l4-hackers November 2024

l4-hackers@os.inf.tu-dresden.de

9 participants
9 discussions

Video Error Reasons?
by Lonnie Cumberland via l4-hackers 27 Nov '24

27 Nov '24

Hello All, I have been experimenting with L4Re and was able to compile the latest snapshot that seems to work well for almost all of the examples in QEMU from the "make qemu" menu which is a very good start, I think. Lately, I have also used the "make grub2iso" which gives me the same menu of examples as the "make qemu" but for which it will generate an ISO of the example. I generated ISO's for all of the examples and tested them on 3 different x64 computer systems which are all Intel with 2 being NUC's and 1 being a Dell XPS 8950 but when I boot any of the generated L4Re ISO's, it seems to boot all of the core modules but then gets to an error message that seems to be related to the video mode. ------------------------------------------- error: no suitable video mode found ------------------------------------------- And then the screen shows a bunch of lines. I have been looking around though the L4Re code in the snapshot release, but I do not yet have a clue where how to change things so that these ISO's will boot completely on some hardware although things seem to boot up in QEMU. I am thinking that there might just be some setting somewhere that I need to adjust, or something. Any thoughts, suggestions, or ideas would be greatly appreciated. Have a great evening, Lonnie _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

4 4

CPU Virtualization in L4
by Mohamed Dawod 25 Nov '24

25 Nov '24

I know that Scheduling proxy in L4 is used to set cores and priority ranges for a dedicated task. For example, The below scheduling proxy makes the task runs on cores 1,2,3 with priority range [52,62]. scheduler = vmm.new_sched(0x50, 0xE) When I switch to debugging mode, I see that this task has priority = 52 in pr column! So why does scheduling proxy set priority range instead of a single value like Linux ? How does L4 use the priority range ? My second question is about the relationship between physical CPUs and virtual CPUs in L4. I know that CPU virtualization should give the ability to virtualize the available physical CPUs so that if we have single physical CPU core, CPU virtualization enables us to provide multiple virtual CPU cores for the VMs running ontop of the hypervisor. Actually I don't see this behaviour in the scheduling proxy in L4! instead, the cores parameter only takes a bitmap of the physical cores. Can I use the scheduling proxy or any other method/workarround to provide CPU Virtualization ? Thanks, Mohamed Dawod _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

2 1

Porting apps to L4Re?
by Lonnie via l4-hackers 18 Nov '24

18 Nov '24

Hello All, As part of the project effort that I am working on with L4Re, I am considering 2 possible pathways of which both need graphics capabilities to interact with the uvmm for a guest OS: Possible pathways: 1. Use the framebuffer "spectrum" example and port something like FreeRDP, rdesktop or other, so that this will allow for a loabable RDP service VM whose only job is to connect to other VM's. This would be for having a Docker/Podman Container engine running and to be able to connect to a container via a web browser VM that has a graphic console in fullscreen mode. 2. Find a way to have L4Re be able to access the graphic console (VGA) of each uvmm guest directly and then be able to HotKey switch between active VM's. This might be like having multiple guest OS's running (i.e. Ubuntu 24.04 and Windows 10 for example) and then be able to switch the console between them. This is also an idea to allow L4Re to boot all of the OS's that might reside on a dualboot or multiboot system. I actually need something this is really a cross between both of these since in one configuration case will be (1) and in another case will be (2). Wanted to get any thoughts or suggestions that you might have towards this. Thanks and have a great day, Lonnie _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

3 2

Generating EFI files
by Lonnie Cumberland 13 Nov '24

13 Nov '24

Hello All, While exploring and testing L4Re, I have also been testing some files from the AMD64 downloads: https://l4re.org/download/snapshots/pre-built-images/amd64/ While currently the only the elf32 file do run a bit and the efi files are now known to have some problems, I was wondering how the efi files were generated. I know that in the build for l4re that you can use "make -j24" to build the core as well as "make qemu" to show some available examples that I am trying to also get to work, but I was wondering how these above "pre-built-images" were generated? Also, I am very interested in the "l4re_vm-multi.efi" and "l4re_vm-multi-p2p.efi" in how they can be generated to run under QEMU as well as how to perhaps generate an x64 ISO that can be booted on real hardware. These interest me a great deal and I would really be interested if someone might be able to explain them more to me, especially the "p2p" one since have an interest in p2p networks as well. Thanks in advance and have a great day, Lonnie _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

3 4

vm-basic-pci demo testing
by Mohamed Dawod 13 Nov '24

13 Nov '24

Hi, I was trying the *vm-basic-pci* demo from l4Re version 24.08.0. The demo works and I could boot the Linux VM and login successfully, but I need to test the passed PCI bus to make sure that it works. I'm trying to test it using a *virtio-blk-pci* device from qemu which is expected to be mounted as a block device in */dev/vda*. but when I found no */dev/vda* file in the filesystem. Please find attached : * my ned scripts : vm-basic-pci.log * arm-virt64.io * the dts file : virt-basic_virt-64_pci.dts * and the full logs : vm-basic-pci.log Thanks in advance, Regards -- Mohamed Dawod *Software Engineer, *Avelabs Egypt *Cell Phone : (+20) 1117311726* -- *Driving Innovation! Visit our website www.avelabs.com <http://www.avelabs.com/>*, to read Avelabs Confidentiality Notice, follow this link: http://www.avelabs.com/email/disclaimer.html <http://www.avelabs.com/email/disclaimer.html> _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

5 7

Debugging memory allocation in L4Re
by Paul Boddie 11 Nov '24

11 Nov '24

Hello, I thought I might as well ask this since the mailing list has been somewhat active recently. I have been testing some of my software, but after a certain period of time, I experience errors of the following form: l4re_kernel: ERROR: more-mem(1000): Cannot provide more memory. l4re_kernel: ERROR: mmap() called: unimplemented! size=100000 As far as I can tell, uclibc_morecore and mmap in... pkg/l4re-core/l4re_kernel/server/src/mem.cc ...are respectively responsible for these errors, the former being called by __malloc_trim, itself called by free in... pkg/l4re-core/uclibc/lib/contrib/uclibc/libc/stdlib/malloc-standard/free.c Looking at the uclibc_morecore implementation, it seems that the "program break" is defined only once, with a dataspace of 64 pages being allocated, and any subsequent sbrk call will not cause this allocated space to be extended further. Have I understood this situation correctly? As always, I assume that I am making some kind of mistake, in this case probably not deallocating memory when I should be and thus exhausting the available space. Are there any convenient ways of monitoring memory allocation in L4Re? Thanks for any advice offered! Paul _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

2 2

Qemu Demos
by Lonnie Cumberland 11 Nov '24

11 Nov '24

Hello All, I am on an Intel NUC 13 NHNE (x64) running Ubuntu 23.10 and am working my way through the basic Qemu Demos after following the build instructions https://github.com/kernkonzept/manifest/wiki/BUILDING From there I am in the "~/l4re/build-amd64$" and have added "/l4re/l4/conf/examples" to the "l4/conf/Makeconf.boot" Now I do a "make qemu" and get the list: =============================================== │ │ │ 0 hello │ │ 1 hello-cfg │ │ 2 hello-2 │ │ 3 hello-shared │ │ 4 framebuffer-example │ │ 5 L4Linux-basic │ │ 6 L4Linux-mag │ │ 7 VM-basic │ │ 8 VM-multi │ │ 9 VM-multi-p2p │ │ 10 VM-basic-pci =============================================== For which I have been able to run items 0 - 3, but when I run (4) "framebuffer-example", I get an error about a missing "x86-lagacy.devs" file and I cannot find it anywhere in the sources or builds. =============================================== Could not find 'x86-legacy.devs' within paths /home/lonnie/l4re/build-amd64/assets /home/lonnie/l4re/build-amd64/bin/amd64_gen/l4f /home/lonnie/l4re/build-amd64/bin/amd64_gen/plain /home/lonnie/l4re/build-amd64/lib/amd64_gen/std/l4f /home/lonnie/l4re/build-amd64/lib/amd64_gen/std/plain /home/lonnie/l4re/build-fiasco-amd64 /home/lonnie/l4re/l4/conf/examples make[1]: *** [Makefile:693: qemu] Error 1 make[1]: Leaving directory '/home/lonnie/l4re/l4' make: *** [Makefile:6: do-all-make-goals] Error 2 =============================================== I then restarted "make qemu" and tried (7) VM-basic, but it seems to abort with the messages: =============================================== MOE: Starting: rom/ned rom/vm-basic.cfg MOE: loading 'rom/ned' Ned says: Hi World! Ned: loading file: 'rom/vm-basic.cfg' VMM[]: Created VCPU 0 @ 18000 VMM[]: >>> CAUTION: Support for AMD SVM is experimental, use at your own risk! <<< terminate called after throwing an instance of 'N2L413Runtime_errorE' what: Invalid request: SVM does not support next_rip save. Aborting! =============================================== In trying to run the other VM-????? choices, I also get similar messages: =============================================== vm-1 | VMM[]: Created VCPU 0 @ 18000 vm-1 | VMM[]: >>> CAUTION: Support for AMD SVM is experimental, use at your own risk! <<< vm-1 | terminate called after throwing an instance of 'N2L413Runtime_errorE' vm-2 | VMM[]: Created VCPU 0 @ 18000 vm-2 | VMM[]: >>> CAUTION: Support for AMD SVM is experimental, use at your own risk! <<< vm-3 | VMM[]: Created VCPU 0 @ 18000 vm-3 | VMM[]: >>> CAUTION: Support for AMD SVM is experimental, use at your own risk! <<< vm-2 | terminate called after throwing an instance of 'N2L413Runtime_errorE' vm-1 | what: Invalid request: SVM does not support next_rip save. Aborting! vm-3 | terminate called after throwing an instance of 'N2L413Runtime_errorE' vm-1 | vm-2 | what: Invalid request: SVM does not support next_rip save. Aborting! vm-2 | vm-3 | what: Invalid request: SVM does not support next_rip save. Aborting! vm-3 | ========================================================= Has anyone been able to get all of these to run? I am still exploring but would like to get the be able to compile and run the VM-multi examples on the x64 hardware like in the video. https://l4re.org/cast-multi-vm-qemu.html Any thoughts on how to test out some of these? Best and have a great weekend, Lonnie _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

3 2

Building Screenshots and examples
by Lonnie Cumberland 10 Nov '24

10 Nov '24

Hello All, I hope that your day is going well. Recently, I have decided to explore L4Re as a microhypervisor and capabilities as a possible minimalist component-based microkernel OS. I have just set up Ubuntu 23.10 (x64) in an Intel NUC13 and would am reviewing as much documentation as I can find as well as am building the core L4Re according to the Github Wiki just to see how the process goes. https://github.com/kernkonzept/manifest/wiki/BUILDING As I am in the learning curve at the moment, I also would like to build some examples such as the "Screenshots" (https://l4re.org/screens.html) and demos from the Pre-Built section (https://l4re.org/download/snapshots/pre-built-images/amd64/). I did try to follow the direction on the pre-built sections and grabbed the "l4image" and all of the AMD64 EFI files to try and test, but when I launch them they just seem to hang and do nothing. I do have qemu (x64) installed as well, but still nothing seems to boot. What I would like to ask the mailinglist members is where can I get the source code to the "screenshots" examples as well as the AMD64 "pre-built" examples noted above so that I cam do a fresh compile to see them in action? Any help would be greatly appreciated. Thanks in advance and have a great day, Lonnie _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

4 8

Multiple CPU support for uvmm on virt-arm64 qemu machine
by Mohamed Dawod 06 Nov '24

06 Nov '24

Hello, I'm trying to provide multiple CPUs for a linux VM on top of L4. I'm using the qemu virt machine and building for aarch64. so I used *-smp* option to provide more CPUs. > $ qemu-system-aarch64 -M virt,virtualization=true -cpu cortex-a57 -smp 4 > -m 1024 -kernel ....etc.... Unfortunately, This didn't work. I tried to add more CPU device nodes to the dts file *virt-arm_virt-64.dts *but it also didn't work. I think that it's because of the provided interrupt-controller with *virt-arm_virt-64.dts* in *l4/pkg/uvmm/conf/dts* which mentioned that it supports only one CPU. > icsoc { > compatible = "simple-bus"; > #address-cells = <2>; > #size-cells = <2>; > ranges; > > /* Uvmm will adapt the compatible string depending on the present > gic > * version. It expects reg entries that provide enough space for > the > * Cpu/Dist interface for gicv2 (at least 0x1000, 0x1000) or the > * Dist/Redist interface for gicv3 (0x10000, 0x20000 * number of > cpus). > * > *The entries provided here support any gicv2 setup or a gicv3 setup > * with one Cpu.* > */ > gic: interrupt-controller { > compatible = "arm,gic-400", "arm,cortex-a15-gic", > "arm,cortex-a9-gic"; > #interrupt-cells = <3>; > #address-cells = <0>; > interrupt-controller; > reg = <0 0x40000 0 0x10000>, > <0 0x50000 0 0x20000>; > }; > }; > My question now, is there any workaround to support multiple CPUs for virt machine on arm64 ? Thanks, Regards -- Mohamed Dawod *Software Engineer, *Cairo Egypt -- *Driving Innovation! Visit our website www.avelabs.com <http://www.avelabs.com/>*, to read Avelabs Confidentiality Notice, follow this link: http://www.avelabs.com/email/disclaimer.html <http://www.avelabs.com/email/disclaimer.html> _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

2 9

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

l4-hackers November 2024