add max_pov_size to runtime config and PersistedValidationData (#1984)

* add max_pov_size to runtime config and PersistedValidationData

Closes #1572.

* set default genesis max_pov_size

* apply suggestions from code review

* add default max_pov_size to polkadot_testnet_genesis

polkadot/node/core/av-store/src/tests.rs

@@ -73,6 +73,7 @@ impl Default for TestState {
 			block_number: 5,
 			hrmp_mqc_heads: Vec::new(),
 			dmq_mqc_head: Default::default(),
+			max_pov_size: 1024,
 		};
 
 		let pruning_config = PruningConfig {

polkadot/node/core/backing/src/lib.rs

@@ -1031,6 +1031,7 @@ mod tests {
 					block_number: Default::default(),
 					hrmp_mqc_heads: Vec::new(),
 					dmq_mqc_head: Default::default(),
+					max_pov_size: 1024,
 				},
 				transient: TransientValidationData {
 					max_code_size: 1000,

polkadot/node/core/candidate-validation/src/lib.rs

@@ -347,16 +347,14 @@ async fn spawn_validate_exhaustive(
 /// are passed, `Err` otherwise.
 fn perform_basic_checks(
 	candidate: &CandidateDescriptor,
-	max_block_data_size: Option<u64>,
+	max_pov_size: u32,
 	pov: &PoV,
 ) -> Result<(), InvalidCandidate> {
 	let encoded_pov = pov.encode();
 	let hash = pov.hash();
 
-	if let Some(max_size) = max_block_data_size {
-		if encoded_pov.len() as u64 > max_size {
-			return Err(InvalidCandidate::ParamsTooLarge(encoded_pov.len() as u64));
-		}
+	if encoded_pov.len() > max_pov_size as usize {
+		return Err(InvalidCandidate::ParamsTooLarge(encoded_pov.len() as u64));
 	}
 
 	if hash != candidate.pov_hash {
@@ -412,7 +410,7 @@ fn validate_candidate_exhaustive<B: ValidationBackend, S: SpawnNamed + 'static>(
 	pov: Arc<PoV>,
 	spawn: S,
 ) -> Result<ValidationResult, ValidationFailed> {
-	if let Err(e) = perform_basic_checks(&descriptor, None, &*pov) {
+	if let Err(e) = perform_basic_checks(&descriptor, persisted_validation_data.max_pov_size, &*pov) {
 		return Ok(ValidationResult::Invalid(e))
 	}
 
@@ -819,7 +817,7 @@ mod tests {
 
 	#[test]
 	fn candidate_validation_ok_is_ok() {
-		let validation_data: PersistedValidationData = Default::default();
+		let validation_data = PersistedValidationData { max_pov_size: 1024, ..Default::default() };
 
 		let pov = PoV { block_data: BlockData(vec![1; 32]) };
 
@@ -827,7 +825,7 @@ mod tests {
 		descriptor.pov_hash = pov.hash();
 		collator_sign(&mut descriptor, Sr25519Keyring::Alice);
 
-		assert!(perform_basic_checks(&descriptor, Some(1024), &pov).is_ok());
+		assert!(perform_basic_checks(&descriptor, validation_data.max_pov_size, &pov).is_ok());
 
 		let validation_result = WasmValidationResult {
 			head_data: HeadData(vec![1, 1, 1]),
@@ -859,7 +857,7 @@ mod tests {
 
 	#[test]
 	fn candidate_validation_bad_return_is_invalid() {
-		let validation_data: PersistedValidationData = Default::default();
+		let validation_data = PersistedValidationData { max_pov_size: 1024, ..Default::default() };
 
 		let pov = PoV { block_data: BlockData(vec![1; 32]) };
 
@@ -867,7 +865,7 @@ mod tests {
 		descriptor.pov_hash = pov.hash();
 		collator_sign(&mut descriptor, Sr25519Keyring::Alice);
 
-		assert!(perform_basic_checks(&descriptor, Some(1024), &pov).is_ok());
+		assert!(perform_basic_checks(&descriptor, validation_data.max_pov_size, &pov).is_ok());
 
 		let v = validate_candidate_exhaustive::<MockValidationBackend, _>(
 			MockValidationArg {
@@ -887,7 +885,7 @@ mod tests {
 
 	#[test]
 	fn candidate_validation_timeout_is_internal_error() {
-		let validation_data: PersistedValidationData = Default::default();
+		let validation_data = PersistedValidationData { max_pov_size: 1024, ..Default::default() };
 
 		let pov = PoV { block_data: BlockData(vec![1; 32]) };
 
@@ -895,7 +893,7 @@ mod tests {
 		descriptor.pov_hash = pov.hash();
 		collator_sign(&mut descriptor, Sr25519Keyring::Alice);
 
-		assert!(perform_basic_checks(&descriptor, Some(1024), &pov).is_ok());
+		assert!(perform_basic_checks(&descriptor, validation_data.max_pov_size, &pov).is_ok());
 
 		let v = validate_candidate_exhaustive::<MockValidationBackend, _>(
 			MockValidationArg {

polkadot/node/network/availability-distribution/src/tests.rs

@@ -218,6 +218,7 @@ impl Default for TestState {
 			block_number: Default::default(),
 			hrmp_mqc_heads: Vec::new(),
 			dmq_mqc_head: Default::default(),
+			max_pov_size: 1024,
 		};
 
 		let validator_index = Some((validators.len() - 1) as ValidatorIndex);

polkadot/node/service/src/chain_spec.rs

@@ -777,6 +777,7 @@ fn rococo_staging_testnet_config_genesis(wasm_binary: &[u8]) -> rococo_runtime::
 				validation_upgrade_delay: 300,
 				acceptance_period: 1200,
 				max_code_size: 5 * 1024 * 1024,
+				max_pov_size: 50 * 1024 * 1024,
 				max_head_data_size: 32 * 1024,
 				group_rotation_frequency: 10,
 				..Default::default()
@@ -1229,6 +1230,7 @@ pub fn rococo_testnet_genesis(
 				validation_upgrade_delay: 300,
 				acceptance_period: 1200,
 				max_code_size: 5 * 1024 * 1024,
+				max_pov_size: 50 * 1024 * 1024,
 				max_head_data_size: 32 * 1024,
 				group_rotation_frequency: 10,
 				..Default::default()

polkadot/node/test/service/src/chain_spec.rs

@@ -167,6 +167,7 @@ fn polkadot_testnet_genesis(
 				validation_upgrade_delay: 5,
 				acceptance_period: 1200,
 				max_code_size: 5 * 1024 * 1024,
+				max_pov_size: 50 * 1024 * 1024,
 				max_head_data_size: 32 * 1024,
 				group_rotation_frequency: 10,
 				..Default::default()

polkadot/primitives/src/v1.rs

@@ -271,6 +271,8 @@ pub struct PersistedValidationData<N = BlockNumber> {
 	/// The DMQ MQC head will be used by the validation function to authorize the downward messages
 	/// passed by the collator.
 	pub dmq_mqc_head: Hash,
+	/// The maximum legal size of a POV block, in bytes.
+	pub max_pov_size: u32,
 }
 
 impl<N: Encode> PersistedValidationData<N> {

polkadot/runtime/parachains/src/configuration.rs

@@ -43,6 +43,8 @@ pub struct HostConfiguration<BlockNumber> {
 	pub max_code_size: u32,
 	/// The maximum head-data size, in bytes.
 	pub max_head_data_size: u32,
+	/// THe maximum POV block size, in bytes.
+	pub max_pov_size: u32,
 	/// The amount of execution cores to dedicate to parathread execution.
 	pub parathread_cores: u32,
 	/// The number of retries that a parathread author has to submit their block.
@@ -172,6 +174,16 @@ decl_module! {
 			Ok(())
 		}
 
+		/// Set the max POV block size for incoming upgrades.
+		#[weight = (1_000, DispatchClass::Operational)]
+		pub fn set_max_pov_size(origin, new: u32) -> DispatchResult {
+			ensure_root(origin)?;
+			Self::update_config_member(|config| {
+				sp_std::mem::replace(&mut config.max_pov_size, new) != new
+			});
+			Ok(())
+		}
+
 		/// Set the max head data size for paras.
 		#[weight = (1_000, DispatchClass::Operational)]
 		pub fn set_max_head_data_size(origin, new: u32) -> DispatchResult {
@@ -484,6 +496,7 @@ mod tests {
 				validation_upgrade_delay: 10,
 				acceptance_period: 5,
 				max_code_size: 100_000,
+				max_pov_size: 1024,
 				max_head_data_size: 1_000,
 				parathread_cores: 2,
 				parathread_retries: 5,
@@ -524,6 +537,9 @@ mod tests {
 			Configuration::set_max_code_size(
 				Origin::root(), new_config.max_code_size,
 			).unwrap();
+			Configuration::set_max_pov_size(
+				Origin::root(), new_config.max_pov_size,
+			).unwrap();
 			Configuration::set_max_head_data_size(
 				Origin::root(), new_config.max_head_data_size,
 			).unwrap();

polkadot/runtime/parachains/src/util.rs

@@ -28,6 +28,7 @@ use crate::{configuration, paras, dmp, hrmp};
 pub fn make_persisted_validation_data<T: paras::Trait + hrmp::Trait>(
 	para_id: ParaId,
 ) -> Option<PersistedValidationData<T::BlockNumber>> {
+	let config = <configuration::Module<T>>::config();
 	let relay_parent_number = <frame_system::Module<T>>::block_number() - One::one();
 
 	Some(PersistedValidationData {
@@ -35,6 +36,7 @@ pub fn make_persisted_validation_data<T: paras::Trait + hrmp::Trait>(
 		block_number: relay_parent_number,
 		hrmp_mqc_heads: <hrmp::Module<T>>::hrmp_mqc_heads(para_id),
 		dmq_mqc_head: <dmp::Module<T>>::dmq_mqc_head(para_id),
+		max_pov_size: config.max_pov_size,
 	})
 }