From 233a5cff09fb397d904ad32db9d63ae9a653e425 Mon Sep 17 00:00:00 2001
From: Mikhail Krichanov <mikhailkrichanov@gmail.com>
Date: Thu, 18 Jan 2024 14:00:47 +0300
Subject: [PATCH] Ring3: Fixed LibraryConstructors' initialization and allowed
 user to access ports.

---
 MdeModulePkg/Core/Dxe/DxeMain.inf                | 2 ++
 MdeModulePkg/Core/Dxe/Image/Image.c              | 9 +++++++++
 MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 4 ++++
 3 files changed, 15 insertions(+)

diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf b/MdeModulePkg/Core/Dxe/DxeMain.inf
index 681ad580a2..55169a392d 100644
--- a/MdeModulePkg/Core/Dxe/DxeMain.inf
+++ b/MdeModulePkg/Core/Dxe/DxeMain.inf
@@ -193,6 +193,8 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdImageLargeAddressLoad                   ## CONSUMES
   gEfiMdePkgTokenSpaceGuid.PcdDebugRaisePropertyMask                        ## CONSUMES
   gEfiMdePkgTokenSpaceGuid.PcdImageProtectionPolicy                         ## CONSUMES
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaBase                            ## CONSUMES
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaSize                            ## CONSUMES
 
 # [Hob]
 # RESOURCE_DESCRIPTOR   ## CONSUMES
diff --git a/MdeModulePkg/Core/Dxe/Image/Image.c b/MdeModulePkg/Core/Dxe/Image/Image.c
index 2b45e3b30f..bcca272218 100644
--- a/MdeModulePkg/Core/Dxe/Image/Image.c
+++ b/MdeModulePkg/Core/Dxe/Image/Image.c
@@ -1714,6 +1714,15 @@ CoreStartImage (
       TopOfStack = ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
       // DEBUG ((DEBUG_ERROR, "RING3_CODE64_SEL = 0x%x   RING3_DATA64_SEL = 0x%x\n", (UINT16)RING3_CODE64_SEL, (UINT16)RING3_DATA64_SEL));
 
+      //
+      // Necessary fix for ProcessLibraryConstructorList() -> DxeCcProbeLibConstructor()
+      //
+      SetUefiImageMemoryAttributes (
+        FixedPcdGet32 (PcdOvmfWorkAreaBase),
+        FixedPcdGet32 (PcdOvmfWorkAreaSize),
+        EFI_MEMORY_XP | EFI_MEMORY_USER
+        );
+
       EnterUserImage (
         (SWITCH_STACK_ENTRY_POINT)(UINTN)Image->EntryPoint,
         ImageHandle,
diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
index 5da703641e..503f9a364d 100644
--- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
+++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
@@ -992,6 +992,10 @@ CreateIdentityMappingPageTables (
 
     Eflags.UintN   = AsmReadEflags ();
     Eflags.Bits.AC = 0;
+    //
+    // Allow user image to access ports.
+    //
+    Eflags.Bits.IOPL = 3;
     AsmWriteEflags (Eflags.UintN);
   }