Booting Linaro ARMv8 OE images with Qemu

A quick update - Linaro ARMv8 OpenEmbbeded images work just fine with qemu 2.1 as well:

$ http://releases.linaro.org/14.07/openembedded/aarch64/Image
$ http://releases.linaro.org/14.07/openembedded/aarch64/vexpress64-openembedded_lamp-armv8-gcc-4.9_20140727-682.img.gz
$ qemu-system-aarch64 -m 1024 -cpu cortex-a57 -nographic -machine virt \
 -kernel Image -append 'root=/dev/vda2 rw rootwait mem=1024M console=ttyAMA0,38400n8' \
 -drive if=none,id=image,file=vexpress64-openembedded_lamp-armv8-gcc-4.9_20140727-682.img \
 -netdev user,id=user0 -device virtio-net-device,netdev=user0  -device virtio-blk-device,drive=image 
[    0.000000] Linux version 3.16.0-1-linaro-vexpress64 (buildslave@x86-64-07) (gcc version 4.8.3 20140401 (prerelease) (crosstool-NG linaro-1.13.1-4.8-2014.04 - Linaro GCC 4.8-2014.04) ) #1ubuntu1~ci+140726114341 SMP PREEMPT Sat Jul 26 11:44:27 UTC 20
[    0.000000] CPU: AArch64 Processor [411fd070] revision 0
...
root@genericarmv8:~# 

Quick benchmarking with age-old ByteMark nbench:

Index	Qemu	Foundation	Host
Memory	4.294	0.712	44.534
Integer	6.270	0.686	41.983
Float	1.463	1.065	59.528
Baseline (LINUX) : AMD K6/233*

Qemu is upto 8x faster than Foundation model on Integers, but only 50% faster on Math. Meanwhile, the Host pc spends 7-40x slower emulating ARMv8 than executing native instructions.

Testing qemu 2.1 arm64 support

Qemu 2.1 was just released a few days ago, and is now a available on Debian/unstable. Trying out an (virtual) arm64 machine is now just a few steps away for unstable users:

$ sudo apt-get install qemu-system-arm 
$ wget https://cloud-images.ubuntu.com/trusty/current/trusty-server-cloudimg-arm64-disk1.img
$ wget https://cloud-images.ubuntu.com/trusty/current/unpacked/trusty-server-cloudimg-arm64-vmlinuz-generic
$ qemu-system-aarch64 -m 1024 -cpu cortex-a57 -nographic -machine virt -kernel trusty-server-cloudimg-arm64-vmlinuz-generic \ 
-append 'root=/dev/vda1 rw rootwait mem=1024M console=ttyAMA0,38400n8 init=/usr/lib/cloud-init/uncloud-init ds=nocloud ubuntu-pass=randomstring' \
-drive if=none,id=image,file=trusty-server-cloudimg-arm64-disk1.img \
-netdev user,id=user0 -device virtio-net-device,netdev=user0 -device virtio-blk-device,drive=image 
[    0.000000] Linux version 3.13.0-32-generic (buildd@beebe) (gcc version 4.8.2 (Ubuntu/Linaro 4.8.2-19ubuntu1) ) #57-Ubuntu SMP Tue Jul 15 03:52:14 UTC 2014 (Ubuntu 3.13.0-32.57-generic 3.13.11.4)
[    0.000000] CPU: AArch64 Processor [411fd070] revision 0
...
-snip-
...
ubuntu@ubuntu:~$ cat /proc/cpuinfo 
Processor       : AArch64 Processor rev 0 (aarch64)
processor       : 0
Features        : fp asimd evtstrm 
CPU implementer : 0x41
CPU architecture: AArch64
CPU variant     : 0x1
CPU part        : 0xd07
CPU revision    : 0

Hardware        : linux,dummy-virt
ubuntu@ubuntu:~$

The "init=/usr/lib/cloud-init/uncloud-init ds=nocloud ubuntu-pass=randomstring" is ubuntu cloud stuff that will set the ubuntu user password to "randomstring" - don't use "randomstring" literally there, if you are connected to internets...

For more detailed writeup of using qemu-system-aarch64, check the excellent writeup from Alex Bennee.