driver/qemudriver: add drive interface and kernel boot parameters

[ekronborg]

Description
Make the q35 machine behave similar to pc if a kernel is started directly. Furthermore, the default drive interface has been added. This commit is an addition to 086ba3b3fe1e04bcc8cba0e6dfe558b7747d372d.

Checklist

• Documentation for the feature
• Tests for the feature

• The arguments and description in doc/configuration.rst have been updated

• Add a section on how to use the feature to doc/usage.rst

• Add a section on how to use the feature to doc/development.rst

• CHANGES.rst has been updated

• PR has been tested

• Man pages have been regenerated

[codecov]

Codecov Report

Merging #964 (63560b7) into master (7609cd9) will decrease coverage by 0.0%.
The diff coverage is 0.0%.

@@           Coverage Diff            @@
##           master    #964     +/-   ##
========================================
- Coverage    57.1%   57.1%   -0.1%     
========================================
  Files         150     150             
  Lines       11202   11203      +1     
========================================
  Hits         6402    6402             
- Misses       4800    4801      +1     

Impacted Files	Coverage Δ
labgrid/driver/qemudriver.py	74.7% <0.0%> (-0.5%)	⬇️

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[jluebbe]

I would expect that you'd need if=virtio to get root=/dev/vda to work.

[ekronborg]

I would expect that you'd need if=virtio to get root=/dev/vda to work.

You're right. Let's keep the interface out for now. I rewrote the commit message to reflect this change.

[jluebbe]

Does it work this way? You said that q35 defaults to IDE in #961 (comment).

My preferred approach would be if=virtio, as that avoids the need for legacy IDE drivers and reduces differences between pc and q35.

[ekronborg]

In my case, I am using a bios image (.qcow2) and a raw image (.wic) to mount my filesystem. This setup fails with anything but the standard interface, i.e., if=ide. If there was a way to override the interface, I could add virtio to make q35 and pc more similar, but as far as I can tell you're not able to override it?

[jluebbe]

Ah. You could not set the disk property, as then no -drive property would be generated. Then you could pass that via the extra_args property.

[ekronborg]

OK. That solution is not as elegant as using the disk property, but I can live with that. I will rather get going with tests for our project. I added if=virtio and rewrote the commit message.

[jluebbe]

Thanks a lot for your contribution!