virtio-devices: Pass a list of tuples for virtqueues

Instead of passing separately a list of Queues and the equivalent list
of EventFds, we consolidate these two through a tuple along with the
queue index.

The queue index can be very useful if looking for the actual index
related to the queue, no matter if other queues have been enabled or
not.

It's also convenient to have the EventFd associated with the Queue so
that we don't have to carry two lists with the same amount of items.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

virtio-devices/src/device.rs

@@ -107,8 +107,7 @@ pub trait VirtioDevice: Send {
         &mut self,
         mem: GuestMemoryAtomic<GuestMemoryMmap>,
         interrupt_evt: Arc<dyn VirtioInterrupt>,
-        queues: Vec<Queue<GuestMemoryAtomic<GuestMemoryMmap>>>,
-        queue_evts: Vec<EventFd>,
+        queues: Vec<(usize, Queue<GuestMemoryAtomic<GuestMemoryMmap>>, EventFd)>,
     ) -> ActivateResult;
 
     /// Optionally deactivates this device and returns ownership of the guest memory map, interrupt
@@ -251,19 +250,9 @@ impl VirtioCommon {
 
     pub fn activate(
         &mut self,
-        queues: &[Queue<GuestMemoryAtomic<GuestMemoryMmap>>],
-        queue_evts: &[EventFd],
+        queues: &[(usize, Queue<GuestMemoryAtomic<GuestMemoryMmap>>, EventFd)],
         interrupt_cb: &Arc<dyn VirtioInterrupt>,
     ) -> ActivateResult {
-        if queues.len() != queue_evts.len() {
-            error!(
-                "Cannot activate: length mismatch: queue_evts={} queues={}",
-                queue_evts.len(),
-                queues.len()
-            );
-            return Err(ActivateError::BadActivate);
-        }
-
         if queues.len() < self.min_queues.into() {
             error!(
                 "Number of enabled queues lower than min: {} vs {}",
@@ -290,7 +279,7 @@ impl VirtioCommon {
         self.interrupt_cb = Some(interrupt_cb.clone());
 
         let mut tmp_queue_evts: Vec<EventFd> = Vec::new();
-        for queue_evt in queue_evts.iter() {
+        for (_, _, queue_evt) in queues.iter() {
             // Save the queue EventFD as we need to return it on reset
             // but clone it to pass into the thread.
             tmp_queue_evts.push(queue_evt.try_clone().map_err(|e| {