REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2335



This patch is to check the PCI Memory Base Address Register is valid or not.



*** a\NetworkPkg\SnpDxe\Snp.c           2019-11-11 16:53:40.773300500 +0530

--- b\NetworkPkg\SnpDxe\Snp.c                             2019-11-03 18:46:02.000000000 +0530

*************** SimpleNetworkDriverStart (

*** 266,272 ****

    UINT8                                     BarIndex;

    PXE_STATFLAGS                             InitStatFlags;

    EFI_PCI_IO_PROTOCOL                       *PciIo;

!   EFI_ACPI_QWORD_ADDRESS_SPACE_DESCRIPTOR   *BarDesc = NULL;

    BOOLEAN                                   FoundIoBar;

    BOOLEAN                                   FoundMemoryBar;



--- 266,272 ----

    UINT8                                     BarIndex;

   PXE_STATFLAGS                             InitStatFlags;

    EFI_PCI_IO_PROTOCOL                       *PciIo;

!   EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR         *BarDesc;

    BOOLEAN                                   FoundIoBar;

    BOOLEAN                                   FoundMemoryBar;



*************** SimpleNetworkDriverStart (

*** 481,494 ****

      } else if (EFI_ERROR (Status)) {

        goto Error_DeleteSNP;

      }

!              //PXE boot fails with cards having non-continuous BAR.

!              // From UEFI Spec, GetBarAttributes can have only descriptors of type ACPI_QWORD_ADDRESS_SPACE_DESCRIPTOR

!     // and ACPI_END_TAG_DESCRIPTOR.

!     if( BarDesc->Header.Header.Byte != ACPI_QWORD_ADDRESS_SPACE_DESCRIPTOR )  {

!       FreePool (BarDesc);

!       continue;

!     }

!

      if ((!FoundMemoryBar) && (BarDesc->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM)) {

        Snp->MemoryBarIndex = BarIndex;

        FoundMemoryBar      = TRUE;

--- 481,487 ----

      } else if (EFI_ERROR (Status)) {

        goto Error_DeleteSNP;

      }

!

      if ((!FoundMemoryBar) && (BarDesc->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM)) {

        Snp->MemoryBarIndex = BarIndex;

        FoundMemoryBar      = TRUE;