1 files changed, 67 insertions, 0 deletions
diff --git a/devices/src/virtio/virtio_device.rs b/devices/src/virtio/virtio_device.rs
new file mode 100644
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--- /dev/null
+++ b/devices/src/virtio/virtio_device.rs
@@ -0,0 +1,67 @@
+// Copyright 2018 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+use std::os::unix::io::RawFd;
+use std::sync::Arc;
+use std::sync::atomic::AtomicUsize;
+
+use super::*;
+use sys_util::{EventFd, GuestMemory};
+
+/// Trait for virtio devices to be driven by a virtio transport.
+///
+/// The lifecycle of a virtio device is to be moved to a virtio transport, which will then query the
+/// device. Once the guest driver has configured the device, `VirtioDevice::activate` will be called
+/// and all the events, memory, and queues for device operation will be moved into the device.
+/// Optionally, a virtio device can implement device reset in which it returns said resources and
+/// resets its internal.
+pub trait VirtioDevice: Send {
+    /// A vector of device-specific file descriptors that must be kept open
+    /// after jailing. Must be called before the process is jailed.
+    fn keep_fds(&self) -> Vec<RawFd>;
+
+    /// The virtio device type.
+    fn device_type(&self) -> u32;
+
+    /// The maximum size of each queue that this device supports.
+    fn queue_max_sizes(&self) -> &[u16];
+
+    /// The set of feature bits shifted by `page * 32`.
+    fn features(&self, page: u32) -> u32 {
+        let _ = page;
+        0
+    }
+
+    /// Acknowledges that this set of features should be enabled.
+    fn ack_features(&mut self, page: u32, value: u32) {
+        let _ = page;
+        let _ = value;
+    }
+
+    /// Reads this device configuration space at `offset`.
+    fn read_config(&self, offset: u64, data: &mut [u8]) {
+        let _ = offset;
+        let _ = data;
+    }
+
+    /// Writes to this device configuration space at `offset`.
+    fn write_config(&mut self, offset: u64, data: &[u8]) {
+        let _ = offset;
+        let _ = data;
+    }
+
+    /// Activates this device for real usage.
+    fn activate(&mut self,
+                mem: GuestMemory,
+                interrupt_evt: EventFd,
+                status: Arc<AtomicUsize>,
+                queues: Vec<Queue>,
+                queue_evts: Vec<EventFd>);
+
+    /// Optionally deactivates this device and returns ownership of the guest memory map, interrupt
+    /// event, and queue events.
+    fn reset(&mut self) -> Option<(EventFd, Vec<EventFd>)> {
+        None
+    }
+}