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Re: [RFC PATCH 0/6] Add AMD Secure Nested Paging (SEV-SNP) support
From: |
Brijesh Singh |
Subject: |
Re: [RFC PATCH 0/6] Add AMD Secure Nested Paging (SEV-SNP) support |
Date: |
Wed, 14 Jul 2021 09:23:34 -0500 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 |
On 7/14/21 4:52 AM, Dr. David Alan Gilbert wrote:
> * Brijesh Singh (brijesh.singh@amd.com) wrote:
>>
>> On 7/13/21 3:05 AM, Dov Murik wrote:>
>>> Particularly confusing is the `policy` attribute which is only relevant
>>> for SEV / SEV-ES, while there's a new `snp.policy` attribute for SNP...
>>> Maybe the irrelevant attributes should not be added to the tree when not
>>> in SNP.
>> The policy fields are also applicable to the SNP. The main difference are:
>>
>> - in SEV/SEV-ES the policy is 32-bit compare to 64-bit value in SEV-SNP.
>> However, for SEV-SNP spec uses lower 32-bit value and higher bits are marked
>> reserved.
>>
>> - the bit field meaning are different
> Ah, I see that from the SNP ABI spec (section 4.3).
>
> That's a bit subtle; in that at the moment we select SEV or SEV-ES based
> on the existing guest policy flags; I think you're saying that SEV-SNP
> is enabled by the user explicitly.
Correct. This is one of the reason that I added the "snp" property.
>
>> Based on this, we can introduce a new filed 'snp-policy'.
> Yes, people are bound to confuse them if they're not clearly separated;
> although I guess whatever comes after SNP will probably share that
> longer field?
I am keeping my finger crossed on it. I hope that in future they will
share it.
-Brijesh
- [RFC PATCH 3/6] i386/sev: initialize SNP context, (continued)
- [RFC PATCH 3/6] i386/sev: initialize SNP context, Brijesh Singh, 2021/07/09
- [RFC PATCH 4/6] i386/sev: add the SNP launch start context, Brijesh Singh, 2021/07/09
- [RFC PATCH 5/6] i386/sev: add support to encrypt BIOS when SEV-SNP is enabled, Brijesh Singh, 2021/07/09
- [RFC PATCH 6/6] i386/sev: populate secrets and cpuid page and finalize the SNP launch, Brijesh Singh, 2021/07/09
- Re: [RFC PATCH 0/6] Add AMD Secure Nested Paging (SEV-SNP) support, Tom Lendacky, 2021/07/12
- Re: [RFC PATCH 0/6] Add AMD Secure Nested Paging (SEV-SNP) support, Dov Murik, 2021/07/13