Devel April 2024

devel@sel4.systems

20 participants
14 discussions

Multikernel in RISCV
by David Martin 06 Jun '24

06 Jun '24

Hello, I'm currently working with seL4 & Polarfire (RISCV) and I'm working with a single core at the moment (doing some testing and understanding how seL4 works). Polarfire has 4 cores and I'd like to start using all of them in a multikernel configuration (every hart running its own sel4 kernel). I've found the following RFC: https://sel4.atlassian.net/browse/RFC-17 where Kent McLeod has done some work (https://github.com/kent-mcleod/camkes-manifest/blob/kent/multicore2/master.…) but only for ARM. Does someone know if the same approach will be taken for RISCV? or even better, if someone has already done it? Thanks, David.

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seL4 multicore boot failed on arm64
by Leonid Meyerovich 10 May '24

10 May '24

Hello, I run my seL4 application on 4 core ARMv8. Recently I have developed some more application code (I mention it because file system size is increased an I believe it may change boot time) and from time to time I observed that boot process failed (stuck after the following print) calling schedule calling activate thread kernel boot done.. CPU=1 calling schedule calling activate thread kernel boot done.. CPU=2 calling schedule calling activate thread kernel boot done.. CPU=3 Booting all finished, dropped to user space calling schedule calling activate thread kernel boot done.. CPU=0 Some time I see that only 2 CPU have been booted (like CPU1 and CPU3, or CPU2 and CPU3) Last print is the last one in init_kernel() function Thanks you, Leonid

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seL4 developer hangout reminder
by Birgit Brecknell 29 Apr '24

29 Apr '24

Hi all A friendly reminder that the seL4 developer hangout is on again this week. Wed 1 May, 8:00 UTC. For your local date and time please see https://sel4.systems/contact/. Zoom link: https://unsw.zoom.us/j/82640784431 Birgit Brecknell seL4 Foundation Project Coordinator birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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seL4 summit: deadline extension to 29 April 2024
by Birgit Brecknell 22 Apr '24

22 Apr '24

The deadline to submit a presentation to the seL4 summit 2024 [0] has been extended by 1 week. You now have until 29 April 2024 to propose a talk [1], by uploading an abstract of one page or less to the submission portal [2]. Looking forward to receiving your proposals. We want to hear about your cool seL4 work! And spread the word! If you want to hear about specific seL4 work, ping people around you or let us know at summit(a)sel4.systems. [0] https://sel4.systems/Foundation/Summit/2024/ [1] https://sel4.systems/Foundation/Summit/2024/cfp [2] https://sel4.systems/Foundation/Summit/2024/submit Birgit Brecknell seL4 Foundation Project Coordinator birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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Question about LionsOS
by Isaac Beckett 20 Apr '24

20 Apr '24

Hello! Looking at the LionsOS website and documentation you posted, it seems like Lions is an operating system built using Microkit out of components/drivers that use the sDDF? Do I have the right shape of things in my head? Also, would sDDF drivers for a static OS like Lions (or other OS built in Microkit, since that’s what’s it’s built for) be potentially portable to other operating systems using the seL4 kernel and sDDF? Like, if I design a non-static operating system that uses sDDF drivers, could I use existing code from Lions or would I face issues with code assuming that the system’s components can’t change at runtime? Thanks, Isaac

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seL4 vs QNX and Linux benchmarks
by Andrew Warkentin 20 Apr '24

20 Apr '24

Somebody in the Zoom call the other day (IIRC it was Gernot) said that seL4 IPC is considerably faster than QNX IPC, but it seems that QNX is somehow faster in a simple benchmarking experiment in which a client repeatedly sends messages to a bit-bucket server, using the TSC to determine timing. I'm running both QNX and seL4 under identical VirtualBox configurations with a single core. I'm using a QNX 6.3.1 x86-32 image i have in my collection (x86-64 support was only added in 7.0; this is the most recent image I have with dev tools installed). The seL4 version I'm using is from February 2022 and is built for x86-64 with MCS enabled (the priority of the threads is 255, and both the timeslice and budget are the initial thread default of 5 ms). My benchmark times a loop of 10000 RPCs; for QNX it's just using the regular read() function on /dev/null or a custom server that also acts like /dev/null but forces a copy of the message into a server-provided buffer, and for seL4 I'm directly calling Send()/Recv()/Reply(). I've also tested Linux's /dev/null, and QNX's implementation actually seems somewhat faster than it (for the system /dev/null; the custom server's best case seems only slightly worse than under Linux). Under QNX and Linux I'm running a C implementation of the benchmark and under seL4 I tried both C and Rust implementations (which have very similar performance). The messages on QNX and Linux are 100 bytes, and on seL4 they are 2 words, which should be hitting the fast path. Here are the best and worst cases I got: seL4: 0.114-0.136s QNX, custom null server: 0.006-0.063s QNX, system null server: 0.002-0.022s Linux: 0.004-0.005s Has anyone else benchmarked seL4 IPC against that of QNX and gotten better (or comparable) results for seL4, unlike what I got? Is synchronous IPC just less optimized under seL4 than QNX?

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Release 0.1.0 of LionsOS
by Ivan Velickovic 16 Apr '24

16 Apr '24

Hello all This is a message to let people know that version 0.1.0 of LionsOS has been released. LionsOS is aimed at embedded, IoT and cyberphysical systems and is designed to be formally verifiable, adaptable to a wide class of use cases in the target domain, while at the same time setting the benchmark for performance of microkernel-based operating systems. We expect to achieve all three aims by a highly modular yet ruthlessly performance-oriented design and strict adherence to the time-honoured KISS principle. LionsOS is still in its early stages but we are at the point where we have a non-trivial example system and initial documentation. You can find the website here: https://lionsos.org/ and the source code here: https://github.com/au-ts/lionsos Thanks, Ivan

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One week to go to submit a talk for seL4 summit 2024
by Birgit Brecknell 15 Apr '24

15 Apr '24

One week to go to submit a talk [0] for seL4 summit 2024 [1]! If you’d like to submit a talk, please upload an abstract of one page or less to the submission portal [2]. The seL4 Summit 2024 will be held 15-17 October 2024 at the Holiday Inn Potts Point, Sydney, Australia. The summit will be an in-person event. Registration details to follow soon. We’re looking forward to many exciting proposals! [0] https://sel4.systems/Foundation/Summit/2024/cfp [1] https://sel4.systems/Foundation/Summit/2024/ [2] https://sel4.systems/Foundation/Summit/2024/submit Birgit Brecknell seL4 Foundation Project Coordinator birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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question about the seL4/camkes-vm-examples
by PX 15 Apr '24

15 Apr '24

Hi,All I am trying to build the seL4 VMM example for the qemu-arm-virt platform from seL4/camkes-vm-exmaples. I can build the vmm image successfully, but I cannot run the image. Here are what I did: 1. I use the "../init-build.sh -DCAMKES_VM_APP=vm_minimal -DPLATFORM=qemu-arm-virt" command. 2. ninja After these two steps, the vmm image, capdl-loader-image-arm-qemu-arm-virt is successfully built. But when I run the generated scripts, ./simulate, to run the VMM on qemu, the vmm fails to boot up. The error message is attached below. I use Ubuntu 20.04 and QEMU emulator version 4.2.1. Do I miss something here? Do I use the correct version of the building environment? Any help would be appreciated! ./simulate ./simulate: QEMU command: qemu-system-arm -machine virt,virtualization=on,highmem=off,secure=off -cpu cortex-a15 -nographic -m size=2048 -kernel images/capdl-loader-image-arm-qemu-arm-virt ELF-loader started on CPU: ARM Ltd. Cortex-A15 r2p1 paddr=[61805000..62c02ebf] No DTB passed in from boot loader. Looking for DTB in CPIO archive...found at 6192264c. Loaded DTB from 6192264c. paddr=[60042000..60043fff] ELF-loading image 'kernel' to 60000000 paddr=[60000000..60041fff] vaddr=[e0000000..e0041fff] virt_entry=e0000000 ELF-loading image 'capdl-loader' to 60044000 paddr=[60044000..6140cfff] vaddr=[10000..13d8fff] virt_entry=1880c Enabling hypervisor MMU and paging Jumping to kernel-image entry point... Bootstrapping kernel Warning: Could not infer GIC interrupt target ID, assuming 0. available phys memory regions: 1 [60000000..c0000000] reserved virt address space regions: 4 [e0000000..e0042000] [e0042000..e0043da9] [e0044000..e140d000] [ff000000..ff200000] Booting all finished, dropped to user space *<<*seL4(CPU 0)* [decodeUntypedInvocation/205 T0xffc13400 "rootserver" @1070c]: Untyped Retype: Insufficient memory (1 * 33554432 bytes needed, 0 bytes available).>>* *<<*seL4(CPU 0)* [decodeUntypedInvocation/205 T0xffc13400 "rootserver" @1070c]: Untyped Retype: Insufficient memory (1 * 16777216 bytes needed, 0 bytes available).>>* *<<*seL4(CPU 0)* [decodeUntypedInvocation/205 T0xffc13400 "rootserver" @1070c]: Untyped Retype: Insufficient memory (1 * 16777216 bytes needed, 0 bytes available).>>* *<<*seL4(CPU 0)* [decodeUntypedInvocation/205 T0xffc13400 "rootserver" @1070c]: Untyped Retype: Insufficient memory (1 * 2097152 bytes needed, 0 bytes available).>>* *<<*seL4(CPU 0)* [decodeUntypedInvocation/205 T0xffc13400 "rootserver" @1070c]: Untyped Retype: Insufficient memory (1 * 65536 bytes needed, 0 bytes available).>>* run@main.c:1332 Invalid 'num_vcpus' attribute setting: Exceeds maximum number of supported nodes. Capping value to CONFIG_MAX_NUM_NODES (1) install_vm_devices@main.c:704 module name: map_frame_hack install_vm_devices@main.c:704 module name: init_ram Loading Kernel: 'linux' Loading Initrd: 'linux-initrd' Loading Generated DTB -------- *Pagefault from [vm0]: read prefetch fault @ PC: 0x4 IPA: 0x4, FSR: 0x6* *Context:* *r0: 0x0* *r1: 0xffffffff* *r2: 0x4f000000* *r3: 0x0* *r4: 0x0* *r5: 0x0* *r6: 0x0* *r7: 0x0* *r8: 0x0* *r9: 0x0* *r10: 0x0* *r11: 0x0* *r12: 0x0* *pc: 0x4* *r14: 0x0* *sp: 0x0* *cpsr: 0x9b* m-------- main_continued@main.c:1310 Failed to run VM Halting...

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seL4 developer hangout reminder
by Birgit Brecknell 15 Apr '24

15 Apr '24

Hi all A friendly reminder that the seL4 developer hangout is on again this week. Tue 16 Apr, 22:00 UTC. For your local date and time please see https://sel4.systems/contact/. Zoom link: https://unsw.zoom.us/j/82640784431 Birgit Brecknell seL4 Foundation Project Coordinator birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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