All, These days I am trying to understand the interaction relationship between the libvirt and KVM kernel module, eg. kvm_intel.ko. We know that KVM kernel module expose an entry in form of device file "/dev/kvm" which can be accessed by user space application to control, for example, create a VM using KVM_CREATE_VM with help of ioctl. Now let's say the tool virsh based upon libvirt, we can create a guest domain with the command looks like: #virsh create guest.xml Obviously, the above command will create a VM. But when I try to investigate the libvirt code, I can't find any code play with the "/dev/kvm" to send KVM_CREATE_VM ioctl code to KVM kernel module. But I do found that the reference count of the kvm_intel.ko changed before the virsh create command launched and after. So my question is: how does the libvirt interaction with KVM to create a VM? Anybody can give me some tips about that, eg, the corresponding codes in libvirt? BRs. Dennis