virtio: initialize queue size with max_size

Apparently, PCI needs Queue::size to be initialized to the maximum
possible size supported by the device, otherwise initialization fails.

Signed-off-by: Babis Chalios <[email protected]>

Author: bchalios

src/vmm/src/devices/virtio/queue.rs

@@ -262,7 +262,7 @@ impl Queue {
     pub fn new(max_size: u16) -> Queue {
         Queue {
             max_size,
-            size: 0,
+            size: max_size,
             ready: false,
             desc_table_address: GuestAddress(0),
             avail_ring_address: GuestAddress(0),

src/vmm/src/devices/virtio/transport/mmio.rs

@@ -798,7 +798,7 @@ pub(crate) mod tests {
         assert_eq!(d.queue_select, 3);
 
         d.queue_select = 0;
-        assert_eq!(d.locked_device().queues()[0].size, 0);
+        assert_eq!(d.locked_device().queues()[0].size, 16);
         write_le_u32(&mut buf[..], 16);
         d.write(0x0, 0x38, &buf[..]);
         assert_eq!(d.locked_device().queues()[0].size, 16);

src/vmm/src/devices/virtio/vhost_user.rs

@@ -922,10 +922,10 @@ pub(crate) mod tests {
         // the backend.
         let expected_config = VringData {
             index: 0,
-            size: 0,
+            size: 69,
             config: VringConfigData {
                 queue_max_size: 69,
-                queue_size: 0,
+                queue_size: 69,
                 flags: 0,
                 desc_table_addr: guest_memory
                     .get_host_address(queue.desc_table_address)