In lesson 29 on implementing the IDT, I noticed the function idt_zero does an im...

Hey david thanks for reaching out, in future for faster replies you can get me directly on daniel@dragonzap.com the same goes for anyone reading this, as my replies here can take a few weeks usually, on email within a day. In answer to your question yes you are right it must be an "iret" but the point of this lesson is just to show you how the IDT works at a very basic level, later in the course we refine it properly and "iret" is used. This lesson is designed not to overwhelm beginner kernel developers so it was intentinal what I did it will be refined in the next couple lessons

Thanks