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I have a XP guest in VirtualBox, windows 8 host. The guest shows the processor transparently same as the host (i5 2500k). However most of the installers don't recognize this processors and fail to continue stating non-supported processor.

Is there a way to fool the guest into thinking this is old processor? If I recalll correctly VMWare had a CPU masking feature, is there something similar in virtualbox?

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What software are you installing that checks the CPU model? –  Darth Android Jul 29 '13 at 21:27
Double Agent controls, Orca and Wix. This is for a VB6 project which we are trying to revive. –  IUnknown Jul 30 '13 at 22:48

1 Answer 1

You need to set the VBoxInternal/CPUM/HostCPUID extradata of the virtual machine. This will make VirtualBox report a different CPUID to the guest.

For example to set the model name to Intel(R) Core(TM)2 CPU 6600 @ 2.40 GHz1, run the following vboxmanage commands:

set vm=your-vm-name-or-uuid
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000002/eax 0x65746e49
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000002/ebx 0x2952286c
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000002/ecx 0x726f4320
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000002/edx 0x4d542865
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000003/eax 0x43203229
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000003/ebx 0x20205550
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000003/ecx 0x20202020
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000003/edx 0x20202020
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000004/eax 0x30303636
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000004/ebx 0x20402020
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000004/ecx 0x30342e32
vboxmanage setextradata %vm% VBoxInternal/CPUM/HostCPUID/80000004/edx 0x007a4847

Computer: Intel(R) Core(TM)2 CPU 6600 @ 2.40 GHz

1 The HostCPUID values were taken from bug report #7865.

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