Merge pull request #1275 from hermit-os/virtio-fs-config

refactor(virtio-spec): migrate `FsDevCfgRaw` to virtio-spec

src/drivers/fs/virtio_fs.rs

@@ -2,13 +2,15 @@ use alloc::boxed::Box;
 use alloc::rc::Rc;
 use alloc::string::{String, ToString};
 use alloc::vec::Vec;
+use core::str;
 
 use pci_types::InterruptLine;
+use virtio::fs::ConfigVolatileFieldAccess;
 use virtio::FeatureBits;
+use volatile::access::ReadOnly;
+use volatile::VolatileRef;
 
 use crate::config::VIRTIO_MAX_QUEUE_SIZE;
-#[cfg(feature = "pci")]
-use crate::drivers::fs::virtio_pci::FsDevCfgRaw;
 use crate::drivers::virtio::error::VirtioFsError;
 #[cfg(not(feature = "pci"))]
 use crate::drivers::virtio::transport::mmio::{ComCfg, IsrStatus, NotifCfg};
@@ -23,7 +25,7 @@ use crate::fs::fuse::{self, FuseInterface};
 /// Handling the right access to fields, as some are read-only
 /// for the driver.
 pub(crate) struct FsDevCfg {
-	pub raw: &'static FsDevCfgRaw,
+	pub raw: VolatileRef<'static, virtio::fs::Config, ReadOnly>,
 	pub dev_id: u16,
 	pub features: virtio::fs::F,
 }
@@ -112,7 +114,13 @@ impl VirtioFsDriver {
 		}
 
 		// 1 highprio queue, and n normal request queues
-		let vqnum = self.dev_cfg.raw.get_num_queues() + 1;
+		let vqnum = self
+			.dev_cfg
+			.raw
+			.as_ptr()
+			.num_request_queues()
+			.read()
+			.to_ne() + 1;
 		if vqnum == 0 {
 			error!("0 request queues requested from device. Aborting!");
 			return Err(VirtioFsError::Unknown);
@@ -160,7 +168,10 @@ impl FuseInterface for VirtioFsDriver {
 	}
 
 	fn get_mount_point(&self) -> String {
-		self.dev_cfg.raw.get_tag().to_string()
+		let tag = self.dev_cfg.raw.as_ptr().tag().read();
+		let tag = str::from_utf8(&tag).unwrap();
+		let tag = tag.split('\0').next().unwrap();
+		tag.to_string()
 	}
 }
 

src/drivers/fs/virtio_pci.rs

@@ -1,57 +1,23 @@
 use alloc::vec::Vec;
 
+use volatile::VolatileRef;
+
 use crate::arch::pci::PciConfigRegion;
 use crate::drivers::fs::virtio_fs::{FsDevCfg, VirtioFsDriver};
 use crate::drivers::pci::PciDevice;
 use crate::drivers::virtio::error::{self, VirtioError};
 use crate::drivers::virtio::transport::pci;
 use crate::drivers::virtio::transport::pci::{PciCap, UniCapsColl};
 
-/// Virtio's network device configuration structure.
-/// See specification v1.1. - 5.11.4
-///
-#[derive(Debug, Copy, Clone)]
-#[repr(C)]
-pub(crate) struct FsDevCfgRaw {
-	/// Tag is the name associated with this file system.
-	/// The tag is encoded in UTF-8 and padded with NUL bytes if shorter than the available space.
-	/// This field is not NUL-terminated if the encoded bytes take up the entire field.
-	tag: [u8; 36],
-	/// num_queues is the total number of request virtqueues exposed by the device.
-	/// Each virtqueue offers identical functionality and there are no ordering guarantees between
-	/// requests made available on different queues. Use of multiple queues is intended to increase
-	/// performance.
-	num_queues: i32,
-}
-
-impl FsDevCfgRaw {
-	pub fn get_tag(&self) -> &str {
-		let mut i: usize = 0;
-		let len = loop {
-			if i >= self.tag.len() {
-				break self.tag.len();
-			}
-			if self.tag[i] == 0 {
-				break i;
-			}
-			i += 1;
-		};
-
-		core::str::from_utf8(&self.tag[..len]).unwrap_or_default()
-	}
-
-	pub fn get_num_queues(&self) -> i32 {
-		self.num_queues
-	}
-}
-
 impl VirtioFsDriver {
 	fn map_cfg(cap: &PciCap) -> Option<FsDevCfg> {
-		let dev_cfg: &'static FsDevCfgRaw = match pci::map_dev_cfg::<FsDevCfgRaw>(cap) {
+		let dev_cfg = match pci::map_dev_cfg::<virtio::fs::Config>(cap) {
 			Some(cfg) => cfg,
 			None => return None,
 		};
 
+		let dev_cfg = VolatileRef::from_ref(dev_cfg);
+
 		Some(FsDevCfg {
 			raw: dev_cfg,
 			dev_id: cap.dev_id(),

virtio-spec/src/fs.rs

@@ -0,0 +1,37 @@
+//! File System Device
+
+use volatile::access::ReadOnly;
+use volatile_macro::VolatileFieldAccess;
+
+pub use super::features::fs::F;
+use super::le32;
+
+/// Device configuration
+#[doc(alias = "virtio_fs_config")]
+#[cfg_attr(
+    feature = "zerocopy",
+    derive(zerocopy_derive::FromZeroes, zerocopy_derive::FromBytes)
+)]
+#[derive(VolatileFieldAccess)]
+#[repr(C)]
+pub struct Config {
+    /// This is the name associated with this file system.  The tag is
+    /// encoded in UTF-8 and padded with NUL bytes if shorter than the
+    /// available space.  This field is not NUL-terminated if the encoded bytes
+    /// take up the entire field.
+    #[access(ReadOnly)]
+    tag: [u8; 36],
+
+    /// This is the total number of request virtqueues
+    /// exposed by the device.  Each virtqueue offers identical functionality and
+    /// there are no ordering guarantees between requests made available on
+    /// different queues.  Use of multiple queues is intended to increase
+    /// performance.
+    #[access(ReadOnly)]
+    num_request_queues: le32,
+
+    /// This is the minimum number of bytes required for each
+    /// buffer in the notification queue.
+    #[access(ReadOnly)]
+    notify_buf_size: le32,
+}

virtio-spec/src/lib.rs

@@ -10,6 +10,7 @@ mod bitflags;
 #[macro_use]
 pub mod volatile;
 mod features;
+pub mod fs;
 pub mod mmio;
 pub mod net;
 pub mod pci;
@@ -19,12 +20,6 @@ use num_enum::{FromPrimitive, IntoPrimitive};
 
 pub use self::features::{FeatureBits, F};
 
-pub mod fs {
-    //! File System Device
-
-    pub use super::features::fs::F;
-}
-
 virtio_bitflags! {
     /// Device Status Field
     ///