Proper handling for legacy parachain leases with gaps in coretime migration

relay/polkadot/Cargo.toml

@@ -44,6 +44,7 @@ pallet-balances = { workspace = true }
 pallet-beefy = { workspace = true }
 pallet-beefy-mmr = { workspace = true }
 pallet-bounties = { workspace = true }
+pallet-broker = {workspace = true }
 pallet-child-bounties = { workspace = true }
 pallet-transaction-payment = { workspace = true }
 pallet-transaction-payment-rpc-runtime-api = { workspace = true }
@@ -103,6 +104,9 @@ xcm-runtime-apis = { workspace = true }
 
 sp-debug-derive = { workspace = true }
 
+# just for the coretime migration
+polkadot-parachain-primitives = { workspace = true }
+
 [dev-dependencies]
 sp-keyring = { workspace = true }
 sp-trie = { workspace = true }

relay/polkadot/src/coretime_migration.rs

@@ -0,0 +1,319 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Coretime migration for Polkadot runtime
+
+#[cfg(feature = "try-runtime")]
+use crate::scheduler::common::AssignmentProvider;
+use crate::{
+	coretime::{Config, WeightInfo},
+	parachains_assigner_coretime,
+	parachains_assigner_coretime::PartsOf57600,
+	OriginKind,
+};
+use codec::{Decode, Encode};
+use core::{iter, result};
+#[cfg(feature = "try-runtime")]
+use frame_support::ensure;
+use frame_support::{
+	traits::{OnRuntimeUpgrade, PalletInfoAccess, StorageVersion},
+	weights::Weight,
+};
+use frame_system::pallet_prelude::BlockNumberFor;
+use pallet_broker::{CoreAssignment, CoreMask, ScheduleItem};
+use polkadot_parachain_primitives::primitives::IsSystem;
+use polkadot_primitives::{Balance, BlockNumber, CoreIndex, Id as ParaId};
+use runtime_parachains::configuration;
+
+use sp_arithmetic::traits::SaturatedConversion;
+use sp_core::Get;
+use sp_runtime::BoundedVec;
+use sp_std::{vec, vec::Vec};
+use xcm::prelude::{send_xcm, Instruction, Junction, Location, SendError, WeightLimit, Xcm};
+
+/// Return information about a legacy lease of a parachain.
+pub trait GetLegacyLease<N> {
+	/// If parachain is a lease holding parachain, return the block at which the lease expires.
+	fn get_parachain_lease_in_blocks(para: ParaId) -> Option<N>;
+	// All parachains holding a lease, no matter if there are gaps in the slots or not.
+	fn get_all_parachains_with_leases() -> Vec<ParaId>;
+}
+
+#[derive(Encode, Decode)]
+enum CoretimeCalls {
+	#[codec(index = 1)]
+	Reserve(pallet_broker::Schedule),
+	#[codec(index = 3)]
+	SetLease(pallet_broker::TaskId, pallet_broker::Timeslice),
+	#[codec(index = 19)]
+	NotifyCoreCount(u16),
+	#[codec(index = 20)]
+	NotifyRevenue((BlockNumber, Balance)),
+	#[codec(index = 99)]
+	SwapLeases(ParaId, ParaId),
+}
+
+#[derive(Encode, Decode)]
+enum BrokerRuntimePallets {
+	#[codec(index = 50)]
+	Broker(CoretimeCalls),
+}
+
+/// Migrate a chain to use coretime.
+///
+/// This assumes that the `Coretime` and the `AssignerCoretime` pallets are added at the same
+/// time to a runtime.
+pub struct MigrateToCoretime<T, SendXcm, LegacyLease>(
+	core::marker::PhantomData<(T, SendXcm, LegacyLease)>,
+);
+
+impl<T: Config, SendXcm: xcm::v4::SendXcm, LegacyLease: GetLegacyLease<BlockNumberFor<T>>>
+	MigrateToCoretime<T, SendXcm, LegacyLease>
+{
+	fn already_migrated() -> bool {
+		// We are using the assigner coretime because the coretime pallet doesn't has any
+		// storage data. But both pallets are introduced at the same time, so this is fine.
+		let name_hash = parachains_assigner_coretime::Pallet::<T>::name_hash();
+		let mut next_key = name_hash.to_vec();
+		let storage_version_key =
+			StorageVersion::storage_key::<parachains_assigner_coretime::Pallet<T>>();
+
+		loop {
+			match sp_io::storage::next_key(&next_key) {
+				// StorageVersion is initialized before, so we need to ignore it.
+				Some(key) if &key == &storage_version_key => {
+					next_key = key;
+				},
+				// If there is any other key with the prefix of the pallet,
+				// we already have executed the migration.
+				Some(key) if key.starts_with(&name_hash) => {
+					log::info!("`MigrateToCoretime` already executed!");
+					return true
+				},
+				// Any other key/no key means that we did not yet have migrated.
+				None | Some(_) => return false,
+			}
+		}
+	}
+}
+
+impl<
+		T: Config + runtime_parachains::dmp::Config,
+		SendXcm: xcm::v4::SendXcm,
+		LegacyLease: GetLegacyLease<BlockNumberFor<T>>,
+	> OnRuntimeUpgrade for MigrateToCoretime<T, SendXcm, LegacyLease>
+{
+	fn on_runtime_upgrade() -> Weight {
+		if Self::already_migrated() {
+			return Weight::zero()
+		}
+
+		log::info!("Migrating existing parachains to coretime.");
+		migrate_to_coretime::<T, SendXcm, LegacyLease>()
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade() -> Result<Vec<u8>, sp_runtime::DispatchError> {
+		if Self::already_migrated() {
+			return Ok(Vec::new())
+		}
+
+		let legacy_paras = paras::Parachains::<T>::get();
+		let config = configuration::ActiveConfig::<T>::get();
+		let total_core_count = config.scheduler_params.num_cores + legacy_paras.len() as u32;
+
+		let dmp_queue_size =
+			crate::dmp::Pallet::<T>::dmq_contents(T::BrokerId::get().into()).len() as u32;
+
+		let total_core_count = total_core_count as u32;
+
+		Ok((total_core_count, dmp_queue_size).encode())
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade(state: Vec<u8>) -> Result<(), sp_runtime::DispatchError> {
+		if state.is_empty() {
+			return Ok(())
+		}
+
+		log::trace!("Running post_upgrade()");
+
+		let (prev_core_count, prev_dmp_queue_size) = <(u32, u32)>::decode(&mut &state[..]).unwrap();
+
+		let dmp_queue_size =
+			crate::dmp::Pallet::<T>::dmq_contents(T::BrokerId::get().into()).len() as u32;
+		let new_core_count = parachains_assigner_coretime::Pallet::<T>::session_core_count();
+		ensure!(new_core_count == prev_core_count, "Total number of cores need to not change.");
+		ensure!(
+			dmp_queue_size > prev_dmp_queue_size,
+			"There should have been enqueued at least one DMP messages."
+		);
+
+		Ok(())
+	}
+}
+
+// Migrate to Coretime.
+//
+// NOTE: Also migrates `num_cores` config value in configuration::ActiveConfig.
+fn migrate_to_coretime<
+	T: Config,
+	SendXcm: xcm::v4::SendXcm,
+	LegacyLease: GetLegacyLease<BlockNumberFor<T>>,
+>() -> Weight {
+	// let legacy_paras = paras::Parachains::<T>::get();
+	let legacy_paras = LegacyLease::get_all_parachains_with_leases();
+	let legacy_count = legacy_paras.len() as u32;
+	let now = frame_system::Pallet::<T>::block_number();
+	for (core, para_id) in legacy_paras.into_iter().enumerate() {
+		let r = parachains_assigner_coretime::Pallet::<T>::assign_core(
+			CoreIndex(core as u32),
+			now,
+			vec![(CoreAssignment::Task(para_id.into()), PartsOf57600::FULL)],
+			None,
+		);
+		if let Err(err) = r {
+			log::error!(
+				"Creating assignment for existing para failed: {:?}, error: {:?}",
+				para_id,
+				err
+			);
+		}
+	}
+
+	let config = configuration::ActiveConfig::<T>::get();
+	// num_cores was on_demand_cores until now:
+	for on_demand in 0..config.scheduler_params.num_cores {
+		let core = CoreIndex(legacy_count.saturating_add(on_demand as _));
+		let r = parachains_assigner_coretime::Pallet::<T>::assign_core(
+			core,
+			now,
+			vec![(CoreAssignment::Pool, PartsOf57600::FULL)],
+			None,
+		);
+		if let Err(err) = r {
+			log::error!("Creating assignment for existing on-demand core, failed: {:?}", err);
+		}
+	}
+	let total_cores = config.scheduler_params.num_cores + legacy_count;
+	configuration::ActiveConfig::<T>::mutate(|c| {
+		c.scheduler_params.num_cores = total_cores;
+	});
+
+	if let Err(err) = migrate_send_assignments_to_coretime_chain::<T, SendXcm, LegacyLease>() {
+		log::error!("Sending legacy chain data to coretime chain failed: {:?}", err);
+	}
+
+	let single_weight = <T as Config>::WeightInfo::assign_core(1);
+	single_weight
+		.saturating_mul(u64::from(legacy_count.saturating_add(config.scheduler_params.num_cores)))
+		// Second read from sending assignments to the coretime chain.
+		.saturating_add(T::DbWeight::get().reads_writes(2, 1))
+}
+
+fn migrate_send_assignments_to_coretime_chain<
+	T: Config,
+	SendXcm: xcm::v4::SendXcm,
+	LegacyLease: GetLegacyLease<BlockNumberFor<T>>,
+>() -> result::Result<(), SendError> {
+	let legacy_paras = LegacyLease::get_all_parachains_with_leases();
+	let legacy_paras_count = legacy_paras.len();
+	let (system_chains, lease_holding): (Vec<_>, Vec<_>) =
+		legacy_paras.into_iter().partition(IsSystem::is_system);
+
+	let reservations = system_chains.into_iter().map(|p| {
+		let schedule = BoundedVec::truncate_from(vec![ScheduleItem {
+			mask: CoreMask::complete(),
+			assignment: CoreAssignment::Task(p.into()),
+		}]);
+		mk_coretime_call::<T>(CoretimeCalls::Reserve(schedule))
+	});
+
+	let mut leases = lease_holding.into_iter().filter_map(|p| {
+			log::trace!(target: "coretime-migration", "Preparing sending of lease holding para {:?}", p);
+			let Some(valid_until) = LegacyLease::get_parachain_lease_in_blocks(p) else {
+				log::error!("Lease holding chain with no lease information?!");
+				return None
+			};
+			let valid_until: u32 = match valid_until.try_into() {
+				Ok(val) => val,
+				Err(_) => {
+					log::error!("Converting block number to u32 failed!");
+					return None
+				},
+			};
+			// We assume the coretime chain set this parameter to the recommended value in RFC-1:
+			const TIME_SLICE_PERIOD: u32 = 80;
+			let round_up = if valid_until % TIME_SLICE_PERIOD > 0 { 1 } else { 0 };
+			let time_slice = valid_until / TIME_SLICE_PERIOD + TIME_SLICE_PERIOD * round_up;
+			log::trace!(target: "coretime-migration", "Sending of lease holding para {:?}, valid_until: {:?}, time_slice: {:?}", p, valid_until, time_slice);
+			Some(mk_coretime_call::<T>(CoretimeCalls::SetLease(p.into(), time_slice)))
+		});
+
+	let core_count: u16 = configuration::ActiveConfig::<T>::get()
+		.scheduler_params
+		.num_cores
+		.saturated_into();
+	let set_core_count =
+		iter::once(mk_coretime_call::<T>(CoretimeCalls::NotifyCoreCount(core_count)));
+	log::trace!(target: "coretime-migration", "Set core count to {:?}. legacy paras count is  {:?}",core_count, legacy_paras_count);
+
+	let pool = (legacy_paras_count..core_count.into()).map(|_| {
+		let schedule = BoundedVec::truncate_from(vec![ScheduleItem {
+			mask: CoreMask::complete(),
+			assignment: CoreAssignment::Pool,
+		}]);
+		// Reserved cores will come before lease cores, so cores will change their assignments
+		// when coretime chain sends us their assign_core calls -> Good test.
+		mk_coretime_call::<T>(CoretimeCalls::Reserve(schedule))
+	});
+
+	let message_content = iter::once(Instruction::UnpaidExecution {
+		weight_limit: WeightLimit::Unlimited,
+		check_origin: None,
+	});
+
+	let reservation_content = message_content.clone().chain(reservations).collect();
+	let pool_content = message_content.clone().chain(pool).collect();
+	let leases_content_1 = message_content
+		.clone()
+		.chain(leases.by_ref().take(legacy_paras_count / 2)) // split in two messages to avoid overweighted XCM
+		.collect();
+	let leases_content_2 = message_content.clone().chain(leases).collect();
+	let set_core_count_content = message_content.clone().chain(set_core_count).collect();
+
+	let messages = vec![
+		Xcm(reservation_content),
+		Xcm(pool_content),
+		Xcm(leases_content_1),
+		Xcm(leases_content_2),
+		Xcm(set_core_count_content),
+	];
+
+	for message in messages {
+		send_xcm::<SendXcm>(Location::new(0, Junction::Parachain(T::BrokerId::get())), message)?;
+	}
+
+	Ok(())
+}
+
+fn mk_coretime_call<T: Config>(call: CoretimeCalls) -> Instruction<()> {
+	Instruction::Transact {
+		origin_kind: OriginKind::Superuser,
+		require_weight_at_most: T::MaxXcmTransactWeight::get(),
+		call: BrokerRuntimePallets::Broker(call).encode().into(),
+	}
+}

relay/polkadot/src/lib.rs

@@ -141,6 +141,8 @@ use governance::{
 pub mod impls;
 pub mod xcm_config;
 
+mod coretime_migration;
+
 pub const LOG_TARGET: &str = "runtime::polkadot";
 
 impl_runtime_weights!(polkadot_runtime_constants);
@@ -1936,7 +1938,7 @@ pub mod migrations {
 	use super::*;
 
 	pub struct GetLegacyLeaseImpl;
-	impl coretime::migration::GetLegacyLease<BlockNumber> for GetLegacyLeaseImpl {
+	impl coretime_migration::GetLegacyLease<BlockNumber> for GetLegacyLeaseImpl {
 		fn get_parachain_lease_in_blocks(para: ParaId) -> Option<BlockNumber> {
 			let now = frame_system::Pallet::<Runtime>::block_number();
 			let lease = slots::Leases::<Runtime>::get(para);
@@ -1947,6 +1949,15 @@ pub mod migrations {
 				<slots::Pallet<Runtime> as Leaser<BlockNumber>>::lease_period_index(now)?;
 			Some(index.saturating_add(lease.len() as u32).saturating_mul(LeasePeriod::get()))
 		}
+
+		fn get_all_parachains_with_leases() -> Vec<ParaId> {
+			let mut leases = slots::Leases::<Runtime>::iter()
+				.filter(|(_, lease)| !lease.is_empty())
+				.map(|(para, _)| para)
+				.collect::<Vec<_>>();
+			leases.sort();
+			leases
+		}
 	}
 
 	/// Cancel all ongoing auctions.
@@ -2001,7 +2012,7 @@ pub mod migrations {
 		>,
 		clear_judgement_proxies::Migration,
 		// Migrate from legacy lease to coretime. Needs to run after configuration v11
-		coretime::migration::MigrateToCoretime<
+		coretime_migration::MigrateToCoretime<
 			Runtime,
 			crate::xcm_config::XcmRouter,
 			GetLegacyLeaseImpl,