I tried to tick the box "Enable nested virtualisation" in Configure > Options > Optimization for a couple of Linux virtual machines (Debian 7.4 and Fedora 20, both 64-bit) but then /proc/cpuinfo does not feature the flag vmx whereas sysctl -a does feature it on the host mac pro. This is with the Parallel Tools installed and with Parallel Desktop 9, which is advertised as supporting nested virtualisation for Linux guest. Is this overstated? Or does it only work with a short selection of Linux flavours? Or am I missing something more fundamental?
Thanks for your suggestion. However it does not work: still no vmx flag. Besides, here is the grub config after entering this line in the configuration: where is kernel.nvmx.enable=1?
It is not a linux kernel boot flag. It is boot flag related to VM. You can set it at the VM configuration Editor's page Virtual Machine -> Configure -> Hardware -> Boot Order.
My problem is similar to the OP except I am trying this with CentOS 6.5. I'm running Parallels Desktop 9 for Mac(updated and with Parallel Tools) on an iMac with Mavericks. I've tried the boot flag suggested and there was no difference in results. Now, I have checked all over the internet and have seen some people say that even though you see the VMX flag on your Mac, VT-x may not be turned on. But I have created and been running 3 CentOS VM's and one Fedora VM on my Mac with Parallels so I figure this means that VT-x is enabled. Am I right about that? On the CentOS VM that I am trying nested virtualization the KVM daemon will not start and I get the following message "server1 kernel: kvm: no hardware support" Has anyone had success with nested virtualization?