Question

The mechanism that is executed at certain privilege levels, determined by CPL (Current Privilege Level) and I/O privilege level (IOPL) is

(a) restricted use of segments

(b) restricted accesses to segments

(c) privileged instructions or operations

(d) none of the mentioned

I have been asked this question in an interview.

This key question is from Protection topic in chapter 80286-80287-A Microprocessor with Memory Management and Protection of Microprocessor

Answer 1

Right option is (c) privileged instructions or operations

Easiest explanation: The privileged instructions or operations, also called, privileged instruction check, is executed at certain privilege levels, determined by CPL and I/O privilege level(IOPL), as defined by the flag register.