Worked on the geerlingguy/linux repository to refactor TSC MSR handling within the x86 Sev module, focusing on enhancing guest stability and security. The approach involved modifying the behavior of writes to GUEST_TSC_FREQ and MSR_IA32_TSC, so that instead of terminating the guest or ignoring writes, the system now raises a #GP exception. This change reduces the risk of undefined states and improves robustness in MSR handling. Existing security guarantees for reads were preserved, maintaining guest termination for reads from GUEST_TSC_FREQ with Secure TSC enabled. The work utilized C and leveraged expertise in kernel development, security, and x86 architecture.