feat(vhost-user-vsock): added support

Signed-off-by: João Peixoto <[email protected]>

README.md

@@ -35,7 +35,7 @@ The full list of supported (and work in progress) devices is presented below:
 | Vhost-Net        | [Net](src/virtio/src/net/README.md)            | Vhost   | - |
 | Virtio-Vsock       | [Vsock](src/virtio/src/vsock/README.md)            | VirtIO   | - |
 | Vhost-Vsock       | [Vsock](src/virtio/src/vsock/README.md)            | Vhost   | [x](src/virtio/src/vsock/vhost/README.md) |
-| Vhost-User-Vsock       | [Vsock](src/virtio/src/vsock/README.md)            | Vhost-user   | - |
+| Vhost-User-Vsock       | [Vsock](src/virtio/src/vsock/README.md)            | Vhost-user   | [x](src/virtio/src/vsock/vhost_user/README.md) |
 
 ## Contributing
 Contributions to enhance the functionality and features of Bao Hypervisor VirtIO Device 

src/virtio/src/vsock/vhost_user/README.md

@@ -0,0 +1,31 @@
+# Vhost-user vsock
+
+## Requirements
+- Vhost vsock device support on the Backend VM (e.g. `CONFIG_VHOST_VSOCK` on buildroot)
+
+## Quick start
+
+Follow these steps to quickly set up and run the vhost-user vsock device with Bao Hypervisor.
+
+1. **Prepare Configuration File**: Create a configuration file (*config-virtio-vsock.yaml*) specifying
+the settings for the vhost-user vsock device. One example of a configuration file could be:
+
+```
+devices:
+  - id: 0
+    type: "vsock"
+    mmio_addr: 0xa003e00
+    data_plane: vhost_user
+    socket_path: "/tmp/"
+```
+
+2. Launch the [vhost-user vsock backend](https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-vsock):
+```
+nohup vhost-device-vsock --vm guest-cid=4,uds-path=/tmp/vm4.vsock,socket=/tmp/Vsock.sock > /etc/vhost-vsock.log 2>&1 &
+```
+
+3. Launch the device model:
+
+```
+nohup bao-virtio-dm --config /PATH/TO/YOUR/config-virtio-vsock.yaml > /etc/bao-virtio-dm.log 2>&1 &
+```

src/virtio/src/vsock/vhost_user/device.rs

@@ -54,7 +54,7 @@ impl VirtioDeviceT for VhostUserVsock {
                 config.socket_path.as_ref().unwrap(),
                 VirtioDevType::from(VirtioDevType::Vsock).to_string()
             ),
-            num_queues: 1, // Currently, multiple queues are not supported by the vhost-user backend (feature `VhostUserProtocolFeatures::MQ` not negotiated).
+            num_queues: 2, // The Rust-VMM backend (https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-vsock) does not supports event queues yet.
             queue_size: queues[0].size(),
         };
 
@@ -116,9 +116,10 @@ impl VirtioDeviceT for VhostUserVsock {
         Ok(0)
     }
 
-    fn config_space(config: &DeviceConfig) -> Result<Vec<u8>> {
-        // Retrieve the guest CID from the device configuration space.
-        Ok(config.guest_cid.unwrap().to_le_bytes().to_vec())
+    fn config_space(_config: &DeviceConfig) -> Result<Vec<u8>> {
+        // Here we can leave empty since the vhost-user backend device is responsible for managing the configuration space.
+        // VhostUserProtocolFeatures::CONFIG
+        Ok(Vec::new())
     }
 }
 
@@ -163,7 +164,7 @@ impl VirtioDeviceActions for VhostUserVsock {
             .queues
             .iter()
             .enumerate()
-            .take(1) // Currently, multiple queues are not supported by the vhost-user backend (feature `VhostUserProtocolFeatures::MQ` not negotiated).
+            .take(2) // The Rust-VMM backend (https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-vsock) does not supports event queues yet.
             .zip(ioevents)
             .map(|((i, queue), ioevent)| (i, queue.clone(), ioevent))
             .collect::<Vec<_>>();