Using KVM and Virtual Box side by side

Hi there,
I want to use KVM and Virtual Box side by side on my Linux and this failure appears and closes the processes. Any solution for this ? Can anyone tell me please what I did wrong ?
Thank you experts !

VirtualBox – Error
Filed to open a session for the virtual machine Windows-XP-SP3.
VirtualBox can’t operate in VMX root mode. Please disable the KVM Kernel extension, recompile your kernel and reboot
(VERR_VMX_IN_VMX_ROOT_MODE).
