Our Partners
A fast and reliable operating system requires fast and reliable device drivers. Most current operating systems sacrifice reliability for speed by executing drivers in kernel mode. Given that drivers account for the bulk of kernel code (70% in Linux), and that driver developers are typically not kernel experts, it does not come as a surprise that the majority of OS failures nowadays are caused by bugs in device drivers.
In a microkernel-based system, such as those based on seL4, device drivers run in user mode, as normal processes, encapsulated in their own address space. This encapsulation can be enforced through hardware mechanisms, such as the memory-management unit (MMU) and an IOMMU for devices performing direct memory access (DMA). Our aim is to have seL4-based I/O that performs comparable to Linux, yet achieving high robustness by encapsulating drivers to achieve fault isolation and ideally formally verify drivers.
After much activity on (user-level as well as Linux) device drivers, we had for the past 10 years mostly focussed on other issues. With the maturing and increasing deployment of seL4, drivers have come to the forefront again, and we are working on a driver framework for seL4 and issues arising from that.
The seL4 device driver framework provides a set of interfaces, designs and tools for developing high-performance, encapsulated device drivers for seL4.
At the core of the sDDF is a transport layer that enables low-overhead, shared-memory communication between the driver and its client (an OS service such as a network protocol stack of a file-system server). The transport layer uses ring buffers for data sharing, concurrency control and flow control.
The sDDF is as yet incomplete. It currently provides some guidance for designing systems using drivers (device discovery, separation of control and data planes), and has some libraries for high-throughput, low latency data-plane communication.
The sDDF is also the base for sharing devices between virtual machines and native clients. Here each device has a single driver, encapsulated either in a native component or a virtual machine, and is multiplexed securely between clients.
Formal verification of device drivers is our long-term goal, which is enabled by the strong isolation provided for usermode drivers on seL4, which allows verifying drivers in isolation. We had some limited success at verifying simple drivers in the Cogent project. Our latest attempt at verifying drivers is the Pancake project, which is developing a new low-level programming language reusing the verification framework of CakeML.
Our research on high-performance user-level device drivers predates seL4. In addition we explored a number of approaches in the past, including:
The current sDDF work is financially supported by the seL4 Foundation and the Technology Innovation Institute. See the relevant sub-project pages for supporters and collaborators on those.
We are collaborating with Breakaway Consulting on the sDDF.
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Past
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Johannes Åman Pohjola, Hira Taqdees Syeda, Miki Tanaka, Krishnan Winter, Gordon Sau, Ben Nott, Tiana Tsang Ung, Craig McLaughlin, Remy Seassau, Magnus Myreen, Michael Norrish and Gernot Heiser Pancake: verified systems programming made sweeter Workshop on Programming Languages and Operating Systems (PLOS), Koblenz, DE, October, 2023 |
 
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Gernot Heiser, Lucy Parker, Ivan Velickovic, Peter Chubb and Ben Leslie Can we put the "S" into IoT? IEEE World Forum on Internet of Things, Yokohama, JP, November, 2022 |
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Pavol Cerny, Edmund Clarke, Thomas Henzinger, Arjun Radhakrishna, Leonid Ryzhyk, Roopsha Samanta and Thorsten Tarrach From non-preemptive to preemptive scheduling using synchronization synthesis International Conference on Computer Aided Verification, San Francisco, USA, July, 2015 |
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Niklas Een, Alexander Legg, Nina Narodytska and Leonid Ryzhyk SAT-based strategy extraction in reachability games AAAI, Austin, TX, USA, January, 2015 |
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Leonid Ryzhyk, Adam Christopher Walker, John Keys, Alexander Legg, Arun Raghunath, Michael Stumm and Mona Vij User-guided device driver synthesis USENIX Symposium on Operating Systems Design and Implementation, pp. 661–676, Broomfield, CO, USA, October, 2014 |
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Adam Christopher Walker and Leonid Ryzhyk Predicate abstraction for reactive synthesis Conference on Formal Methods in Computer-Aided Design, Lausanne, Switzerland, October, 2014 |
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Adam Christopher Walker and Leonid Ryzhyk Predicate abstraction for reactive synthesis Technical Report NRL-8281, NICTA, August, 2014 |
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Pavol Cerny, Thomas Henzinger, Arjun Radhakrishna, Leonid Ryzhyk and Thorsten Tarrach Regression-free synthesis for concurrency International Conference on Computer Aided Verification, Vienna, Austria, July, 2014 |
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Niklas Een, Alexander Legg, Nina Narodytska and Leonid Ryzhyk Interpolants in two-player games Abstract, iPRA workshop, July, 2014. |
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Alexander Legg, Nina Narodytska and Leonid Ryzhyk Practical CNF interpolants via BDDs Abstract, iPRA workshop, July, 2014. |
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Nina Narodytska, Alexander Legg, Fahiem Bacchus, Leonid Ryzhyk and Adam Christopher Walker Solving games without controllable predecessor International Conference on Computer Aided Verification, Vienna, Austria, July, 2014 |
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Sidney Amani, Peter Chubb, Alastair Donaldson, Alexander Legg, Keng Chai Ong, Leonid Ryzhyk and Yanjin Zhu Automatic verification of active device drivers ACM Operating Systems Review, Volume 48, Number 1, May, 2014 |
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Mona Vij, John Keys, Arun Raghunath, Scott Hahn, Vincent Zimmer, Leonid Ryzhyk, Adam Christopher Walker and Alexander Legg Device driver synthesis Intel Technology Journal, Volume 17, Number 2, pp. 136–157, December, 2013 |
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Pavol Cerny, Thomas Henzinger, Arjun Radhakrishna, Leonid Ryzhyk and Thorsten Tarrach Efficient synthesis for concurrency by semantics-preserving transformations Proceedings of the 25th International Conference on Computer Aided Verification, pp. 1–16, Saint Petersburg, Russia, July, 2013 |
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Leonid Ryzhyk, Yanjin Zhu and Gernot Heiser The case for active device drivers Asia-Pacific Workshop on Systems (APSys), pp. 25–30, New Delhi, India, August, 2010 |
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Leonid Ryzhyk On the construction of reliable device drivers PhD Thesis, UNSW, Sydney, Australia, January, 2010 |
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Leonid Ryzhyk, Peter Chubb, Ihor Kuz, Etienne Le Sueur and Gernot Heiser Automatic device driver synthesis with Termite ACM Symposium on Operating Systems Principles, pp. 73–86, Big Sky, MT, US, October, 2009 |
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Joshua LeVasseur Device-driver reuse via virtual machines PhD Thesis, UNSW, Sydney, Australia, May, 2009 |
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Myrto Zehnder and Peter Chubb Virtualising PCI Gelato ICE, Singapore, October, 2006 |
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Ben Leslie, Peter Chubb, Nicholas FitzRoy-Dale, Stefan Götz, Charles Gray, Luke Macpherson, Daniel Potts, Yueting (Rita) Shen, Kevin Elphinstone and Gernot Heiser User-level device drivers: Achieved performance Journal of Computer Science and Technology, Volume 20, Number 5, pp. 654–664, September, 2005 |
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Ben Leslie, Peter Chubb, Nicholas FitzRoy-Dale, Stefan Götz, Charles Gray, Luke Macpherson, Daniel Potts, Yueting (Rita) Shen, Kevin Elphinstone and Gernot Heiser User-level device drivers: Achieved performance Technical Report PA005043, NICTA, July, 2005 |
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Peter Chubb Get more device drivers out of the kernel! Ottawa Linux Symposium, Ottawa, Canada, July, 2004 |
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Peter Chubb Linux kernel infrastructure for user-level device drivers 5th Linux.conf.au, Adelaide, Australia, January, 2004 |
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Ben Leslie, Nicholas FitzRoy-Dale and Gernot Heiser Encapsulated user-level device drivers in the Mungi operating system Proceedings of the Workshop on Object Systems and Software Architectures 2004, Victor Harbor, South Australia, Australia, January, 2004 |
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Ben Leslie and Gernot Heiser Towards untrusted device drivers Technical Report UNSW-CSE-TR-0303, School of Computer Science and Engineering, March, 2003 |