Enable support of the in-kernel vhost-vsock driver

Implement vhost_kern::Vsock to control the in-kernel vhost-vsock driver.
The implementation is derived from the crosvm project.

Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/src/vhost_kern/vsock.rs b/src/vhost_kern/vsock.rs
new file mode 100644
index 0000000..7483744
--- /dev/null
+++ b/src/vhost_kern/vsock.rs
@@ -0,0 +1,84 @@
+// Copyright (C) 2019 Alibaba Cloud Computing. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause
+//
+// Copyright 2017 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-BSD-Google file.
+
+//! Kernel-based vsock vhost backend.
+
+use std::fs::{File, OpenOptions};
+use std::marker::PhantomData;
+use std::os::unix::fs::OpenOptionsExt;
+use std::os::unix::io::{AsRawFd, RawFd};
+
+use super::vhost_binding::{VHOST_VSOCK_SET_GUEST_CID, VHOST_VSOCK_SET_RUNNING};
+use super::{ioctl_result, Error, Result, VhostKernBackend};
+use libc;
+use vm_memory::GuestMemory;
+use vmm_sys_util::ioctl::ioctl_with_ref;
+
+const VHOST_PATH: &str = "/dev/vhost-vsock";
+
+/// Handle for running VHOST_VSOCK ioctls.
+pub struct Vsock<'a, M: GuestMemory> {
+    fd: File,
+    mem: M,
+    _phatomdata: PhantomData<&'a M>, // Get rid of unused type parameter `a
+}
+
+impl<'a, M: GuestMemory> Vsock<'a, M> {
+    /// Open a handle to a new VHOST-VSOCK instance.
+    pub fn new(mem: M) -> Result<Self> {
+        Ok(Vsock {
+            fd: OpenOptions::new()
+                .read(true)
+                .write(true)
+                .custom_flags(libc::O_CLOEXEC | libc::O_NONBLOCK)
+                .open(VHOST_PATH)
+                .map_err(Error::VhostOpen)?,
+            mem,
+            _phatomdata: PhantomData,
+        })
+    }
+
+    /// Set the CID for the guest.  This number is used for routing all data destined for
+    /// running in the guest. Each guest on a hypervisor must have an unique CID
+    ///
+    /// # Arguments
+    /// * `cid` - CID to assign to the guest
+    pub fn set_guest_cid(&self, cid: u64) -> Result<()> {
+        let ret = unsafe { ioctl_with_ref(&self.fd, VHOST_VSOCK_SET_GUEST_CID(), &cid) };
+        ioctl_result(ret, ())
+    }
+
+    /// Tell the VHOST driver to start performing data transfer.
+    pub fn start(&self) -> Result<()> {
+        self.set_running(true)
+    }
+
+    /// Tell the VHOST driver to stop performing data transfer.
+    pub fn stop(&self) -> Result<()> {
+        self.set_running(false)
+    }
+
+    fn set_running(&self, running: bool) -> Result<()> {
+        let on: ::std::os::raw::c_int = if running { 1 } else { 0 };
+        let ret = unsafe { ioctl_with_ref(&self.fd, VHOST_VSOCK_SET_RUNNING(), &on) };
+        ioctl_result(ret, ())
+    }
+}
+
+impl<'a, M: GuestMemory> VhostKernBackend<'a> for Vsock<'a, M> {
+    type M = M;
+
+    fn mem(&self) -> &Self::M {
+        &self.mem
+    }
+}
+
+impl<'a, M: GuestMemory> AsRawFd for Vsock<'a, M> {
+    fn as_raw_fd(&self) -> RawFd {
+        self.fd.as_raw_fd()
+    }
+}