vmm/lib.rs: api_event fd changes

Removed the api_event field from struct Vmm. The Vmm::new constructor
now expects a control_fd: &AsRawFd parameter instead of the old
api_event_fd: EventFd. The new parameter is only used to register an
event source with the epoll set. Since it's now possible to handle
control events from outside the Vmm implementation, the outer logic also
handles the lifetime of the actual object that is associated with the
epoll fd. The from_api member continues to be required, until we
figure out what to do with the API server going forward.

Signed-off-by: Alexandru Agache <[email protected]>

Author: alexandruag

vmm/src/device_manager/mmio.rs

@@ -403,7 +403,7 @@ mod tests {
         let (_to_vmm, from_api) = channel();
         Vmm::new(
             shared_info,
-            EventFd::new().expect("cannot create eventFD"),
+            &EventFd::new().expect("cannot create eventFD"),
             from_api,
             0,
         )

vmm/src/lib.rs

@@ -632,7 +632,7 @@ impl EpollContext {
     /// Given a file descriptor `fd`, and an EpollDispatch token `token`,
     /// associate `token` with an `EPOLLIN` event for `fd`, through the
     /// `dispatch_table`.
-    fn add_event<T: AsRawFd>(&mut self, fd: &T, token: EpollDispatch) -> Result<()> {
+    fn add_event<T: AsRawFd + ?Sized>(&mut self, fd: &T, token: EpollDispatch) -> Result<()> {
         // The index in the dispatch where the new token will be added.
         let dispatch_index = self.dispatch_table.len() as u64;
 
@@ -806,7 +806,6 @@ struct Vmm {
     epoll_context: EpollContext,
 
     // API resources.
-    api_event_fd: EventFd,
     from_api: Receiver<Box<VmmAction>>,
 
     write_metrics_event_fd: TimerFd,
@@ -818,15 +817,15 @@ struct Vmm {
 impl Vmm {
     fn new(
         api_shared_info: Arc<RwLock<InstanceInfo>>,
-        api_event_fd: EventFd,
+        control_fd: &AsRawFd,
         from_api: Receiver<Box<VmmAction>>,
         seccomp_level: u32,
     ) -> Result<Self> {
         let mut epoll_context = EpollContext::new()?;
         // If this fails, it's fatal; using expect() to crash.
         epoll_context
-            .add_event(&api_event_fd, EpollDispatch::VmmActionRequest)
-            .expect("Cannot add API eventfd to epoll.");
+            .add_event(control_fd, EpollDispatch::VmmActionRequest)
+            .expect("Cannot add API control_fd to epoll.");
 
         let write_metrics_event_fd =
             TimerFd::new_custom(ClockId::Monotonic, true, true).map_err(Error::TimerFd)?;
@@ -861,7 +860,6 @@ impl Vmm {
             pio_device_manager: PortIODeviceManager::new().map_err(Error::CreateLegacyDevice)?,
             device_configs,
             epoll_context,
-            api_event_fd,
             from_api,
             write_metrics_event_fd,
             seccomp_level,
@@ -2165,7 +2163,7 @@ pub fn start_vmm_thread(
         .name("fc_vmm".to_string())
         .spawn(move || {
             // If this fails, consider it fatal. Use expect().
-            let mut vmm = Vmm::new(api_shared_info, api_event_fd, from_api, seccomp_level)
+            let mut vmm = Vmm::new(api_shared_info, &api_event_fd, from_api, seccomp_level)
                 .expect("Cannot create VMM");
 
             if let Some(json) = config_json {
@@ -2200,7 +2198,7 @@ pub fn start_vmm_thread(
                             FC_EXIT_CODE_OK
                         }
                         EventLoopExitReason::ControlAction => {
-                            if let Err(e) = vmm.api_event_fd.read() {
+                            if let Err(e) = api_event_fd.read() {
                                 error!("Error reading VMM API event_fd {:?}", e);
                                 FC_EXIT_CODE_GENERIC_ERROR
                             } else {
@@ -2385,7 +2383,7 @@ mod tests {
         let (_to_vmm, from_api) = channel();
         Vmm::new(
             shared_info,
-            EventFd::new().expect("cannot create eventFD"),
+            &EventFd::new().expect("cannot create eventFD"),
             from_api,
             seccomp::SECCOMP_LEVEL_NONE,
         )