Gramine
A library OS for Linux multi-process applications
...The idea is that instead of running a full guest OS in a VM, you embed your application inside Gramine, which handles the system-call interface, process and thread management, file system, and network abstractions — everything the application expects — but strips out the overhead and complexity of a full OS stack. One particularly strong use-case is confidential computing: Gramine supports Intel® SGX enclaves, allowing applications to run inside hardware-protected memory regions even while using standard Linux binaries with minimal porting effort.