- Devel - lists.sel4.systems

Survey about the seL4 summit 2023's location
by June Andronick (seL4 Foundation) 21 Nov '22

21 Nov '22

Dear seL4 friends, With the great success of the seL4 summit 2022 behind us, we are now already looking at the seL4 summit 2023! This should happen around Sep/Oct 2023. We have started investigating options for the location, and we would like your feedback. We would very much appreciate if you could fill in this very short survey to tell us your opinion between USA (likely Minneapolis) and Australia (likely Sydney) or any other feedback you have: https://forms.gle/k4XxYaYeudYUie9U8 <https://forms.gle/k4XxYaYeudYUie9U8> Please do so by Nov 22nd 2022. Feel free to forward to anyone you believe may want to attend the summit next year. Many thanks! June -- June Andronick CEO of the seL4 Foundation https://sel4.systems/Foundation

1 1

Experimental project on seL4 microbenchmarking
by Nataliya Korovkina 20 Nov '22

20 Nov '22

Hi seL4 friends, I’d like to share an experimental project on seL4 microbenchmarking inspired with my experience with sel4bench suite. Your thoughts on the concept and its practical use will be greatly appreciated. Motivation (informal) Measuring execution times of short code paths, which we can meet in seL4 microbenchmarking, is a good way to immerse oneself into the domain of compiler and microarchitectural optimizations. Implementation of “early processing” measurement methodology in sel4bench suite (for Notification delivery case, as a trial step; PR #26) was an amazing experience in that respect. So, I gladly share the work highlights to explain my motivation. First, latencies of some microarchitectural events can be comparable with execution time of a measured code path. So, if microarchitectural event not planned by a benchmark design happens during a measuring period, deviation of the observed value considerably increases. Second, the both kinds of optimizations of instrumental code cause instability of measured values from one measurement iteration to another. Third, debugging the instrumental code is very challenging. Injection of diagnostic code into it changes effects of the both types of optimizations; therefore, initially witnessed symptoms effectively transform to other ones. When you think about how to control optimizations effects, the situation appears uninspiring, considering the need to treat various microarchitectures and optimization features. As a result, the situation left me with the question on hands: how to distance a benchmark design from necessity to control optimizations effects in instrumental code that impair repeatability? Eventually, it reduced to the foundational one: What we measure, and Why? This experimental work is attempt to find and try the solution for the challenge: designing more predictable measurement context. The work was published in github. Description paper https://github.com/malus-brandywine/sel4KanataBench-papers/blob/main/Kanata… Project repository https://github.com/malus-brandywine/sel4KanataBench Project manifest repository https://github.com/malus-brandywine/sel4KanataBench-manifest Tables of data collected on four TS platforms: files KBenchTable-xxxx.pdf in https://github.com/malus-brandywine/sel4KanataBench-papers Thank you!

1 0

Reminder seL4 developer hangout
by Birgit Brecknell 14 Nov '22

14 Nov '22

Hi all A friendly reminder that the seL4 developer hangout is on again this week: Wed, Nov 16, 6am (UTC), Topics: (open) * Sydney: Wed, Nov 16, 5pm * Central Europe: Wed, Nov 16, 7am * US Pacific Time: Tue, Nov 15, 10pm Zoom link: https://unsw.zoom.us/j/82640784431 cheers Birg --- Dr. Birgit Brecknell Project Officer Trustworthy Systems, UNSW, birgit.brecknell(a)unsw.edu.au<mailto:birgit.brecknell@unsw.edu.au> seL4 Foundation, birgit(a)sel4.systems<mailto:birgit@sel4.systems> 0433 880 571 Mon 9am-5pm Wed 9am-12pm Fri 9am-5pm

1 0

Reminder seL4 developer hangout
by Birgit Brecknell 31 Oct '22

31 Oct '22

Hi all A friendly reminder that the seL4 developer hangout is on again next week: Tue, Nov 1, 9pm (UTC), Topics: (open) * Sydney: Wed, Nov 2, 8am * Central Europe: Tue, Nov 1, 10pm * US Pacific Time: Tue, Nov 1, 2pm Zoom link: https://unsw.zoom.us/j/82640784431 cheers Birg --- Dr. Birgit Brecknell Project Officer Trustworthy Systems, UNSW, birgit.brecknell(a)unsw.edu.au<mailto:birgit.brecknell@unsw.edu.au> seL4 Foundation, birgit(a)sel4.systems<mailto:birgit@sel4.systems> 0433 880 571 Mon 9am-5pm Wed 9am-12pm Fri 9am-5pm

1 0

Cross Core IPC
by Sid Agrawal 24 Oct '22

24 Oct '22

Hi, I came across Gernot Heiser's blog post on "How to use seL4 IPC" [1]. The article explicitly says that doing cross-core IPC is a bad idea. This statement led to a series of questions for me, which I hope you guys can help me with. Scenario ------------ We have a system with two cores. Let's say that a physical memory server is running on core0, my application is on core1, and they are somehow pinned to those cores. The application wants some physical memory (frame capabilities) from the memory server. Questions ------------- Q1. Will the application be able to invoke the endpoint given that the TCB which will respond to it is on a separate core? If yes, will sending a capability back via cross-core IPC be allowed? I did not read anything in the manual which said otherwise. Q2. Why is a cross-core IPC a bad idea? This might be a loaded question, but I am not able to appreciate the badness of the idea :) Q3. What would be the right way to do it? For example, in Barrelfish(limited experience from a course), the application(on core1) would make an IPC to a monitor running on the same core1. This monitor did synchronization with another monitor running on the other core(core0) via a shared memory region (all in user space). That monitor(core0) then sent an IPC to the memory server running on core0. And then back again via the monitors. Best, Sid [1] https://microkerneldude.org/2019/03/07/how-to-and-how-not-to-use-sel4-ipc/

3 2

Suitability for a project
by James Hillman 19 Oct '22

19 Oct '22

Hi Sel4 developers, I am new to this forum and hoping this is the right place to bounce my project idea off. I typically use FPGA to enforce security in my products but there are lots of reasons why FPGAs are not suitable for all use cases. I have also used low end microcontroller where one can review all the code to understand the security risks. My latest project however involves two USB processes (one for each physical connection) with high throughput expectations. And to pass data streams at high typical throughput between them. Due to the wide range of USB type of devices I fear this would be too much code to review - it feels very OS like. Note, I don't need a GUI, it's headless. So I'm interested in sel4 as I could run the processes in Linux VMs if I understand sel4 correctly. And whilst it's not the smallest processors I think they need to be more powerful to support the speeds. So this is fine . I am unsure how much of this project is already done, mainly thinking the usb driver perspective. Thanks in advance, Best wishes James

5 10

new RFC: seL4 Device Driver Framework
by Gerwin Klein 19 Oct '22

19 Oct '22

A new RFC has just landed: https://sel4.atlassian.net/browse/RFC-12 If you have any feedback, please comment there. Cheers, Gerwin

8 16

Re: Suitability for a project
by James Hillman 19 Oct '22

19 Oct '22

Thanks Gernot. Thoughts on throughput rates thats might be achieved?

1 0

Re: Suitability for a project
by James Hillman 19 Oct '22

19 Oct '22

I was interested to see the Google news re. KataOS which I suspect confirms that my sort of requirement / entry point is someway out. I was also reading about ARM Morello / CHERI work. Although I appreciate this is taking a different, perhaps flawed, path of some new hardware memory protection. Appreciate any feedback you can humour me with.

2 1

seL4 dev hangout reminder
by Gerwin Klein 17 Oct '22

17 Oct '22

Hi all A friendly reminder that the seL4 developer hangout is on again this week: Wed, Oct 19, 6am (UTC), Topics: (open) * Sydney: Wed, Oct 19, 5pm * Central Europe: Wed, Oct 19, 8am * US Pacific Time: Tue, Oct 18, 11pm Zoom link: https://unsw.zoom.us/j/82640784431 Cheers, Gerwin

1 0