In earlier blog posts, I discussed QEMU’s debugcon device and presented a minimal driver for it written in x86 assembly. In this blog post, we go a little higher and write a driver for Linux in C. The driver should provide a /dev/debugcon device so that processes can open the Read more…
This is an educational resource I wish I had when I started digging into low-level and operating systems during my early time of my studies at the university. However, dear past me, I got your back! Do you want to see a minimal way to communicate with (virtual) hardware and Read more…
In the previous blog post we talked about how to use QEMUs debugcon feature. To do this responsibly, we should only do this if the binary runs in fact inside QEMU. To find this out, one can use the cpuid instruction. It gives us a lot of information about our Read more…
QEMU is a VMM often used for low-level OS/kernel development and testing. Especially when you write your own OS/kernel, things can get really hard and difficult to debug. Furthermore, there are not many debug capabilities, as you can’t write to files or print to the screen in early boot phases, Read more…