Long-term L1 execution layer proposal: replace the EVM with RISC-V

2025-04-21 15:01:31 Primitive Reading

This post proposes a radical idea for the future of the Ethereum execution layer, one that is equally as ambitious as the beam chain effort is for the consensus layer. It aims to greatly improve the efficiency of the Ethereum execution layer, resolving one of the primary scaling bottlenecks, and can also greatly improve the execution layer’s simplicity - in fact, it is perhaps the only way to do so.

The idea: replace the EVM with RISC-V as the virtual machine language that smart contracts are written in.

Important clarifications:

The concepts of accounts, cross-contract calls, storage, etc would stay exactly the same. These abstractions work fine and developers are used to them. Opcodes like SLOAD, SSTORE, BALANCE, CALL, etc, would become RISC-V syscalls.
In such a world, smart contracts could be written in Rust, but I expect most developers would keep writing smart contracts in Solidity (or Vyper), which would adapt to add RISC-V as a backend. This is because smart contracts written in Rust are actually quite ugly, and Solidity and Vyper are much more readable. Potentially, devex would change very little and developers might barely notice the change at all.
Old-style EVM contracts will continue to work and will be fully two-way interoperable with new-style RISC-V contracts. There are a couple ways to do this, which I will get into later in this post.

One precedent for this is the Nervos CKB VM, which is basically RISC-V.

Why do this?

In the short term, the main bottlenecks to Ethereum L1 scalability are addressed with upcoming EIPs like block-level access lists, delayed execution and distributed history storage plus EIP-4444. In the medium term, we address further issues with statelessness and ZK-EVMs. In the long term, the primary limiting factors on Ethereum L1 scaling become:

Stability of data availability sampling and history storage protocols
Desire to keep block production a competitive market
ZK-EVM proving capabilities

I will argue that replacing the ZK-EVM with RISC-V solves a key bottleneck in (2) and (3).

This is a table of the number of cycles that the Succinct ZK-EVM uses to prove different parts of the EVM execution layer:

Disclaimer: This specification is preliminary and is subject to change at any time without notice. Amazon Finance assumes no responsibility for any errors contained herein.