path: root/Hurd/QemuImageForL4.mdwn

This page is initially taken from <http://perso.ens-lyon.fr/alexandre.buisse/hurd.html> with the following signature:

> 04-02-2005 Alexandre Buisse
>
> Send any comments or ameliorations to <Nattfodd@gmailNOSPAM.com>

----

This is a howto on how to get a working image of Hurd/L4 with qemu, on ia32 arch.

# <a name="1_Floppy_image"> 1. Floppy image </a>

You will need the following :

* automake 1.7 (or greater)
* autoconf 2.53 (or greater)
* grub
* the CVS version of hurd-l4, which you can retrieve from the savannah server: `export CVS_RSH=ssh && cvs -z3 -d:ext:anoncvs@savannah.gnu.org:/cvsroot/hurd co hurd-l4`
* two flavours of Pistachio, the L4 kernel, which can be found at <http://www.l4ka.org/projects/pistachio/download.php>. Take the demodisk for ia32 (`pistachio-ia32-0.4-demodisk.bin.bz2`), we'll checkout the CVS later (the 0.4 tarball isn't recent enough).

We will begin with the hurd itself (these steps are taken from the `README`).

    $ cd hurd-l4
    $ autoreconf -f -i -s

You shouldn't have any warnings with this autoreconf. If that is not the case, it probably hasn't used the good version of automake or autoconf. For instance, on Gentoo Linux, you must set WANT\_AUTOCONF to 2.5 and WANT\_AUTOMAKE to 1.7.

    $ ./configure --enable-maintainer-mode --prefix=/l4
    $ make
    $ make install
    $ mkdir /l4/boot
    $ install -s laden/laden /l4/boot
    $ install -s wortel/wortel /l4/boot
    $ install -s physmem/physmem /l4/boot
    $ install -s task/task /l4/boot
    $ install -s deva/deva /l4/boot
    $ install -s ruth/ruth /l4/boot

Now we'll prepare the Pistachio kernel :

    $ cd ..
    $ cvs -d:pserver:guest@cvs.l4ka.org:/public-cvs login

When asked for a password, answer `guest`

    $ cvs -z3 -d:pserver:guest@cvs.l4ka.org:/public-cvs co pistachio
    $ cd pistachio

We must apply some patchs for it to work properly with The Hurd. They are located in `hurd-l4/README`:

    $ patch -p1 < ../hurd-l4/README

We will first compile sigma0 (and some other tools) :

    $ cd user
    $ autoreconf -f -i -s
    $ mkdir BUILDDIR
    $ cd BUILDDIR

We need to change the linkbase of sigma0 :

    $ ../configure --with-s0-linkbase=0x40000 --prefix=/l4
    $ make
    $ make install

And now the kernel itself :

    $ cd ../../kernel

You can use any builddir as long as the directory doesn't yet exist.

    $ make BUILDDIR=/tmp/pistachio-build
    $ cd /tmp/pistachio-build
    $ vi Makeconf.local

You should modify the first three lines to :

    ARCH=ia32
    CPU=i586
    PLATFORM=pc99

now run:

    $ make menuconfig

Set the options as they fit you but for qemu to work, you must have the following hardware :

    IA32        Basic Architecture
    Pentium1    Processor Type

You can now:

    $ make

You should obtain a file named ia32-kernel into your build directory.

    $ cp ia32-kernel /l4/boot
    $ cp /l4/libexec/l4/sigma0 /l4/boot

We now have to modify a little bit the demodisk to use the kernel and servers we just obtained :

    $ mkdir qemu
    $ mkdir qemu/image
    $ cd qemu
    $ cp ~/pistachio-ia32-0.4-demodisk.bin.bz2 .
    $ bunzip2 pistachio-ia32-0.4-demodisk.bin.bz2
    $ mount -o loop pistachio-ia32-0.4-demodisk.bin image
    $ cd image/boot
    $ cp /l4/boot/* .
    $ cd grub
    $ vi menu.lst

Your should edit `menu.lst` to make it look like :

    title  GNU Hurd on L4
    kernel /boot/laden -D -o serial,uart1,speed=9600
    module /boot/ia32-kernel
    module /boot/sigma0
    module /boot/wortel -D -o serial,uart1,speed=9600
    module /boot/physmem
    module /boot/task
    module /boot/deva
    module /boot/task
    module /boot/ruth

The two -D are intended for debug, you can delete them if you want. It is possible that filenames are limited to 8 characters, check your image/boot directory for ia32-kernel. If it has been renamed into ia32-ker, modify the according line in menu.lst

When you start qemu, you will have two windows : the shell from which you launched it and a VGA window. You can interact with L4 in both windows (switching with the `config/console` command in the debugger). You can choose to have wortel and laden output to the serial device (the shell), which is default behaviour, or to VGA (change `-o serial,urt1,speed=9600` by `-o vga` in your menu.lst).

The image is now ready :

    $ cd ../../../
    $ umount image

We can launch qemu:

    $ qemu -dummy-net  -serial stdio -fda pistachio-ia32-0.4-demodisk.bin -boot a

Congratulations, you just booted Hurd/L4 ! To start the Kernel Debugger, press `ESC`. To switch the KDB mode from character (I find it unusable) to command line, type

    > c
    /conf> m

# <a name="2_Disk_Image"> 2. Disk Image </a>

Everything went fine, and Hurd/L4 should have shown you a nice boot on our floppy image. Our next step will be to make banner run and show us its nice ASCII Art on this brand new OS.

However, there is one problem : banner linked with the libc weights about 6MB, and we only have a 1.44MB floppy. We will then begin with making an image of a whole hard disk instead of a simple floppy.

We still will work with qemu, of course, but we'll also use Bochs to install Grub on the image (I have not yet tried with qemu).

To begin with, some mathematics. We'll make a 30MB image but you can adapt this value to your need. A disk is made of heads, cylinders and sectors (we won't go in detail about what these really mean). A sector has a constant size of 512 bytes and there are at most 255 heads and 63 sectors. The total size of a disk is C \* H \* S \* 512. We'll use the maximum capacity for S and 16 sectors and that will give us how much cylinders we need : C = E(30,000,000 / (16 \* 63 \* 512)) = 58. The exact size of our image will then be : 58 \* 16 \* 63 \* 512 = 29,933,568 bytes and we will have 58 \* 16 \* 63 = 58464 pieces of 512 bytes.

Let's create it : we use the magic command `dd` on the special device which contain an infinity of 0.

    $ dd if=/dev/zero of=hurd_l4.img bs=512 count=58464
      58464+0 records in
      58464+0 records out

We will mount it in loopback :

    $ losetup /dev/loop0 hurd_l4.img

We need now to have it recognized as a hard disk :

    $ fdisk -u -C58 -S63 -H16 /dev/loop0
      Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
      Building a new DOS disklabel. Changes will remain in memory only,
     until you decide to write them. After that, of course, the previous
     content won't be recoverable.

      Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

      Command (m for help):

We should create a new primary partition (press: `'n'`, `'p'`, `'1'`, default, default) and toggle it bootable (`'a'`, `'1'`). Now, if you press `'p'`, you should see something like :

      Command (m for help): p

      Disk /dev/loop0: 29 MB, 29933568 bytes
      16 heads, 63 sectors/track, 58 cylinders, total 58464 sectors
      Units = sectors of 1 * 512 = 512 bytes

            Device Boot      Start         End      Blocks   Id  System
      /dev/loop0p1   *          63       58463       29200+  83  Linux

If everything is fine (especially check the `Start` and `End` fields), you can press `'w'` to write the table on the disk:

      Command (m for help): w
      The partition table has been altered!

      Calling ioctl() to re-read partition table.

      WARNING: Re-reading the partition table failed with error 22: Invalid argument.
      The kernel still uses the old table.
      The new table will be used at the next reboot.
      Syncing disks.

You will have noticed that the partition only starts at the 63rd sector. The beginning of the disk contains the MBR which is used for booting. We must then remount the disk making sure that this part is skipped before formating it. We know that a sector uses 512 bytes so we should begin at 63 \* 512 = 32256 :

    $ losetup -d /dev/loop0
    $ losetup -o32256 /dev/loop0 hurd_l4.img

Now comes time to format it into a decent filesystem :

    $ mke2fs /dev/loop0
      mke2fs 1.35 (28-Feb-2004)
      Filesystem label=
      OS type: Linux
      Block size=1024 (log=0)
      Fragment size=1024 (log=0)
      7328 inodes, 29200 blocks
      1460 blocks (5.00%) reserved for the super user
      First data block=1
      4 block groups
      8192 blocks per group, 8192 fragments per group
      1832 inodes per group
      Superblock backups stored on blocks:
              8193, 24577

      Writing inode tables: done
      Writing superblocks and filesystem accounting information: done

      This filesystem will be automatically checked every 22 mounts or
     180 days, whichever comes first.  Use tune2fs -c or -i to override.

We should now be able to mount it the right way :

    $ mkdir mnt
    $ losetup -d /dev/loop0
    $ mount -o loop,offset=32256 hurd_l4.img mnt/

Here comes grub time (I assume you have the grub files in `/boot/grub` and the `menu.lst` we've obtained in the previous section is in `~/`) :

    $ mkdir -p mnt/boot/grub
    $ cp /boot/grub/stage1 /boot/grub/stage2 /boot/grub/e2fs_stage1_5 mnt/boot/grub/
    $ cp ~/menu.lst mnt/boot/grub

We will make a grub bootimage and boot it with bochs :

    $ cat stage1 stage2 > grubboot.img

Copy the following into `.bochsrc` (replace the parts in caps by the right info) :

    config_interface: textconfig
    display_library: x
    romimage: file=/usr/share/bochs/BIOS-bochs-latest, address=0xf0000
    megs: 32
    vgaromimage: /usr/share/bochs/VGABIOS-elpin-2.40
    floppya: 1_44=PATH_TO_YOUR_GRUBBOOT_IMAGE, status=inserted
    ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
    ata1: enabled=0, ioaddr1=0x170, ioaddr2=0x370, irq=15
    ata0-master: type=disk, path="PATH_TO_YOUR_DISK_IMAGE", cylinders=NUMBER_OF_CYLINDERS, heads=16, spt=63
    newharddrivesupport: enabled=1
    boot: a

    log: /dev/stdout
    panic: action=ask
    error: action=report
    info: action=report
    debug: action=ignore
    debugger_log: -
    com1: enabled=1, dev=/dev/ttyS0
    vga_update_interval: 300000
    keyboard_serial_delay: 250
    keyboard_paste_delay: 100000
    floppy_command_delay: 500
    ips: 1000000
    mouse: enabled=0
    private_colormap: enabled=0
    fullscreen: enabled=0
    screenmode: name="sample"
    keyboard_mapping: enabled=0, map=/usr/share/bochs/keymaps/x11-pc-fr.map
    i440fxsupport: enabled=0

And start Bochs with this configuration :

    $ bochs -qf .bochsrc

When asked, choose `5. begin simulation`. It is possible that you enter first into a debuuger, answer `'c'` to make it continue. You should see a grub commandline. Tell it to install grub on the disk :

    grub> root (hd0,0)
      Filesystem type is ext2fs, partition type 0x83

    grub> setup (hd0)
      Checking if "/boot/grub/stage1" exists... yes
      Checking if "/boot/grub/stage2" exists... yes
      Checking if "/boot/grub/e2fs_stage1_5" exists... yes
      Running "embed /boot/grub/e2fs_stage1_5 (hd0)"... 15 sectors are embedded. succeeded
      Running "install /boot/grub/stage1 (hd0) (hd0)1+15 p (hd0,0)/boot/grub/stage2/boot/grub/menu.lst"... succeeded.
      Done.

Quit by pressing `^C q` in the shell from which you launched bochs. Our image is now ready. Copy all the releving files in `mnt/boot` like for the floppy and then umount it and launch qemu :

    $ cp /l4/boot/* mnt/boot/
    $ umount mnt
    $ qemu -serial stdio -dummy-net -hda hurd_l4.img -boot c

# <a name="3_Running_Banner"> 3. Running Banner </a>

Still under construction but you should have no problems following `hurd-l4/libc/README` now that the hdd image works.

----

-- [[Main/OgnyanKulev]] - 05 Feb 2005

I didn't bother to licence it as it is so small, but consider it is under some sort of creative commons that allows redistribution and modification. <br /> -- Alexandre Buisse &lt; <nattfodd@gmailNOSPAM.com> &gt;

-- [[Main/JoachimNilsson]] - 05 Feb 2005

Comments from Marcus Brinkmann:

> Thanks a lot for that. Some comments:
>
>     $ ../configure --with-s0-linkbase=0x40000 --prefix=/l4
>
> I'd recommend to explain how to use `--without-com0` here (or whatever it is called, don't remember) to choose VGA output, or how to configure the serial port. If you use vga, no `-o` option to laden and wortel should be used so you get all output on vga (but of course you can also mix it, whatever you want).
>
> Serial 1 is currently going to be used for remote debugging of userland apps.
>
> QEMU supports up to four serial ports, I use: `-serial stdio` and `-serial pty` and then I get the debugging output and kernel debugger in the terminal I started qemu in, and can use the pty for remote debugging with gdb (the latter doesn't work yet).
>
> Next:
>
>     You should modify the first three lines to :
>      ARCH=ia32
>      CPU=i586
>      PLATFORM=pc99
>
> I never did that. I did change the menu item Processor Type to Pentium1 though. Maybe it has the same effect (and then your document would be a bit redundant here).
>
> Somebody should at some point document all those menu options, some are quite useful for debugging!
>
> Thanks, Marcus

-- [[Main/OgnyanKulev]] - 05 Feb 2005

I've been doing this sort of thing (See also `info grub` for making bootable eltorito grub cd ISOs):

    $ cd /usr/src/controlled/qemu-images
    $ ls -R l4
    ls -R l4
    l4:
    boot  deva  ia32-kernel  laden   physmem  sigma0  task  wortel

    l4/boot:
    grub

    l4/boot/grub:
    menu.lst  stage2_eltorito

    $ cd /usr/src/controlled/qemu-images # dir above "l4" dir.
    $ mkisofs -R -b boot/grub/stage2_eltorito -no-emul-boot \
      -boot-load-size 4 -boot-info-table \
      -o /usr/src/controlled/qemu-images/l4.iso l4

    $ qemu -boot d -cdrom /usr/src/controlled/qemu-images/l4.iso

-- [[Main/DerekDavies]] - 07 Feb 2005

You don't need a compiler targeting the Hurd. The above works with a compiler targeting Linux which are quite a bit easier to find. By adding "--target=i686-unknown-linux-gnu" to my configure line, I was able to cross compile hurd-l4 from Cygwin.

-- [[Main/MichaelAdams]] - 22 Feb 2005