feat(virtio-spec): add NotificationData

Signed-off-by: Martin Kröning <[email protected]>

virtio-spec/Cargo.toml

@@ -9,6 +9,7 @@ keywords = ["virtio", "driver", "volatile"]
 categories = ["no-std", "no-std::no-alloc"]
 
 [dependencies]
+bitfield-struct = "0.6"
 bitflags = "2"
 endian-num = { version = "0.1", features = ["bitflags", "linux-types"] }
 volatile = { version = "0.5.3", features = ["derive"] }

virtio-spec/src/lib.rs

@@ -14,6 +14,7 @@ pub mod mmio;
 pub mod net;
 pub mod pci;
 
+use bitfield_struct::bitfield;
 pub use endian_num::{be128, be16, be32, be64, le128, le16, le32, le64};
 
 pub use self::features::{FeatureBits, F};
@@ -73,3 +74,33 @@ virtio_bitflags! {
         const DEVICE_NEEDS_RESET = 64;
     }
 }
+
+/// Notification Data.
+#[bitfield(u32, inner = le32, from = le32::from_ne, into = le32::to_ne)]
+pub struct NotificationData {
+    /// VQ number to be notified.
+    pub vqn: u16,
+
+    /// Offset
+    /// within the ring where the next available ring entry
+    /// will be written.
+    /// When [`VIRTIO_F_RING_PACKED`] has not been negotiated this refers to the
+    /// 15 least significant bits of the available index.
+    /// When `VIRTIO_F_RING_PACKED` has been negotiated this refers to the offset
+    /// (in units of descriptor entries)
+    /// within the descriptor ring where the next available
+    /// descriptor will be written.
+    ///
+    /// [`VIRTIO_F_RING_PACKED`]: F::RING_PACKED
+    #[bits(15)]
+    pub next_off: u16,
+
+    /// Wrap Counter.
+    /// With [`VIRTIO_F_RING_PACKED`] this is the wrap counter
+    /// referring to the next available descriptor.
+    /// Without `VIRTIO_F_RING_PACKED` this is the most significant bit
+    /// (bit 15) of the available index.
+    ///
+    /// [`VIRTIO_F_RING_PACKED`]: F::RING_PACKED
+    pub next_wrap: bool,
+}