In-Progress Rebase to QEMU 8.1.0 - some issues

[SpencerCBrown]

Hi. I have been working on rebasing QEMU-Nyx to a more recent version of QEMU. I’ve made some good progress, and I think it’s almost working, though at the moment it’s failing during snapshot reload. After a panic/crash during fuzzing, sometimes just not resuming the target, but I’ve also had a few segfaults. It seems to be happening in fdl_fast_reload while the saved fields are being copied from self->copy back to self->ptr.

I’m still trying to track down the root cause, but it’s slow going because I don’t fully understand the snapshot process. Working theory is maybe some device or field temporarily exists at snapshot creation time but then not at reload time (so those pointers to fields are no longer valid)?

As an aside, my code could use some tidying as I've been focused on getting the functionality working, and I've temporarily disabled some unit tests until I can fix some build issues associated with the move to Meson.

Any pointers would be welcome, as would feedback on the rebase since my goal would be to submit a PR eventually.

Fork with the in-progress rebase is at
https://github.com/SpencerCBrown/QEMU-Nyx/tree/kafl-qemu-8.1.0

[kiwids0220]

I myself is also digging into the internals of QEMU-Nyx a bit and troubleshooting the process. What I found really helpful is that to connect the QEMU monitor and do whatever you need (dump guest memory, list devices) with the help of GDB.

Hopefully this help! Keep up the good work