SIMD 0054: Sysvar for active stake

proposals/0054-sysvar-get-active-stake.md

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+---
+simd: '0054'
+title: Sysvar for active stake
+authors:
+  - x19
+category: Standard
+type: Core
+status: Draft
+created: 2023-06-7
+feature: (fill in with feature tracking issues once accepted)
+---
+
+## Summary
+
+We propose to add a new sysvar that contains vote account pubkeys and 
+their corresponding active stake.
+
+## Motivation
+
+Currently, if a validator wants to prove its active stake to a program, 
+it needs to 
+pass in all of the stake accounts which have delegated to it. This is 
+infeasible due to the large number of stake accounts this would require.
+
+Using the proposed sysvar, a program can look up the corresponding 
+vote account and verify the amount of active stake it has delegated to it.
+
+This sysvar would unlock new use cases which use stake amount in their logic 
+including on-chain governance, attestations, and more.
+
+## Alternatives Considered
+
+None
+
+## New Terminology
+
+None
+
+## Detailed Design
+
+- sysvar structure: `Vec<(vote_account: Pubkey, active_stake_in_lamports: u64)>`
+- sysvar address: `SysvarStakeWeight11111111111111111111111111`
+
+Stake weight information should already be available on full node clients 
+since it's required to construct the leader schedule. Since stake weights 
+can only be
+modified on a per-epoch basis, validators will only need to update this 
+account on epoch boundaries.
+
+We would also need a new feature gate to activate this sysvar.
+
+## Impact
+
+Implementing the proposed sysvar will enable new types of programs which are 
+not possible now,
+improving Solana's ecosystem.
+
+## Security Considerations
+
+None 
+
+## Backwards Compatibility
+
+Existing programs are not impacted at all.