How to run gem5 on KVM on ARM with multiple cores?

Question

Single core worked with fs.py at a5bc2291391b0497fdc60fdc960e07bcecebfb8f (Nov 2018), but multicore hanged in early in the boot process. Is multicore KVM supported on ARM or not?

Answer 1

As of October 2019, gem5's ARM KVM is generally not robust enough to be generally recommended.

Multicore works on some setups and fails on others, so there are likely outstanding bugs, although I haven't seen a clear investigation that pinpointed those bugs yet.

There are also issues with GICv2 vs GICv3 version incompatibilities: only GICv2 hosts were supported natively at that point, although the option was added to use an emulated gem5 GICv2 with KVM https://gem5-review.googlesource.com/c/public/gem5/+/30921

It is likely not extremely hard to get it working, but it does require someone to sit down and focus on it for a few weeks.

Related threads:

• https://gem5.atlassian.net/browse/GEM5-694 for more than 8 cores, make sure to enable the GICv2 gem5 extensions if you are using the gem5 GICv2 emulation as mentioned: How to run a gem5 arm aarch64 full system simulation with fs.py with more than 8 cores?