July 2021 - Devel - lists.sel4.systems

seL4 test on x86
by Yevgeny Lavrov 30 Jan '25

30 Jan '25

Hello, I'm new to seL4 and I'm just doing it for learning purpose. I'm trying to run seL4 test suite or simple hello world task from seL4 tutorials on the real hardware. So far I had no problems compiling seL4 test suite and running via QEMU for both x32 and x64 platforms. However, when I try to run it on the actual hardware following Running on real hardware tutorial for x86 I end up with no output at all and no error msgs that can give me a clue on where something went wrong. After compiling seL4test for x86, I ended up with two images in sel4_dir/images/ folder. Copied them over to /boot/sel4/ folder and created a new GRUB2 entry that looks like this menuentry “seL4 test suite” --class os { load video insmod gzio insmod part_msdos insmod ext2 set root=’(hd0,msdos5)’ multiboot /boot/sel4/kernel-ia32-pc99 module /boot/sel4/sel4test-driver-image-ia32-pc99 } update grub, restart and select the new entry from GRUB menu. I end up with blinking cursor on the top-left side of the screen. Please advise.

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Stuck during invalidate local TLB in Tx2
by Muneeswaran Rajendran 16 Oct '24

16 Oct '24

Hi seL4 Dev team, Can someone explain the reason (share the reference) to invalidate the local TLB during kernel vspace activation as part CPU initialisation. The Tx2 board stuck while performing this operation. As per my understanding both Tx1 and Tx2 are using same A57 core. so the TLB initialisation and invalidation remain same for Tx2 and should not stuck during invalidation.Please correct me if anything wrong here. I understand from that instruction (tlbi vmalle1) which is invalidating stage 1 entries associated to the current VMID. Also from arm mmu code the seL4 setting up (TCR_EL1) TCR register addressing space as 48bit, ASID as 16bit and page table setup 4k granular size. I am using MRS macro to dump the spsr_el1 and dspsr_el0 register to see the state of processor but its throwing synchronous exception. Do we have any other option to dump all the register content to see the state of processor like we have one in 'sel4debug_dump_registers' which is used in sel4test code. Regards, Muneeswaran R

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Questions about Memory Management in seL4
by Daniel Wang 19 May '23

19 May '23

Hi all, Sorry to bother, I have some basic questions about seL4 memory management. Can someone help me? 1. where is the kernel’s address space? I know there are basically three methods: a) separate virtual address space, e.g. through changing page tables on entry into privileged mode to access b) physical space, e.g. through disable automatic hardware translation of virtual addresses on entry into privilege mode c) privilege region in each process’s virtual address space, e.g. through page table to map kernel address into use-mode process. My question is which of this is being used by seL4 microkernel? 2. Objects like CSpace, VSpace, CNode, TCB, Endpoint, etc. are called kernel objects, but it seems all dynamically allocated in thread running/creating time. Are those objects (e.g. Figure 3.3 in seL4 manual) in kernel space or in user space? 3. I read that after the kernel boot up, it passes all resources, untyped memory to the first thread. Are those untyped memory physical memory or virtual memory in a single page? The reason I ask is I’m learning the code of the UNSW AOS project (two of the assignment projects are implementing frame and papers). I’m confused that before the implementation of frames and pages what kind of memory is passed to the the first thread? I saw int AOS project, it uses ut_table_init(), ut_steal_mem(), I wonder what kind of memory it operates on? Thanks -Dan

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VM Kernel Modules
by Michael Neises 20 Nov '21

20 Nov '21

Hello all, I recently spent a lot of time getting the camkes-vm-linux tutorial to work, because it is the only example I could find of compiling a kernel module for the linux vm as a part of the camkes build process. Unfortunately, the kernel module doesn't seem to work. For more information, see the previous email chain as well as https://github.com/NeisesResearch/vm_measure/wiki/Building-the-camkes_vm_li… . In lieu of doing things the right way, I believe I could compile a kernel module for the linux kernel that is provided as part of the camkes build system. I believe this is how the introspect-app accomplishes its work. However, I need to have the exact kernel and exact configuration in order to compile the kernel module correctly. Can anyone point me to the correct kernel version and configuration, so that I can target the provided linux kernel for module compilation? Or if there's a better way to get a kernel module in there, please let me know. Cheers, Michael Neises

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ethernet pass-through using CAmkES VM on x86
by meshkat os 29 Sep '21

29 Sep '21

hi I am new to camkes VM on x86. I want to connect the guest to the host via the ethernet network. and I used this ( https://docs.sel4.systems/projects/camkes-vm/) tutorial to create pass-through in minimal example x86. run in qemu on ubuntu 17.10. but the guest os doesn't create an ethernet interface. I also tested zmq example this is qemu options: qemu-system-x86_64 -machine q35,accel=kvm,kernel-irqchip=split -cpu Nehalem,+vme,+pdpe1gb,-xsave,-xsaveopt,-xsavec,-fsgsbase,-invpcid,enforce,+vmx -nographic -serial mon:stdio -m size=2G -enable-kvm -net nic,model=e1000 -net tap,script=no,ifname=tap0 -kernel images/kernel-ia32-pc99 -initrd images/capdl-loader-image-ia32-pc99 and minimal.camkes configs: configuration { VM_CONFIGURATION_DEF() VM_PER_VM_CONFIG_DEF(0) vm0.simple_untyped23_pool = 20; vm0.heap_size = 0x2000000; vm0.guest_ram_mb = 128; vm0.kernel_cmdline = VM_GUEST_CMDLINE; vm0.kernel_image = "bzimage"; vm0.kernel_relocs = "bzimage"; vm0.initrd_image = "rootfs.cpio"; vm0.iospace_domain = 0x0f; vm0_config.pci_devices_iospace = 1; vm0_config.ioports = [ {"start":0x4080, "end":0x4090, "pci_device":0x1f, "name":"SATA"}, {"start":0x4090, "end":0x40a0, "pci_device":0x1f, "name":"SATA"}, {"start":0x40b0, "end":0x40b8, "pci_device":0x1f, "name":"SATA"}, {"start":0x40b8, "end":0x40c0, "pci_device":0x1f, "name":"SATA"}, {"start":0x40c8, "end":0x40cc, "pci_device":0x1f, "name":"SATA"}, {"start":0x40cc, "end":0x40d0, "pci_device":0x1f, "name":"SATA"}, {"start":0x3000, "end":0x3020, "pci_device":0, "name":"Ethernet5"}, ]; vm0_config.pci_devices = [ { "name":"SATA", "bus":0, "dev":0x1f, "fun":2, "irq":"SATA", "memory":[], }, { "name":"Ethernet5", "bus":5, "dev":0, "fun":0, "irq":"Ethernet5", "memory":[ {"paddr":0xc0500000, "size":0x20000, "page_bits":12}, {"paddr":0xc0520000, "size":0x4000, "page_bits":12}, ], }, ]; vm0_config.irqs = [ {"name":"SATA", "source":19, "level_trig":1, "active_low":1, "dest":11}, {"name":"Ethernet5", "source":0x11, "level_trig":1, "active_low":1, "dest":10}, ]; } thanks

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Operating Systems built on top of seL4
by Sidhartha Agrawal 02 Aug '21

02 Aug '21

Hello sel4-devs, I am a first-year graduate student at the University of British Columbia at their Systopia Lab <https://systopia.cs.ubc.ca/> working on operating systems research. My advisor is Prof. Margo Seltzer <https://www.seltzer.com/margo>. In a past life, I have worked as a software engineer at Oracle and Arista Networks. My research is on General Purpose Isolation Mechanism in the OS. We ask whether we really need to have N different isolation mechanisms or whether instead, we could develop a framework in which all these different mechanisms represent points on a continuum. Here is a write-up <https://sid-agrawal.ca/#research-projects> with some more details. I am using seL4 as the microkernel base to build my research idea. At this stage, I am not looking in to the formal verification aspect of seL4, but that might change once I have a better idea about the type of mechanism I want to build. I would also like to keep the changes in the kernel to be minimum and try to demonstrate my ideas using user space processes. I have tried out the tutorials on the seL4 website. Currently, I am wading through the different helper libraries in seL4/seL4_libs <https://github.com/seL4/seL4_libs>. As someone who is just starting with seL4 ecosystem, I had a few high-level questions: - Are there are example OSes built with seL4, which would be a good place to look at? Specifically, I am looking for components such as basic versions of a process-server, vm-server, pager, file-systems server. - I came across refOS <https://github.com/seL4/refos>, but wasn't sure if it is still being maintained. - Another option was Genode <https://genode.org/documentation/general-overview/index>. This seemed to be maintained by another community and has many layers of abstractions since it supports multiple kernel backends. I am looking forward to engaging with this community, learning about seL4 and making meaningful contributions. Best, Sid sid-agrawal.ca

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Sel4 rumprun has issues compiling
by Vortex 01 Aug '21

01 Aug '21

Hello, I would like to bring this issue to the attention of the community. Sel4’s fork of the rumprun unikernel no longer compiles. Due to the usage of Werror flag, the compiler produces repeated warnings which in turn creates errors. It seems like the rump kernel was tested on an older version of gcc and because it is older, raises warnings and causes the build to fail on newer compilers. This is a similar issue to https://github.com/rumpkernel/rumprun/issues/82 I have tested rumprun in the sel4 docker container. My build logs are also attached to this email. Thank you for taking attention to this issue. Sincerely, Ellis

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Docker for ARM?
by dave＠synergy.org 27 Jul '21

27 Jul '21

I recently moved and my x86-64 machines are in storage. Are there docker images for Debian ARM/32 or Raspbian I can use to build seL4 on my Raspberry Pi? It is my target platform. Thanks, Dave

2 1

Camkes and native tcp/ip and networking
by Amirreza Zarraby 27 Jul '21

27 Jul '21

Hello seL4 team, I am try trying to use camkes to write a simple firewall. I am wondering if you can direct me to any existing camkes project which uses tcp/ip and network driver that I can look into as starting point. There is a seL4 based webserver but it seems to use vm and Linux. Thank you for your time. - Amir

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Jetson AGX Xavier board porting
by bobding＠msn.com 27 Jul '21

27 Jul '21

Has anyone ported to Nvidia AGX Xavier board?

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