Re: [PATCH v9 2/2] KVM: SEV: Add SEV-SNP CipherTextHiding support

[Kalra, Ashish]

On 8/21/2025 5:30 AM, Kim Phillips wrote:
> On 8/20/25 6:23 PM, Kalra, Ashish wrote:
>> On 8/20/2025 5:45 PM, Randy Dunlap wrote:
>>> On 8/20/25 1:50 PM, Ashish Kalra wrote:
>>>> @@ -3064,10 +3070,32 @@ void __init sev_hardware_setup(void)
>>>>   out:
>>>>       if (sev_enabled) {
>>>>           init_args.probe = true;
>>>> +
>>>> +        if (sev_is_snp_ciphertext_hiding_supported())
>>>> +            init_args.max_snp_asid = min(nr_ciphertext_hiding_asids,
>>>> +                             min_sev_asid - 1);
>>>> +
>>>>           if (sev_platform_init(&init_args))
>>>>               sev_supported = sev_es_supported = sev_snp_supported = false;
>>>>           else if (sev_snp_supported)
>>>>               sev_snp_supported = is_sev_snp_initialized();
>>>> +
>>>> +        if (sev_snp_supported)
>>>> +            nr_ciphertext_hiding_asids = init_args.max_snp_asid;
>>>> +
>>>> +        /*
>>>> +         * If ciphertext hiding is enabled, the joint SEV-ES/SEV-SNP
>>>> +         * ASID range is partitioned into separate SEV-ES and SEV-SNP
>>>> +         * ASID ranges, with the SEV-SNP range being [1..max_snp_asid]
>>>> +         * and the SEV-ES range being [max_snp_asid..max_sev_es_asid].
>>>                                       [max_snp_asid + 1..max_sev_es_asid]
>>> ?
>> Yes.
> 
> So why wouldn't you have left Sean's original "(max_snp_asid..max_sev_es_asid]" as-is?
> 
> Kim
> 

Because that i believe is a typo and the correct SEV-ES range is [max_snp_asid + 1..max_sev_es_asid].

Ashish