make -C build.nova-x86_64 run/demo results in -no-kvm option

[J T]

While trying out different parts of the genode build tree I tried
doing a make -C build.nova-x86_64 run/demo which resulted in something
like this:

...
genode build completed
using NOVA kernel at /home/xx/src/genode/build.nova-x86_64/kernel/hypervisor
creating ISO image...
spawn qemu-system-x86_64 -no-kvm -cpu core2duo -m 256 -serial
mon:stdio -cdrom var/run/demo.iso
qemu-system-x86_64: -no-kvm: invalid option
...

I'm currently running centos 6 as a remote server and doing the builds
there and initially I didn't have qemu-system available on it. It took
me a while to locate an rpm (in rpmforge-extras) that had
qemu-system_x86_64 - however it does not recognise the -no-kvm command
line option.

In fact I'm having trouble locating any documentation for QEMU that
mentions that command line option so I'm wondering whether the option
is bogus or I need to be looking elsewhere to get a qemu install that
has the command with that argument.