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>

fuzz/fuzz_targets/block.rs

@@ -84,9 +84,8 @@ fuzz_target!(|bytes| {
     q.state.ready = true;
     q.state.size = QUEUE_SIZE / 2;
 
-    let queue_evts: Vec<EventFd> = vec![EventFd::new(0).unwrap()];
-    let queue_fd = queue_evts[0].as_raw_fd();
-    let queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(queue_fd)) };
+    let evt = EventFd::new(0).unwrap();
+    let queue_evt = unsafe { EventFd::from_raw_fd(libc::dup(evt.as_raw_fd())) };
 
     let shm = memfd_create(&ffi::CString::new("fuzz").unwrap(), 0).unwrap();
     let disk_file: File = unsafe { File::from_raw_fd(shm) };
@@ -110,8 +109,7 @@ fuzz_target!(|bytes| {
         .activate(
             guest_memory,
             Arc::new(NoopVirtioInterrupt {}),
-            vec![q],
-            queue_evts,
+            vec![(0, q, evt)],
         )
         .ok();