CAN, GPIO, RNG vhost-devices for virtio-loopback [v6]quillback_16.92.0quillback/16.92.016.92.0

This patch adds key components of the viritio-loopback architecture:
- kernel-module-virtio-loopback: the virtio loopback kernel driver
- CAN, GPIO and RNG vhost-user devices from meta-virtualization (commit a215d8320edee0a317a6511e7e2efa5bba867486)

Notes:
- libgpiod, comes from meta-openembedded commit 3029554ceb0b0bb52a8d8ec3f0a75c5113662fe6
- cleaned eg-virt from unused drivers (kernel-module-virtio-video)

Bug-AGL: SPEC-4834

V2 changes:
- related meta-virtualization commit message added in the cover letter
- updated libgpio recipe to v2.1
- SPEC reference added in cover letter

v3
- add vhost-device-can preliminary version. This is placed here with
  the objective to share the link when proposing the new device to
  the rust-vmm/vhost-device community
- remove cargo-update-recipe-crates includes in bb file because it is
  not supported by the rust mixin layer
- vhost-device folder README changes

v4
- fixed libgpiod required version
- tested ref hw and qemu x86/64 builds
- vsock, scsi and i2c rust devices removed from the build as they
  are not yet integrated in virtiod-loopback
- cleaned-up kernel modules kernel-module-virtio-video and
  gstreamer1.0-plugins-bad
- virtio-loopback-driver set to 2-or-later

v5
- Merge with Jan-Simon version v4:
   - remove broken kernel-module-virtio-video
   - use FEATURE_PACKAGES instead of IMAGE_INSTALL:append
   - rename virtio-loopback-driver.bb to
     kernel-module-virtio-loopback_git.bb for consistency

v6
- adding version in the title
- removing MODULE_GIT_REPOSITORY in kernel-modules

Change-Id: Id6cc58e777b9edad03b6c50d0dddaac8601edeaf
Signed-off-by: Michele Paolino <m.paolino@virtualopensystems.com>
Signed-off-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>

1 files changed, 170 insertions, 0 deletions

diff --git a/meta-egvirt/recipes-extended/vhost-device-can/vhost-device-can-0.1.0/src/backend.rs b/meta-egvirt/recipes-extended/vhost-device-can/vhost-device-can-0.1.0/src/backend.rs
new file mode 100644
index 00000000..177c76cc
--- /dev/null
+++ b/meta-egvirt/recipes-extended/vhost-device-can/vhost-device-can-0.1.0/src/backend.rs
@@ -0,0 +1,170 @@
+// VIRTIO CAN Emulation via vhost-user
+//
+// Copyright 2023 VIRTUAL OPEN SYSTEMS SAS. All Rights Reserved.
+//          Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
+//
+// SPDX-License-Identifier: Apache-2.0 or BSD-3-Clause
+
+use log::{error, info, warn};
+use std::process::exit;
+use std::sync::{Arc, RwLock};
+use std::thread::{spawn, JoinHandle};
+
+use clap::Parser;
+use thiserror::Error as ThisError;
+use vhost::{vhost_user, vhost_user::Listener};
+use vhost_user_backend::VhostUserDaemon;
+use vm_memory::{GuestMemoryAtomic, GuestMemoryMmap};
+
+use crate::can::{CanController};
+use crate::vhu_can::VhostUserCanBackend;
+
+pub(crate) type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Debug, ThisError)]
+/// Errors related to low level CAN helpers
+pub(crate) enum Error {
+    #[error("Invalid socket count: {0}")]
+    SocketCountInvalid(usize),
+    #[error("Failed to join threads")]
+    FailedJoiningThreads,
+    #[error("Could not create can controller: {0}")]
+    CouldNotCreateCanController(crate::can::Error),
+    #[error("Could not create can backend: {0}")]
+    CouldNotCreateBackend(crate::vhu_can::Error),
+    #[error("Could not create daemon: {0}")]
+    CouldNotCreateDaemon(vhost_user_backend::Error),
+}
+
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about = None)]
+struct CanArgs {
+    /// Location of vhost-user Unix domain socket. This is suffixed by 0,1,2..socket_count-1.
+    #[clap(short, long)]
+    socket_path: String,
+
+    /// A can device name to be used for reading (ex. vcan, can0, can1, ... etc.)
+    #[clap(short = 'i', long)]
+    can_in: String,
+
+    /// A can device name to be used for writing (ex. vcan, can0, can1, ... etc.)
+    #[clap(short = 'o', long)]
+    can_out: String,
+
+    /// Number of guests (sockets) to connect to.
+    #[clap(short = 'c', long, default_value_t = 1)]
+    socket_count: u32,
+}
+
+#[derive(PartialEq, Debug)]
+struct CanConfiguration {
+    socket_path: String,
+    socket_count: u32,
+    can_in: String,
+    can_out: String,
+}
+
+impl TryFrom<CanArgs> for CanConfiguration {
+    type Error = Error;
+
+    fn try_from(args: CanArgs) -> Result<Self> {
+
+        if args.socket_count == 0 {
+            return Err(Error::SocketCountInvalid(0));
+        }
+
+		let can_in = args.can_in.trim().to_string();
+		let can_out = args.can_out.trim().to_string();
+
+        Ok(CanConfiguration {
+            socket_path: args.socket_path,
+			socket_count: args.socket_count,
+            can_in,
+            can_out,
+        })
+    }
+}
+
+fn start_backend(args: CanArgs) -> Result<()> {
+
+	println!("start_backend function!\n");
+
+    let config = CanConfiguration::try_from(args).unwrap();
+    let mut handles = Vec::new();
+
+    for _ in 0..config.socket_count {
+        let socket = config.socket_path.to_owned();
+        let can_in = config.can_in.to_owned();
+        let can_out = config.can_out.to_owned();
+
+        let handle: JoinHandle<Result<()>> = spawn(move || loop {
+            // A separate thread is spawned for each socket and can connect to a separate guest.
+            // These are run in an infinite loop to not require the daemon to be restarted once a
+            // guest exits.
+            //
+            // There isn't much value in complicating code here to return an error from the
+            // threads, and so the code uses unwrap() instead. The panic on a thread won't cause
+            // trouble to other threads/guests or the main() function and should be safe for the
+            // daemon.
+
+            let controller =
+                CanController::new(can_in.clone(), can_out.clone()).map_err(Error::CouldNotCreateCanController)?;
+			let shared_controller_1 =  Arc::new(RwLock::new(controller));
+			let shared_controller_2 =  shared_controller_1.clone();
+            let vu_can_backend = Arc::new(RwLock::new(
+                VhostUserCanBackend::new(shared_controller_1).map_err(Error::CouldNotCreateBackend)?,
+            ));
+			let _read_hanlde = CanController::start_read_thread(shared_controller_2);
+
+            let mut daemon = VhostUserDaemon::new(
+                String::from("vhost-device-can-backend"),
+                vu_can_backend.clone(),
+                GuestMemoryAtomic::new(GuestMemoryMmap::new()),
+            )
+            .map_err(Error::CouldNotCreateDaemon)?;
+
+			/* Start the read thread -- need to handle it after termination */
+			let vring_workers = daemon.get_epoll_handlers();
+			vu_can_backend.read()
+						  .unwrap()
+						  .set_vring_worker(&vring_workers[0]);
+
+            let listener = Listener::new(socket.clone(), true).unwrap();
+            daemon.start(listener).unwrap();
+
+            match daemon.wait() {
+                Ok(()) => {
+                    info!("Stopping cleanly.");
+                }
+                Err(vhost_user_backend::Error::HandleRequest(
+                    vhost_user::Error::PartialMessage | vhost_user::Error::Disconnected,
+                )) => {
+                    info!("vhost-user connection closed with partial message. If the VM is shutting down, this is expected behavior; otherwise, it might be a bug.");
+                }
+                Err(e) => {
+                    warn!("Error running daemon: {:?}", e);
+                }
+            }
+
+            // No matter the result, we need to shut down the worker thread.
+            vu_can_backend.read().unwrap().exit_event.write(1).unwrap();
+        });
+
+        handles.push(handle);
+    }
+
+    for handle in handles {
+        handle.join().map_err(|_| Error::FailedJoiningThreads)??;
+    }
+
+    Ok(())
+}
+
+pub(crate) fn can_init() {
+    env_logger::init();
+	println!("Can_init function!");
+    if let Err(e) = start_backend(CanArgs::parse()) {
+        error!("{e}");
+        exit(1);
+    }
+}