Re: [PATCH v4 1/2] x86/sev: Clear RMPOPT when segmented RMP is disabled by firmware

[Kalra, Ashish]

On 11/2/2026 3:43 PM, Borislav Petkov wrote:
> On Mon, Nov 02, 2026 at 03:25:52PM -0600, Tom Lendacky wrote:
>> The current code clears X86_FEATURE_RMPOPT when
>> probe_segmented_rmptable_info() fails. The above code doesn't.
> 
> See the hunk in cpuid-deps.c
> 
>> But since SNP will be disabled on failure of snp_probe_rmptable_info(),
>> I guess it doesn't matter. In which case you can eliminate the goto by
>> doing:
> 
>>
>> 	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();
>> 	}
>>
>> 	setup_clear_cpu_cap(X86_FEATURE_RMPOPT);
>> 	return probe_contiguous_rmptable_info();
>>
>> Which looks pretty clean.
> 
> Yap.

LGTM, tested on HW.

Thanks,
Ashish

> 
>>> diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
>>> index 99801e844b30..acbcec394ef1 100644
>>> --- a/arch/x86/kernel/cpu/cpuid-deps.c
>>> +++ b/arch/x86/kernel/cpu/cpuid-deps.c
>>> @@ -93,6 +93,7 @@ static const struct cpuid_dep cpuid_deps[] = {
>>>  	{ X86_FEATURE_SPEC_CTRL_SSBD,		X86_FEATURE_SPEC_CTRL },
>>>  	{ X86_FEATURE_LASS,			X86_FEATURE_SMAP      },
>>>  	{ X86_FEATURE_INVLPGB,			X86_FEATURE_PCID      },
>>> +	{ X86_FEATURE_RMPOPT,			X86_FEATURE_SEV_SNP   },
> 
> This hunk.
>