[PATCH 3/3] MdeModulePkg: Notify BeforeExitBootServices in CoreExitBootServices

["Dionna Glaze" <dionnaglaze@google.com>]

Location of notification is has been specified in UEFI v2.9.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: "Min M. Xu" <min.m.xu@intel.com>
Cc: Andrew Fish <afish@apple.com>
Cc: "Michael D. Kinney" <michael.d.kinney@intel.com>
Cc: Ray Ni <ray.ni@intel.com>

Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
---
 MdeModulePkg/Core/Dxe/DxeMain.inf       | 1 +
 MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf b/MdeModulePkg/Core/Dxe/DxeMain.inf
index e4bca89577..35d5bf0dee 100644
--- a/MdeModulePkg/Core/Dxe/DxeMain.inf
+++ b/MdeModulePkg/Core/Dxe/DxeMain.inf
@@ -100,6 +100,7 @@
   gEfiEventVirtualAddressChangeGuid             ## CONSUMES             ## Event
   ## CONSUMES   ## Event
   ## PRODUCES   ## Event
+  gEfiEventBeforeExitBootServicesGuid
   gEfiEventExitBootServicesGuid
   gEfiHobMemoryAllocModuleGuid                  ## SOMETIMES_CONSUMES   ## HOB
   gEfiFirmwareFileSystem2Guid                   ## CONSUMES             ## GUID # Used to compare with FV's file system guid and get the FV's file system format
diff --git a/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c b/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c
index 5733f0c8ec..4683016ed7 100644
--- a/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c
+++ b/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c
@@ -763,6 +763,12 @@ CoreExitBootServices (
 {
   EFI_STATUS  Status;
 
+  //
+  // Notify other drivers of their last chance to use boot services
+  // before the memory map is terminated.
+  //
+  CoreNotifySignalList (&gEfiEventBeforeExitBootServicesGuid);
+
   //
   // Disable Timer
   //
-- 
2.38.1.431.g37b22c650d-goog