PolkaVM parachain runtimes MVP

[s0me0ne-unkn0wn]

Overview

This PR aims to enable parachain runtime authors to use PolkaVM as a compilation and execution target for PVFs. It brings in numerous advantages of PolkaVM over the Wasm executor:

• One-shot execution with near-instant compilation; compilation artifacts are not stored on disk anymore;
• Much less performance degradation compared to native execution;
• More deterministic execution;
• Out-of-the-box sandboxing;
• ...
• PROFIT!

Although PolkaVM potentially enables us also to use advanced gas metering for PVFs in the future, eliminating a lot of non-determinism issues, it's out of the scope of this MVP PR for now.

Current status

Fully working hacky PoC. Leaks host memory. Doesn't use execution workers and blocks the candidate validation subsystem on execution instead.

CC @eskimor @sandreim @koute @bkchr

[koute]

Note that we've recently updated the builder crate to use the newest PolkaVM and we're also updating the executor here, so you'll have to align to those changes.

[jasl]

Questions:

• Can pallet-revive gain advantages if the parachain runtime is based on PolkaVM?
• When Polkadot-SDK supports PolkaVM-based parachain, do we have to wait for Polkadot/Kusama support?
• Is there a PoC for a standalone PolkaVM-based runtime?
• Is it possible to migrate an existing WASM-based runtime to a PolkaVM-based runtime?

[athei]

Can pallet-revive gain advantages if the parachain runtime is based on PolkaVM?

No it doesn't make any difference for pallet-revive. Unless we also enable gas metering for the runtime itself. Then we could get rid of a lot of annoying benchmarks there.

When Polkadot-SDK supports PolkaVM-based parachain, do we have to wait for Polkadot/Kusama support?

I guess the relay chain runtime can stay wasm. But they still need to be updated to accept PVM PvFs. So yes they need to support this.

Is there a PoC for a standalone PolkaVM-based runtime?

We currently build the following runtimes to PVM as part of CI:

polkadot-sdk/.github/workflows/build-misc.yml

Lines 42 to 45 in 65a4e5e

	forklift cargo check -p minimal-template-runtime
	forklift cargo check -p westend-runtime
	forklift cargo check -p rococo-runtime
	forklift cargo check -p polkadot-test-runtime

Is it possible to migrate an existing WASM-based runtime to a PolkaVM-based runtime?

Yeah sure. It will just be like a runtime upgrade. You replace the wasm blob with a PVM blob that does the same thing.

[paritytech-workflow-stopper]

All GitHub workflows were cancelled due to failure one of the required jobs.
Failed workflow url: https://github.com/paritytech/polkadot-sdk/actions/runs/12481565251
Failed job name: test-linux-stable-no-try-runtime