X64 HOOK IDT

kd> dt nt!_KIDTENTRY64 @idtr + @@(sizeof(nt!_KIDTENTRY64))
   +0x000 OffsetLow        : 0x44c0
   +0x002 Selector         : 0x10
   +0x004 IstIndex         : 0y000
   +0x004 Reserved0        : 0y00000 (0)
   +0x004 Type             : 0y01110 (0xe)
   +0x004 Dpl              : 0y00
   +0x004 Present          : 0y1
   +0x006 OffsetMiddle     : 0x40e
   +0x008 OffsetHigh       : 0xfffff800
   +0x00c Reserved1        : 0
   +0x000 Alignment        : 0x40e8e00`001044c0
kd> !idt 1

Dumping IDT:

01:        fffff800040e44c0 nt!KiDebugTrapOrFault

#pragma pack(1)
typedef struct{
        USHORT limit;
        ULONG64 BASE;


}IDT_INFO,*PIDT_INFO;


typedef union _KIDTENTRY64
{
        struct
         {
                USHORT OffsetLow;
                USHORT Selector;
                USHORT IstIndex : 3;
                USHORT Reserved0 : 5;
                USHORT Type : 5;
                USHORT Dpl : 2;
                USHORT Present : 1;
                USHORT OffsetMiddle;
                ULONG OffsetHigh;
                ULONG Reserved1;
                };
        UINT64 Alignment;
        } KIDTENTRY64, *PKIDTENTRY64;

#pragma pack()
typedef NTSTATUS(NTAPI *_KeSetAffinityThread)(
        IN PKTHREAD Thread,
        IN KAFFINITY Affinity
        );
NTSTATUS HOOKIDT(ULONG IDTID, PVOID NewfcuncAddress,__out  PVOID * oldTRAP1){


KIRQL oldIrql;
ULONG lowpart;
KAFFINITY processOrs;
PKTHREAD thread;
LONG i;
IDT_INFO idtinfo;
ULONG_PTR oldTrap = 0;
ULONG_PTR newTrap;
KIDTENTRY64*idt_entry;
UNICODE_STRING ustrKeSetAffinityThread;
_KeSetAffinityThread KeSetAffinityThread;
RtlInitUnicodeString(&ustrKeSetAffinityThread, L"KeSetAffinityThread");
KeSetAffinityThread = (_KeSetAffinityThread)MmGetSystemRoutineAddress(&ustrKeSetAffinityThread);
processOrs = KeQueryActiveProcessors();
thread = KeGetCurrentThread();
newTrap = (ULONG_PTR)NewfcuncAddress;
if (!MmIsAddressValid(oldTRAP1)) 
{ return 1; }


for (i = 0; i < 32; i++){
KAFFINITY curProc = processOrs &(1 << i);
if (curProc != 0){

KeSetAffinityThread(thread, curProc);
__sidt(&idtinfo);
idt_entry = idtinfo.BASE;


oldTrap = (ULONG_PTR)((((ULONGLONG)idt_entry[IDTID].OffsetHigh) << 32) | (ULONGLONG)(((idt_entry[IDTID].OffsetMiddle << 16) | idt_entry[IDTID].OffsetLow) & 0x00000000ffffffff));
if ( *oldTRAP1 == NULL)
{
*oldTRAP1 = (PVOID)oldTrap;
}



KeRaiseIrql(HIGH_LEVEL, &oldIrql);
lowpart = (ULONG)((ULONGLONG)(newTrap));
idt_entry[IDTID].OffsetLow = (USHORT)lowpart;
idt_entry[IDTID].OffsetMiddle = (USHORT)(lowpart >> 16);
idt_entry[IDTID].OffsetHigh = (ULONG)((ULONGLONG)newTrap >> 32);
KeLowerIrql(oldIrql);
}



}
KeSetAffinityThread(thread, processOrs);


return STATUS_SUCCESS;
}