Contributor
Contributor

Linux: nested virtualization is not working

Hi,

the options reported here:

https://www.server-world.info/en/note?os=CentOS_7&p=vmware_player&f=3

appear when I use the player under windows but not under linux.

I need to be able to set at least "Intel VT-x/EPT or AMD-V/RVI" but in this screen the only option available is related to the counters.

Can you help me to use nested virt even under linux, please?

Massimo

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5 Replies
Contributor
Contributor

Auto reply for other people who may incors in the same problem:

I had also VirtualBox in my machine. I have to disinstall it and now it works.

Best,

Massimo

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Contributor
Contributor

I spoke too early.

By using an Ubuntu 20.04 to create a new VM, the option during the VM creation are disabled.

Anyone who can help me, please?

M

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Virtuoso
Virtuoso

The "Preferred Mode" dropdown is no longer available starting from version 14. It will use Intel VT-x/EPT (or AMD-V/RVI) automatically for the VM. Binary translation for VM execution and software-based shadowing for virtual RAM management was removed from version 14.

If Hyper-V is enabled on the Windows host, starting from version 15.5.5, power up of VM will fail if either "Virtualize Intel VT-x/EPT ir AMD-V/RVI" is enabled or "Virtualize CPU performance counters" is enabled. This is because the ring 3 User Level Monitor (ULM) that uses the Windows Hypervisor API is the virtual machine monitor instead of the usual ring 0 VMM.

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Contributor
Contributor

After different attempts, I figure out that this option is not available during the creation of the VM, but after created that, I have the options enabled.

I'm running android studio in a Ubuntu VM 20.04.

The problem now is the performance: in my Fedora 32, with i7 and 16 GB of ram the emulator started by android studio is too slow.

I changed my laptop due to android studio running on my physiscal machine. It seems that I have to change it again for android studio but this time inside a VM. Too bad.

Best,

M

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Virtuoso
Virtuoso

For nested virtualisation, it is best to have at least Haswell generation (4th gen Core) or newer. For laptop CPUs, it gets a little bit trickier as not all Haswell virtualisation features that are good for running nested VMs are available in all models.

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