Qemu Virt Machine from flash device image

Issue

I have been developing the OS for a prototype device using hardware. Unfortunately, it's a very manual and buggy process to flash the OS each time and then debug the issues.

I'd like to switch to developing the OS in QEMU, so that I can be sure that the OS is loading correctly before going through the faff of programming the device for real. This will come in handy later for Continuous Integration work.

I have a full copy of the NVM device that is generated from my build process. This is a known working image I'd like to run in QEMU as a start point. This is ready to then be JTAG'd onto the device. The partition layout is:

P0 - loader - Flash of IDBLoader from rockchip loader binaries

P1 - Uboot - Flash of Uboot

P2 - trust - Flash of Trust image for rockchip specific loader

P3 - / - Root partition with Debian based image and packages required for application

P4 - data partition - Application Data

I have not changed anything with the Rockchip partitions (P0 - P2) apart from the serial console settings. When trying to boot the image though, nothing happens. There is no output at all, but the VM shows as still running. I use the following command to run it:

qemu-system-aarch64 -machine virt -cpu cortex-a53 \
            -kernel u-boot-nodtb.bin \
            -drive format=raw,file=image.img \
            -boot c -serial stdio

I have no error information to go on to understand what is going on with it, where can I get more information or debug?

Solution

For anyone else trying to figure this out, I found good resources here:

https://translatedcode.wordpress.com/2017/07/24/installing-debian-on-qemus-64-bit-arm-virt-board/

and

https://azeria-labs.com/emulate-raspberry-pi-with-qemu/

Looking at the information though, you need to extract the kernel from your image and provide that to the qemu command line as an argument. You'll also need to append an argument telling the system which partition to use as a root drive.

My final command line for starting the machine looks like this:

qemu-system-aarch64 -machine virt -cpu cortex-a53 \
            -drive format=raw,file=image.img,id=hd \
            -boot c -serial stdio
            -kernel <kernelextracted> -append "root=fe04"

Answered By - FreakShow