[PATCH] SourceLevelDebugPkg: Avoid to re-init IDT table again at SMI entry

[Jeff Fan <jeff.fan@intel.com>]

Current SmmDebugAgentLib will initialize IDT table to support source debugging
at each time SMI entry on SMM BSP. Actually, we only need to initialize IDT
table at first time SMI entry.

Add one flag to avoid re-initializing IDT table.

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
---
 .../Library/DebugAgent/SmmDebugAgent/SmmDebugAgentLib.c        | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/SourceLevelDebugPkg/Library/DebugAgent/SmmDebugAgent/SmmDebugAgentLib.c b/SourceLevelDebugPkg/Library/DebugAgent/SmmDebugAgent/SmmDebugAgentLib.c
index 701c4be..6216142 100644
--- a/SourceLevelDebugPkg/Library/DebugAgent/SmmDebugAgent/SmmDebugAgentLib.c
+++ b/SourceLevelDebugPkg/Library/DebugAgent/SmmDebugAgent/SmmDebugAgentLib.c
@@ -19,6 +19,7 @@ DEBUG_AGENT_MAILBOX         mLocalMailbox;
 UINTN                       mSavedDebugRegisters[6];
 IA32_IDT_GATE_DESCRIPTOR    mIdtEntryTable[33];
 BOOLEAN                     mSkipBreakpoint = FALSE;
+BOOLEAN                     mSmmDebugIdtInitFlag = FALSE;
 
 CHAR8 mWarningMsgIgnoreSmmEntryBreak[] = "Ignore smmentrybreak setting for SMI issued during DXE debugging!\r\n";
 
@@ -276,7 +277,14 @@ InitializeDebugAgent (
 
   case DEBUG_AGENT_INIT_ENTER_SMI:
     SaveDebugRegister ();
-    InitializeDebugIdt ();
+    if (!mSmmDebugIdtInitFlag) {
+      //
+      // We only need to initialize Debug IDT table at first SMI entry
+      // after SMM relocation.
+      //
+      InitializeDebugIdt ();
+      mSmmDebugIdtInitFlag = TRUE;
+    }
     //
     // Check if CPU APIC Timer is working, otherwise initialize it.
     //
-- 
2.9.3.windows.2