RTA-LWHVR – Lightweight Hypervisor

Hypervisor in use within a microcontroller

The ETAS RTA-LWHVR (Lightweight Hypervisor) makes it possible to divide an ECU into individual partitions, so-called Virtual Machines (VM). With its low memory requirements and fast access times, the ETAS RTA-LWHVR is specifically optimized for use in automotive ECUs. It is designed for automotive microcontrollers that don’t include virtualization hardware.

Enables agile function and software development

The Hypervisor allows a single microcontroller to run several Virtual Machines independently and in parallel. Each machine could run applications bare metal or with its own operating system (e.g. RTA-OS) or even a full AUTOSAR stack (e.g. RTA-CAR). Each Virtual Machine provides an abstraction of the underlying hardware, which means that it is possible to use software from different suppliers in some cases with minimal adaptations.

Software on a VM can run with an ETAS-AUTOSAR-Stack, third-party-AUTOSAR stack or "bare metal"

The Virtual Machines are strictly decoupled from each other and have their own secure area on the ECU. This makes it possible to update VMs independently of each other. Thus, the Lightweight Hypervisor from ETAS forms the basis for agile software and function development in the automotive sector. It enables different suppliers to develop the same ECU independently of each other without the need to share their software code.

A Hypervisor also allows AUTOSAR and non-AUTOSAR compliant software with different security levels to be executed simultaneously on one and the same ECU. The corresponding inter-core communication (ICC) between a master core and several application cores ensures that individual VMs can request additional time budgets if required. In this way, real-time requirements can be served without errors and without compromising the execution of other functions.

General Benefits of Hypervisors

OEMs are looking to reduce vehicle costs by reducing the number of ECUs. Hypervisors help this by making it easy to integrate software from different ECUs into a single ECU. Using a Hypervisor in this way offers the following benefits:

  • simultaneous and independent ECU-development by different suppliers
  • lower integration effort of the individual software components
  • intellectual property protection between development partners
  • protection against software errors through mutual influence of the functions
  • homologation support, where one part of the software must remain unchanged

Many of today’s automotive microcontrollers do not feature virtualization hardware. To meet the needs of AUTOSAR on automotive microcontrollers anyway, ETAS has developed its Lightweight Hypervisor RTA-LWHVR.

RTA-LWHVR – For today’s Microcontrollers without virtualization support

The Lightweight Hypervisor provides most of the features and the resulting benefits of Hypervisors without the need of hardware virtualization support. Thus, the RTA-LWHVR offers a wide range of operational areas.

With the ETAS Lightweight Hypervisor only Tier-1 applications need to control hardware and process interrupts. Tier-1 code runs “bare metal” on the Master Core and handles all I/O. The Lightweight Hypervisor itself runs on Slave Cores and only requires a small amount of memory, down to 5kB. Customer applications in “simple” VMs also run on slave Cores.


  • “simple” Virtual Machines mitigate against the inefficiency of missing hardware virtualization support
  • suitable for applications up to ISO 26262 ASIL B


  • minimal access time of the software
  • low memory requirements
  • wide range of operational modes
  • no mutual interferences between VMs

Areas of application

The RTA-LWHVR is best recommended for body control type applications and other applications without hard real time requirements.

In order to meet higher demands and the microcontrollers of the future, ETAS is currently developing a hypervisor RTA-HVR. Please contact us for more details.