Merge branch 'enhancement-ikc-faster' into dev

Cargo.toml

@@ -3,7 +3,7 @@
 
 [package]
 name = "kernel"
-version = "0.3.4"
+version = "0.4.0"
 license-file = "LICENSE.txt"
 edition = "2021"
 authors = ["The Maintainers of Nanvix"]
@@ -29,7 +29,7 @@ bitmap = { git = "https://github.com/nanvix/bitmap", branch = "releases/v0.0.5"
 error = { git = "https://github.com/nanvix/error", branch = "releases/v0.0.5" }
 raw-array = { git = "https://github.com/nanvix/raw-array", branch = "releases/v0.0.5" }
 slab = { git = "https://github.com/nanvix/slab", branch = "releases/v0.0.5" }
-sys = { git = "https://github.com/nanvix/sys", branch = "releases/v1.3.1" }
+sys = { git = "https://github.com/nanvix/sys", branch = "releases/v1.4.0" }
 
 [features]
 default = ["qemu-pc"]

src/hal/platform/microvm.rs

@@ -53,6 +53,14 @@ pub struct Platform {
 /// Bootloader magic number.
 pub const MICROVM_BOOT_MAGIC: u32 = 0x0c00ffee;
 
+/// Port number used for write requests to the standard output.
+#[cfg(feature = "stdio")]
+const STDOUT_PORT: u16 = 0xe9;
+
+/// Port number used read requests from the standard input.
+#[cfg(feature = "stdio")]
+const STDIN_PORT: u16 = 0xea;
+
 //==================================================================================================
 // Standalone Functions
 //==================================================================================================
@@ -80,11 +88,11 @@ pub unsafe fn putb(b: u8) {
 ///
 /// # Description
 ///
-/// Writes the 32 bit value `val` to the platform's standard output device.
+/// Places a write request to the platform's standard output device.
 ///
 /// # Parameters
 ///
-/// - `val`: Value to write.
+/// - `addr`: Address where data should be written from.
 ///
 /// # Safety
 ///
@@ -94,18 +102,20 @@ pub unsafe fn putb(b: u8) {
 /// - It does not prevent concurrent access to the standard output device.
 ///
 #[cfg(feature = "stdio")]
-pub unsafe fn out32(val: u32) {
-    ::arch::io::out32(0xe9, val);
+pub unsafe fn vmbus_write(addr: *const u8) {
+    use core::hint;
+
+    hint::black_box(::arch::io::out32(STDOUT_PORT, addr as u32));
 }
 
 ///
 /// # Description
 ///
-/// Reads a 32-bit value from the platform's standard input device.
+/// Places a read request to the platform's standard input device.
 ///
-/// # Return
+/// # Parameters
 ///
-/// The 32-bit value read from the standard input device.
+/// - `addr`: Address where data should be read into.
 ///
 /// # Safety
 ///
@@ -115,8 +125,10 @@ pub unsafe fn out32(val: u32) {
 /// - It does not prevent concurrent access to the standard input device.
 ///
 #[cfg(feature = "stdio")]
-pub unsafe fn in32() -> u32 {
-    ::arch::io::in32(0xe9)
+pub unsafe fn vmbus_read(addr: *mut u8) {
+    use core::hint;
+
+    hint::black_box(::arch::io::out32(STDIN_PORT, addr as u32))
 }
 
 ///

src/stdio.rs

@@ -5,6 +5,7 @@
 // Imports
 //==================================================================================================
 
+use crate::hal::platform;
 use ::core::mem;
 use ::error::{
     Error,
@@ -15,13 +16,6 @@ use ::sys::ipc::{
     MessageType,
 };
 
-//==================================================================================================
-// Constants
-//==================================================================================================
-
-/// End of file flag.
-const EOF_FLAG: u32 = 1 << 31;
-
 //==================================================================================================
 // Standalone Functions
 //==================================================================================================
@@ -59,11 +53,8 @@ pub fn write(message: Message) -> Result<(), Error> {
     // Write message to the kernel's standard output.
     // SAFETY: The standard output is present, initialized and thread-safe to write.
     unsafe {
-        for b in bytes {
-            crate::hal::platform::out32(b as u32);
-        }
-        let eof: u32 = EOF_FLAG;
-        crate::hal::platform::out32(eof);
+        // NOTE: we assume that page is tagged as writethrough-enabled and cache-disabled.
+        platform::vmbus_write(&bytes as *const u8);
     }
 
     Ok(())
@@ -80,37 +71,30 @@ pub fn write(message: Message) -> Result<(), Error> {
 /// messages.  Upon failure, an error is returned instead.
 ///
 pub fn read() -> Result<Option<Message>, Error> {
-    // Read first byte.
-    let value: u32 = unsafe { crate::hal::platform::in32() };
-
-    // Check for EOF.
-    if value & EOF_FLAG != 0 {
-        return Ok(None);
-    }
-
-    // NOTE: trace command after reading the first byte, to avoid flooding the log.
-    trace!("read()");
-
     const NBYTES: usize = core::mem::size_of::<Message>();
     let mut message: [u8; NBYTES] = [0; NBYTES];
 
-    message[0] = (value & 0xff) as u8;
-
-    // Read message from platform.
-    for byte in message[1..].iter_mut() {
-        let value: u32 = unsafe { crate::hal::platform::in32() };
-
-        // Check for EOF.
-        if value & EOF_FLAG != 0 {
-            break;
-        }
-
-        *byte = (value & 0xff) as u8;
-    }
+    // Read message from the kernel's standard input.
+    // SAFETY: The standard input is present, initialized and thread-safe to read.
+    unsafe {
+        // NOTE: we assume that page is tagged as writethrough-enabled and cache-disabled.
+        platform::vmbus_read(&mut message as *mut u8);
+    };
 
     // Convert message to Message struct.
     match Message::try_from_bytes(message) {
-        Ok(message) => Ok(Some(message)),
+        Ok(message) => {
+            // Check if message is empty.
+            if message.message_type == MessageType::Empty {
+                Ok(None)
+            } else {
+                // NOTE: trace command after reading the first byte, to avoid flooding the log.
+                trace!("read()");
+                Ok(Some(message))
+            }
+        },
+        // No message available.
+        Err(e) if e.code == ErrorCode::NoMessageAvailable => Ok(None),
         Err(e) => {
             warn!("read(): {:?} ", e);
             Err(e)