10

After installing Ubuntu 11.10 and copying my KVM images which were created on Ubuntu 11.04 over to the new system, I notice that Virt-manager says it's using QEMU and not KVM. Also when running virsh version it says Running hypervisor: QEMU 0.14.1.

However, when I run kvm-ok it says INFO: /dev/kvm exists and KVM acceleration can be used. Also, the XML file of my VM clearly states it should use KVM: <domain type='kvm'> <emulator>/usr/bin/kvm</emulator>.

Furthermore, lsmod |grep kvm shows the following (when the VM is running):

kvm_intel              61643  3
kvm                   383822  1 kvm_intel

So how do I know if KVM or QEMU is being used? And why am I getting such contradictory output of these different commands?

9

Because kvm builds on top of QEMU, it's just a hw acceleration.

With this you can see that the actual process running your VM is a kvm process.

ps xa| grep "[b]in/kvm"
  • Fantastic, that clearly shows I'm really using KVM. Thanks! – iGadget Oct 29 '11 at 12:10
4

http://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine#Design

By itself, KVM does not perform any emulation. Instead, a user-space program uses the /dev/kvm interface to set up the guest VM's address space, feeds it simulated I/O and maps its video display back onto the host's. QEMU versions 0.10.0 and later make use of this.

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