VT-X/AMD-V grayed out

Discussions related to using VirtualBox on Mac OS X hosts.
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EdgarM19964
Posts: 2
Joined: 1. Dec 2022, 17:24

VT-X/AMD-V grayed out

Post by EdgarM19964 »

Using a 2016 macbook pro and running VirtualBox 6.1.40 r154048, I've noticed that nested virtualisation is not "working." When I run a linux guest os (centos 7) and excute "grep vmx /proc/cpuinfo" I get no results. Why not? Do I need to enable things in Monterey? I've attached the log VM log file.

Kind regards, Edgar Matzinger.
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ghdl-2022-12-01-16-21-31.log
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scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: VT-X/AMD-V grayed out

Post by scottgus1 »

Your Intel processor is missing an important feature for good nested virtualization:
Forum guru fth0's nested VM feature list wrote:00:00:00.127135 VMX - Virtual-Machine Extensions = 0 (1)
00:00:00.127147 Ept - Extended Page Tables = 0 (1)
00:00:00.127153 UnrestrictedGuest - Unrestricted guest = 0 (1)
00:00:00.127155 VmcsShadowing - VMCS shadowing = 0 (0)
The other three may let a nested VM run, but not as well. Additionally, not all features get passed through completely: for example, Windows Virtualbox can pass VT-x into the VM for a Windows OS to run nested Virtualbox. But the first Windows VM cannot run its Hyper-V, because SLAT cannot pass through yet.

Perhaps the feature your command tests does not pass through.
EdgarM19964
Posts: 2
Joined: 1. Dec 2022, 17:24

Re: VT-X/AMD-V grayed out

Post by EdgarM19964 »

Hello Scott,

thanks for the information. It seems that the CPU in my macbook pro doesn't support vmcs shadowing. Ah well, too bad.

Edgar.
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