When live migrating from ESX 3.0.2 to ESX 3.5 VMware gives an error:”Migration will cause the virtual machine’s configuration to be modified, to preserve the CPU feature requirements for its guest OS.” This error indicates that the .vmx file is about to be changed.


In my case VMware added the following bit:

cpuid.1.eax = “xxxx————xx————–”
cpuid.1.ecx = “——–R–RR——————-”
cpuid.1.edx = “—————————T—-”
cpuid.80000001.eax.amd = “xxxx————xx————–”
cpuid.80000001.ecx.amd = “—————————-0—”
cpuid.80000001.edx = “——————–H———–”
cpuid.80000001.edx.amd = “—–R————–H——T—-”

This CPU masking surprised me because both Servers are completely the same. Than again ESX 3.5 contains Paravirtualization and Virtualized MMU, and I can image that this functionality is exposed to the VCPU and doesn’t need to be exposed in ESX 3.0.2. Anyone else any thoughts on this?