Re: [PATCH v11 3/6] x86/sev: Initialize RMPOPT configuration MSRs

[Kalra, Ashish]

On 7/29/2026 10:39 PM, Borislav Petkov wrote:
> On Thu, Jul 30, 2026 at 08:25:37AM +0530, K Prateek Nayak wrote:
>> I believe there can be cases where CPUID advertises
>> X86_FEATURE_SEGMENTED_RMP but rmf_cfg doesn't set
>> MSR_AMD64_SEG_RMP_ENABLED because otherwise checking rmp_cfg in
>> addition to the feature bit makes no sense.
>>
>> In that case we should attempt a probe_contiguous_rmptable_info() even
>> for X86_FEATURE_SEGMENTED_RMP.
>>
>> Essentially drop that "else" and do something like:
>>
>> bool snp_probe_rmptable_info(void)
>> {
>> 	if (cpu_feature_enabled(X86_FEATURE_SEGMENTED_RMP)) {
>> 		rdmsrq(MSR_AMD64_RMP_CFG, rmp_cfg);
>>
>> 		if (rmp_cfg & MSR_AMD64_SEG_RMP_ENABLED)
>> 			return probe_segmented_rmptable_info();
>> 	}
>>
>> 	/*
>> 	 * Segmented RMP is either not supported on the platform or
>> 	 * is disabled by the firmware. RMPOPT is not not supported
>> 	 * without segmented RMP.
>> 	 */
>> 	setup_clear_cpu_cap(X86_FEATURE_RMPOPT);
>>
>> 	return probe_contiguous_rmptable_info();
>> }
> 
> That makes sense.
> 

Ack.

Thanks,
Ashish