Re: [PATCH V6 1/1] OvmfPkg: Enable TDX in ResetVector

["Min Xu" <min.m.xu@intel.com>]

On September 16, 2021 3:55 PM, Gerd Hoffman wrote:
> 
> >  typedef struct _CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER {
> >    UINT8                   GuestType;
> > -  UINT8                   Reserved1[3];
> > +  UINT8                   SubType;
> > +  UINT8                   Reserved1[2];
> >  } CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER;
> 

In [PATCH v7 19/31] UefiCpuPkg: Define ConfidentialComputingGuestAttr
There are below ConfidentialComputingGuestAttr:

+  ## This dynamic PCD indicates the memory encryption attribute of the guest.
+  # @Prompt Memory encryption attribute
+  
+ gUefiCpuPkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr|0|UINT64|0
+ x60000017
+
+
+typedef enum {
+  /* The guest is running with memory encryption disabled. */
+  CCAttrNotEncrypted = 0,
+
+  /* The guest is running with AMD SEV memory encryption enabled. */
+  CCAttrAmdSev      = 0x100,
+  CCAttrAmdSevEs    = 0x101,
+  CCAttrAmdSevSnp   = 0x102,
+
+  /* The guest is running with Intel TDX memory encryption enabled. */
+  CCAttrIntelTdx    = 0x200,
+} CONFIDENTIAL_COMPUTING_GUEST_ATTR;
+

ConfidentialComputingGuestAttr is a 64-bit PCD, the byte[1] indicates the Guest type, byte[0] seems the sub type of the guest.

And in the current definition of  CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER:
typedef struct _CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER {
   UINT8                   GuestType;
  UINT8                   Reserved1[3];
} CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER;
Byte[0] is the Guest type.

I am not sure what you mean:
> we should use the same approach (and the same enum) we are planing to use 
> for the ConfidentialComputing PCD (see discussion in the other patch series).

Shall we update CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER so that byte[0] is sub type, and byte[1] indicates the Guest type?

Thanks!
Min