Re: [edk2-devel] [PATCH v3 6/6] OvmfPkg/AmdSev: Expose the Sev Secret area using a configuration table

["James Bottomley" <jejb@linux.ibm.com>]

On Wed, 2020-12-09 at 07:46 -0800, James Bottomley wrote:
> On Wed, 2020-12-09 at 12:02 +0000, Yao, Jiewen wrote:
> > Would you please take a look at intel-tdx-guest-hypervisor-
> > communication-interface, section 4.4 storage volume key data.

OK, I read through the spec.

> > We defined multiple key layout, key type and key format. Please let
> > us know if you have any thought.
> 
> I really think the standard GUIDed form:
> 
> GUID|len|data
> 
> Works best because a GUID is big enough to define for any number of
> uses and it also means we don't have to define key types or anything,
> because all a new consumer has to do is define their data structure
> and give it a guid.  The single uefi config table is passed through
> to all the elements until it gets to one that recognizes the GUID.

The only other thing I would add here, is that you have indirect ACPI
tables whereas the above is direct.  I think indirect might be useful
at the low level for scatter gather injection if it has to be done for
the architecture, but I think to make it easier for the consumers above
OVMF we gather all the information into on GUIDed table with no
indirection, which makes the above GUIDed form the best description.

James