[Xen-devel] [PATCH] MdeModulePkg: mark completion of PCI enumeration in PciEnumeratorLight

[Wei Liu <wei.liu2@xxxxxxxxxx>]

I had an issue when trying to boot Xen HVM guest with latest OVMF
master. Guest crashed with memory violation, and the bisection pointed
to 66b280df2 ("OvmfPkg: AcpiPlatformDxe: make dependency on PCI
enumeration explicit"). That commit made AcpiPlatformDxe depend on PCI
enumeration using gEfiPciEnumerationCompleteProtocolGuid, which is a
very reasonable change.

The real culprit is that Xen HVM is using PciEnumeratorLight which
doesn't install gEfiPciEnumerationCompleteProtocolGuid. This, in
combination with 66b280df2, makes AcpiPlatformDxe not able to be loaded,
resulting in guest crash.

The fix is to install gEfiPciEnumerationCompleteProtocolGuid in
PciEnumeratorLight.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Feng Tian <feng.tian@xxxxxxxxx>
Cc: Anthony Perard <anthony.perard@xxxxxxxxxx>
Cc: Laszlo Ersek <lersek@xxxxxxxxxx>
Cc: Jordan Justen <jordan.l.justen@xxxxxxxxx>
---
 MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c 
b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
index 9e7ac74..7659585 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
@@ -2256,6 +2256,7 @@ PciEnumeratorLight (
 {
 
   EFI_STATUS                        Status;
+  EFI_HANDLE                        HostBridgeHandle;
   EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL   *PciRootBridgeIo;
   PCI_IO_DEVICE                     *RootBridgeDev;
   UINT16                            MinBus;
@@ -2288,6 +2289,11 @@ PciEnumeratorLight (
     return Status;
   }
 
+  //
+  // Get the host bridge handle
+  //
+  HostBridgeHandle = PciRootBridgeIo->ParentHandle;
+
   Status = PciRootBridgeIo->Configuration (PciRootBridgeIo, (VOID **) 
&Descriptors);
 
   if (EFI_ERROR (Status)) {
@@ -2348,7 +2354,14 @@ PciEnumeratorLight (
     Descriptors++;
   }
 
-  return EFI_SUCCESS;
+  Status = gBS->InstallProtocolInterface (
+                  &HostBridgeHandle,
+                  &gEfiPciEnumerationCompleteProtocolGuid,
+                  EFI_NATIVE_INTERFACE,
+                  NULL
+                  );
+
+  return Status;
 }
 
 /**
-- 
1.9.1


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