Index: /trunk/src/VBox/VMM/VMMAll/IEMAllCImplVmxInstr.cpp.h
===================================================================
--- /trunk/src/VBox/VMM/VMMAll/IEMAllCImplVmxInstr.cpp.h	(revision 74668)
+++ /trunk/src/VBox/VMM/VMMAll/IEMAllCImplVmxInstr.cpp.h	(revision 74669)
@@ -3351,4 +3351,5 @@
     Assert(ExitInstrInfo.StrIo.iSegReg < X86_SREG_COUNT);
     Assert(ExitInstrInfo.StrIo.u3AddrSize == 0 || ExitInstrInfo.StrIo.u3AddrSize == 1 || ExitInstrInfo.StrIo.u3AddrSize == 2);
+    Assert(uInstrId != VMXINSTRID_IO_INS || ExitInstrInfo.StrIo.iSegReg == X86_SREG_ES);
 
     bool const fIntercept = iemVmxIsIoInterceptSet(pVCpu, u16Port);