How to run vagrant in Windows which is running in VMWare Fusion?

I'm running vagrant inside Windows 7.1 which is running in VMWare Fusion on a MacBook Pro (2014 model.)

The problem is that I believe the "vagrant up" needs the VT extensions to be enabled so that I can use ssh to connect to the instance.

I have tried turning this on in VMWare Fusion's settings (obviously I can't do this in the BIOS because Windows in running in a virtual machine) but I get other errors (such as failed startup and messages saying that it is running in gurumaintenance mode(?))

How can I configure my VM Ware Windows 7.1 to let me run vagrant in Windows?