> ...most cloud hypervisors, for security/performance/complexity reasons, have stopped emulating the older hardware a lot of "basic osdev projects" rely on.
If you're really determined to do basic/hobbyist OS dev on EC2, you can always just run it under QEMU, which is pretty much what you'd do if you're developing on your own hardware, anyway. I know that's kinda beside the point, and reintroduces all those performance issues, but, security isn't a concern here, and it's certainly no more complex than just running it on your own machine.
If you're really determined to do basic/hobbyist OS dev on EC2, you can always just run it under QEMU, which is pretty much what you'd do if you're developing on your own hardware, anyway. I know that's kinda beside the point, and reintroduces all those performance issues, but, security isn't a concern here, and it's certainly no more complex than just running it on your own machine.