
                 =======================================
                 Future Challenges of the Genode project
                 =======================================


Abstract
########

This document compiles various ideas to pursue in the context of Genode. It is
meant as source of inspiration for individuals who are interested in getting
involved with the project and for students who want to base their student
research projects on Genode.


Applications and library infrastructure
#######################################

:VNC server implementing Genode's framebuffer session interface:

  With 'Input' and 'Framebuffer', Genode provides two low-level interfaces
  used by interactive applications. For example, the Nitpicker GUI server uses
  these interfaces as a client and, in turn, exports multiple virtual
  'Framebuffer' and 'Input' interfaces to its clients. This enables a
  highly modular use of applications such as the nesting of GUIs. By
  implementing the 'Framebuffer' and 'Input' interfaces with a VNC server
  implementation, all graphical workloads of Genode would become available over
  the network. One immediate application of this implementation is the remote
  testing of graphical Genode applications running on a headless server.

:Interfacing with the SAFE network:

  The [https://safenetwork.org/ - SAFE network] is an attempt to fix many
  shortcomings of the internet - in particular with respect to privacy and
  freedom - at an architectural level. It is a peer-to-peer communication
  and storage network that does not depend on single point of
  failure or control. It is intriguing to explore the opportunity of
  integrating support for the SAFE network not merely as an application but
  integrated in the operating system, i.e., in the form of Genode components
  or a set of Genode VFS plugins.

:Interactive sound switchbox based on Genode's Audio_out session interface:

  Since version 10.05, Genode features a highly flexible configuration concept
  that allows the arbitrary routing of session requests throughout the
  hierarchic process structure. Even though primarily designed for expressing
  mandatory-access control rules, the concept scales far beyond this use case.
  For example, it can be used to run an arbitrary number of processes
  implementing the same interface and connecting the different interface
  implementations. One special case of this scenario is a chain of audio
  filters with each using the 'Audio_out' session interface for both roles
  client and server. Combined with the Nitpicker GUI server and Genode's
  support for real-time priorities, this base techniques enable the creation of
  flexible audio mixer / switchboard applications, which require dedicated
  frameworks (e.g., Jack audio) on traditional operating systems. The goal of
  this project is to create a showcase implementation demonstrating the
  feasibility for creating high-quality audio applications on Genode.
  Furthermore, we wish for feedback regarding the current design of our bulk
  streaming interface when used for low-latency applications.

:Graphical on-target IPC tracing tool using Qt:

  Analysing the interaction of components of a multi-server operating system
  such as Genode is important to discover bottlenecks of the system and for
  debugging highly complex usage scenarios involving many processes. Currently,
  Genode handles this problem with two approaches. First, Genode's
  recursive structure enables the integration of a subsystem in a basic
  OS setup featuring only those drivers and components used for the particular
  subsystem. After the successful integration of such a subsystem, it can
  be embedded into a far more complex application scenario without any changes.
  With this approach, the subject to analyse can be kept at a reasonable level
  at integration time. For debugging purposes, the current approach is using
  the debugging facilities of the respective base platforms (e.g., using
  GDB on Linux, the Fiasco kernel debugger, the OKL4 kernel debugger).

  However, in many cases, bottlenecks do not occur when integrating individual
  sub systems but after integrating multiple of such subsystems into a large
  application scenario. For such scenarios, existing debugging methodologies do
  not scale. A tool is desired that is able to capture the relationships
  between processes of a potentially large process hierarchy, to display
  communication and control flows between those processes, and to visualize the
  interaction of threads with the kernel's scheduler.

  Since Qt is available natively on Genode, the creation of both offline and
  on-target analysis tools has become feasible. The first step of this project
  is creating an interactive on-target tool, that displays the interaction
  of communicating threads as captured on the running system. The tool should
  work on a selected kernel that provides a facility for tracing IPC messages.

  The underlying light-weight tracing infrastructure is
  [https://genode.org/documentation/release-notes/19.08#Tracinghttps://genode.org/documentation/release-notes/19.08#Tracing - already in place].
  The Qt-based tracing tools would complement this infrastructure with
  an interactive front end.

:Ports of popular software:

  Genode features a ports mechanism to cleanly integrate 3rd-party software.
  Thanks to the C runtime, the flexible per-component VFS, the standard
  C++ library, and the Noux runtime (for UNIX software), porting software
  to Genode is relatively straight forward. The
  [https://genode.org/documentation/developer-resources/porting - porting guide]
  explains the typical steps. A wish list of software that we'd like to
  have available on Genode is available at
  [https://usr.sysret.de/jws/genode/porting_wishlist.html].

:Native Open-Street-Maps (OSM) client:

  When using Sculpt OS, we regularly need to spawn a fully fledged web
  browser in a virtual machine for using OSM or Google maps. The goal
  of this project would be a native component that makes maps functionality
  directly available on Genode, alleviating the urge to reach for a SaaS
  product. The work would include a review of existing OSM clients regarding
  their feature sets and the feasibility of porting them to Genode.
  Depending on the outcome of this review, an existing application could
  be ported or a new component could be developed, e.g., leveraging Genode's
  Qt support.


Application frameworks and runtime environments
###############################################

:OpenJDK:

  [https://openjdk.java.net/ - OpenJDK] is the reference implementation of the
  Java programming language and hosts an enormous ecosystem of application
  software.

  Since
  [https://genode.org/documentation/release-notes/19.02#Showcase_of_a_Java-based_network_appliance - version 19.02], 
  Genode features a port of OpenJDK that allows the use of Java for networking
  applications.

  The next step would be the creation of Genode-specific native classes that
  bridge the gap between the Java world and Genode, in particular the glue
  code to run graphical applications as clients of Genode's GUI server. Since
  OpenJDK has been ported to numerous platforms (such as Haiku), there exists
  a comforting number of implementations that can be taken as reference.

:Android's ART VM natively on Genode:

  ART is a Java virtual machine that is used for executing applications on
  Android. By running ART directly on Genode, the Linux kernel could be
  removed from the trusted computing base of Android, facilitating the use of
  this mobile OS in high-assurance settings.

:Go language runtime:

  Go is a popular language in particular for web applications. In the past,
  there were numerous attempts to make the Go runtime available on Genode
  but so far, none of those undertakings have landed in the official
  Genode source tree. To goal of this project is the hosting of
  Go-written applications - in particular networking applications - as
  Genode components. The topic comprises work on the tool-chain
  and build-system integration, the porting the runtime libraries, and
  the glue between the Go and Genode environments.

:Combination of CAmkES with Genode:

  [https://wiki.sel4.systems/CAmkES - CAmkES] is a component framework for
  seL4. In contrast to Genode, which is a dynamic system, CAmkES-based systems
  are defined at design time and remain fixed at runtime. Hence, CAmkES and
  Genode can be seen as the opposite ends of component-based used-land
  architectures. The goal of this project is to build a bridge between
  both projects with the potential to cross-pollinate the respective communities.
  Among the principal approaches are embedding of a single CAmkES
  component as a Genode component (e.g., an individual device driver),
  the hosting of a dynamic Genode system as a component within a
  CAmkES system, or the hosting of a CAmkES system composition as a Genode
  subsystem.

:Runtime for the D programming language:

  The D systems programming language was designed to overcome many gripes that
  exists with C++. In particular, it introduces a sane syntax for meta
  programming, supports unit tests, and contract-based programming. These
  features make D a compelling language to explore when implementing OS
  components. Even though D is a compiled language, it comes with a runtime
  providing support for exception handling and garbage collection. The goal of
  the project is to explore the use of D for Genode programs, porting the
  runtime to Genode, adapting the Genode build system to accommodate D
  programs, and interfacing D programs with other Genode components written in
  C++.

:Using Haskell as systems-development language:

  The goal of this project is the application of functional programming
  i.e., Haskell, for the implementation of low-level Genode components.
  Implementing critical functionalities in such a high-level language instead
  of a classical systems language such as C or C++ would pave the way towards
  analyzing such components with formal methods.

  The use of Haskell for systems development was pioneered by the
  [https://programatica.cs.pdx.edu/House/ - House Project]. A more recent
  development is [https://halvm.org - HalVM] - a light-weight OS runtime for
  Xen that is based on Haskell.

:Xlib compatibility:

  Developments like Wayland notwithstanding, most application software on
  GNU/Linux systems is built on top of the Xlib programming interface.
  However, only a few parts of this wide interface are actually used today.
  I.e., modern applications generally deal with pixel buffers instead of
  relying on graphical drawing primitives of the X protocol. Hence, it seems
  feasible to reimplement the most important parts of the Xlib interface to
  target Genode's native GUI interfaces (nitpicker) directly. This would
  allow us to port popular application software to Sculpt OS without
  changing the application code.

:Bump-in-the-wire components for visualizing session interfaces:

  Genode's session interfaces bear the potential for monitoring and
  visualizing their use by plugging a graphical application
  in-between any two components. For example, by intercepting block
  requests issued by a block-session client to a block-device driver,
  such a bump-in-the-wire component could visualize
  the access patterns of a block device. Similar ideas could be pursued for
  other session interfaces, like the audio-out (sound visualization) or NIC
  session (live visualization of network communication).

  The visualization of system behavior would offer valuable insights,
  e.g., new opportunities for optimization. But more importantly, they
  would be extremely fun to play with.


Virtualization
##############

:VirtualBox on top of KVM on Linux:

  Genode's version of VirtualBox replaces the original in-kernel VirtualBox
  hypervisor by the virtualization mechanism of the NOVA hypervisor or the
  Muen separation kernel. Those mechanisms look very similar the KVM
  interface of the Linux kernel. It should in principle be possible to
  re-target Genode's version of VirtualBox to KVM. This way, VirtualBox and
  Qemu/KVM-based virtual machines could co-exist on the same system, which
  is normally not possible. Also, complex Genode scenarios (like Turmvilla)
  could be prototyped on GNU/Linux.

:Xen as kernel for Genode:

  Using Xen as kernel for Genode would clear the way to remove the
  overly complex Linux OS from the trusted computing base of Xen
  guests OSes.

  Xen is a hypervisor that can host multiple virtual machines on one physical
  machine. For driving physical devices and for virtual-machine management, Xen
  relies on a privileged guest OS called Dom0. Currently, Linux is the
  predominant choice to be used as Dom0, which implicates a trusted computing
  base of millions of lines of code for the other guest OSes.

  Even though Xen was designed as hypervisor, a thorough analysis done by Julian
  Stecklina concludes that Xen qualifies well as a kernel for Genode. For
  example, Julian implemented a version of Genode's IPC framework that utilizes
  Xen's communication mechanisms (event channels and shared memory).

:Genode as virtualization layer for Qubes OS:

  [https://www.qubes-os.org/ - Qubes OS] is a desktop operating system
  that follows the principle of security through compartmentalization.
  In spirit, it is closely related to Genode. In contrast Genode's
  clean-slate approach of building a fine-grained multi-component system,
  Qubes employs Xen-based virtual machines as sandboxing mechanism. In
  [https://blog.invisiblethings.org/2015/10/01/qubes-30.html - version 3.0],
  Qubes introduced a Hypervisor Abstraction Layer, which decouples Qubes
  from the underlying virtualization platform. This exploration project
  pursues the goal of replacing Xen by Genode as virtualization layer
  for Qubes.

:Qemu:

  As we use Qemu as primary testing platform for most of the kernels, a port
  of Qemu to Genode is needed in order to move our regular work flows to
  Genode as development platform. The basic prerequisites namely libSDL and a
  C runtime are already available such that this porting work seems to be
  feasible. In our context, the ia32, amd64, and ARM platforms are of most
  interest. Note that the project does not have the immediate goal of
  using hardware-based virtualization. However, if there is interest,
  the project bears the opportunity to explore the provisioning of the
  KVM interface based on Genode's VFS plugin concept.

:Hardware-accelerated graphics for virtual machines:

  In
  [https://genode.org/documentation/release-notes/17.08#Hardware-accelerated_graphics_for_Intel_Gen-8_GPUs - Genode 17.08],
  we introduced a GPU multiplexer for Intel Broadwell along with support
  for Mesa-based 3D-accelerated applications.
  While designing Genode's GPU-session interface, we also aimed at supporting
  the hardware-accelerated graphics for Genode's virtual machine monitors like
  VirtualBox or Seoul, but until now, we did not took the practical steps of
  implementing a virtual GPU device model.

  The goal of this project is the offering of a virtual GPU to a Linux guest
  OS running on top of Genode's existing virtualization and driver
  infrastructure.


Device drivers
##############

:Sound on the Raspberry Pi:

  The goal of this project is a component that uses the Raspberry Pi's
  PWM device to implement Genode's audio-out-session interface. Since
  Genode's version of libSDL already supports this interface as audio
  backend, the new driver will make the sound of all SDL-based games
  available on the Raspberry Pi.

:Data Plane Development Kit (DPDK):

  Genode utilizes the network device drivers of the iPXE project, which
  perform reasonably well for everyday use cases but are obviously not
  designated for high-performance networking.
  The [https://dpdk.org/ - DPDK] is a vendor-supported suite of network device
  drivers that is specifically developed for high-performance applications.
  It presents an attractive alternative to iPXE-based drivers. This project
  has the goal to make DPDK drivers available as a Genode component.


Platforms
#########

:Microkernelizing Linux:

  Thanks to Genode's generic interfaces for I/O access as provided by core, all
  Genode device drivers including drivers ported from Linux and gPXE can be
  executed as user-level components on all supported microkernels. However, so
  far, we have not enabled the use of these device drivers on Linux as base
  platform. The goal of this project is the systematic replacement of in-kernel
  Linux device drivers by Genode processes running in user space, effectively
  reducing the Linux kernel to a runtime for Genode's core process. But moving
  drivers to Genode processes is just the beginning. By employing further
  Genode functionality such as its native GUI, lwIP, and Noux, many protocol
  stacks can effectively be removed from the Linux kernel.

  In 2018, Johannes Kliemann pursued this topic to a state where Genode
  could be used as init process atop a customized Linux kernel.
  [https://lists.genode.org/pipermail/users/2018-May/006066.html - His work]
  included the execution of Genode's regular device drivers for VESA and
  PS/2 as regular Genode components so that Genode's interactive demo
  scenario ran happily on a laptop. At this time, however, only parts of
  his results were merged into Genode's mainline.

  The goal of this project is to follow up on Johannes' work, bring the
  [https://github.com/genodelabs/genode/pull/2829 - remaining parts] into
  shape for the inclusion into Genode, and address outstanding topics, in
  particular the handling of DMA by user-level device drivers. Further down
  the road, it would be tempting to explore the use of
  [https://en.wikipedia.org/wiki/Seccomp - seccomp] as sandboxing mechanism
  for Genode on Linux and the improvement of the Linux-specific implementation
  of Genode's object-capability model.

:Support for the HelenOS/SPARTAN kernel:

  [http://www.helenos.org - HelenOS] is a microkernel-based multi-server OS
  developed at the university of Prague. It is based on the SPARTAN microkernel,
  which runs on a wide variety of CPU architectures including Sparc, MIPS, and
  PowerPC. This broad platform support makes SPARTAN an interesting kernel to
  look at alone. But a further motivation is the fact that SPARTAN does not
  follow the classical L4 road, providing a kernel API that comes with an own
  terminology and different kernel primitives. This makes the mapping of
  SPARTAN's kernel API to Genode a challenging endeavour and would provide us
  with feedback regarding the universality of Genode's internal interfaces.
  Finally, this project has the potential to ignite a further collaboration
  between the HelenOS and Genode communities.

:Support for the XNU kernel (Darwin):

  XNU is the kernel used by Darwin and Mac OS X. It is derived from the
  MACH microkernel and extended with a UNIX-like syscall API. Because the
  kernel is used for Mac OS X, it could represent an industry-strength
  base platform for Genode supporting all CPU features as used by Mac OS X.

:Genode on the Librem5 phone hardware:

  Even though there exists a great variety of ARM-based SoCs, Genode
  primarily focuses on the NXP i.MX family because it is - in contrast
  to most SoCs in the consumer space - very liberal in terms of
  good-quality public documentation and reference code, and it scales
  from industrial to end-user-facing use cases (multi-media).

  The [https://puri.sm/products/librem-5/ - Librem5] project - with its
  mission to build a trustworthy mobile phone - has chosen the i.MX family as
  the basis for their product for likely the same reasons that attract us.

  To goal of this work is bringing Genode to the Librem5 hardware.
  For the Librem5 project, Genode could pave the ground towards new use cases
  like high-security markets where a regular Linux-based OS would not be
  accepted. For the Genode community, the Librem5 hardware could become an
  attractive mobile platform for everyday use, similar to how we developers
  use our Genode-based [https://genode.org/download/sculpt - Sculpt OS] on our
  laptops.


System management
#################

:Remote management of Sculpt OS via Puppet:

  [https://en.wikipedia.org/wiki/Puppet_(company)#Puppet - Puppet] is a
  software-configuration management tool for administering a large amount
  of machines from one central place. Genode's
  [https://genode.org/download/sculpt - Sculpt OS] lends itself to such
  an approach of remote configuration management by the means of the
  "config" file system (for configuring components and deployments) and
  the "report" file system (for obtaining the runtime state of components).
  The project would explore the application of the Puppet approach and tools
  to Sculpt OS.


Optimizations
#############

:De-privileging the VESA graphics driver:

  The VESA graphics driver executes the graphics initialization code provided
  by the graphics card via an x86 emulator. To initialize a graphics mode, this
  code needs to access device hardware. Currently, we permit access to all
  device registers requested by the graphics-card's code. These devices include
  the system timer, the PCI configuration registers, and the interrupt
  controller, which are critical for the proper operating of the kernel. The
  goal of this work is to restrict the permissions of the VESA driver to a
  minimum by virtualizing all devices but the actual graphics card.

