>echo console=\"comconsole\" >>/boot/loader.conf</userinput>
>+&prompt.root; <userinput>sed -i -e '/^ttyu0/s/off/on/' /etc/ttys</userinput></screen>
>+
>+ <para>As always with virtualization, lowering <varname>kern.hz</varname>
>+ helps performance also with <application>QEMU</application>:</para>
>+
>+ <screen>&prompt.root; <userinput>echo kern.hz=100 >>/boot/loader.conf</userinput></screen>
>+
>+ <para>When you are finished with the guest, shut it down, this should
>+ make <application>QEMU</application> quit gracefully:</para>
>+
>+ <screen>&prompt.root; <userinput>shutdown -p now</userinput></screen>
>+
>+ <para>If the serial console is configured, now you can boot the
>+ guest with <option>-nographic</option>:</para>
>+
>+ <screen>&prompt.user; <userinput>qemu -m 256 -hda 7.0.img -boot c -nographic</userinput></screen>
>+
>+ <para>With <option>-nographic</option>, the guest console and
>+ <application>QEMU</application>'s monitor are multiplexed on
>+ <application>QEMU</application>'s tty, hit
>+ <keycombo action="simul"><keycap>Ctrl</keycap>
>+ <keycap>a</keycap></keycombo> and then
>+ <keycap>h</keycap> to show a small help.</para>
>+
>+ <note>
>+ <para>Qemu can emulate several different mode of network card,
>+ try <option>pcnet</option>, <option>i82557b</option>
>+ or <option>e1000</option>, they should be faster
>+ and use less guest <acronym>CPU</acronym> than the
>+ default <option>ne2kpci</option>.</para>
>+
>+ <para>With the <option>-vnc</option> <replaceable>display</replaceable>
>+ option, <application>QEMU</application> will listen on
>+ <acronym>VNC</acronym> display <replaceable>display</replaceable>
>+ and redirect the <acronym>VGA</acronym> display over the
>+ <acronym>VNC</acronym> session. If the host or
>+ <application>QEMU</application> build lacks X11 and
>+ <option>-nographic</option> or <option>-curses</option>
>+ is not an available option. <option>-vnc</option> works best with
...Something missing after `option'?
>+ an en-us keymap on the host.
>+ Use the port <filename role="package">net/tightvnc</filename>
>+ with <application>QEMU</application>. The X keymap on the host
>+ can be changed temporarily using <command>setxkbmap</command>,
>+ see the manual pages for more information.</para>
>+ </note>
>+ </sect3>
>+
>+ <sect3 id="virtualization-host-qemu-linuxguest">
>+ <title>&linux; guest examples</title>
>+
>+ <para>As an example, we run the well known <ulink
>+ url="http://knoppix.net">Knoppix</ulink> &linux; live-CD/DVD in qemu:</para>
>+
>+ <screen>&prompt.user; <userinput>qemu -m 256 -cdrom KNOPPIX_V5.3.1DVD-2008-03-26-EN.iso -boot d -monitor stdio -soundhw es1370</userinput></screen>
>+
>+ <para>In this example we launched <application>QEMU</application>
>+ with an ES1370 sound card enabled for the guest OS.</para>
>+
>+ <para>Click into the guest window to access the guest
>+ mouse pointer and hit <keycombo action="simul"><keycap>Alt</keycap>
>+ <keycap>Ctrl</keycap></keycombo> to leave the guest window
>+ mouse grab.</para>
>+
>+ <note>
>+ <para>Debian/Ubuntu (and their offsprings) have a record of
>+ shipping partially broken <application>QEMU</application>
>+ bioses, so if you have problems using a packaged
>+ <application>QEMU</application> these distros also try
...on these distros?
>+ using the bios found in that <application>QEMU</application>
>+ version's source tarball (<filename>pc-bios/bios.bin</filename>
>+ in there) instead of the one installed by your distro
>+ package.</para>
>+ </note>
>+ </sect3>
>+
>+ <sect3 id="virtualization-host-qemu-tuntap">
>+ <title>Simple Example for using <application>QEMU</application>
>+ tuntap networking on &os; Hosts</title>
>+
>+ <para>In cases where you want a <application>QEMU</application>
>+ guest to appear as a seperate (virtual) host on your network,
>+ or when you are on an amd64 host where the default usermode
>+ networking doesn't quite work, or when you are simply concerned
>+ about virtual network performance, you may want to use tuntap
>+ networking.</para>
>+
>+ <para>The idea here is to have <application>QEMU</application>
>+ talk to a &man.tap.4; interface, which bridge with your host's
>+ physical interface, and that <application>QEMU</application>
>+ then passes the traffic of the emulated NIC that the guest
>+ uses on. Since you don't want to run <application>QEMU</application>
>+ as root you first need to setup permissions on the tap device in
>+ &man.devfs.conf.5; so that <application>QEMU</application>
>+ running as your user can acess it. For example add:</para>
>+
>+ <programlisting>own tap0 <replaceable><username or uid></replaceable></programlisting>
>+
>+ <para>Next figure out two IPs in an unused sub-subnet of your
>+ host's network, one for the tap interface and the other for the
>+ guest (this is important so the host itself can talk to the guest's
>+ emulated nic properly), and then edit qemu's tuntap setup script
>+ that gets executed after qemu opens a tap device,
>+ <filename>/usr/local/etc/qemu-ifup</filename> to read something
>+ like this:</para>
>+
>+ <programlisting>#!/bin/sh
>+sudo /sbin/ifconfig $1 <replaceable><IP for the tap interface></replaceable> netmask <replaceable><sub-subnet's netmask></replaceable>
>+case "`/sbin/ifconfig bridge0`" in
>+ *" $1 "*) ;; # already in the bridge
>+ *) sudo /sbin/ifconfig bridge0 addm $1 ;;
>+esac</programlisting>
>+
>+ <para>sudo is in ports as
>+ <filename role="package">security/sudo</filename>, if your user
>+ is in the wheel group you can add the following line to
>+ <filename>/usr/local/etc/sudoers</filename>:</para>
>+
>+ <programlisting>%wheel ALL=/sbin/ifconfig</programlisting>
>+
>+ <para>Then load the kernel modules <filename>if_tap.ko</filename> and
>+ <filename>if_bridge.ko</filename>, restart devfs, set the
>+ <varname>net.link.tap.user_open</varname> sysctl, create
>+ the bridge and add your host's physical interface to it:</para>
>+
>+ <screen>&prompt.root; <userinput>kldload if_tap if_bridge</userinput>
>+&prompt.root; <userinput>/etc/rc.d/devfs restart</userinput>
>+&prompt.root; <userinput>sysctl net.link.tap.user_open=1</userinput>
>+&prompt.root; <userinput>ifconfig bridge0 create</userinput>
>+&prompt.root; <userinput>ifconfig bridge0 addm <replaceable><host's physical interface></replaceable> up</userinput></screen>
>+
>+ <para>Now start the <application>QEMU</application>:</para>
>+
>+ <screen>&prompt.user; <userinput>qemu -m 256 -hda guest.img -boot c -net nic -net tap,ifname=tap0</userinput></screen>
>+
>+ <para>Then configure the NIC in the guest like
>+ other hosts on your physical network.</para>
>+
>+ <note>
>+ <para>If you have more than one <application>QEMU</application>
>+ guest on a network you need to make sure they use different
>+ MAC addresses, the MAC address can be set via
>+ <option>-net nic,macaddr</option>.</para>
>+ </note>
>+
>+ <para>To make the settings permanent, add the following lines
>+ in <filename>/boot/loader.conf</filename>:</para>
>+
>+ <programlisting>if_tap_load="YES"
>+if_bridge_load="YES"</programlisting>
>+
>+ <para>Add the following line in <filename>/etc/sysctl.conf</filename>:</para>
>+
>+ <programlisting>net.link.tap.user_open=1</programlisting>
>+
>+ <para>And add the bridge configuration in <filename>/etc/rc.conf</filename>:</para>
>+
>+ <programlisting>cloned_interfaces="bridge0"
>+ifconfig_bridge0="addm <replaceable><host's physical interface></replaceable> up"</programlisting>
>+ </sect3>
>+
>+ <sect3 id="virtualization-host-qemu-help">
>+ <title>User Documentation and Resources</title>
>+
>+ <para>The <application>QEMU</application> package
>+ includes qemu(1) man page and the following locally installed html
>+ documents:</para>
>+
>+ <itemizedlist>
>+ <listitem><para><filename>/usr/local/share/doc/qemu/qemu-doc.html</filename></para></listitem>
>+ <listitem><para><filename>/usr/local/share/doc/qemu/qemu-tech.html</filename></para></listitem>
>+ </itemizedlist>
>+
>+ <para>Places to check other than the official documentation:</para>
>+
>+ <itemizedlist>
>+ <listitem>
>+ <para><filename role="package">emulators/qemu-devel</filename>
>+ <ulink url="http://www.freebsd.org/cgi/cvsweb.cgi/ports/emulators/qemu-devel/pkg-message">
>+ pkg-message</ulink></para>
>+ </listitem>
Well actually you want the pkg-message of the qemu port you are using,
i.e. emulators/qemu/pkg-message when you are using that, they can differ
slightly. (like, atm kqemu only works for qemu-system-x86_64 on amd64
hosts with emulators/qemu, while with qemu-devel it also works for the
32 bit `qemu'.)
Oh and also cvsweb can be wrong when you are running an old version
of the port, like when someone pkg_add -r 's release packages, so maybe
better just stick with `pkg_info -D qemu\* |less' as I had it.
>+ <listitem>
>+ <para>The <ulink
>+ url="http://lists.freebsd.org/pipermail/freebsd-emulation/">
>+ freebsd-emulation mailing list archive</ulink>.</para>
>+ </listitem>
>+ <listitem>
>+ <para>The <ulink
>+ url="http://qemu-forum.ipi.fi/">
>+ qemu forum</ulink>
>+ has howtos, patches, and code snapshots. Note, however
>+ that the qemu sources won't build on &os; without some changes.</para>
>+ </listitem>
>+ <listitem>
>+ <para>The <ulink
>+ url="http://lists.gnu.org/archive/html/qemu-devel/">
>+ qemu-devel mailing list archive</ulink>.</para>
>+ </listitem>
>+ </itemizedlist>
>+ </sect2>
> </sect1>
>
> </chapter>
Ok that seems to be it for now.
Thanx,
Juergen
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