Fusion 12.2 on macOS 12.0.1; is there a way to configure the guest's OS's CPUID (enable MSRs)

[srwarner]

investigating further - anyone know if it is possible to present the host's CPUID/information to the guest?

At present the configuration is showing an "Unknown" processor, which of course is different than the host.  This has ramifications on the processor cache topology, and presumably effects the MSR's enabled to be read/written to.

Sam

[srwarner]

my thinking is I might be using the wrong product to achieve what I desire, and that perhaps ESXi is what I need, or perhaps a platform simulator/emulator.  Yet, from what little I found I think this boils down to being able to modify the Hardware platform description (which presently is version 19) to something else.  Yet, it appears there isn't a mechanism to enable modifying the hardware platform for the users.

- anyone know if ESXi is they way to go?

or

- if this is just a transient issue and is WIP to get resolved?

[bluefirestorm]

I don't know about Fusion 12.x as I am still on Fusion 11.5.7 on a Catalina host.

The CPUID info for Intel CPUs such as Family/Model/Stepping, brand string and which features (such as instruction sets) are available in the VM can be manipulated with Fusion 11.x and earlier. Normally it is to mask off features as it is silly/dangerous to present a feature to the VM that doesn't exist in the CPU. I am not so sure about enabling MSRs for the VM to see though. Similar configuration also exists for Workstation Pro/Player on Windows/Linux hosts. All of these configuration while not officially documented, VMware still had to write code to make it possible (i.e. read from config file and make the appropriate VT-x calls).

This undocumented configuration feature is probably a consequence of the vMotion capability in vSphere ESXi where a VM can be moved to run from a newer generation CPU to an older generation CPU (thus certain features needs to be masked).

As 12.x already moved to the Apple Hypervisor Framework, it is really down to Apple Hypervisor Framework. But given that the Apple designed ARM-based CPU ship has already sailed, it is hard to see Apple and/or VMware making more features available for Intel-based CPUs/virtualisation a priority.

[srwarner · Accepted solution]

yes - Apple's product direction tends to make this scenario a bit less valuable - and the only long term solution is a Instruction-Set simulator like Quemu or Simics or etc.  Though with Intel product SKUs still utilizing macOS (MacPro and one variant of the iMac) there still 'hope' for the Intel-macOs-host virtualization. 

For now, the v12 macOS on Intel virtualization solution is only via vSphere.  While Apple provides the API facilities within their architecture - apparently only vShphere allows for this use-case.

progress, :), and products... and yeh, the "Enable" feature disappeared in BigSur or Fusion 12, IDK which - but the option of the mask change, would require a software coupling through to the guest, and it's more work than I cared to do given the above two solutions (ISS or vSphere).   Assuming vSphere works for both the MSR access and general virtualization of the guest  I'll likely transition to solely using this product and drop Fusion.