Exception interception

  • By default, exception happens within the guest-mode is processed entirely within the guest
    • Delivered through current (guest) IDT
    • Processed by the guest OS
  • A hypervisor can optionally intercept them as VM exits
    • Intel: Exception Bitmap VMCS 📖25.6.3 Exception Bitmap
    • AMD: Intercept exception vectors (offset 0x8) 📖15.12 Exception Intercepts
  • To enable, set the bits that correspond to exception numbers you want to intercept, eg set 1 << 0xe to intercept #PF (0xe)