For some reason, it got rewritten and lost. I agree this needs to be documented again.

We need to add that only a single hypervisor per host is supported. Shared access to VTx can cause instability issues, and in other cases it prevents the second hypervisor to even start.

You should be aware that when Hyper-V is enabled, it prevents any other hypervisor (such as VirtualBox) from accessing VT-x., per this Technet discussion thread.

Some users may wish to install both Hyper-V and Virtual-Box, enabling only one at a time. Such users evidently can only use minishift with Virtualbox, as the presence of an installed (and disabled) Virtualbox means that minishift will try to use it, even when the user passes in the command-line argument "vm-driver=hyperv". That was certainly my experience, as mentioned in #1335

@budhrg agree lets add it to the documentation.

@chrisfalter And this is expected. I know this is what people use to kinda play with having two hypervisors on Windows, But when VTx is disabled it means that VirtualBox does not run optimally, as it can not use the Virtualization Extensions. Hyper-V requires exclusive access to the VTx: https://technet.microsoft.com/en-us/library/cc731898(v=ws.11).aspx, https://technet.microsoft.com/en-us/library/hh831531(v=ws.11).aspx

In short; you can not install both at the same time (and expect them to work). This is a known limitation: https://en.wikipedia.org/wiki/Hyper-V#VT-x_handling I was unable to find the related TechNet articles, but if Wikipedia states it, it must be true ;-). The same goes for using VirtualBox or xhyve on macOS, and VirtualBox or KVM on Linux. You can not use both on the same host. See also: https://forums.virtualbox.org/viewtopic.php?f=6&t=69011#p328864 However, you might be able to try the BCDedit workaround: https://derekgusoff.wordpress.com/2012/09/05/run-hyper-v-and-virtualbox-on-the-same-machine/ But there is no support from us for this and it is not a setup we will ever consider or recommend. I personally test only on exclusive hypervisor setups (stability and consistency is important)

The behaviour as you mentioned is due to libmachine. When VirtualBox is installed alongside the requested 'other' hypervisor, libmachine willp ignore the passed vm-driver. I believe they handle the same reasoning for this due to the shared VTx limitation.

For KVM users, We should ask to cross check if kvm kernel module is loaded or not. If the kvm kernel module is not loaded that means either the required module is not loaded or VTx is not enabled in the BIOS.

$ sudo lsmod | grep kvm
[sudo] password for lmohanty: 
kvm_intel             200704  4
kvm                   598016  1 kvm_intel
irqbypass              16384  1 kvm

@robin-owen old, but very relevant issue

BTW, support for VT-x can be tested for with msr-tools, but that would be an entry in the troubleshooting section.

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