[edk2-devel] [PATCH v2] UefiCpuPkg/PiSmmCpuDxeSmm: Update mPatchCetSupported set condition

[Wenxing Hou]

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3584

Function AsmCpuid should frist check the value for Basic CPUID Information.
The fix is to update the mPatchCetSupported judgment statement.


Signed-off-by: Wenxing Hou <wenxing.hou at intel.com>
Cc: Eric Dong   <eric.dong at intel.com>
Cc: Ray Ni      <ray.ni at intel.com>
Cc: Rahul Kumar <rahul1.kumar at intel.com>
Cc: Sheng W     <w.sheng at intel.com>
Cc: Yao Jiewen  <jiewen.yao at intel.com>
---
 UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c |  7 +++++--
 UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c     | 15 ++++++++-------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
index db68e1316e..67ad9a4c07 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
@@ -729,8 +729,8 @@ PiCpuSmmEntry (
 
   DEBUG ((DEBUG_INFO, "PcdControlFlowEnforcementPropertyMask = %d\n", PcdGet32 (PcdControlFlowEnforcementPropertyMask)));
   if (PcdGet32 (PcdControlFlowEnforcementPropertyMask) != 0) {
-    AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
-    if (RegEax > CPUID_EXTENDED_FUNCTION) {
+    AsmCpuid (CPUID_SIGNATURE, &RegEax, NULL, NULL, NULL);
+    if (RegEax >= CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS) {
       AsmCpuidEx (CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS, CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS_SUB_LEAF_INFO, NULL, NULL, &RegEcx, &RegEdx);
       DEBUG ((DEBUG_INFO, "CPUID[7/0] ECX - 0x%08x\n", RegEcx));
       DEBUG ((DEBUG_INFO, "  CET_SS  - 0x%08x\n", RegEcx & CPUID_CET_SS));
@@ -747,6 +747,9 @@ PiCpuSmmEntry (
         AsmCpuidEx(CPUID_EXTENDED_STATE, 12, &RegEax, NULL, &RegEcx, NULL);
         DEBUG ((DEBUG_INFO, "CPUID[D/12] EAX - 0x%08x, ECX - 0x%08x\n", RegEax, RegEcx));
       }
+    } else {
+      mCetSupported = FALSE;
+      PatchInstructionX86(mPatchCetSupported, mCetSupported, 1);
     }
   } else {
     mCetSupported = FALSE;
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
index d7ed9ab7a7..972bdc2859 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
@@ -985,13 +985,14 @@ CheckFeatureSupported (
   MSR_IA32_MISC_ENABLE_REGISTER  MiscEnableMsr;
 
   if ((PcdGet32 (PcdControlFlowEnforcementPropertyMask) != 0) && mCetSupported) {
-    AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
-    if (RegEax <= CPUID_EXTENDED_FUNCTION) {
-      mCetSupported = FALSE;
-      PatchInstructionX86 (mPatchCetSupported, mCetSupported, 1);
-    }
-    AsmCpuidEx (CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS, CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS_SUB_LEAF_INFO, NULL, NULL, &RegEcx, NULL);
-    if ((RegEcx & CPUID_CET_SS) == 0) {
+    AsmCpuid (CPUID_SIGNATURE, &RegEax, NULL, NULL, NULL);
+    if (RegEax >= CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS) {
+      AsmCpuidEx (CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS, CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS_SUB_LEAF_INFO, NULL, NULL, &RegEcx, NULL);
+      if ((RegEcx & CPUID_CET_SS) == 0) {
+        mCetSupported = FALSE;
+        PatchInstructionX86 (mPatchCetSupported, mCetSupported, 1);
+      }
+    } else {
       mCetSupported = FALSE;
       PatchInstructionX86 (mPatchCetSupported, mCetSupported, 1);
     }
-- 
2.26.2.windows.1



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