feat: new per-enqueued-call gas limit

barretenberg/cpp/src/barretenberg/vm/avm/trace/helper.hpp

@@ -4,6 +4,7 @@
 
 #include "barretenberg/vm/avm/trace/common.hpp"
 #include "barretenberg/vm/avm/trace/trace.hpp"
+#include "barretenberg/vm/constants.hpp"
 
 namespace bb::avm_trace {
 
@@ -37,6 +38,14 @@ template <typename FF_> VmPublicInputs<FF_> convert_public_inputs(std::vector<FF
         throw_or_abort("Public inputs vector is not of PUBLIC_CIRCUIT_PUBLIC_INPUTS_LENGTH");
     }
 
+    // WARNING: this must be constrained by the kernel!
+    // Here this is just a sanity check to prevent generation of proofs that
+    // will be thrown out by the kernel anyway.
+    if (public_inputs_vec[L2_START_GAS_LEFT_PCPI_OFFSET] > MAX_L2_GAS_PER_ENQUEUED_CALL) {
+        throw_or_abort(
+            "Cannot allocate more than MAX_L2_GAS_PER_ENQUEUED_CALL to the AVM for execution of an enqueued call");
+    }
+
     std::array<FF_, KERNEL_INPUTS_LENGTH>& kernel_inputs = std::get<KERNEL_INPUTS>(public_inputs);
 
     // Copy items from PublicCircuitPublicInputs vector to public input columns

barretenberg/cpp/src/barretenberg/vm/aztec_constants.hpp

@@ -12,6 +12,7 @@
 #define MAX_NULLIFIER_NON_EXISTENT_READ_REQUESTS_PER_CALL 16
 #define MAX_L1_TO_L2_MSG_READ_REQUESTS_PER_CALL 16
 #define MAX_UNENCRYPTED_LOGS_PER_CALL 4
+#define MAX_L2_GAS_PER_ENQUEUED_CALL 1500000
 #define AZTEC_ADDRESS_LENGTH 1
 #define GAS_FEES_LENGTH 2
 #define GAS_LENGTH 2

l1-contracts/src/core/libraries/ConstantsGen.sol

@@ -116,6 +116,7 @@ library Constants {
     14061769416655647708490531650437236735160113654556896985372298487345;
   uint256 internal constant DEFAULT_GAS_LIMIT = 1000000000;
   uint256 internal constant DEFAULT_TEARDOWN_GAS_LIMIT = 100000000;
+  uint256 internal constant MAX_L2_GAS_PER_ENQUEUED_CALL = 1500000;
   uint256 internal constant DEFAULT_MAX_FEE_PER_GAS = 10;
   uint256 internal constant DEFAULT_INCLUSION_FEE = 0;
   uint256 internal constant DA_BYTES_PER_FIELD = 32;

noir-projects/noir-protocol-circuits/crates/public-kernel-lib/src/components/enqueued_call_data_validator.nr

@@ -5,6 +5,7 @@ use dep::types::{
     kernel_circuit_public_inputs::PublicKernelCircuitPublicInputs, enqueued_call_data::EnqueuedCallData,
     public_call_request::PublicCallRequest, validation_requests::PublicValidationRequestArrayLengths
 },
+    constants::MAX_L2_GAS_PER_ENQUEUED_CALL,
     utils::arrays::array_length
 };
 
@@ -89,15 +90,19 @@ impl EnqueuedCallDataValidator {
     // Validates that the start gas injected into the vm circuit matches the remaining gas.
     fn validate_start_gas(self, previous_kernel: PublicKernelCircuitPublicInputs) {
         let enqueued_call_start_gas = self.enqueued_call.data.start_gas_left;
+        // NOTE: the AVM circuit will fail to generate a proof if its "start gas" is > MAX_L2_GAS_PER_ENQUEUED_CALL,
+        // so the kernel never allocates more than that maximum to one enqueued call.
         if self.phase != PublicKernelPhase.TEARDOWN {
             // An enqueued call's start gas is the remaining gas left in the transaction after the previous kernel.
             let tx_gas_limits = previous_kernel.constants.tx_context.gas_settings.gas_limits;
-            let computed_start_gas = tx_gas_limits.sub(previous_kernel.end.gas_used).sub(previous_kernel.end_non_revertible.gas_used);
+            let mut computed_start_gas = tx_gas_limits.sub(previous_kernel.end.gas_used).sub(previous_kernel.end_non_revertible.gas_used);
+            computed_start_gas.l2_gas = std::cmp::min(computed_start_gas.l2_gas, MAX_L2_GAS_PER_ENQUEUED_CALL);
             assert_eq(
                 enqueued_call_start_gas, computed_start_gas, "Start gas for enqueued call does not match transaction gas left"
             );
         } else {
-            let teardown_gas_limit = previous_kernel.constants.tx_context.gas_settings.teardown_gas_limits;
+            let mut teardown_gas_limit = previous_kernel.constants.tx_context.gas_settings.teardown_gas_limits;
+            teardown_gas_limit.l2_gas = std::cmp::min(teardown_gas_limit.l2_gas, MAX_L2_GAS_PER_ENQUEUED_CALL);
             assert_eq(
                 enqueued_call_start_gas, teardown_gas_limit, "Start gas for enqueued call does not match teardown gas allocation"
             );

noir-projects/noir-protocol-circuits/crates/public-kernel-lib/src/components/public_kernel_output_composer.nr

@@ -134,6 +134,8 @@ impl PublicKernelOutputComposer {
             let gas_used = self.output_builder.end.gas_used;
             self.output_builder.end = PublicAccumulatedDataBuilder::empty();
             self.output_builder.end.gas_used = gas_used;
+            // TODO: consume all remaining gas on revert?
+            //self.output_builder.end.gas_used = self.output_builder.constants.tx_context.gas_settings.gas_limits;
         }
     }
 
@@ -143,6 +145,10 @@ impl PublicKernelOutputComposer {
 
     fn update_gas_used(&mut self, enqueued_call: VMCircuitPublicInputs, phase: u8) {
         let call_gas_used = enqueued_call.accumulated_data.gas_used;
+        // TODO: since we're using gas used here, this should be fine
+        // but if vm circuit public inputs change to use expose gas_left instead,
+        // then we need to compute the call's gas used as start_gas_left - end_gas_left
+        //let call_gas_used = enqueued_call.start_gas_left - enqueued_call.accumulated_data.gas_left;
         if phase == PublicKernelPhase.SETUP {
             self.output_builder.end_non_revertible.gas_used += call_gas_used;
         }

noir-projects/noir-protocol-circuits/crates/types/src/constants.nr

@@ -167,6 +167,7 @@ global DEPLOYER_CONTRACT_INSTANCE_DEPLOYED_MAGIC_VALUE = 0x85864497636cf755ae7bd
 // GAS DEFAULTS
 global DEFAULT_GAS_LIMIT: u32 = 1_000_000_000;
 global DEFAULT_TEARDOWN_GAS_LIMIT: u32 = 100_000_000;
+global MAX_L2_GAS_PER_ENQUEUED_CALL: u32 = 1_500_000;
 global DEFAULT_MAX_FEE_PER_GAS: Field = 10;
 global DEFAULT_INCLUSION_FEE: Field = 0;
 global DA_BYTES_PER_FIELD: u32 = 32;

yarn-project/circuits.js/src/constants.gen.ts

@@ -101,6 +101,7 @@ export const DEPLOYER_CONTRACT_INSTANCE_DEPLOYED_MAGIC_VALUE =
   14061769416655647708490531650437236735160113654556896985372298487345n;
 export const DEFAULT_GAS_LIMIT = 1000000000;
 export const DEFAULT_TEARDOWN_GAS_LIMIT = 100000000;
+export const MAX_L2_GAS_PER_ENQUEUED_CALL = 1500000;
 export const DEFAULT_MAX_FEE_PER_GAS = 10;
 export const DEFAULT_INCLUSION_FEE = 0;
 export const DA_BYTES_PER_FIELD = 32;

yarn-project/circuits.js/src/scripts/constants.in.ts

@@ -77,6 +77,7 @@ const CPP_CONSTANTS = [
   'MEM_TAG_U64',
   'MEM_TAG_U128',
   'MEM_TAG_FF',
+  'MAX_L2_GAS_PER_ENQUEUED_CALL',
 ];
 
 const PIL_CONSTANTS = [

yarn-project/simulator/src/avm/avm_simulator.ts

@@ -14,12 +14,14 @@ import {
 } from './errors.js';
 import type { Instruction } from './opcodes/index.js';
 import { decodeFromBytecode } from './serialization/bytecode_serialization.js';
+import { MAX_L2_GAS_PER_ENQUEUED_CALL } from '@aztec/circuits.js';
 
 export class AvmSimulator {
   private log: DebugLogger;
   private bytecode: Buffer | undefined;
 
   constructor(private context: AvmContext) {
+    assert(context.machineState.gasLeft.l2Gas > MAX_L2_GAS_PER_ENQUEUED_CALL, `Cannot allocate more than ${MAX_L2_GAS_PER_ENQUEUED_CALL} to the AVM for execution of an enqueued call`);
     this.log = createDebugLogger(`aztec:avm_simulator:core(f:${context.environment.functionSelector.toString()})`);
   }