Removing CPUID settings?

[justin_emerson]

I'm working on a cluster where it seems like half the VMs have advanced CPUID settings on them. We are migrating them to vSphere and we need to remove all these (EVC will do it for us). I've seen several threads on how to set this value, but nothing on how to remove it. What I'm looking for is the POwerCLI equivalent of checking the 'expose NX flag to guest" radio button (the second option). I could set the advanced CPU mask to all -'s but that's different that removing everything. Any suggestions? The API documentation doesn't show how to remove it, as far as I can tell (of course, I'm not a master when it comes to the actual API).

Any help would be very appreciated.

[LucD]

The following script should allow you to set the Nx flag to Hidden or Exposed.

filter Set-NxFlag {
	param([switch]$hide = $false)
	$view = get-view $_.id

	$vmConfigSpec = new-object VMware.Vim.VirtualMachineConfigSpec
	$featureMask = new-object VMware.Vim.VirtualMachineCpuIdInfoSpec
	$featureMask.Operation = "edit"
	$featureMask.info = new-object VMware.Vim.HostCpuIdInfo
	$featureMaskAMD = new-object VMware.Vim.VirtualMachineCpuIdInfoSpec
	$featureMaskAMD.Operation = "edit"
	$featureMaskAMD.info = new-object VMware.Vim.HostCpuIdInfo

	if($hide){
		$featureMask.info.edx = "-----------0--------------------"
		$featureMaskAMD.info.edx = "-----------0--------------------"
	}
	else{
		$featureMask.info.edx = "-----------H--------------------"
		$featureMaskAMD.info.edx = "-----------H--------------------"
	}

	$featureMask.info.level = 0x80000001
	$featureMaskAMD.info.level = 0x80000001
	$featureMaskAMD.info.vendor = "amd"
	$vmConfigSpec.CpuFeatureMask = $featureMask,$featureMaskAMD

	$view.ReconfigVM($vmConfigSpec)
}

Get-VM <VM-name> | Set-NxFlag -Hide:$false

The function Set-NxFlag is conceived as a filter, this will allow you to use it in a pipeline.

The -Hide switch allows to specify if the Nx flag should be hidden (-Hide:$true) or exposed (-Hidden:$false).

[justin_emerson]

LucD,

Thank you so much. Will this erase all the custom CPUID settings that are set?

[LucD · Accepted solution]

Yes, it will. The script does the same as the "expose NX flag to guest" radio button.

You want to just set the Nx flag bit in the mask ? Like the "Advanced" option ?

That requires a different logic but is possible as well.

Just let me know.

[justin_emerson]

LucD,

Setting the radio button (which removes all the custom attributes) is exactly what I need. Thanks so much, I'll let you know if it works.

[justin_emerson]

LucD,

This did exactly what I needed. Thanks again. A "you're welcome" post would earn you an extra 1 forum point

[LucD]

You're welcome

Seriously, feel free to ask.

[ngerasim]

What would happen if this was run against a group of VMs that were still powered on?

My understanding was this change should/could only be made when the VM is in a powered off state. Any advice?

[LucD]

I think the script will run without a problem, but when you power off the guest the values in the VMX file will be overwritten with the active CPUID settings.

____________

Blog: LucD notes

Twitter: lucd22

[ngerasim]

So in theory if I was to run this, and then power cycle the VMs after, they would attain the new reset values?

[ngerasim]

I get the error.

The ' | Set-NxFlag -Hide:$true

[LucD]

The text "<VM-name>" serves as a placeholder.

You would have to replace that string with a name of one of your VMs.

____________

Blog: LucD notes

Twitter: lucd22

[ngerasim]

What if I wanted to use this as a wildcard though?

[LucD]

That would work without a problem with the filter function.

The last line would be something like this

Get-VM PC* | Set-NxFlag -Hide:$false

which would select all guests whose name starts with "PC".

____________

Blog: LucD notes

Twitter: lucd22