Apparatus and method for updating set of limited access model specific registers in a microprocessor

A method for protecting access to model specific registers (MSRs) within a microprocessor, the method comprising:

• encountering an instruction that accesses a specified MSR of the MSRs;
• determining whether a fuse associated with the specified MSR is blown or unblown;
• using a default value associated with the specified MSR as an indicator of whether the specified MSR is protected if the fuse associated with the specified MSR is unblown;
• toggling the default value associated with the MSR to generate the indicator if the fuse associated with the specified MSR is blown;
• protecting access to the specified MSR if the indicator indicates the specified MSR is protected;
• and
• refraining from protecting access to the specified MSR if the indicator indicates the specified MSR is non-protected.

A computer program product for use with a computing device, the computer program product comprising:

• a computer usable storage medium, having computer readable program code embodied in said medium, for specifying a microprocessor having model specific registers (MSRs), the computer readable program code comprising:
• first program code for specifying for each of the MSRs, an associated default value that indicates whether the MSR is protected or non-protected;
• and
• second program code for specifying for each of the MSRs, an associated fuse that, if blown, toggles the associated default value from protected to non-protected or non-protected to protected.