Run Zephyr OS for qemu_x86 and access guest Filesystem

RE: Run Zephyr OS for qemu_x86 and access guest Filesystem

n.marty — Mon, 14 Jun 2021 12:25:24 GMT

Simon I found a workaround process which gives me some basic testing abilities.

use the cmake function "generate_inc_file_for_target"
include resulting hex values in application and use the data in init function at startup
write data to littleFS file using default file api
the application can now use this file and I am able to run my tests

So currently my limitation is that I am only able to modify files during build time. For my current testing purposes this is ok, not perfect but ok.
I'm still watching https://github.com/zephyrproject-rtos/zephyr/issues/4911 and I'm still hoping to find a solution to be able to read/write files during runtime from outside qemu without having to implement some special features in the application.

RE: Run Zephyr OS for qemu_x86 and access guest Filesystem

Simon — Mon, 14 Jun 2021 10:12:54 GMT

Hello Marty,

Sorry for the delay on this. Have you made any progress, or does the questions still stand?

RE: Run Zephyr OS for qemu_x86 and access guest Filesystem

n.marty — Fri, 28 May 2021 14:05:09 GMT

Hi Simon

Thank you for your efforts.

In the meantime i managed to enable a LittleFS partition in qemu_x86 and the zepyhr file system shell. This allows me to access the filesystem with special uart commands (see here: https://docs.zephyrproject.org/latest/samples/subsys/shell/fs/README.html). Making the uart accessible from outside qemu was not a big deal (see here: https://fadeevab.com/how-to-setup-qemu-output-to-console-and-automate-using-shell-script/).
This interface now allows me to interact with files but it is very inefficient when I try to write large files in the magnitude of a megabyte.

The second approach which I am investigating is to use "-drive" Parameter when executing qemu in order to make my data accessible to the Zephyr Guest OS. There was this issue here, which looks really similar to what I would like to achieve: https://github.com/zephyrproject-rtos/zephyr/issues/4911. Unfortunately it was closed some time ago and never got resolved.
I'm struggling to understand how this drive Parameter works and how the Zephyr Guest OS can make use of this.
Is this going to be some peripheral device for Zephyr OS, any idea?

The third idea is to somehow write data to the LittleFS partition before the Zephyr OS inside QEMU is booting. This way it would look like there was already a file and I can use that for my tests. Currently each time when I start Zephyr in qemu, the LittleFS partition is empty again. Any idea on how to achieve that?

best regards

RE: Run Zephyr OS for qemu_x86 and access guest Filesystem

Simon — Thu, 27 May 2021 16:58:45 GMT

I don't have a good overview of this. I've asked internally and currently waiting for an answer.

You could also try to ask in any of the places here: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.1/zephyr/guides/getting-help.html#asking-for-help

If you don't get help, I will put off some time and look into this.

Best regards,

Simon