Replace ByteValued with zerocopy

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## Upcoming Release
+
+## Removed
+
+- \[[#374](https://github.com/rust-vmm/vm-memory/pull/374)\] Removed `ByteValued` trait and `endian` module in favor of the `zerocopy` crate.
+    `ByteValued`'s functionality is now provided by `zerocopy::IntoBytes`, `zerocopy::FromBytes` and `zerocopy::Zeroed`.
+    `ByteValued::as_bytes` can be replaced with `VolatileSlices::from` for `&mut [u8]`.
+
 ## 0.18.0
 
 ### Changed

Cargo.toml

@@ -27,6 +27,7 @@ bitflags = { version = "2.4.0", optional = true }
 rangemap = { version = "1.5.1", optional = true }
 thiserror = "2.0.16"
 vmm-sys-util = { version = ">=0.12.1, <=0.15.0", optional = true }
+zerocopy = "0.8.48"
 
 [target.'cfg(target_family = "windows")'.dependencies.winapi]
 version = "0.3"

DESIGN.md

@@ -35,12 +35,11 @@ The `vm-memory` is derived from two upstream projects:
 The high level abstraction of the VM memory has been heavily refactored to
 provide a VMM agnostic interface.
 
-The `vm-memory` crate could be divided into four logic parts as:
+The `vm-memory` crate could be divided into three logic parts as:
 
 - [Abstraction of Address Space](#abstraction-of-address-space)
 - [Specialization for Virtual Machine Physical Address Space](#specialization-for-virtual-machine-physical-address-space)
 - [Backend Implementation Based on `mmap`](#backend-implementation-based-on-mmap)
-- [Utilities and helpers](#utilities-and-helpers)
 
 ### Address Space Abstraction
 
@@ -146,20 +145,6 @@ object to translate I/O virtual addresses (IOVAs) into VMM user addresses
 (VUAs), which are then passed to the inner `GuestMemoryBackend`
 implementation (like `GuestMemoryMmap`).
 
-### Utilities and Helpers
-
-The following utilities and helper traits/macros are imported from the
-[crosvm project](https://chromium.googlesource.com/chromiumos/platform/crosvm/)
-with minor changes:
-
-- `ByteValued` (originally `DataInit`): types which are safe to be initialized
-  from raw data. A type `T` is `ByteValued` if and only if it can be
-  initialized by reading its contents from a byte array. This is generally true
-  for all plain-old-data structs.  It is notably not true for any type that
-  includes a reference.
-- `{Le,Be}_{16,32,64}`: explicit endian types useful for embedding in structs
-  or reinterpreting data.
-
 ## Relationships between Traits, Structs and Types
 
 **Traits**:

benches/mmap/mod.rs

@@ -16,29 +16,27 @@ use std::path::Path;
 
 use core::hint::black_box;
 use criterion::Criterion;
+use zerocopy::{FromBytes, IntoBytes};
 
-use vm_memory::{ByteValued, Bytes, GuestAddress, GuestMemoryBackend};
+use vm_memory::{Bytes, GuestAddress, GuestMemoryBackend};
 
 const REGION_SIZE: usize = 0x8000_0000;
 const REGIONS_COUNT: u64 = 8;
 const ACCESS_SIZE: usize = 0x200;
 
 #[repr(C)]
-#[derive(Copy, Clone, Default)]
+#[derive(Copy, Clone, Default, FromBytes, IntoBytes)]
 struct SmallDummy {
     a: u32,
     b: u32,
 }
-unsafe impl ByteValued for SmallDummy {}
 
 #[repr(C)]
-#[derive(Copy, Clone, Default)]
+#[derive(Copy, Clone, Default, FromBytes, IntoBytes)]
 struct BigDummy {
     elements: [u64; 12],
 }
 
-unsafe impl ByteValued for BigDummy {}
-
 fn make_image(size: usize) -> Vec<u8> {
     let mut image: Vec<u8> = Vec::with_capacity(size);
     for i in 0..size {

coverage_config_x86_64.json

@@ -1,5 +1,5 @@
 {
-  "coverage_score": 90.56,
+  "coverage_score": 89.86,
   "exclude_path": "mmap_windows.rs",
   "crate_features": "backend-mmap,backend-atomic,backend-bitmap,iommu"
 }