Crate rvm_memory 

RVM Memory Manager

Guest physical address space management for the RVM microhypervisor, as specified in ADR-136 and ADR-138. Provides a safe abstraction over four-tier coherence-driven memory with reconstruction capability.

Four-Tier Memory Model (ADR-136)

Tier	Name	Description
0	Hot	Per-core SRAM / L1-adjacent; always resident during execution
1	Warm	Shared DRAM; resident if residency rule is met
2	Dormant	Compressed checkpoint + delta; reconstructed on demand
3	Cold	Persistent archival; accessed only during recovery

Key Components

• tier::TierManager – Coherence-driven tier placement and transitions
• allocator::BuddyAllocator – Power-of-two physical page allocator
• region::RegionManager – Owned region lifecycle and address translation
• reconstruction::ReconstructionPipeline – Dormant state restoration

Design Constraints

• #![no_std] with zero heap allocation
• #![forbid(unsafe_code)]
• Works without the coherence engine (DC-1 static fallback thresholds)
• All tier transitions are explicit, not demand-paged

Re-exports

pub use allocator::BuddyAllocator;

pub use reconstruction::create_checkpoint;

pub use reconstruction::CheckpointId;

pub use reconstruction::CompressedCheckpoint;

pub use reconstruction::ReconstructionPipeline;

pub use reconstruction::ReconstructionResult;

pub use reconstruction::WitnessDelta;

pub use region::AddressMapping;

pub use region::OwnedRegion;

pub use region::RegionConfig;

pub use region::RegionManager;

pub use tier::RegionTierState;

pub use tier::Tier;

pub use tier::TierManager;

pub use tier::TierThresholds;

Modules

allocator

Buddy allocator for physical page allocation (ADR-136).

reconstruction

Dormant state reconstruction pipeline (ADR-136).

region

Region management for guest physical address space (ADR-136, ADR-138).

tier

Memory tier management per ADR-136.

Structs

MemoryPermissions

Access permissions for a memory mapping.

MemoryRegion

A legacy memory region descriptor (ADR-138 compatibility).

Constants

PAGE_SIZE

Page size in bytes (4 KiB).

Functions

regions_overlap

Check whether two memory regions overlap in guest physical space.

regions_overlap_host

Check whether two memory regions overlap in host physical space.

validate_region

Validate that a memory region descriptor is well-formed.