Running qemu on ARM with KVM acceleration

Question

I'm trying to emulate an ARM VM on an ARM host, a cubieboard2 embedded board, by means of qemu. I've compiled qemu from the source code and enabled kvm. Now the problem is that launching qemu-system-arm as follows:

$ /usr/local/bin/qemu-system-arm -M accel=kvm -cpu host -kernel vmlinuz-3.2.0-4-vexpress -initrd initrd.img-3.2.0-4-vexpress -sd debian_wheezy-_armhf_standard.qcow2 -append "console=ttyAMA0 root=/dev/mmcblk0p2" -nographic

I have this error:

qemu-system-arm: -M accel=kvm: Unsupported machine type
Use -machine help to list supported machines!

What is wrong in the command I've typed. How to enable kvm?

Answer 1

How about reading this:

https://groups.google.com/forum/#!topic/cubieboard/4EGONZMoIAU

And yes, you are right, as the Cubieboard2 has A15, HYP hypervisor is implemented and KVM should be running in it.

More about HYP mode is covered here:

http://lwn.net/Articles/557132/

there is another way you can see the failing mode (why qemu command failed): execute your command under "strace", and you will be able to clearly see when /dev/kvm is opened, and if it succeed, non-zero fd will be returned after open("/dev/kvm") is called. and before all this - "lsmod" should return a line indicating "kvm.ko" kernel module is running, and if you can read your kernel's config file, there should be a "CONFIG_KVM" embedded within.

Answer 2

-M takes a machine name (eg "vexpress-a15" or "virt"), not a set of suboption=value settings. You want -machine suboption=value,... for that.

("-M name" is a shortcut for "-machine type=name".)

You also need to specify a machine name, either via -machine type=name or -M name, otherwise QEMU will complain that you didn't specify one.