The Kernel Abstraction - Operating Systems: Principles and Practice - page 92

Guest
Process

Guest
Process
...
syscall
...

Guest/Host
User Mode

guest
program
counter

Guest Kernel

Host User
Mode/Guest
Kernel Mode

timer
handler

guest
exception
stack

guest
interrupt
table

guest file system
and other kernel
services

guest P C
guest SP
guest flags

syscall
handler

Host Kernel

Host Kernel
Mode

timer
handler

host
exception
stack

host
interrupt
table

host PC
host SP
host flags

Virtual
Disk

syscall
handler

Physical
Disk

Hardware

Figure2.18: Emulation of user/kernel mode transfer for processes running
inside a virtual machine.

During boot, the host operating system initializes its interrupt table to point
to its own interrupt handlers in the host kernel memory region. When the host
operating system starts the virtual machine, the guest operating system starts
running as if it is being booted:

The host operating system loads the guest bootloader from the virtual
disk and starts it running.

The guest bootloader loads the guest operating operating system from the
virtual disk into memory and starts it running.

The guest operating system then initializes its own interrupt tables to
point to the interrupt handlers within the guest kernel.