[edk2-devel] [PATCH V4 17/31] OvmfPkg: Update Sec to support Tdx

[Gerd Hoffmann]

> +EFI_STATUS
> +EFIAPI
> +BspAcceptMemoryResourceRange (
> +  IN EFI_PHYSICAL_ADDRESS  PhysicalAddress,
> +  IN EFI_PHYSICAL_ADDRESS  PhysicalEnd
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINT32      AcceptPageSize;
> +  UINT64      StartAddress1;
> +  UINT64      StartAddress2;
> +  UINT64      StartAddress3;
> +  UINT64      TotalLength;
> +  UINT64      Length1;
> +  UINT64      Length2;
> +  UINT64      Length3;
> +  UINT64      Pages;
> +
> +  AcceptPageSize = FixedPcdGet32 (PcdTdxAcceptPageSize);
> +  TotalLength    = PhysicalEnd - PhysicalAddress;
> +  StartAddress1  = 0;
> +  StartAddress2  = 0;
> +  StartAddress3  = 0;
> +  Length1        = 0;
> +  Length2        = 0;
> +  Length3        = 0;
> +
> +  if (TotalLength == 0) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  if ((AcceptPageSize == SIZE_4KB) || (TotalLength <= SIZE_2MB)) {
> +    //
> +    // if total length is less than 2M, then we accept pages in 4k
> +    //
> +    StartAddress1  = 0;
> +    Length1        = 0;
> +    StartAddress2  = PhysicalAddress;
> +    Length2        = PhysicalEnd - PhysicalAddress;
> +    StartAddress3  = 0;
> +    Length3        = 0;
> +    AcceptPageSize = SIZE_4KB;

You've zero-initialized everything above, no need to do that again.
You also can just use StartAddress1 + Length1 which uses 4k pages
anyway.

> +  } else if (AcceptPageSize == SIZE_2MB) {
> +    //
> +    // Total length is bigger than 2M and Page Accept size 2M is supported.
> +    //
> +    if ((PhysicalAddress & ALIGNED_2MB_MASK) == 0) {

The logic is rather messy.  It should become much simpler if you update
PhysicalAddress and TotalLength.  You can also use the alignment macros.

    if (ALIGN_VALUE(PhysicalAddress, SIZE_2MB) != PhysicalAddress) {
        StartAddress1 = PhysicalAddress;
        Length1 = ALIGN_VALUE(PhysicalAddress, SIZE_2MB) - PhysicalAddress;
        PhysicalAddress += Length1;
        TotalLength -= Length1;
    }
    if (TotalLength > SIZE_2MB) {
        StartAddress2 = PhysicalAddress;
        Length2 = TotalLength & ~(UINT64)ALIGNED_2MB_MASK
        PhysicalAddress += Length2;
        TotalLength -= Length2;
    }
    if (TotalLength) {
        StartAddress3 = PhysicalAddress;
        Length3 = TotalLength;
    }

take care,
  Gerd



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