Unable to Write in MSR_EBC_FREQUENCY_ID (0x2C) on Pentium 4 Processor

Question

I want to modify "Core Clock Frequency to System Bus Frequency Ratio BITS[31:24]" in register MSR_EBC_FREQUENCY_ID (0x2C) on Pentium 4 desktop processor by developing a Linux Kernel Module (LKM/Driver). Below the processor details.

Name: Intel(R) Pentium(R) 4, Type: 0, Family: 15 (0xF), Model: 2, Stepping: 7

Ref: https://software.intel.com/sites/default/files/managed/22/0d/335592-sdm-vol-4.pdf (Page-316, Table 2-44).

But the write call (wrmsr) unable to write the desired value in the register!!!

Please let me know how can I write on this MSR? Do I need to do other things to write on this register?

Thanks in advance.

Answer 1

These bits are read-only according to Intel SDM:

31:24 Core Clock Frequency to System Bus Frequency Ratio (R)