xen: remove unwraps in listen

Author: Wenzel

src/driver/xen.rs

@@ -329,7 +329,7 @@ impl Introspectable for Xen {
 
     fn listen(&mut self, timeout: u32) -> Result<Option<Event>, Box<dyn Error>> {
         let mut fds: [PollFd; 1] = [self.evtchn_pollfd];
-        let event: Option<Event> = match poll(&mut fds, timeout.try_into().unwrap()).unwrap() {
+        let event: Option<Event> = match poll(&mut fds, timeout.try_into()?)? {
             0 => {
                 // timeout. no file descriptors were ready
                 None
@@ -356,7 +356,7 @@ impl Introspectable for Xen {
                         }
                         // unmask
                         self.xev
-                            .xenevtchn_unmask(pending_event_port.try_into().unwrap())?;
+                            .xenevtchn_unmask(pending_event_port.try_into()?)?;
                     }
                 };
                 let back_ring_ptr = &mut self.back_ring;
@@ -367,8 +367,8 @@ impl Introspectable for Xen {
                         if req.version != VM_EVENT_INTERFACE_VERSION {
                             panic!("version mismatch");
                         }
-                        let xen_event_type = (self.xc.get_event_type(req)).unwrap();
-                        let vcpu: u32 = req.vcpu_id.try_into().unwrap();
+                        let xen_event_type = (self.xc.get_event_type(req))?;
+                        let vcpu: u32 = req.vcpu_id.try_into()?;
                         let event_type: EventType = match xen_event_type {
                             XenEventType::Cr { cr_type, new, old } => EventType::Cr {
                                 cr_type: match cr_type {
@@ -390,10 +390,10 @@ impl Introspectable for Xen {
                         };
                         // associate VCPU => vm_event_request_t
                         // to find it in reply_event()
-                        let vcpu_index: usize = vcpu.try_into().unwrap();
+                        let vcpu_index: usize = vcpu.try_into()?;
                         self.vec_events[vcpu_index] = Some(req);
                         Some(Event {
-                            vcpu: vcpu.try_into().unwrap(),
+                            vcpu: vcpu.try_into()?,
                             kind: event_type,
                         })
                     }
@@ -414,7 +414,7 @@ impl Introspectable for Xen {
             EventReplyType::Continue => VM_EVENT_FLAG_VCPU_PAUSED,
         };
         // get the request back
-        let vcpu_index: usize = event.vcpu.try_into().unwrap();
+        let vcpu_index: usize = event.vcpu.try_into()?;
         let req: vm_event_request_t = mem::replace(&mut self.vec_events[vcpu_index], None).unwrap();
         let mut rsp: vm_event_response_t =
             unsafe { mem::MaybeUninit::<vm_event_response_t>::zeroed().assume_init() };