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VMX option to disable use of XSAVE instruction under Big Sur

  • 1.  VMX option to disable use of XSAVE instruction under Big Sur

    Posted Sep 18, 2020 04:59 PM

    I am running Big Sur on "unsupported" hardware - a Mac Pro 5,1. With updated graphics and WiFi/BLE it is actually running without patches,

    To avoid KEXTs VMware 12 is using some extended instructions  like XSAVE under Big Sur. Parallels still allows using it with KEXTs and works fine right now.

    Is there a VMX parameter to disable this?

    monitor.allowLegacyCPU = "true" does not do it.



  • 2.  RE: VMX option to disable use of XSAVE instruction under Big Sur

    Broadcom Employee
    Posted Sep 18, 2020 07:48 PM

    Unlikely... on Big Sur it's an entirely new monitor stack.

    We would have to load the entire vmx86 kext, and that can't happen on Big Sur.

    I'm curious tho, what is the use case behind the request?



  • 3.  RE: VMX option to disable use of XSAVE instruction under Big Sur

    Posted Sep 19, 2020 08:58 AM

    The use case?

    That's easy, you can not use VMWare Fusion 12 at cMP 5.1 any longer. I have the same problem, it's not possible to open a VM because there is an error message of missing XSAVE support.

    sysctl -a | grep machdep.cpu.features

    machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX SMX EST TM2 SSSE3 CX16 TPR PDCM SSE4.1 SSE4.2 POPCNT AES PCID

    Independently of the guest OS, nothing works. As guest OS it's no problem to start Big Sur with Fusion 12 on Catalina (same machine cMP 4.1 > 5.1, 2x X5680 @3.33GHz).

    I'm wondering why Parallels has no problems with this, Big Sur as host starts all old Parallel VMs and also Big Sur as guest OS with the latest version 16. So technically it's possible.



  • 4.  RE: VMX option to disable use of XSAVE instruction under Big Sur

    Posted Sep 22, 2020 12:13 AM

    Parallels loads the KEXT and it works.

    Guess I am switching. I have used VMware products since Workstation 1 beta!



  • 5.  RE: VMX option to disable use of XSAVE instruction under Big Sur

    Broadcom Employee
    Posted Sep 22, 2020 01:08 AM

    Looks like you're using Big Sur... That Mac Pro isn't supported on macOS 11.x.

    On Big Sur, we've completely done away with Kernel Extensions, quite deliberately.

    As such, the remaining limitations are due to Apple's hypervisor API implementation. It requires certain hardware features.

    I'm surprised it even boots on that Mac, tbh.



  • 6.  RE: VMX option to disable use of XSAVE instruction under Big Sur

    Posted Sep 22, 2020 08:27 AM

    I know that the hardware is not supported but this has been the case since Catalina, regardless Fusion worked perfect for me. The point is that Parallels 16 works anyway on Mac Pro 5.1. For me as normal user it's totally irrelevant how they technically implemented it, it works.

    I will not buy a new machine only because Fusion is not working any longer on this machine, but Big Sur does. I guess it's time to say good bye after years. What a bummer, Fusion was always the better solution for me because of the interchange with VM Workstation on Windows.

    There are a lot of Mac's which are unsupported but still will run Big Sur -> https://forums.macrumors.com/threads/macos-11-big-sur-on-unsupported-macs-thread.2242172/ .

    At least an option to handle this would be nice, like haralds​ asked for.



  • 7.  RE: VMX option to disable use of XSAVE instruction under Big Sur

    Posted Nov 01, 2020 08:06 PM

    I would like to add that running VMWare 12 on Big Sur on a MacPro5,1 is a desired use case for me as well.



  • 8.  RE: VMX option to disable use of XSAVE instruction under Big Sur