Function build_engine

examples/mpk.rs:185–215

Build a pool-allocated engine with `num_memories` slots.

(args: &Args, num_memories: u32, enable_mpk: Enabled)

/// Build a pool-allocated engine with `num_memories` slots.
fn build_engine(args: &Args, num_memories: u32, enable_mpk: Enabled) -> Result<usize> {
    // Configure the memory pool.
    let mut pool = PoolingAllocationConfig::default();
    let max_memory_size =
        usize::try_from(args.memory_size).expect("memory size should fit in `usize`");
    pool.max_memory_size(max_memory_size)
        .total_memories(num_memories)
        .memory_protection_keys(enable_mpk);

    // Configure the engine itself.
    let mut config = Config::new();
    if let Some(memory_reservation) = args.memory_reservation {
        config.memory_reservation(memory_reservation);
    }
    if let Some(memory_guard_size) = args.memory_guard_size {
        config.memory_guard_size(memory_guard_size);
    }
    config.allocation_strategy(InstanceAllocationStrategy::Pooling(pool));

    // Measure memory use before and after the engine is built.
    let mapped_bytes_before = num_bytes_mapped()?;
    let engine = Engine::new(&config)?;
    let mapped_bytes_after = num_bytes_mapped()?;

    // Ensure we actually use the engine somehow.
    engine.increment_epoch();

    let mapped_bytes = mapped_bytes_after - mapped_bytes_before;
    info!("{num_memories}-slot pool ({enable_mpk:?}): {mapped_bytes} bytes mapped");
    Ok(mapped_bytes)
}

/// Add up the sizes of all the mapped virtual memory regions for the current
/// Linux process.