-Utilized Option instead of Vector to store IRQ lines for MMIO devices.

-Add test to test this.
-Update existing tests

Signed-off-by: Andrew Yao <andrewyao@utexas.edu>
Co-authored-by: Himanshu Reddy <himanshureddy@utexas.edu>
Co-authored-by: Goldin Vo <goldinbaokimvo@utexas.edu>

src/vmm/src/device_manager/mmio.rs

@@ -741,7 +741,6 @@ mod tests {
  assert_eq!(dummy.queues().len(), QUEUE_SIZES.len());
  }
 
- // NOTE: we are also failing this test now 
  #[test]
  fn test_device_info() {
  let start_addr1 = GuestAddress(0x0);
@@ -820,30 +819,31 @@ mod tests {
  }
 
  #[test]
- fn test_slot_irq_allocation() {
+ fn test_no_irq_allocation() {
  let mut device_manager = MMIODeviceManager::new();
  let mut resource_allocator = ResourceAllocator::new().unwrap();
+
  let device_info = device_manager
  .allocate_mmio_resources(&mut resource_allocator, 0)
  .unwrap();
  assert!(device_info.irq.is_none());
+ }
+
+ #[test]
+ fn test_irq_allocation() {
+ let mut device_manager = MMIODeviceManager::new();
+ let mut resource_allocator = ResourceAllocator::new().unwrap();
+
  let device_info = device_manager
  .allocate_mmio_resources(&mut resource_allocator, 1)
  .unwrap();
  assert_eq!(device_info.irq.unwrap().get(), crate::arch::IRQ_BASE);
- assert_eq!(
- format!(
- "{}",
- device_manager
- .allocate_mmio_resources(
- &mut resource_allocator,
- crate::arch::IRQ_MAX - crate::arch::IRQ_BASE + 1
- )
- .unwrap_err()
- ),
- "Invalid MMIO IRQ configuration."
- .to_string()
- );
+ }
+
+ #[test]
+ fn test_allocation_failure() {
+ let mut device_manager = MMIODeviceManager::new();
+ let mut resource_allocator = ResourceAllocator::new().unwrap(); 
  assert_eq!(
  format!(
  "{}",
@@ -854,8 +854,5 @@ mod tests {
  "Invalid MMIO IRQ configuration."
  .to_string()
  );
- device_manager
- .allocate_mmio_resources(&mut resource_allocator, 0)
- .unwrap();
  }
 }