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cirosantilli2 / issues

Hello! If you have anything to say to me, feel free to open an issue, and I will reply. For gem5 issues, prefer asking on Stack Overflow or the mailing list: https://www.gem5.org/mailing_lists/ or: https://github.com/cirosantilli2/gem5-issues
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gem5 KVM support for ARM with a GICv3-only host without GICv2 #8

Closed austinharris closed 4 years ago

austinharris commented 4 years ago

Hello,

I was wondering what the current state of KVM support for armv8 looks like?

I have been trying to run on a graviton2 instance and I made a little bit of progress by hard-coding kvm_gicv2_class = Gic400 since the gicv2 device doesn't exist in this host (will this work?).

However I get this output:

0: system.cpu_cluster.cpus: Entering KVM... 0: system.cpu_cluster.cpus: KVM: Executing for 18446744073709551615 ticks 0: global: Arming POSIX timer: 18446744073709551615 ticks

I let it run for quite awhile and it never seemed to come back. Additionally when I hit ctrl-c it outputs:

0: system.cpu_cluster.cpus: KVM: Executed 0 instructions in 352981159642 cycles

So it seems like KVM isn't even executing any instructions?

Is the only way to get this working to add gic v3 support?

Thanks a lot! Austin

cirosantilli2 commented 4 years ago

Hi Austin,

Please don't open issues here in the future, this repo was only created before they finally accepted to create an official issue tracker for the project at: https://gem5.atlassian.net/browse/GEM5 , use that instead next time, I see all messages there, and sooner when they are marked with arch-arm.

About KVM, generally things are flaky because we are lacking the manpower/expertise to make it work amazingly, even though we would really like it to, and will review patches.

I don't fully understand things myself, but I'm certain it does not work out of box with a non-GICv2 host.

There are two options:

After that though, there are likely to be other bugs, e.g.: https://stackoverflow.com/questions/53523087/how-to-run-gem5-on-kvm-on-arm-with-multiple-cores

austinharris commented 4 years ago

Hi Ciro,

I also tried this out on a graviton (1st-gen) which supports the GiCv2 device and I had the same results. Do you happen to know of any configuration where KVM was working that could help me narrow down the issue, since it doesn't appear to be the GiC?

Thanks, Austin

austinharris commented 4 years ago

https://gem5.atlassian.net/browse/GEM5-547 comment added to similar issue here.

Thanks a lot!