(5) Handle: The hypervisor typically emulates the event and does (3), repeating the process

  • Hypervisor determines the cause of VM exit from the context structure
    • Intel: Exit reason field 📖28.2 RECORDING VM-EXIT INFORMATION AND UPDATING VM-ENTRY CONTROL FIELDS
    • AMD: EXITCODE field 📖15.6 #VMEXIT
  • Hypervisor emulates the event on behalf of the guest
    • eg, for CPUID
      1. inspects guest's EAX and ECX as input
      2. updates guest's EAX, EBX, ECX, EDX as output
      3. updates guest's RIP
  • Hypervisor switches to the guest with VMRESUME/VMRUN