HOWTO: build qemu from cvs (incl. accelerator)

[notz]

goto to your portage overlay

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cd /usr/local/portage

download & extract the ebuild

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wget ftp://notz.homelinux.com/qemu-cvs.tar.gz
tar -xzf qemu-cvs.tar.gz

add arch keyword to package.keywords i.e. ~x86

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echo "=app-emulation/qemu-cvs-0.0.1 ~x86" >> /etc/portage/package.keywords

for accelerator add kqemu use flag

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echo "app-emulation/qemu-cvs kqemu" >> /etc/portage/package.use

emerge qemu

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emerge qemu-cvs

load kqemu (accelerator module)

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/etc/init.d/kqemu start

to load the accelerator module on startup

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rc-update add kqemu default

start qemu as usual

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qemu -hda hd.img -boot c

enjoy it and feel free to add your coments, hints and tips.

changelog:
2005-03-14: fixed runscript for udev only users (thx to pussi)

[AlterEgo]

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wget ftp://notz.homelinux.com/qemu-cvs.tar.gz
--22:24:09--  ftp://notz.homelinux.com/qemu-cvs.tar.gz
           => `qemu-cvs.tar.gz'
Resolving notz.homelinux.com... 62.99.150.84
Connecting to notz.homelinux.com[62.99.150.84]:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD not needed.
==> PORT ... done.    ==> RETR qemu-cvs.tar.gz ...
Error in server response, closing control connection.
Retrying.

Fetching the file manually does work

But the rest: excellent work, thanks!

[watashiwaotaku7]

When using qemu, trying to install windows xp it dies with "bus error" when trying to format the image as fat32 (or ntfs) I invoke qemu with "qemu -user-net -enable-audio -m 384 -hda hd.img -cdrom /dev/hdc -boot d" and created the hd image by going to / and invoking "dd of=hd.img bs=1024 seek=30000000 count=0" my root partition is set as device /dev/md0 using md raid, is this what is causing my problem? I also tried making the image on a empty fat32 partition and replacing -hda hd.img with /mnt/hda/hd.img, can anyone tell me what I am doing wrong?

EDIT: FIXED! I removed the -m 384 argument, from what I can tell this is for using virtual memory only, and you must compile qemu with a certain flag in order for this to work, installing now.

[bravecobra]

To have both access to internet and your local network from within qemu, check my blog: http://blog.bravecobra.com/index.php/li ... _with_qemu

[PraetorZero]

Pardon my n00b-ness, but would this pull whatever is the current version in CVS when you emerge it? So... if I were to find at a later time a new version is out, all I would have to do is clear the cache and re-emerge qemu?

[1der]

I also got the same result as watashiwaotaku7.

What did u do to fix it ? What compile flag did you use?

running the old qemu (6.1) was fine.

[watashiwaotaku7]

1der, per my edit, I removed -m 384, if you search there is a thread in portage and programming aobut qemu and the accelerator that talks about using some flag which causes qemu to use only virtual memory.

Having said that, I am still having problems but at least it is installed, everything is working fine, but for some reason it doesnt seem to be using system memory to run windows, which is causing it to be very very slow, I am only using 94 mb of memory total and I have 512 mb so I was hoping to have my emulated OS running on this too, how exactly do I do that? I also imagine other people will want to know since my slowdown running this on raid 0 is big enough, it must be worse with just a regular drive.

[bravecobra]

the -m 384 sets the amount of memory you want to assign to qemu. Note that this is the amount of memory you won't be able to use for your host then.

[notz]

the mem given to qemu should be lower than /dev/shm

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root # df | grep shm
none                    240944         0    240944   0% /dev/shm

so mine is about 240M....

if you need more, you should edit your fstab and increase /dev/shm ....

[watashiwaotaku7]

none /dev/shm tmpfs defaults , is my /dev/shm line, how do I edit this to change the size?

also,

has anyone experimented with different windows versions to see which is the most responsive?

how does qemu deal with graphics? (eg: does graphic rendering have the same type of slowdown as everything else or does it just use the native drivers to do everything?)

has anyone attempted to register their windows xp on qemu? I'm using an OEM version of windows from dell, and it tells me the registration key is invalid, how will the microsoft support staff feel about me trying to register and emulated version of XP?

[jdgill0]

Use the "size" option:

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none                    /dev/shm                  tmpfs           size=256m               0 0

[corefile]

To have both access to internet and your local network from within qemu, check my blog: http://blog.bravecobra.com/index.php/li ... _with_qemu

Thanks for the link, helped alot. I was wondering if its posiible to setup networking so that i can set up smb (to access HOST file system) Internet AND local network (printer on the network). So basically I wan't to be about to easially access the host files, use the internet, and use printer on my network

[at6]

great howto.

qemu works like a charm. thanks!

best regards
marc

[bravecobra]

You should be able to able all of that, following the guidelines. Maybe you need to adjust your smb.conf? I haven't tested this, but it should possible. The only thing you won't be able to do, is run services on the qemu host, unless you set upset a forwarding to your host's gateway.
As you can see in the screenshot (might be a little small), I was able to access my network through samba from within qemu and had access to the internet.

[pussi]

Note that if you are using udev, /dev/kqemu is not created automatically when you boot, and acceleration won't work.
( http://fabrice.bellard.free.fr/qemu/kqemu-doc.html#SEC4 )

If youre using udev you need to create the file yourself:

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mknod /dev/kqemu c 250 0
chmod 666 /dev/kqemu

Or you can edit the /etc/init.d/kqemu file:

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#!/sbin/runscript

udev() {
	# Create the KQEMU device if using udev
	if [ -a /dev/kqemu ] ; then
		einfo "/dev/kqemu exists"
	else
		ebegin "Creating /dev/kqemu"
		mknod /dev/kqemu c 250 0
		chmod 666 /dev/kqemu
	fi
}

start() {
	ebegin "Loading kqemu module"
	/sbin/modprobe kqemu
	udev
	eend $?
}

stop() {
	ebegin "Unloading kqemu module"
	/sbin/modprobe -r kqemu
	eend $?
}

[techiem2]

The Howto is wonderful and worked fine.
I am having one problem though.

When I try to boot my old Win98SE vm, it dies with a Windows Protection Error.
Starting it with -no-kqemu works fine as before.

Any suggestions?

I'm currently trying to install win2k in a new vm to see if that works.

Mark II

[pussi]

When I try to boot my old Win98SE vm, it dies with a Windows Protection Error.
Starting it with -no-kqemu works fine as before.

Any suggestions?

I'm currently trying to install win2k in a new vm to see if that works.

Mark II

This happened to me also and it seems to be known bug in qemu.
Win2k works fine with me. :)

[Koala Kid]

Guys, how can I access my local files and directories from the guest OS ?

[techiem2]

You have to setup the networking and use smb (at least from win) to access the host.
There's a link higher in the thread about how to set that up.

Direct access to the host fs would be a nice feature.

[stonent]

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Aurora ~ # /etc/init.d/kqemu start
 * Loading kqemu module ...
FATAL: Error inserting kqemu (/lib/modules/2.6.10-gentoo-r4/misc/kqemu.ko): Invalid module format

Something happened that wasn't right...

[Lejban]

Guys, how can I access my local files and directories from the guest OS ?

I use winSCP from the guest (winXP) to any computer including the host (gentoo). Much easier then setting up a smb-server on the host.

[Koala Kid]

Guys, how can I access my local files and directories from the guest OS ?

I use winSCP from the guest (winXP) to any computer including the host (gentoo). Much easier then setting up a smb-server on the host.

Can you write some details about that ? it sounds me like chinese...
What's that winSCP thing ?

Thanks in advance

[Lejban]

Guys, how can I access my local files and directories from the guest OS ?

I use winSCP from the guest (winXP) to any computer including the host (gentoo). Much easier then setting up a smb-server on the host.

Can you write some details about that ? it sounds me like chinese...
What's that winSCP thing ?

Thanks in advance

scp is coping over ssh, winscp is a windows app to do this, come on, one google serch would give you this info...

[Debentoo_Gao]

Note that if you are using udev, /dev/kqemu is not created automatically when you boot, and acceleration won't work.
( http://fabrice.bellard.free.fr/qemu/kqemu-doc.html#SEC4 )

If youre using udev you need to create the file yourself:

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mknod /dev/kqemu c 250 0
chmod 666 /dev/kqemu

Or you can edit the /etc/init.d/kqemu file:

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#!/sbin/runscript

udev() {
	# Create the KQEMU device if using udev
	if [ -a /dev/kqemu ] ; then
		einfo "/dev/kqemu exists"
	else
		ebegin "Creating /dev/kqemu"
		mknod /dev/kqemu c 250 0
		chmod 666 /dev/kqemu
	fi
}

start() {
	ebegin "Loading kqemu module"
	/sbin/modprobe kqemu
	udev
	eend $?
}

stop() {
	ebegin "Unloading kqemu module"
	/sbin/modprobe -r kqemu
	eend $?
}

I just did all the thing above,but when I start qemu in cosole,it still said "Could not open '/dev/kqemu' - QEMU acceleration layer not activated'

[pussi]

I just realized that it don't work with me eiter

I know it should work as it reads in Qemu acceleration module manual, but for some reason it don't.