dragonball: add io manager wrapper

Wrapper over IoManager to support device hotplug.

Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>
Signed-off-by: jingshan <jingshan@linux.alibaba.com>
Signed-off-by: Chao Wu <chaowu@linux.alibaba.com>
Signed-off-by: wllenyj <wllenyj@linux.alibaba.com>

src/dragonball/src/io_manager.rs

@@ -0,0 +1,60 @@
+// Copyright (C) 2022 Alibaba Cloud. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+use std::sync::Arc;
+
+use arc_swap::{ArcSwap, Cache};
+use dbs_device::device_manager::Error;
+use dbs_device::device_manager::IoManager;
+
+/// A specialized version of [`std::result::Result`] for IO manager related operations.
+pub type Result<T> = std::result::Result<T, Error>;
+
+/// Wrapper over IoManager to support device hotplug with [`ArcSwap`] and [`Cache`].
+#[derive(Clone)]
+pub struct IoManagerCached(pub(crate) Cache<Arc<ArcSwap<IoManager>>, Arc<IoManager>>);
+
+impl IoManagerCached {
+    /// Create a new instance of [`IoManagerCached`].
+    pub fn new(io_manager: Arc<ArcSwap<IoManager>>) -> Self {
+        IoManagerCached(Cache::new(io_manager))
+    }
+
+    #[cfg(target_arch = "x86_64")]
+    #[inline]
+    /// Read data from IO ports.
+    pub fn pio_read(&mut self, addr: u16, data: &mut [u8]) -> Result<()> {
+        self.0.load().pio_read(addr, data)
+    }
+
+    #[cfg(target_arch = "x86_64")]
+    #[inline]
+    /// Write data to IO ports.
+    pub fn pio_write(&mut self, addr: u16, data: &[u8]) -> Result<()> {
+        self.0.load().pio_write(addr, data)
+    }
+
+    #[inline]
+    /// Read data to MMIO address.
+    pub fn mmio_read(&mut self, addr: u64, data: &mut [u8]) -> Result<()> {
+        self.0.load().mmio_read(addr, data)
+    }
+
+    #[inline]
+    /// Write data to MMIO address.
+    pub fn mmio_write(&mut self, addr: u64, data: &[u8]) -> Result<()> {
+        self.0.load().mmio_write(addr, data)
+    }
+
+    #[inline]
+    /// Revalidate the inner cache
+    pub fn revalidate_cache(&mut self) {
+        let _ = self.0.load();
+    }
+
+    #[inline]
+    /// Get immutable reference to underlying [`IoManager`].
+    pub fn load(&mut self) -> &IoManager {
+        self.0.load()
+    }
+}

src/dragonball/src/lib.rs

@@ -5,6 +5,7 @@
 //! Machine(KVM) which is optimized for container workloads.
 
 #![warn(missing_docs)]
+
 //TODO: Remove this, after the rest of dragonball has been committed.
 #![allow(dead_code)]
 
@@ -20,3 +21,6 @@ pub mod error;
 pub mod resource_manager;
 /// Virtual machine manager for virtual machines.
 pub mod vm;
+
+mod io_manager;
+pub use self::io_manager::IoManagerCached;