Unifying eBPF across Platforms: Formal Semantics, Conformance Testing, and Specifications
eBPF is no longer a single-platform technology. It runs in the Linux kernel, on Windows, in user space, on microcontrollers, and in blockchain virtual machines, on independently built runtimes. The IETF ISA standard, RFC 9669, pins down the core instructions but leaves out features that real programs depend on, such as helper functions and maps. We are building an executable formal semantics for eBPF in F* that explicitly distinguishes cross-platform and platform-specific behaviors. Our semantics passes the BPF conformance test suite on par with uBPF, bpftime, Linux, and Windows, and we are extending it beyond the core ISA to other shared features the RFC omits. Using Meta-F* metaprogramming, we can also generate prose specifications in structured English that provably match the model. We envision this semantics as a practical foundation for a uniform, trustworthy eBPF across platforms.