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>>>>   } >>>>   +static bool check_and_enable_sev_snp_ciphertext_hiding(void) >>>> +{ >>>> +    unsigned int ciphertext_hiding_asid_nr = 0; >>>> + >>>> +    if (!sev_is_snp_ciphertext_hiding_supported()) { >>>> +        pr_warn("Module parameter ciphertext_hiding_asids specified but ciphertext hiding not supported or enabled\n"); >>>> +        return false; >>>> +    } >>>> + >>>> +    if (isdigit(ciphertext_hiding_asids[0])) { >>>> +        if (kstrtoint(ciphertext_hiding_asids, 10, &ciphertext_hiding_asid_nr)) { >>>> +            pr_warn("Module parameter ciphertext_hiding_asids (%s) invalid\n", >>>> +                ciphertext_hiding_asids); >>>> +            return false; >>>> +        } >>>> +        /* Do sanity checks on user-defined ciphertext_hiding_asids */ >>>> +        if (ciphertext_hiding_asid_nr >= min_sev_asid) { >>>> +            pr_warn("Requested ciphertext hiding ASIDs (%u) exceeds or equals minimum SEV ASID (%u)\n", >>>> +                ciphertext_hiding_asid_nr, min_sev_asid); >>>> +            return false; >>>> +        } >>>> +    } else if (!strcmp(ciphertext_hiding_asids, "max")) { >>>> +        ciphertext_hiding_asid_nr = min_sev_asid - 1; >>>> +    } else { >>>> +        pr_warn("Module parameter ciphertext_hiding_asids (%s) invalid\n", >>>> +            ciphertext_hiding_asids); >>>> +        return false; >>>> +    } >>> >>> This code can be made much simpler if all the invalid >>> cases were combined to emit a single pr_warn(). >>> >> >> There definitely has to be a different pr_warn() for the sanity check case and invalid parameter cases and sanity check has to be done if the >> specified parameter is an unsigned int, so the check needs to be done separately. >> >> I can definitely add a branch just for the invalid cases. >> >>>> @@ -3036,7 +3090,9 @@ void __init sev_hardware_setup(void) >>>>               min_sev_asid, max_sev_asid); >>>>       if (boot_cpu_has(X86_FEATURE_SEV_ES)) >>>>           pr_info("SEV-ES %s (ASIDs %u - %u)\n", >>>> -            str_enabled_disabled(sev_es_supported), >>>> +            sev_es_supported ? min_sev_es_asid < min_sev_asid ? "enabled" : >>>> +                                        "unusable" : >>>> +                                        "disabled", >>>>               min_sev_es_asid, max_sev_es_asid); >>>>       if (boot_cpu_has(X86_FEATURE_SEV_SNP)) >>>>           pr_info("SEV-SNP %s (ASIDs %u - %u)\n", >>> >>> If I set ciphertext_hiding_asids=99, I get the new 'unusable': >>> >>> kvm_amd: SEV-SNP ciphertext hiding enabled >>> ... >>> kvm_amd: SEV enabled (ASIDs 100 - 1006) >>> kvm_amd: SEV-ES unusable (ASIDs 100 - 99) >>> kvm_amd: SEV-SNP enabled (ASIDs 1 - 99) >>> >>> Ok. >> >> Which is correct. >> >> This is similar to the SEV case where min_sev_asid can be greater than max_sev_asid and that also emits similarly : >> SEV unusable (ASIDs 1007 - 1006) (this is an example of that case). >> > > Also do note that the message above is printing the exact values of min_sev_es_asid and max_sev_es_asid, as they have been computed. > > And it adds that SEV-ES is now unusable as now min_sev_es_asid > max_sev_es_asid. Right, it'd be nice if that were made clearer to the user, too: min_sev_es_asid 100 > max_sev_es_asid 99 >>> Now, if I set ciphertext_hiding_asids=0, I get: >>> >>> kvm_amd: SEV-SNP ciphertext hiding enabled >>> ... >>> kvm_amd: SEV enabled (ASIDs 100 - 1006) >>> kvm_amd: SEV-ES enabled (ASIDs 1 - 99) >>> kvm_amd: SEV-SNP enabled (ASIDs 1 - 0) >>> >>> ..where SNP is unusable this time, yet it's not flagged as such. >>> >> >> Actually SNP still needs to be usable/enabled in this case, as specifying ciphertext_hiding_asids=0 is same as specifying that ciphertext hiding feature should >> not be enabled, so code-wise this is behaving correctly, but messaging needs to be fixed, which i will fix. >> > > And i do need to fix this case for ciphertext_hiding_asids==0, i.e., ciphertext hiding feature is not enabled, as the above is not functioning correctly. Right, it's not just messaging, SNP should still be enabled when ciphertext_hiding_asids==0, whereas this is not the case with this patchset. > > Thanks, > Ashish > >> >>> If there's no difference between "unusable" and not enabled, then >>> I think it's better to keep the not enabled messaging behaviour >>> and just not emit the line at all:  It's confusing to see the >>> invalid "100 - 99" and "1 - 0" ranges. Please also consider this. Thanks, Kim