Lead maintainer Avi Kivity recently posted an article on his personal blog about upcoming nested virtualizaton support for intel hosts in kvm. This comes about a year after kvm supported nested virtualization in amd hosts because of the relative complexity of the intel vmx extensions. This feature will also include extended page table (EPT) support for guests which is important for reasonable guest performance. For more details you can read the origianl post at the link below.

http://avikivity.blogspot.com/2009/09/nested-vmx-support-coming-to-kvm.html