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Multi-VM (cross-VM calls)

A multi-VM rollup runs an EVM execution layer that can call into CosmWasm contracts on the QoreChain Native (Wasm) runtime through a dedicated cross-VM precompile. The RDK ships the TypeScript tooling to encode those calls and a scaffold template to start from.

This tooling covers EVM → QoreChain Native (CosmWasm contracts) only. SVM is a separate runtime and is not part of the cross-VM precompile.

note

As of RDK v0.4.2 the Wasm runtime's VM option identifier is native (QoreChain Native); cosmwasm remains an accepted legacy alias, and both map to cosmwasm on the wire — the chain, explorer, and the cross-VM precompile ABI (executeCrossVMCall) are unchanged.

The precompile​

The cross-VM precompile is exposed at a fixed address:

import { CROSS_VM_PRECOMPILE } from "@qorechain/rdk";

console.log(CROSS_VM_PRECOMPILE); // 0x…0901

Encoding a cross-VM call​

encodeCrossVmCalldata builds the calldata your EVM contract sends to the precompile to invoke a CosmWasm contract. functionSelector computes the 4-byte selector for a Solidity function signature.

import { encodeCrossVmCalldata, functionSelector } from "@qorechain/rdk";

const calldata = encodeCrossVmCalldata({
  contract: "qor1cosmwasmcontractaddress...",
  msg: { transfer: { recipient: "qor1...", amount: "100" } },
});

const selector = functionSelector("callCosmwasm(string,bytes)");

The Solidity side​

From an EVM contract you call the precompile address with the encoded calldata. The multivm-rollup template includes a contracts/CrossVmCaller.sol snippet along these lines:

// contracts/CrossVmCaller.sol
address constant CROSS_VM_PRECOMPILE = 0x0000000000000000000000000000000000000901;

function callCosmwasm(bytes memory calldata_) internal returns (bytes memory) {
    (bool ok, bytes memory out) = CROSS_VM_PRECOMPILE.call(calldata_);
    require(ok, "cross-vm call failed");
    return out;
}

Scaffold a multi-VM rollup​

A new template, multivm-rollup, scaffolds an EVM rollup wired to call CosmWasm, including the CrossVmCaller.sol snippet:

npm create qorechain-rollup my-app -- --template multivm-rollup

See Deploying a Rollup for all scaffolder templates.