vmm: Add an identifier to the --vsock device

It's possible to have multiple vsock devices so in preparation for
hotplug/unplug it is important to be able to have a unique identifier
for each device.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Rob Bradford <robert.bradford@intel.com>

src/main.rs

@@ -196,7 +196,8 @@ fn create_app<'a, 'b>(
             Arg::with_name("vsock")
                 .long("vsock")
                 .help(
-                    "Virtio VSOCK parameters \"cid=<context_id>,sock=<socket_path>,iommu=on|off\"",
+                    "Virtio VSOCK parameters \
+                    \"cid=<context_id>,sock=<socket_path>,iommu=on|off,id=<device_id>\"",
                 )
                 .takes_value(true)
                 .number_of_values(1)

vmm/src/config.rs

@@ -1136,12 +1136,14 @@ pub struct VsockConfig {
     pub sock: PathBuf,
     #[serde(default)]
     pub iommu: bool,
+    #[serde(default)]
+    pub id: Option<String>,
 }
 
 impl VsockConfig {
     pub fn parse(vsock: &str) -> Result<Self> {
         let mut parser = OptionParser::new();
-        parser.add("sock").add("cid").add("iommu");
+        parser.add("sock").add("cid").add("iommu").add("id");
         parser.parse(vsock).map_err(Error::ParseVsock)?;
 
         let sock = parser
@@ -1157,8 +1159,14 @@ impl VsockConfig {
             .convert("cid")
             .map_err(Error::ParseVsock)?
             .ok_or(Error::ParseVsockCidMissing)?;
+        let id = parser.get("id");
 
-        Ok(VsockConfig { cid, sock, iommu })
+        Ok(VsockConfig {
+            cid,
+            sock,
+            iommu,
+            id,
+        })
     }
 }
 
@@ -1878,7 +1886,8 @@ mod tests {
             VsockConfig {
                 cid: 1,
                 sock: PathBuf::from("/tmp/sock"),
-                iommu: false
+                iommu: false,
+                id: None,
             }
         );
         assert_eq!(
@@ -1886,7 +1895,8 @@ mod tests {
             VsockConfig {
                 cid: 1,
                 sock: PathBuf::from("/tmp/sock"),
-                iommu: true
+                iommu: true,
+                id: None,
             }
         );
         Ok(())

vmm/src/device_manager.rs

@@ -14,7 +14,7 @@ extern crate vm_device;
 use crate::config::ConsoleOutputMode;
 #[cfg(feature = "pci_support")]
 use crate::config::DeviceConfig;
-use crate::config::{DiskConfig, FsConfig, NetConfig, PmemConfig, VmConfig};
+use crate::config::{DiskConfig, FsConfig, NetConfig, PmemConfig, VmConfig, VsockConfig};
 use crate::interrupt::{
     KvmLegacyUserspaceInterruptManager, KvmMsiInterruptManager, KvmRoutingEntry,
 };
@@ -76,6 +76,7 @@ const VFIO_DEVICE_NAME_PREFIX: &str = "vfio";
 const DISK_DEVICE_NAME_PREFIX: &str = "disk";
 const NET_DEVICE_NAME_PREFIX: &str = "net";
 const PMEM_DEVICE_NAME_PREFIX: &str = "pmem";
+const VSOCK_DEVICE_NAME_PREFIX: &str = "vsock";
 
 /// Errors associated with device manager
 #[derive(Debug)]
@@ -1120,7 +1121,7 @@ impl DeviceManager {
         devices.append(&mut self.make_virtio_pmem_devices()?);
 
         // Add virtio-vsock if required
-        devices.append(&mut self.make_virtio_vsock_device()?);
+        devices.append(&mut self.make_virtio_vsock_devices()?);
 
         devices.append(&mut self.make_virtio_mem_devices()?);
 
@@ -1642,10 +1643,12 @@ impl DeviceManager {
 
     fn make_virtio_vsock_device(
         &mut self,
-    ) -> DeviceManagerResult<Vec<(VirtioDeviceArc, bool, Option<String>)>> {
+        vsock_cfg: &mut VsockConfig,
-        let mut devices = Vec::new();
+    ) -> DeviceManagerResult<(VirtioDeviceArc, bool, Option<String>)> {
-        // Add vsock if required
+        if vsock_cfg.id.is_none() {
-        if let Some(vsock_cfg) = &self.config.lock().unwrap().vsock {
+            vsock_cfg.id = self.next_device_name(VSOCK_DEVICE_NAME_PREFIX)?;
+        }
+
         let socket_path = vsock_cfg
             .sock
             .to_str()
@@ -1659,13 +1662,28 @@ impl DeviceManager {
                 .map_err(DeviceManagerError::CreateVirtioVsock)?,
         ));
 
-            devices.push((Arc::clone(&vsock_device) as VirtioDeviceArc, false, None));
-
         let migratable = Arc::clone(&vsock_device) as Arc<Mutex<dyn Migratable>>;
         let id = migratable.lock().unwrap().id();
         self.migratable_devices.push((id, migratable));
+
+        Ok((
+            Arc::clone(&vsock_device) as VirtioDeviceArc,
+            false,
+            vsock_cfg.id.clone(),
+        ))
     }
 
+    fn make_virtio_vsock_devices(
+        &mut self,
+    ) -> DeviceManagerResult<Vec<(VirtioDeviceArc, bool, Option<String>)>> {
+        let mut devices = Vec::new();
+
+        let mut vsock = self.config.lock().unwrap().vsock.clone();
+        if let Some(ref mut vsock_cfg) = &mut vsock {
+            devices.push(self.make_virtio_vsock_device(vsock_cfg)?);
+        }
+        self.config.lock().unwrap().vsock = vsock;
+
         Ok(devices)
     }