OvmfPkg: PciHostBridgeLib: set RootBus->Segment

This is the first of the patches that set the fields of PCI_ROOT_BRIDGE.
The structure is zero-filled as a precaution for later field additions.

Here we set the Segment member explicitly to zero (so that any later
customization can be easier).

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.c

@@ -17,6 +17,7 @@
 
 #include <IndustryStandard/Pci.h>
 
+#include <Library/BaseMemoryLib.h>
 #include <Library/DebugLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/PciHostBridgeLib.h>
@@ -63,6 +64,13 @@ InitRootBridge (
   OUT PCI_ROOT_BRIDGE *RootBus
   )
 {
+  //
+  // Be safe if other fields are added to PCI_ROOT_BRIDGE later.
+  //
+  ZeroMem (RootBus, sizeof *RootBus);
+
+  RootBus->Segment = 0;
+
   return EFI_OUT_OF_RESOURCES;
 }
 

OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf

@@ -39,6 +39,7 @@
   OvmfPkg/OvmfPkg.dec
 
 [LibraryClasses]
+  BaseMemoryLib
   DebugLib
   MemoryAllocationLib
   PciLib