Simd 118: extend EpochRewards sysvar (solana-labs#428)

* Update EpochRewards sysvar

* Update Clone trait

* Update doctests

* Update bank to new sysvar fields

* Update runtime tests

* Update syscall test

* Update tests

* Clean up doctest EpochRewards construction

account-decoder/src/parse_sysvar.rs

@@ -372,9 +372,11 @@ mod test {
         );
 
         let epoch_rewards = EpochRewards {
+            distribution_starting_block_height: 42,
             total_rewards: 100,
             distributed_rewards: 20,
-            distribution_complete_block_height: 42,
+            active: true,
+            ..EpochRewards::default()
         };
         let epoch_rewards_sysvar = create_account_for_test(&epoch_rewards);
         assert_eq!(

programs/bpf_loader/src/syscalls/mod.rs

@@ -3317,16 +3317,20 @@ mod tests {
         src_rent.burn_percent = 3;
 
         let mut src_rewards = create_filled_type::<EpochRewards>(false);
+        src_rewards.distribution_starting_block_height = 42;
+        src_rewards.num_partitions = 2;
+        src_rewards.parent_blockhash = Hash::new(&[3; 32]);
+        src_rewards.total_points = 4;
         src_rewards.total_rewards = 100;
         src_rewards.distributed_rewards = 10;
-        src_rewards.distribution_complete_block_height = 42;
+        src_rewards.active = true;
 
         let mut sysvar_cache = SysvarCache::default();
         sysvar_cache.set_clock(src_clock.clone());
         sysvar_cache.set_epoch_schedule(src_epochschedule.clone());
         sysvar_cache.set_fees(src_fees.clone());
         sysvar_cache.set_rent(src_rent.clone());
-        sysvar_cache.set_epoch_rewards(src_rewards);
+        sysvar_cache.set_epoch_rewards(src_rewards.clone());
 
         let transaction_accounts = vec![
             (
@@ -3519,10 +3523,14 @@ mod tests {
             assert_eq!(got_rewards, src_rewards);
 
             let mut clean_rewards = create_filled_type::<EpochRewards>(true);
+            clean_rewards.distribution_starting_block_height =
+                src_rewards.distribution_starting_block_height;
+            clean_rewards.num_partitions = src_rewards.num_partitions;
+            clean_rewards.parent_blockhash = src_rewards.parent_blockhash;
+            clean_rewards.total_points = src_rewards.total_points;
             clean_rewards.total_rewards = src_rewards.total_rewards;
             clean_rewards.distributed_rewards = src_rewards.distributed_rewards;
-            clean_rewards.distribution_complete_block_height =
-                src_rewards.distribution_complete_block_height;
+            clean_rewards.active = src_rewards.active;
             assert!(are_bytes_equal(&got_rewards, &clean_rewards));
         }
     }

programs/sbf/rust/sysvar/tests/lib.rs

@@ -27,9 +27,11 @@ async fn test_sysvars() {
     );
 
     let epoch_rewards = epoch_rewards::EpochRewards {
+        distribution_starting_block_height: 42,
         total_rewards: 100,
         distributed_rewards: 50,
-        distribution_complete_block_height: 42,
+        active: true,
+        ..epoch_rewards::EpochRewards::default()
     };
     program_test.add_sysvar_account(epoch_rewards::id(), &epoch_rewards);
     let (mut banks_client, payer, recent_blockhash) = program_test.start().await;

runtime/src/bank.rs

@@ -1673,13 +1673,12 @@ impl Bank {
 
         let slot = self.slot();
         let credit_start = self.block_height() + self.get_reward_calculation_num_blocks();
-        let credit_end_exclusive = credit_start + stake_rewards_by_partition.len() as u64;
 
         self.set_epoch_reward_status_active(stake_rewards_by_partition);
 
         // create EpochRewards sysvar that holds the balance of undistributed rewards with
-        // (total_rewards, distributed_rewards, credit_end_exclusive), total capital will increase by (total_rewards - distributed_rewards)
-        self.create_epoch_rewards_sysvar(total_rewards, distributed_rewards, credit_end_exclusive);
+        // (total_rewards, distributed_rewards, credit_start), total capital will increase by (total_rewards - distributed_rewards)
+        self.create_epoch_rewards_sysvar(total_rewards, distributed_rewards, credit_start);
 
         datapoint_info!(
             "epoch-rewards-status-update",
@@ -3615,14 +3614,16 @@ impl Bank {
         &self,
         total_rewards: u64,
         distributed_rewards: u64,
-        distribution_complete_block_height: u64,
+        distribution_starting_block_height: u64,
     ) {
         assert!(self.is_partitioned_rewards_code_enabled());
 
         let epoch_rewards = sysvar::epoch_rewards::EpochRewards {
             total_rewards,
             distributed_rewards,
-            distribution_complete_block_height,
+            distribution_starting_block_height,
+            active: true,
+            ..sysvar::epoch_rewards::EpochRewards::default()
         };
 
         self.update_sysvar_account(&sysvar::epoch_rewards::id(), |account| {

runtime/src/bank/sysvar_cache.rs

@@ -6,7 +6,7 @@ mod tests {
     use {
         super::*,
         solana_sdk::{
-            feature_set, genesis_config::create_genesis_config, pubkey::Pubkey,
+            feature_set, genesis_config::create_genesis_config, hash::Hash, pubkey::Pubkey,
             sysvar::epoch_rewards::EpochRewards,
         },
         std::sync::Arc,
@@ -121,14 +121,18 @@ mod tests {
         // inject a reward sysvar for test
         bank1.activate_feature(&feature_set::enable_partitioned_epoch_reward::id());
         let expected_epoch_rewards = EpochRewards {
+            distribution_starting_block_height: 42,
+            num_partitions: 0,
+            parent_blockhash: Hash::default(),
+            total_points: 0,
             total_rewards: 100,
             distributed_rewards: 10,
-            distribution_complete_block_height: 42,
+            active: true,
         };
         bank1.create_epoch_rewards_sysvar(
             expected_epoch_rewards.total_rewards,
             expected_epoch_rewards.distributed_rewards,
-            expected_epoch_rewards.distribution_complete_block_height,
+            expected_epoch_rewards.distribution_starting_block_height,
         );
 
         bank1

runtime/src/bank/tests.rs

@@ -12715,9 +12715,13 @@ fn test_epoch_rewards_sysvar() {
 
     // create epoch rewards sysvar
     let expected_epoch_rewards = sysvar::epoch_rewards::EpochRewards {
+        distribution_starting_block_height: 42,
+        num_partitions: 0,
+        parent_blockhash: Hash::default(),
+        total_points: 0,
         total_rewards,
         distributed_rewards: 10,
-        distribution_complete_block_height: 42,
+        active: true,
     };
 
     bank.create_epoch_rewards_sysvar(total_rewards, 10, 42);
@@ -12732,9 +12736,13 @@ fn test_epoch_rewards_sysvar() {
     assert_eq!(account.lamports(), total_rewards - 20);
     let epoch_rewards: sysvar::epoch_rewards::EpochRewards = from_account(&account).unwrap();
     let expected_epoch_rewards = sysvar::epoch_rewards::EpochRewards {
+        distribution_starting_block_height: 42,
+        num_partitions: 0,
+        parent_blockhash: Hash::default(),
+        total_points: 0,
         total_rewards,
         distributed_rewards: 20,
-        distribution_complete_block_height: 42,
+        active: true,
     };
     assert_eq!(epoch_rewards, expected_epoch_rewards);
 

sdk/program/src/epoch_rewards.rs

@@ -6,20 +6,37 @@
 //!
 //! [`sysvar::epoch_rewards`]: crate::sysvar::epoch_rewards
 
-use std::ops::AddAssign;
+use {crate::hash::Hash, solana_sdk_macro::CloneZeroed, std::ops::AddAssign};
 
-#[repr(C)]
-#[derive(Debug, Serialize, Deserialize, PartialEq, Eq, Default, Clone, Copy, AbiExample)]
+#[repr(C, align(16))]
+#[derive(Debug, Serialize, Deserialize, PartialEq, Eq, Default, AbiExample, CloneZeroed)]
 pub struct EpochRewards {
-    /// total rewards for the current epoch, in lamports
+    /// The starting block height of the rewards distribution in the current
+    /// epoch
+    pub distribution_starting_block_height: u64,
+
+    /// Number of partitions in the rewards distribution in the current epoch,
+    /// used to generate an EpochRewardsHasher
+    pub num_partitions: u64,
+
+    /// The blockhash of the parent block of the first block in the epoch, used
+    /// to seed an EpochRewardsHasher
+    pub parent_blockhash: Hash,
+
+    /// The total rewards points calculated for the current epoch, where points
+    /// equals the sum of (delegated stake * credits observed) for all
+    /// delegations
+    pub total_points: u128,
+
+    /// The total rewards for the current epoch, in lamports
     pub total_rewards: u64,
 
-    /// distributed rewards for the current epoch, in lamports
+    /// The rewards currently distributed for the current epoch, in lamports
     pub distributed_rewards: u64,
 
-    /// distribution of all staking rewards for the current
-    /// epoch will be completed at this block height
-    pub distribution_complete_block_height: u64,
+    /// Whether the rewards period (including calculation and distribution) is
+    /// active
+    pub active: bool,
 }
 
 impl EpochRewards {
@@ -38,12 +55,13 @@ mod tests {
         pub fn new(
             total_rewards: u64,
             distributed_rewards: u64,
-            distribution_complete_block_height: u64,
+            distribution_starting_block_height: u64,
         ) -> Self {
             Self {
                 total_rewards,
                 distributed_rewards,
-                distribution_complete_block_height,
+                distribution_starting_block_height,
+                ..Self::default()
             }
         }
     }
@@ -54,7 +72,7 @@ mod tests {
 
         assert_eq!(epoch_rewards.total_rewards, 100);
         assert_eq!(epoch_rewards.distributed_rewards, 0);
-        assert_eq!(epoch_rewards.distribution_complete_block_height, 64);
+        assert_eq!(epoch_rewards.distribution_starting_block_height, 64);
     }
 
     #[test]

sdk/program/src/sysvar/epoch_rewards.rs

@@ -1,11 +1,19 @@
 //! Epoch rewards for current epoch
 //!
 //! The _epoch rewards_ sysvar provides access to the [`EpochRewards`] type,
-//! which tracks the progress of epoch rewards distribution. It includes the
-//!   - total rewards for the current epoch, in lamports
-//!   - rewards for the current epoch distributed so far, in lamports
-//!   - distribution completed block height, i.e. distribution of all staking rewards for the current
-//!     epoch will be completed at this block height
+//! which tracks whether the rewards period (including calculation and
+//! distribution) is in progress, as well as the details needed to resume
+//! distribution when starting from a snapshot during the rewards period. The
+//! sysvar is repopulated at the start of the first block of each epoch.
+//! Therefore, the sysvar contains data about the current epoch until a new
+//! epoch begins. Fields in the sysvar include:
+//!   - distribution starting block height
+//!   - the number of partitions in the distribution
+//!   - the parent-blockhash seed used to generate the partition hasher
+//!   - the total rewards points calculated for the epoch
+//!   - total rewards for epoch, in lamports
+//!   - rewards for the epoch distributed so far, in lamports
+//!   - whether the rewards period is active
 //!
 //! [`EpochRewards`] implements [`Sysvar::get`] and can be loaded efficiently without
 //! passing the sysvar account ID to the program.
@@ -43,9 +51,16 @@
 //! #
 //! # use solana_program::sysvar::SysvarId;
 //! # let p = EpochRewards::id();
-//! # let l = &mut 1120560;
-//! # let d = &mut vec![0, 202, 154, 59, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0];
-//! # let a = AccountInfo::new(&p, false, false, l, d, &p, false, 0);
+//! # let l = &mut 1559040;
+//! # let epoch_rewards = EpochRewards {
+//! #     distribution_starting_block_height: 42,
+//! #     total_rewards: 100,
+//! #     distributed_rewards: 10,
+//! #     active: true,
+//! #     ..EpochRewards::default()
+//! # };
+//! # let mut d: Vec<u8> = bincode::serialize(&epoch_rewards).unwrap();
+//! # let a = AccountInfo::new(&p, false, false, l, &mut d, &p, false, 0);
 //! # let accounts = &[a.clone(), a];
 //! # process_instruction(
 //! #     &Pubkey::new_unique(),
@@ -86,9 +101,16 @@
 //! #
 //! # use solana_program::sysvar::SysvarId;
 //! # let p = EpochRewards::id();
-//! # let l = &mut 1120560;
-//! # let d = &mut vec![0, 202, 154, 59, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0];
-//! # let a = AccountInfo::new(&p, false, false, l, d, &p, false, 0);
+//! # let l = &mut 1559040;
+//! # let epoch_rewards = EpochRewards {
+//! #     distribution_starting_block_height: 42,
+//! #     total_rewards: 100,
+//! #     distributed_rewards: 10,
+//! #     active: true,
+//! #     ..EpochRewards::default()
+//! # };
+//! # let mut d: Vec<u8> = bincode::serialize(&epoch_rewards).unwrap();
+//! # let a = AccountInfo::new(&p, false, false, l, &mut d, &p, false, 0);
 //! # let accounts = &[a.clone(), a];
 //! # process_instruction(
 //! #     &Pubkey::new_unique(),
@@ -109,9 +131,17 @@
 //! # use anyhow::Result;
 //! #
 //! fn print_sysvar_epoch_rewards(client: &RpcClient) -> Result<()> {
+//! #   let epoch_rewards = EpochRewards {
+//! #       distribution_starting_block_height: 42,
+//! #       total_rewards: 100,
+//! #       distributed_rewards: 10,
+//! #       active: true,
+//! #       ..EpochRewards::default()
+//! #   };
+//! #   let data: Vec<u8> = bincode::serialize(&epoch_rewards)?;
 //! #   client.set_get_account_response(epoch_rewards::ID, Account {
 //! #       lamports: 1120560,
-//! #       data: vec![0, 202, 154, 59, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0],
+//! #       data,
 //! #       owner: solana_sdk::system_program::ID,
 //! #       executable: false,
 //! #       rent_epoch: 307,