[exp] zkvm backend: Ceno

Makefile

@@ -10,6 +10,9 @@ export RUST_LOG
 OPENVM_RUST_TOOLCHAIN ?= nightly-2025-08-18
 export OPENVM_RUST_TOOLCHAIN
 
+CENO_RUST_TOOLCHAIN ?= +nightly-2025-11-20
+export CENO_RUST_TOOLCHAIN
+
 # Set GPU config if GPU=1 is set
 ifeq ($(GPU),1)
 CARGO_CONFIG_FLAG = --features scroll-zkvm-integration/cuda
@@ -86,6 +89,28 @@ prove-zisk-chunk:
 prove-zisk-chunk-cpu:
 	cd zisk && PATH="$$HOME/.zisk/bin:$$PATH" cargo run --release -p scroll-zkvm-zisk-prover-test -- --circuit chunk --prove --emulator
 
+# ---- Ceno backend (see ceno/AGENTS.md) ----
+CENO_PROVER_FEATURES ?= gpu,jemalloc,aot-x86_64,parallel
+CENO_MAX_CELL_PER_SHARD ?= 1245708288
+CENO_CARGO_ENV = CARGO_NET_GIT_FETCH_WITH_CLI=true
+CENO_GPU_E2E_ENV = $(CENO_CARGO_ENV) RUSTFLAGS="-C target-feature=+avx2" JEMALLOC_SYS_WITH_MALLOC_CONF=retain:true,background_thread:true,metadata_thp:always,thp:always,dirty_decay_ms:10000,muzzy_decay_ms:10000,abort_conf:true RUST_MIN_STACK=536870912 CENO_EMULATOR_BACKEND=aot CENO_GPU_ENABLE_WITGEN=0 CENO_GPU_WITGEN=0 CENO_CONCURRENT_CHIP_PROVING=1 CENO_GPU_MEM_TRACKING=0 CENO_GPU_CACHE_LEVEL=1 CENO_GPU_JAGGED_RESHAPE_LOG_HEIGHT=23 CENO_GPU_LARGE_TASK_BOOKING_MARGIN_MB=3048 CENO_MAX_CELL_PER_SHARD=$(CENO_MAX_CELL_PER_SHARD)
+
+build-guest-ceno:
+	cd ceno && $(CENO_CARGO_ENV) cargo run --release -p scroll-zkvm-build-guest-ceno -- --mode force
+	cd ceno && $(CENO_CARGO_ENV) RUSTFLAGS="-C target-feature=+avx2" JEMALLOC_SYS_WITH_MALLOC_CONF=retain:true,background_thread:true,metadata_thp:always,thp:always,dirty_decay_ms:10000,muzzy_decay_ms:10000,abort_conf:true cargo build --release -p scroll-zkvm-ceno-prover-test --features $(CENO_PROVER_FEATURES)
+
+test-e2e-ceno-chunk:
+	@if [ "$(GPU)" != "1" ]; then echo "GPU=1 is required for Ceno GPU E2E"; exit 1; fi
+	cd ceno && $(CENO_GPU_E2E_ENV) cargo run --release -p scroll-zkvm-ceno-prover-test --features $(CENO_PROVER_FEATURES) -- --circuit chunk --gpu
+
+test-e2e-ceno-batch:
+	@if [ "$(GPU)" != "1" ]; then echo "GPU=1 is required for Ceno GPU E2E"; exit 1; fi
+	cd ceno && $(CENO_GPU_E2E_ENV) cargo run --release -p scroll-zkvm-ceno-prover-test --features $(CENO_PROVER_FEATURES) -- --circuit batch --gpu
+
+test-e2e-ceno-bundle:
+	@if [ "$(GPU)" != "1" ]; then echo "GPU=1 is required for Ceno GPU E2E"; exit 1; fi
+	cd ceno && $(CENO_GPU_E2E_ENV) cargo run --release -p scroll-zkvm-ceno-prover-test --features $(CENO_PROVER_FEATURES) -- --circuit bundle --gpu
+
 # In-guest recursion PoC: prove the bundle stub, then verify that child proof inside
 # the batch recursion guest via zisk-verifier. We use the prebuilt emulator (`-l`) because
 # the ASM microservice path times out on this machine for tiny proofs.

ceno/.gitignore

@@ -0,0 +1,3 @@
+/target/
+/releases/dev/ceno/*/app
+/releases/dev/ceno/prover-test/

ceno/AGENTS.md

@@ -0,0 +1,30 @@
+# AGENTS.md - Ceno backend
+
+This directory is an isolated Ceno Cargo workspace. Keep Ceno dependencies and patches here;
+do not add Ceno crates to the root OpenVM workspace.
+
+The workspace uses remote Ceno dependencies in `Cargo.toml`, isolated from the root OpenVM
+workspace:
+
+- `scroll-tech/ceno` on branch `master`.
+- `scroll-tech/ceno-gpu` on branch `main`, via the `cuda_hal` patch. This may require
+  GitHub SSH access on fresh machines.
+
+Build and validation commands:
+
+```bash
+cd ceno && cargo check --workspace --all-targets
+make build-guest-ceno
+GPU=1 make test-e2e-ceno-chunk
+GPU=1 make test-e2e-ceno-batch
+GPU=1 make test-e2e-ceno-bundle
+```
+
+`GPU=1` is required for E2E proof commands. CPU fallback is intentionally rejected so the
+commands fail loudly when GPU proving is unavailable.
+
+Artifact layout:
+
+- `ceno/releases/dev/ceno/{chunk,batch,bundle}/app` - compiled Ceno guest ELFs.
+- `ceno/releases/dev/ceno/prover-test/<circuit>/` - hints, app proofs, root proof,
+  verifying-key metadata, and public-output digests.