Revision as of 12:52, 11 January 2012

QEMU on IGEP Boards

QEMU  is a generic and open source machine emulator and virtualizer.

When used as a machine emulator, QEMU can run OSes and programs made for one machine (e.g. an ARM board) on a different machine (e.g. your own PC). By using dynamic translation, it achieves very good performance.

When used as a virtualizer, QEMU achieves near native performances by executing the guest code directly on the host CPU. QEMU supports virtualization when executing under the Xen hypervisor or using the KVM kernel module in Linux. When using KVM, QEMU can virtualize x86, server and embedded PowerPC, and S390 guests.

QEMU documentation can be found here.

Build QEMU with IGEP support

Download QEMU sources from linaro git repository:

$ git clone git://git.linaro.org/qemu/qemu-linaro.git

Download IGEP support patch for QEMU from this link and after that apply the patch as:

$ cd qemu-linaro

$ patch -p1 < 0001-IGEP_QEMU_support.path

Configure the sources for build with this command:

$ ./configure --target-list=arm-softmmu --prefix=/opt/qemu-linaro

Build the sources:

$ make 

Install QEMU:

$ make install

Optionally you can download from here the QEMU binaries, we suggest install it under /opt directory with the right user execution permissions.

Board Emulation

Go to your qemu install directory.

$ cd /opt/qemu-linaro/bin

We provide a QEMU ready image based on Ubuntu/Linaro Nano (Oneric 11.11) image, it can be download from here (first uncompress first).

The image has 2 partitions (you can see the partitions using fdisk -ul command as: fdisk -ul igep-nano.img)

Device                 Boot      Start         End      Blocks   Id  System

igep-nano.img1   *            63            106494       53232    c  FAT32 LBA (Boot)

igep-nano.img2                106496     1048575      470016   83  Linux (Root filesystem)

Optionally you can mount the partitions in you host PC and modify the content as:

First Partition: 
$ mount -o loop,offset$[63*512] igep-nano.img /mnt/tmp

Second Partition: 
$ mount -o loop,offset$[106496*512] igep-nano.img /mnt/tmp

Now you're ready for execute the emulator in a console with this command:

qemu-system-arm -M igep -m 512 -clock unix -serial stdio -drive file=igep-nano.img,if=sd,cache=writeback -usb -monitor telnet:localhost:7100,server,nowait,nodelay -device usb-kbd -device usb-mouse

Parameters:

-m : Memory assigned to the Virtualized board in Mega Bytes.

Tips

Resize Rootfs Partition

We will resize our rootfs partition adding 1 GB at end.

First we create a new raw file using qemu-img as:

$ qemu-img create -f raw addon.raw 1G 

With addon.raw we concatenate it at end of our image file as:

$ cat addon.raw >> igep-nano.img 

Next step it's modify the partition table information. We will use cfdisk utility for modify the information.

$ sudo cfdisk igep-nano.img  

Next step it's select your rootfs partition as this picture shows

We will write the changes to the disk using the commit menu option and select YES (confirm the changes).

The next step it's update the file-system structure.

$ sudo losetup /dev/loop0 igep-nano.img -o $[106496*512]

$ sudo e2fsck -f /dev/loop0

e2fsck 1.41.14 (22-Dec-2010)
rootfs: recovering journal
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information

rootfs: ***** FILE SYSTEM WAS MODIFIED *****
rootfs: 11969/5579872 files (0.6% non-contiguous), 1126338/22491136 blocks

$ sudo resize2fs /dev/loop0

$ sudo losetup -d /dev/loop0

Now you should see your new partition with your wished new size.