Not "yet" with "virtio-balloon", so basically where firecracker was for quite some time. With that you can only grow, but not shrink memory if I understand correctly. So useful for "I'll run and terminate" but not for "I'll run next to others with varying runtime and memory usage".
Will be interesting to see how https://github.com/rust-vmm/rust-vmm is going to develop, sounds like something like that could have a lot of use-cases for privilege separation but also embedded testing frameworks.