Re: [edk2-devel] [PATCH v12 32/32] UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation NAE event to launch APs

["Brijesh Singh" <brijesh.singh@amd.com>]

On 11/11/21 8:09 PM, Ni, Ray wrote:
> Acked-by: Ray Ni <ray.ni@intel.com>

thanks!

> 
> 3 comments:
> 
> 1. It seems to me that the latest SevSnp doesn't need much special handling in AP waking up flow.
>       Is there a plan to drop the old SevEs so that the MpInitLib logic can have a chance to be back to normal?


The EPYC3 family supports SEV, SEV-ES and SEV-SNP.
The EPYC2 family supports SEV and SEV-ES.
The EPYC1 family supports SEV.

So, as you can depending on the user platform/configuration, they may 
boot the VM using the SEV-ES. We may have to keep it around for sometime 
and see how it goes.

> 
>>   [Sources.IA32]
>> +  Ia32/AmdSev.c
>>     Ia32/MpFuncs.nasm
>>
>>   [Sources.X64]
>> +  X64/AmdSev.c
>>     X64/MpFuncs.nasm
> 
> 2. I am not sure if it's a good idea that "THREE" files share the same name. Any objections from others?
> 
>> @@ -1056,9 +1057,12 @@ AllocateResetVector (
>>                                       );
>>       //
>>       // The AP reset stack is only used by SEV-ES guests. Do not allocate it
>> -    // if SEV-ES is not enabled.
>> +    // if SEV-ES is not enabled. An SEV-SNP guest is also considered
>> +    // an SEV-ES guest, but uses a different method of AP startup, eliminating
>> +    // the need for the allocation.
>>       //
>> -    if (ConfidentialComputingGuestHas (CCAttrAmdSevEs)) {
>> +    if (ConfidentialComputingGuestHas (CCAttrAmdSevEs) &&
>> +        !ConfidentialComputingGuestHas (CCAttrAmdSevSnp)) {
> 
> 3. Can you use "CpuMpData->UseSevEsAPMethod" in above if check?
> 
> 
>   
>