diff --git a/UefiCpuPkg/Library/CpuArchLib/CpuGdt.c b/UefiCpuPkg/Library/CpuArchLib/CpuGdt.c
index cf571138e5..7457eb840e 100644
--- a/UefiCpuPkg/Library/CpuArchLib/CpuGdt.c
+++ b/UefiCpuPkg/Library/CpuArchLib/CpuGdt.c
@@ -14,104 +14,174 @@
 // Global descriptor table (GDT) Template
 //
 STATIC GDT_ENTRIES  mGdtTemplate = {
-  //
-  // NULL_SEL
-  //
-  {
-    0x0,            // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x0,            // type
-    0x0,            // limit 19:16, flags
-    0x0,            // base 31:24
+  .Null = {
+    .SegmentLimit_15_0  = 0x0,
+    .BaseAddress_15_0   = 0x0,
+    .BaseAddress_23_16  = 0x0,
+    .Type               = 0x0,
+    .S                  = 0,
+    .DPL                = 0,
+    .P                  = 0,
+    .SegmentLimit_19_16 = 0x0,
+    .AVL                = 0,
+    .L                  = 0,
+    .D_B                = 0,
+    .G                  = 0,
+    .BaseAddress_31_24  = 0x0
   },
-  //
-  // LINEAR_SEL
-  //
-  {
-    0x0FFFF,        // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x092,          // present, ring 0, data, read/write
-    0x0CF,          // page-granular, 32-bit
-    0x0,
+  .Linear = {
+    .SegmentLimit_15_0        = 0xFFFF,
+    .BaseAddress_15_0         = 0x0,
+    .BaseAddress_23_16        = 0x0,
+
+    .Accessed                 = 0,
+    .Writable                 = 1,
+    .ExpansionDirection       = 0,
+    .IsCode                   = 0,
+    .IsNotSystemSegment       = 1,
+    .DescriptorPrivilegeLevel = 0,
+    .SegmentPresent           = 1,
+
+    .SegmentLimit_19_16       = 0xF,
+    .Available                = 0,
+    .Reserved                 = 0,
+    .UpperBound               = 1,
+    .Granularity              = 1,
+    .BaseAddress_31_24        = 0x0
   },
-  //
-  // LINEAR_CODE_SEL
-  //
-  {
-    0x0FFFF,        // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x09F,          // present, ring 0, code, execute/read, conforming, accessed
-    0x0CF,          // page-granular, 32-bit
-    0x0,
+  .LinearCode = {
+    .SegmentLimit_15_0        = 0xFFFF,
+    .BaseAddress_15_0         = 0x0,
+    .BaseAddress_23_16        = 0x0,
+
+    .Accessed                 = 1,
+    .Readable                 = 1,
+    .Conforming               = 1,
+    .IsCode                   = 1,
+    .IsNotSystemSegment       = 1,
+    .DescriptorPrivilegeLevel = 0,
+    .SegmentPresent           = 1,
+
+    .SegmentLimit_19_16       = 0xF,
+    .Available                = 0,
+    .Reserved                 = 0,
+    .Is32Bit                  = 1,
+    .Granularity              = 1,
+    .BaseAddress_31_24        = 0x0
   },
-  //
-  // SYS_DATA_SEL
-  //
-  {
-    0x0FFFF,        // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x093,          // present, ring 0, data, read/write, accessed
-    0x0CF,          // page-granular, 32-bit
-    0x0,
+  .SysData = {
+    .SegmentLimit_15_0        = 0xFFFF,
+    .BaseAddress_15_0         = 0x0,
+    .BaseAddress_23_16        = 0x0,
+
+    .Accessed                 = 1,
+    .Writable                 = 1,
+    .ExpansionDirection       = 0,
+    .IsCode                   = 0,
+    .IsNotSystemSegment       = 1,
+    .DescriptorPrivilegeLevel = 0,
+    .SegmentPresent           = 1,
+
+    .SegmentLimit_19_16       = 0xF,
+    .Available                = 0,
+    .Reserved                 = 0,
+    .UpperBound               = 1,
+    .Granularity              = 1,
+    .BaseAddress_31_24        = 0x0
   },
-  //
-  // SYS_CODE_SEL
-  //
-  {
-    0x0FFFF,        // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x09A,          // present, ring 0, code, execute/read
-    0x0CF,          // page-granular, 32-bit
-    0x0,
+  .SysCode = {
+    .SegmentLimit_15_0        = 0xFFFF,
+    .BaseAddress_15_0         = 0x0,
+    .BaseAddress_23_16        = 0x0,
+
+    .Accessed                 = 0,
+    .Readable                 = 1,
+    .Conforming               = 0,
+    .IsCode                   = 1,
+    .IsNotSystemSegment       = 1,
+    .DescriptorPrivilegeLevel = 0,
+    .SegmentPresent           = 1,
+
+    .SegmentLimit_19_16       = 0xF,
+    .Available                = 0,
+    .Reserved                 = 0,
+    .Is32Bit                  = 1,
+    .Granularity              = 1,
+    .BaseAddress_31_24        = 0x0
   },
-  //
-  // SYS_CODE16_SEL
-  //
-  {
-    0x0FFFF,        // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x09A,          // present, ring 0, code, execute/read
-    0x08F,          // page-granular, 16-bit
-    0x0,            // base 31:24
+  .SysCode16 = {
+    .SegmentLimit_15_0        = 0xFFFF,
+    .BaseAddress_15_0         = 0x0,
+    .BaseAddress_23_16        = 0x0,
+
+    .Accessed                 = 0,
+    .Readable                 = 1,
+    .Conforming               = 0,
+    .IsCode                   = 1,
+    .IsNotSystemSegment       = 1,
+    .DescriptorPrivilegeLevel = 0,
+    .SegmentPresent           = 1,
+
+    .SegmentLimit_19_16       = 0xF,
+    .Available                = 0,
+    .Reserved                 = 0,
+    .Is32Bit                  = 0,
+    .Granularity              = 1,
+    .BaseAddress_31_24        = 0x0
   },
-  //
-  // LINEAR_DATA64_SEL
-  //
-  {
-    0x0FFFF,        // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x092,          // present, ring 0, data, read/write
-    0x0CF,          // page-granular, 32-bit
-    0x0,
+  .LinearData64 = {
+    .SegmentLimit_15_0        = 0xFFFF,
+    .BaseAddress_15_0         = 0x0,
+    .BaseAddress_23_16        = 0x0,
+
+    .Accessed                 = 0,
+    .Writable                 = 1,
+    .ExpansionDirection       = 0,
+    .IsCode                   = 0,
+    .IsNotSystemSegment       = 1,
+    .DescriptorPrivilegeLevel = 0,
+    .SegmentPresent           = 1,
+
+    .SegmentLimit_19_16       = 0xF,
+    .Available                = 0,
+    .Reserved                 = 0,
+    .UpperBound               = 1,
+    .Granularity              = 1,
+    .BaseAddress_31_24        = 0x0
   },
-  //
-  // LINEAR_CODE64_SEL
-  //
-  {
-    0x0FFFF,        // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x09A,          // present, ring 0, code, execute/read
-    0x0AF,          // page-granular, 64-bit code
-    0x0,            // base (high)
+  .LinearCode64 = {
+    .Reserved1                = 0x0,
+    .Reserved2                = 0x0,
+
+    .Accessed                 = 0,
+    .Readable                 = 1,
+    .Conforming               = 0,
+    .IsCode                   = 1,
+    .IsNotSystemSegment       = 1,
+    .DescriptorPrivilegeLevel = 0,
+    .SegmentPresent           = 1,
+
+    .Reserved3                = 0x0,
+    .Available                = 0,
+    .LongMode                 = 1,
+    .Is32Bit                  = 0,
+    .Granularity              = 1,
+    .Reserved4                = 0x0
   },
-  //
-  // SPARE5_SEL
-  //
-  {
-    0x0,            // limit 15:0
-    0x0,            // base 15:0
-    0x0,            // base 23:16
-    0x0,            // type
-    0x0,            // limit 19:16, flags
-    0x0,            // base 31:24
+  .Spare5 = {
+    .SegmentLimit_15_0  = 0x0,
+    .BaseAddress_15_0   = 0x0,
+    .BaseAddress_23_16  = 0x0,
+    .Type               = 0x0,
+    .S                  = 0,
+    .DPL                = 0,
+    .P                  = 0,
+    .SegmentLimit_19_16 = 0x0,
+    .AVL                = 0,
+    .L                  = 0,
+    .D_B                = 0,
+    .G                  = 0,
+    .BaseAddress_31_24  = 0x0,
   },
 };
 
diff --git a/UefiCpuPkg/Library/CpuArchLib/CpuGdt.h b/UefiCpuPkg/Library/CpuArchLib/CpuGdt.h
index b09f15725a..62bf5c8a36 100644
--- a/UefiCpuPkg/Library/CpuArchLib/CpuGdt.h
+++ b/UefiCpuPkg/Library/CpuArchLib/CpuGdt.h
@@ -20,26 +20,145 @@
 // Global Descriptor Entry structures
 //
 
-typedef struct _GDT_ENTRY {
-  UINT16    Limit15_0;
-  UINT16    Base15_0;
-  UINT8     Base23_16;
-  UINT8     Type;
-  UINT8     Limit19_16_and_flags;
-  UINT8     Base31_24;
+typedef struct {
+  UINT16    SegmentLimit_15_0;
+  UINT16    BaseAddress_15_0;
+  UINT8     BaseAddress_23_16;
+  UINT8     Type : 4;
+  UINT8     S    : 1;
+  UINT8     DPL  : 2;
+  UINT8     P    : 1;
+  UINT8     SegmentLimit_19_16 : 4;
+  UINT8     AVL                : 1;
+  UINT8     L                  : 1;
+  UINT8     D_B                : 1;
+  UINT8     G                  : 1;
+  UINT8     BaseAddress_31_24;
+} SEGMENT_DESCRIPTOR;
+
+typedef struct {
+  UINT16    SegmentLimit_15_0;
+  UINT16    BaseAddress_15_0;
+  UINT8     BaseAddress_23_16;
+  //
+  // Type
+  //
+  UINT8     Accessed           : 1;
+  UINT8     Writable           : 1;
+  UINT8     ExpansionDirection : 1;
+  UINT8     IsCode             : 1;
+  UINT8     IsNotSystemSegment       : 1;
+  UINT8     DescriptorPrivilegeLevel : 2;
+  UINT8     SegmentPresent           : 1;
+
+  UINT8     SegmentLimit_19_16 : 4;
+  UINT8     Available          : 1;
+  UINT8     Reserved           : 1;
+  UINT8     UpperBound         : 1;
+  UINT8     Granularity        : 1;
+  UINT8     BaseAddress_31_24;
+} DATA_SEGMENT_32;
+
+typedef struct {
+  UINT16    SegmentLimit_15_0;
+  UINT16    BaseAddress_15_0;
+  UINT8     BaseAddress_23_16;
+  //
+  // Type
+  //
+  UINT8     Accessed   : 1;
+  UINT8     Readable   : 1;
+  UINT8     Conforming : 1;
+  UINT8     IsCode     : 1;
+  UINT8     IsNotSystemSegment       : 1;
+  UINT8     DescriptorPrivilegeLevel : 2;
+  UINT8     SegmentPresent           : 1;
+
+  UINT8     SegmentLimit_19_16 : 4;
+  UINT8     Available          : 1;
+  UINT8     Reserved           : 1;
+  UINT8     Is32Bit            : 1;
+  UINT8     Granularity        : 1;
+  UINT8     BaseAddress_31_24;
+} CODE_SEGMENT_32;
+
+typedef struct {
+  UINT32    Reserved1;
+  UINT8     Reserved2;
+  //
+  // Type
+  //
+  UINT8     Accessed   : 1;
+  UINT8     Readable   : 1;
+  UINT8     Conforming : 1;
+  UINT8     IsCode     : 1;
+  UINT8     IsNotSystemSegment       : 1;
+  UINT8     DescriptorPrivilegeLevel : 2;
+  UINT8     SegmentPresent           : 1;
+
+  UINT8     Reserved3   : 4;
+  UINT8     Available   : 1;
+  UINT8     LongMode    : 1;
+  UINT8     Is32Bit     : 1;
+  UINT8     Granularity : 1;
+  UINT8     Reserved4;
+} CODE_SEGMENT_64;
+
+typedef struct {
+  UINT16    SegmentLimit_15_0;
+  UINT16    BaseAddress_15_0;
+  UINT8     BaseAddress_23_16;
+
+  UINT8     Type                     : 4;
+  UINT8     IsNotSystemSegment       : 1;
+  UINT8     DescriptorPrivilegeLevel : 2;
+  UINT8     SegmentPresent           : 1;
+
+  UINT8     SegmentLimit_19_16 : 4;
+  UINT8     Reserved           : 3;
+  UINT8     Granularity        : 1;
+  UINT8     BaseAddress_31_24;
+} SYSTEM_SEGMENT;
+
+typedef struct {
+  UINT16    OffsetInSegment_15_0;
+  UINT16    SegmentSelector;
+
+  UINT8     ParameterCount : 5;
+  UINT8     Reserved       : 3;
+
+  UINT8     Type                     : 4;
+  UINT8     IsNotSystemSegment       : 1;
+  UINT8     DescriptorPrivilegeLevel : 2;
+  UINT8     SegmentPresent           : 1;
+  UINT16    OffsetInSegment_31_16;
+} CALL_GATE_32;
+
+typedef struct {
+  CALL_GATE_32  Common;
+  UINT32        OffsetInSegment_63_31;
+  UINT32        Reserved;
+} CALL_GATE_64;
+
+typedef union {
+  DATA_SEGMENT_32    DataSegment32;
+  CODE_SEGMENT_32    CodeSegment32;
+  CODE_SEGMENT_64    CodeSegment64;
+  CALL_GATE_32       CallGate32;
+  SYSTEM_SEGMENT     SystemSegment;
+  SEGMENT_DESCRIPTOR SegmentDescriptor;
 } GDT_ENTRY;
 
-typedef
-  struct _GDT_ENTRIES {
-  GDT_ENTRY    Null;
-  GDT_ENTRY    Linear;
-  GDT_ENTRY    LinearCode;
-  GDT_ENTRY    SysData;
-  GDT_ENTRY    SysCode;
-  GDT_ENTRY    SysCode16;
-  GDT_ENTRY    LinearData64;
-  GDT_ENTRY    LinearCode64;
-  GDT_ENTRY    Spare5;
+typedef struct {
+  SEGMENT_DESCRIPTOR Null;
+  DATA_SEGMENT_32    Linear;
+  CODE_SEGMENT_32    LinearCode;
+  DATA_SEGMENT_32    SysData;
+  CODE_SEGMENT_32    SysCode;
+  CODE_SEGMENT_32    SysCode16;
+  DATA_SEGMENT_32    LinearData64;
+  CODE_SEGMENT_64    LinearCode64;
+  SEGMENT_DESCRIPTOR Spare5;
 } GDT_ENTRIES;
 
 #pragma pack ()