Add descriptor structure definition

sdk/xtdk/amd64/ketypes.h

@@ -181,6 +181,14 @@ typedef struct ALIGN(16) _CONTEXT
     ULONG64 LastExceptionFromRip;
 } CONTEXT, *PCONTEXT;
 
+/* Pseudo 64-bit descriptor structure definition */
+typedef struct _KDESCRIPTOR
+{
+    USHORT Pad[3];
+    USHORT Limit;
+    PVOID Base;
+} KDESCRIPTOR, *PKDESCRIPTOR;
+
 /* Global Descriptor Table (GDT) entry union definition */
 typedef struct _KGDTENTRY
 {

sdk/xtdk/amd64/xtstruct.h

@@ -21,6 +21,7 @@ typedef struct ALIGN(16) _CONTEXT CONTEXT, *PCONTEXT;
 typedef struct _CPUID_REGISTERS CPUID_REGISTERS, *PCPUID_REGISTERS;
 typedef struct _FLOATING_SAVE_AREA FLOATING_SAVE_AREA, *PFLOATING_SAVE_AREA;
 typedef struct _HARDWARE_PTE HARDWARE_PTE, *PHARDWARE_PTE;
+typedef struct _KDESCRIPTOR KDESCRIPTOR, *PKDESCRIPTOR;
 typedef struct _KEXCEPTION_FRAME KEXCEPTION_FRAME, *PKEXCEPTION_FRAME;
 typedef struct _KGDTENTRY KGDTENTRY, *PKGDTENTRY;
 typedef struct _KIDTENTRY KIDTENTRY, *PKIDTENTRY;