MdeModulePkg/PciBusDxe: don't create bogus descriptor if no resources needed

If the current PCI configuration requires no resources to be allocated at
all (i.e., unpopulated bus), the PCI enumeration code creates a single
ACPI_ADDRESS_SPACE_DESCRIPTOR memory descriptor with all fields cleared.
This is rejected by the SubmitResources() implementation of the generic
PciHostBridgeDxe in the following way:

  PciHostBridge: SubmitResources for PcieRoot(0x0)
   Mem: Granularity/SpecificFlag = 0 / 00
        Length/Alignment = 0x0 / 0x0
  PciBus: HostBridge->SubmitResources() - Invalid Parameter

  ASSERT_EFI_ERROR (Status = Invalid Parameter)
  ASSERT [PciBusDxe] .../PciBusDxe/PciLib.c(561): !EFI_ERROR (Status)

So instead, create the empty configuration as a single entry of type
EFI_ACPI_END_TAG_DESCRIPTOR.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c
index 597c0834e0..469a2ddb8a 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c
@@ -1307,15 +1307,12 @@ ConstructAcpiResourceRequestor (
     //

     // If there is no resource request

     //

-    Configuration = AllocateZeroPool (sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) + sizeof (EFI_ACPI_END_TAG_DESCRIPTOR));

+    Configuration = AllocateZeroPool (sizeof (EFI_ACPI_END_TAG_DESCRIPTOR));

     if (Configuration == NULL) {

       return EFI_OUT_OF_RESOURCES;

     }

 

-    Ptr               = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *) (Configuration);

-    Ptr->Desc         = ACPI_ADDRESS_SPACE_DESCRIPTOR;

-

-    PtrEnd            = (EFI_ACPI_END_TAG_DESCRIPTOR *) (Ptr + 1);

+    PtrEnd            = (EFI_ACPI_END_TAG_DESCRIPTOR *) (Configuration);

     PtrEnd->Desc      = ACPI_END_TAG_DESCRIPTOR;

     PtrEnd->Checksum  = 0;

   }