Run Keystone on the gem5 simulator using O3CPU

[ruanliuq]

I was originally using the MinorCPU in gem5（v23.0.0.0）. When running Keystone with this CPU, it operated normally, and the terminal output was as follows:

Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
Saving random seed: [ 9.392464] random: crng init done
OK
Starting network: Waiting for interface eth0 to appear............... timeout!
run-parts: /etc/network/if-pre-up.d/wait_iface: exit status 1
FAIL
Starting dropbear sshd: OK
Welcome to Buildroot
buildroot login:

However, when I switched from MinorCPU to O3CPU and ran it again, it got stuck right before the login interface. The specific terminal output is as follows:

Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
Saving random seed: [ 9.392464] random: crng init done
OK
Starting network: Waiting for interface eth0 to appear

Unable to proceed to the next step, cannot output "timeout!".
After that, I removed the network-related initialization scripts from the Keystone disk image（rootfs.ext2）. For example, I renamed etc/init.d/S40network to S40network.disabled, and deleted the following code segment from the /etc/network/interfaces file:

auto eth0
iface eth0 inet dhcp
pre-up /etc/network/nfs_check
wait-delay 15
hostname $(hostname)

However, it still cannot output completely and the login interface never appears.

Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
Saving random seed: [ 9.392464] random: crng init done
OK
Starting network: OK
Starting dropbear sshd: OK

I would like to ask what is causing Keystone to fail to run properly with the O3CPU. Is it because Keystone's boot process does not support out-of-order CPUs, or are there other reasons?