[quruquru]

Agree, and I'll add 3 other really useful QEMU features for osdev:

1) Record & Replay: Record an execution and replay it back. You can even attach GDB while replaying, and go back in time while debugging with "reverse-next" and "reverse-continue": https://qemu-project.gitlab.io/qemu/system/replay.html

2) The QEMU monitor, especially the "gva2gpa" and "xp" commands which are very useful to debug stuff with virtual memory

3) "-d mmu,cpu_reset,guest_errors,unimp": Basically causes QEMU to log when your code does something wrong. Also check "trace:help", there's a bunch of useful stuff to debug drivers

[kotborealis]

Record & replay sounds really nice, but the actual reverse-debugging is broken, see https://gitlab.com/qemu-project/qemu/-/issues/2634

[jannesan]

thanks for sharing! qemu is very powerful, but it’s hard to discocer a lot of these features