On 12/17/2024 4:27 PM, Borislav Petkov wrote: > On Thu, Dec 12, 2024 at 10:23:01AM +0530, Nikunj A. Dadhania wrote: >> @@ -1477,19 +1480,13 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt) >> case MSR_SVSM_CAA: >> return __vc_handle_msr_caa(regs, write); >> case MSR_IA32_TSC: >> - return __vc_handle_msr_tsc(regs, write); >> + case MSR_AMD64_GUEST_TSC_FREQ: >> + if (sev_status & MSR_AMD64_SNP_SECURE_TSC) >> + return __vc_handle_msr_tsc(regs, write); With the above change, non-Secure TSC SNP guest will return following error: $ sudo rdmsr 0xc0010134 rdmsr: CPU 0 cannot read MSR 0xc0010134 $ > Now push that conditional inside the function too. With the condition inside the function, even tough the MSR is not valid in this configuration, I am getting value 0. Is this behavior acceptable ? $ sudo rdmsr 0xc0010134 0 $ Regards, Nikunj
