Xen can do full virtualization on systems that support virtualization extensions, but can also work as a hypervisor on machines that don't have the virtualization extensions. KVM is a hypervisor that is in the mainline Linux kernel. ... If you want to run a Xen host, you need to have a supported kernel.

If you get output from the following command:

egrep '^flags.*(vmx|svm)' /proc/cpuinfo

It means your processor CPU can should support KVM

This will provide good info as well:

dmesg | grep kvm

If you have trouble with hypervisor it might simply be disabled in the BIOS.  reboot enable and you will be able to install hypervisors