Re: [PATCH V2 04/10] OvmfPkg/IntelTdx: Implement other helper functions in SecTdxHelperLib

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

On January 19, 2023 5:54 PM, Gerd Hoffmann wrote:
> > @@ -807,7 +880,47 @@ TdxHelperMeasureTdHob (
> >    VOID
> >    )
> >  {
> > -  return EFI_UNSUPPORTED;
> > +  EFI_PEI_HOB_POINTERS  Hob;
> > +  EFI_STATUS            Status;
> > +  UINT8                 Digest[SHA384_DIGEST_SIZE];
> > +  OVMF_WORK_AREA        *WorkArea;
> > +  VOID                  *TdHob;
> > +
> > +  TdHob   = (VOID *)(UINTN)FixedPcdGet32 (PcdOvmfSecGhcbBase);
> > +  Hob.Raw = (UINT8 *)TdHob;
> > +
> > +  //
> > +  // Walk thru the TdHob list until end of list.
> > +  //
> > +  while (!END_OF_HOB_LIST (Hob)) {
> > +    Hob.Raw = GET_NEXT_HOB (Hob);
> > +  }
> 
> Hmm?  Isn't there just a single TdHob?  Why do you need to walk the list here?
No, TdHob is a HobList and it contains several Hobs, including the ResourceDescriptorHobs which describe the memory regions. So we have to walk thru the hob list to find out its length.

> 
> > +#pragma pack(1)
> > +
> > +#define HANDOFF_TABLE_DESC  "TdxTable"
> > +typedef struct {
> > +  UINT8                      TableDescriptionSize;
> > +  UINT8                      TableDescription[sizeof (HANDOFF_TABLE_DESC)];
> > +  UINT64                     NumberOfTables;
> > +  EFI_CONFIGURATION_TABLE    TableEntry[1];
> > +} TDX_HANDOFF_TABLE_POINTERS2;
> > +
> > +#define FV_HANDOFF_TABLE_DESC  "Fv(XXXXXXXX-XXXX-XXXX-XXXX-
> XXXXXXXXXXXX)"
> > +typedef struct {
> > +  UINT8                   BlobDescriptionSize;
> > +  UINT8                   BlobDescription[sizeof (FV_HANDOFF_TABLE_DESC)];
> > +  EFI_PHYSICAL_ADDRESS    BlobBase;
> > +  UINT64                  BlobLength;
> > +} FV_HANDOFF_TABLE_POINTERS2;
> > +
> > +#pragma pack()
> 
> Why do you need this?  For standard event types we should have those
> structs already defined somewhere in edk2 I think ...
These structs are defined in SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c. Let me think can they be moved  to a common header file. Thanks for reminder.

Thanks
Min