pci: virtio: refactor: remove BAR handling from PciConfiguration

Previous commit created a separate `Bars` type to handle
BARs region and made VirtioPciDevice type to use it instead of
PciConfiguration to handle BARs region. This made BARs handling
in PciConfiguration redundant, so this commit removes it.
This also removes `detect_bar_reprogramming` support from
PciConfiguration. But Firecracker does not support BAR relocation
anyway, this does not affect functionality.
The removal of `detect_bar_reprogramming` also required to remove
the unit test for it in the pci/bus.rs.

No functional change.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

src/vmm/src/pci/bus.rs

@@ -492,12 +492,6 @@ mod tests {
         reloc_cnt: AtomicUsize,
     }
 
-    impl RelocationMock {
-        fn cnt(&self) -> usize {
-            self.reloc_cnt.load(std::sync::atomic::Ordering::SeqCst)
-        }
-    }
-
     impl DeviceRelocation for RelocationMock {
         fn move_bar(
             &self,
@@ -516,7 +510,7 @@ mod tests {
 
     impl PciDevMock {
         fn new() -> Self {
-            let mut config = PciConfiguration::new_type0(
+            let config = PciConfiguration::new_type0(
                 0x42,
                 0x0,
                 0x0,
@@ -526,9 +520,6 @@ mod tests {
                 0x12,
                 None,
             );
-
-            config.add_pci_bar(0, 0x1000, 0x1000);
-
             PciDevMock(config)
         }
     }
@@ -550,10 +541,10 @@ mod tests {
 
         fn detect_bar_reprogramming(
             &mut self,
-            reg_idx: u16,
-            data: &[u8],
+            _reg_idx: u16,
+            _data: &[u8],
         ) -> Option<BarReprogrammingParams> {
-            self.0.detect_bar_reprogramming(reg_idx, data)
+            None
         }
     }
 
@@ -936,56 +927,4 @@ mod tests {
         read_mmio_config(&mut mmio_config, 0, 0, 0, 15, 0, &mut buffer);
         assert_eq!(buffer[0], 0x42);
     }
-
-    #[test]
-    fn test_bar_reprogramming() {
-        let (mut mmio_config, _, mock) = initialize_bus();
-        let mut buffer = [0u8; 4];
-        assert_eq!(mock.cnt(), 0);
-
-        read_mmio_config(&mut mmio_config, 0, 1, 0, 0x4, 0, &mut buffer);
-        let old_addr = u32::from_le_bytes(buffer) & 0xffff_fff0;
-        assert_eq!(old_addr, 0x1000);
-
-        // Writing the lower 32bits first should not trigger any reprogramming
-        write_mmio_config(
-            &mut mmio_config,
-            0,
-            1,
-            0,
-            0x4,
-            0,
-            &u32::to_le_bytes(0x1312_0000),
-        );
-
-        read_mmio_config(&mut mmio_config, 0, 1, 0, 0x4, 0, &mut buffer);
-        let new_addr = u32::from_le_bytes(buffer) & 0xffff_fff0;
-        assert_eq!(new_addr, 0x1312_0000);
-        assert_eq!(mock.cnt(), 0);
-
-        // Writing the upper 32bits first should now trigger the reprogramming logic
-        write_mmio_config(&mut mmio_config, 0, 1, 0, 0x5, 0, &u32::to_le_bytes(0x1110));
-        read_mmio_config(&mut mmio_config, 0, 1, 0, 0x5, 0, &mut buffer);
-        let new_addr = u32::from_le_bytes(buffer);
-        assert_eq!(new_addr, 0x1110);
-        assert_eq!(mock.cnt(), 1);
-
-        // BAR2 should not be used, so reading its address should return all 0s
-        read_mmio_config(&mut mmio_config, 0, 1, 0, 0x6, 0, &mut buffer);
-        assert_eq!(buffer, [0x0, 0x0, 0x0, 0x0]);
-
-        // and reprogramming shouldn't have any effect
-        write_mmio_config(
-            &mut mmio_config,
-            0,
-            1,
-            0,
-            0x5,
-            0,
-            &u32::to_le_bytes(0x1312_1110),
-        );
-
-        read_mmio_config(&mut mmio_config, 0, 1, 0, 0x6, 0, &mut buffer);
-        assert_eq!(buffer, [0x0, 0x0, 0x0, 0x0]);
-    }
 }