From fd3f2b62eb9dd3181fdecc5702fd8c2af39fdd29 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?=
 <martin.kroening@eonerc.rwth-aachen.de>
Date: Mon, 29 Apr 2024 17:56:00 +0200
Subject: [PATCH] feat(virtio-def): add `zerocopy` support
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Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>
---
 Cargo.lock            |  2 ++
 virtio-def/Cargo.toml |  5 +++++
 virtio-def/src/lib.rs | 41 ++++++++++++++++++++++++++---------------
 virtio-def/src/num.rs |  1 +
 virtio-def/src/pci.rs |  4 ++++
 5 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 9bb953b58e..3a366e438f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1442,6 +1442,8 @@ version = "0.0.0"
 dependencies = [
  "bitflags 2.5.0",
  "volatile 0.5.4",
+ "zerocopy",
+ "zerocopy-derive",
 ]
 
 [[package]]
diff --git a/virtio-def/Cargo.toml b/virtio-def/Cargo.toml
index 2413fa748d..399ce5426a 100644
--- a/virtio-def/Cargo.toml
+++ b/virtio-def/Cargo.toml
@@ -11,3 +11,8 @@ categories = ["no-std", "no-std::no-alloc"]
 [dependencies]
 bitflags = "2"
 volatile = { version = "0.5.3", features = ["derive"] }
+zerocopy = { version = "0.7", optional = true, default-features = false }
+zerocopy-derive = { version = "0.7", optional = true }
+
+[features]
+zerocopy = ["dep:zerocopy", "dep:zerocopy-derive"]
diff --git a/virtio-def/src/lib.rs b/virtio-def/src/lib.rs
index 03cd3a0ab9..944690c789 100644
--- a/virtio-def/src/lib.rs
+++ b/virtio-def/src/lib.rs
@@ -10,22 +10,33 @@ pub mod pci;
 
 use bitflags::bitflags;
 
+/// Device Status Field
+///
+/// During device initialization by a driver,
+/// the driver follows the sequence of steps specified in
+/// _General Initialization And Device Operation / Device
+/// Initialization_.
+///
+/// The `device status` field provides a simple low-level
+/// indication of the completed steps of this sequence.
+/// It's most useful to imagine it hooked up to traffic
+/// lights on the console indicating the status of each device.  The
+/// following bits are defined (listed below in the order in which
+/// they would be typically set):
+#[cfg_attr(
+    feature = "zerocopy",
+    derive(
+        zerocopy_derive::FromZeroes,
+        zerocopy_derive::FromBytes,
+        zerocopy_derive::AsBytes
+    )
+)]
+#[derive(Clone, Copy, Debug)]
+#[repr(transparent)]
+pub struct DeviceStatus(u8);
+
 bitflags! {
-    /// Device Status Field
-    ///
-    /// During device initialization by a driver,
-    /// the driver follows the sequence of steps specified in
-    /// _General Initialization And Device Operation / Device
-    /// Initialization_.
-    ///
-    /// The `device status` field provides a simple low-level
-    /// indication of the completed steps of this sequence.
-    /// It's most useful to imagine it hooked up to traffic
-    /// lights on the console indicating the status of each device.  The
-    /// following bits are defined (listed below in the order in which
-    /// they would be typically set):
-    #[derive(Clone, Copy, Debug)]
-    pub struct DeviceStatus: u8 {
+    impl DeviceStatus: u8 {
         /// Indicates that the guest OS has found the
         /// device and recognized it as a valid virtio device.
         const ACKNOWLEDGE = 1;
diff --git a/virtio-def/src/num.rs b/virtio-def/src/num.rs
index bf31c95cba..f2c0dd0475 100644
--- a/virtio-def/src/num.rs
+++ b/virtio-def/src/num.rs
@@ -5,6 +5,7 @@ macro_rules! le_impl {
         #[doc = concat!("A ", stringify!($bits), "-bit unsigned integer stored in ", $order, " byte order.")]
         #[allow(non_camel_case_types)]
         #[must_use]
+        #[cfg_attr(feature = "zerocopy", derive(zerocopy_derive::FromZeroes, zerocopy_derive::FromBytes, zerocopy_derive::AsBytes))]
         #[derive(Hash, PartialEq, Eq, Clone, Copy, Debug)]
         #[repr(transparent)]
         pub struct $SelfT($ActualT);
diff --git a/virtio-def/src/pci.rs b/virtio-def/src/pci.rs
index f348377778..e426892513 100644
--- a/virtio-def/src/pci.rs
+++ b/virtio-def/src/pci.rs
@@ -10,6 +10,10 @@ use crate::DeviceStatus;
 ///
 /// The common configuration structure is found at the bar and offset within the [`VIRTIO_PCI_CAP_COMMON_CFG`] capability.
 #[doc(alias = "virtio_pci_common_cfg")]
+#[cfg_attr(
+    feature = "zerocopy",
+    derive(zerocopy_derive::FromZeroes, zerocopy_derive::FromBytes)
+)]
 #[derive(VolatileFieldAccess)]
 #[allow(non_camel_case_types)]
 #[repr(C)]