vhost-user-vsock implementation

Cargo.toml

@@ -2,4 +2,5 @@
 
 members = [
     "i2c",
+    "vsock"
 ]

README.md

@@ -9,6 +9,7 @@ crates.
 Here is the list of device backends that we support:
 
 - [I2C](https://github.com/rust-vmm/vhost-device/blob/main/i2c/README.md)
+- [VSOCK](vsock/README.md)
 
 ## Separation of Concerns
 

vsock/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "vhost-user-vsock"
+version = "0.1.0"
+authors = ["Harshavardhan Unnibhavi <harshanavkis@gmail.com>"]
+description = "A virtio-vsock device using the vhost-user protocol."
+repository = "https://github.com/rust-vmm/vhost-device"
+readme = "README.md"
+keywords = ["vhost", "vsock"]
+license = "Apache-2.0 OR BSD-3-Clause"
+edition = "2018"
+
+[dependencies]
+byteorder = "1"
+clap = { version = "=3.0.0-beta.2",  features = ["yaml"] }
+epoll = "4.3.1"
+futures = { version = "0.3", features = ["thread-pool"] }
+log = "0.4.14"
+thiserror = "1.0"
+vhost = { version = "0.3", features = ["vhost-user-slave"] }
+vhost-user-backend = "0.1"
+virtio-bindings = ">=0.1"
+virtio-queue = "0.1"
+vm-memory = "0.7"
+vmm-sys-util = "=0.9.0"
+
+[dev-dependencies]
+virtio-queue = { version = "0.1", features = ["test-utils"] }

vsock/README.md

@@ -0,0 +1,108 @@
+# vhost-user-vsock
+
+## Design
+
+The crate introduces a vhost-user-vsock device that enables communication between an
+application running in the guest i.e inside a VM and an application running on the
+host i.e outside the VM. The application running in the guest communicates over VM
+sockets i.e over AF_VSOCK sockets. The application running on the host connects to a
+unix socket on the host i.e communicates over AF_UNIX sockets. The main components of
+the crate are split into various files as described below:
+
+- [packet.rs](src/packet.rs)
+  - Introduces the **VsockPacket** structure that represents a single vsock packet
+  processing methods.
+- [rxops.rs](src/rxops.rs)
+  - Introduces various vsock operations that are enqueued into the rxqueue to be sent to the
+  guest. Exposes a **RxOps** structure.
+- [rxqueue.rs](src/rxqueue.rs)
+  - rxqueue contains the pending rx operations corresponding to that connection. The queue is
+  represented as a bitmap as we handle connection-oriented connections. The module contains
+  various queue manipulation methods. Exposes a **RxQueue** structure.
+- [thread_backend.rs](src/thread_backend.rs)
+  - Multiplexes connections between host and guest and calls into per connection methods that
+  are responsible for processing data and packets corresponding to the connection. Exposes a
+  **VsockThreadBackend** structure.
+- [txbuf.rs](src/txbuf.rs)
+  - Module to buffer data that is sent from the guest to the host. The module exposes a **LocalTxBuf**
+  structure.
+- [vhost_user_vsock_thread.rs](src/vhost_user_vsock_thread.rs)
+  - Module exposes a **VhostUserVsockThread** structure. It also handles new host initiated
+  connections and provides interfaces for registering host connections with the epoll fd. Also
+  provides interfaces for iterating through the rx and tx queues.
+- [vsock_conn.rs](src/vsock_conn.rs)
+  - Module introduces a **VsockConnection** structure that represents a single vsock connection
+  between the guest and the host. It also processes packets according to their type.
+- [vhu_vsock.rs](src/lib.rs)
+  - exposes the main vhost user vsock backend interface.
+
+## Usage
+
+Run the vhost-user-vsock device:
+```
+vhost-user-vsock --guest-cid=4 --uds-path=/tmp/vm4.vsock --socket=/tmp/vhost4.socket
+```
+
+Run qemu:
+
+```
+qemu-system-x86_64 -drive file=/path/to/disk.qcow2 -enable-kvm -m 512M \
+  -smp 2 -vga virtio -chardev socket,id=char0,reconnect=0,path=/tmp/vhost4.socket \
+  -device vhost-user-vsock-pci,chardev=char0 \
+  -object memory-backend-file,share=on,id=mem,size="512M",mem-path="/dev/hugepages" \
+  -numa node,memdev=mem -mem-prealloc
+```
+
+### Guest listening
+
+#### iperf
+
+```sh
+# https://github.com/stefano-garzarella/iperf-vsock
+guest$ iperf3 --vsock -s
+host$  iperf3 --vsock -c /tmp/vm4.vsock
+```
+
+#### netcat
+
+```sh
+guest$ nc --vsock -l 1234
+
+host$  nc -U /tmp/vm4.vsock
+CONNECT 1234
+```
+
+### Host listening
+
+#### iperf
+
+```sh
+# https://github.com/stefano-garzarella/iperf-vsock
+host$  iperf3 --vsock -s -B /tmp/vm4.vsock
+guest$ iperf3 --vsock -c 2
+```
+
+#### netcat
+
+```sh
+host$ nc -l -U /tmp/vm4.vsock_1234
+
+guest$ nc --vsock 2 1234
+```
+
+```rust
+use my_crate;
+
+...
+```
+
+## License
+
+**!!!NOTICE**: The BSD-3-Clause license is not included in this template.
+The license needs to be manually added because the text of the license file
+also includes the copyright. The copyright can be different for different
+crates. If the crate contains code from CrosVM, the crate must add the
+CrosVM copyright which can be found
+[here](https://chromium.googlesource.com/chromiumos/platform/crosvm/+/master/LICENSE).
+For crates developed from scratch, the copyright is different and depends on
+the contributors.

vsock/src/cli.yaml

@@ -0,0 +1,36 @@
+name: vhost-device-vsock
+version: "0.1.0"
+author: "Harshavardhan Unnibhavi <harshanavkis@gmail.com>"
+about: Virtio VSOCK backend daemon.
+
+settings:
+    - ArgRequiredElseHelp
+
+args:
+  # CID of the guest
+  - guest_cid:
+      long: guest-cid
+      value_name: INT
+      takes_value: true
+      about: Context identifier of the guest which uniquely identifies the device for its lifetime. Defaults to 3 if not specified.
+  # Socket paths
+  - uds_path:
+      long: uds-path
+      value_name: FILE
+      takes_value: true
+      about: Unix socket to which a host-side application connects to.
+  - socket:
+      long: socket
+      value_name: FILE
+      takes_value: true
+      about: Unix socket to which a hypervisor conencts to and sets up the control path with the device.
+
+groups:
+  - required_args:
+      args:
+        - guest_cid
+      args:
+        - uds_path
+      args:
+        - socket
+      required: true