There seem to be 3 likely files changed in 4.8.18 which could be responsible for this problem: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/log/arch/x86/kvm/mmu.c?h=v4.18.8 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/log/arch/x86/kvm/vmx.c?h=v4.18.8 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/log/arch/x86/kvm/x86.c?h=v4.18.8 Can you tell if any of these is the cause of virtualisation not working on Conroe ?