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I'ms crawling among docs, sites etc. to understood relation between two ESXi parameters of VMs: "Expose hardware assisted" and "CPU/MMU configuration".

The first is about to authorize VM to directly use VT-X/AMD-V instruction and not virtualize/emulate it (64bits VM or nested deployement)

But i didn't get about the second one... VMWare's documentation talk also about CPU VT-X access for this parameters... so i was wondering about any overlapping or relationship (is the second one could be consider as the policy for the first one?)..

If an expert could enlight me?

thanks!

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Answering (and solved) by myself (many thanks also to Amin Masoudifard):

https://communities.vmware.com/message/2886984#2886984

You understood MMU hardware assisted will avoid the use of guest shadow tables, and roughly, the result is to reduce latency to access to page tables.

But what about the CPU? Why can we activate CPU hardware virtualization here ("CPU/MMU virtualization: Hardware CPU, software MMU") and also on the other parameters ("Hardware virtualization: Expose hardware assisted virutalization to the guest os")?

What are the differences between the two CPU features? Because when you red documentation for "*CPU/MMU virtualization: Hardware CPU, software MM***U" and "***Hardware virtualization: Expose hardware assisted virutalization to the guest os*" they are talking together about using VT-X.

Here is the answers:

  • Do your VM are 64 bits are need to make nested virtualization? Check Expose hardware assisted virutalization to the guest os

    => this is for Guest optimization

  • Do you have VT-X/AMD-V instructions? To optimize VMWare VMM mechanisms, select CPU Hardware.

    => this is for Host optimization

  • Do you have Intel EPT/AMD NPT instructions? To optimize VMWare VMM mechanisms, select MMU Hardware.

    => this is for Host optimization

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