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Mohanr23
Contributor
Contributor

Need help CPUID masking to work with Coffee lake processor

Hi Friends,

I tried building my first ever home lab using latest and fast CPU i7 8700 hoping this will help me to test most of the VMware products, however I ended up with problems now.

I am not sure if I made a wrong choice but I am ended up with a problem where I am unable to get VMs powered on on a neated ESXi host configured on VMware workstation.

I tried by installing ESXi(any version 6/6.5/6.7) os on an intel i7 8700 processor with Z370 chipset on my home lab. When I verified the VMware.log for the vm hosted on nested esxi os found a list with feature compatible and required one's.

Later I realized this CPU family is not in VMware HCL.

Now I am trying a way to get my home lab to work.

I visited many blogs and what I understand is that I have to make a CPUID change that can fool the VM as if it's running on the older INTEL CPU family.

Now I am looking for some help for changing the CPUID in the VMX file for the VM to behave like a i7 7700 or even lower CPU family.

Kindly help me to get my home lab working.

Also please suggest if any other method to get this working.

Also I wanted to understand if Windows 10 is causing some problem as I read similar iaauis reported in community blogs for VMware.

Thanks,

Murali

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bluefirestorm
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You don't describe the problem(s) that you face with the ESXi VM running under Workstation Pro on Coffee Lake CPU. You also don't mention what the version of Workstation Pro. Workstation 12.x does not recognise even Kaby Lake CPUs.

Generally, if the CPU is not recognised certain advanced functions may not work but as far as other features, VMware ESXi (even Workstation Pro) does not decide based on CPU model alone. It does an actual inquiry into the actual capabilities.

If you look at the compatibility guide CPU series, it goes up to only Skylake.

https://www.vmware.com/resources/compatibility/detail.php?deviceCategory=cpu&productid=119

You can shut down the ESXi VM and add the following lines to mask it to look like a Skylake Xeon.

cpuid.1.eax = "0000:0000:0000:0101:0000:0110:0101:100"

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Mohanr23
Contributor
Contributor

Hi,

Thanks for your reply.

I tried installing esxi on VMware workstation 14 and also on workstation 15 on a Windows 10 os.

I was able to install esxi 6.0/6.5/6.7 on the workstation VMs. However when I try to create VM within ESXi it gets created but its failing to power on. After sometime the ESXi VM hosted on VMware workstation stops responding in web client (faced this issue only on version 6.5 and 6.0) but able to manage in DCUI.

When I look into the VMware.log for VM I can see logs for "CPU feature required" ones and also I see Difference in CPUID is different from the host CPUID. So I was suspecting masking CPUID could help me out with this problem.

I will try to upload some screenshots and the VMware.log soon.

Thanks,

Murali

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Mohanr23
Contributor
Contributor

Also forgot to mention ESXi host 6.0 and 6.5 stops responding to ping it gets crashed sometimes. I didn't face this problem with version 6.7

Thanks

Murali

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bluefirestorm
Champion
Champion

Giving you the CPUID mask may not solve the problem as I don't know what exactly the problem is. You asked for the masking and it is analogous to going to a doctor to get some medication that may not necessarily be what is needed.

Yes, it is best to attach the vmware.log of the ESXi VM.

There is an "Attach" link at the lower right hand side of this Reply box.

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Mohanr23
Contributor
Contributor

Hi, Sorry for the late response. I did few more tests and found issues with Windows 10 os. Tried to fix the issues using MS KB article however they didn't help me much. Really not sure if third-party antivirus software avg or Avast caused an issue to the virtualization feature of Windows defender. I reinstalled Windows 10 OS and I am able to get the nested virtualization working fine on my new coffee lake i7 8700 processor.

Thanks,

Murali

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