graphic: 0.657
device: 0.604
semantic: 0.494
debug: 0.487
boot: 0.475
performance: 0.297
PID: 0.238
other: 0.220
network: 0.172
permissions: 0.167
socket: 0.154
vnc: 0.130
files: 0.070
KVM: 0.014

unable to boot arm64 image

Hi

Now I facing boot linux-5.3 arm64 image failed, without any log, just hang here.

Host machine: ubuntu-18.04 with 4.15.0-70-generic kernel
Qemu version: qemu-system-aarch64-version 4.1.0
use command: qemu-system-aarch64 -kernel <IAMGE> -append "console=ttyAMA0" -m 2048M -smp 2 -M virt -cpu cortex-a57 -nographic

could anyone teach me how to debug this?

You don't say anything about the kernel image you're trying to boot, but "nothing happens" is the expected result of trying to run a kernel which is not correctly configured to run on QEMU. You can debug in the same way you would debug "my kernel didn't boot on real hardware": try the gdb debugstub, try looking at the kernel config and comparing against a working version, etc.

https://translatedcode.wordpress.com/2017/07/24/installing-debian-on-qemus-64-bit-arm-virt-board/ is an example of a working setup of an aarch64 guest, which is probably a good place to start.