arch-x86,O3,KVM switching to full simulation bug #910
Comments
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@Foxy-Boxes, I would suggest enabling the exec debug flag after switching CPUs to check if there is something obviously wrong. During the CPU switch, when calling |
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I have not changed switching behavior and this is still a bug in the simulator, I am using a workaround to avoid this situation. If I had time I would attempt fixing it but for now I will continue to use the workaround. |
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Hello, my name is Lukas and I’m working with my partner Emily on a final project for our Virtualization class. We are Computer Science at the University of Texas at Austin and currently enrolled in CS360V Virtualization, taught by Dr. Chidambaram (VJ). As part of our coursework, we are required to contribute to a few issues within an open-source repository relevant to the class. After reviewing the gem5 repository, we believe that the particular issue aligns well with our objectives and skill set and were wondering if we may be assigned to this issue. If that's possible, before proceeding, we wanted to ask if there are any additional details or considerations regarding this issue that we should be aware of. We are committed to completing all three issues by May 6th to the best of our abilities. Thank you for considering our request. |
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Awesome! Yes, please feel free to try to tackle this issue. If you have any questions, don't hesitate to ask. @BobbyRBruce has successfully reproduced the issue, but we haven't had the resources to fix it. Hopefully Ivana's comment above gives you a starting point. |
Describe the bug
When using the full system simulation m5_switch_cpu_addr followed by m5_exit or m5_exit_addr causes either the simulation to segfault or the simulated program to segfault(One might also see an unexpected jump, I am guessing that is the same bug).
Affects version
gem5 stable c890e6b
gem5 Modifications
I have modified the config file, added my disk, and wrote a simple program to reproduce the bug. Also changed the default disk device for X86 KernelDiskWorkload to "/dev/sda".
https://github.com/Foxy-Boxes/gem5-bug, has the necessary changes.
To Reproduce
download this tarred image to the repo: https://drive.google.com/file/d/1qH7QNoz23UIyuU07Rf7AoEvS3Opvcl74/view?usp=sharing
scons build/X86/gem5.debug -j `nproc` ./one_time.sh ./make_disk.sh ./build/X86/gem5.debug ./configs/example/gem5_library/x86-ubuntu-run-with-kvm-test.pyTerminal Output
In the case where we get a segfault
When gem5 does not segfault but the simulation jumps to an unexpected location, this is the m5term output:
Expected behavior
This is what we are trying to execute:
Therefore I would expect an infinite loop after the "Hello world\n" print.
Host Operating System
Ubuntu 22.04
Host ISA
X86
Compiler used
g++ 11.4
Additional information
This bug is at least as old as the commit 1db206b on stable
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