Assert PCI config space accesses are aligned

pcid/src/pcie/fallback.rs

@@ -42,18 +42,14 @@ impl Pci {
     }
 
     fn address(address: PciAddress, offset: u8) -> u32 {
-        // TODO: Find the part of pcid that uses an unaligned offset!
-        //
-        // assert_eq!(offset & 0xFC, offset, "pci offset is not aligned");
-        //
-        let offset = offset & 0xFC;
-
         assert_eq!(
             address.segment(),
             0,
             "usage of multiple segments requires PCIe extended configuration"
         );
 
+        assert_eq!(offset & 0xFC, offset, "pci offset is not aligned");
+
         0x80000000
             | (u32::from(address.bus()) << 16)
             | (u32::from(address.device()) << 11)

pcid/src/pcie/mod.rs

@@ -205,6 +205,8 @@ impl Pcie {
             "multiple segments not yet implemented"
         );
 
+        assert_eq!(offset & 0xFC, offset, "pci offset is not aligned");
+
         let bus_addr = match self.bus_maps.get(address.bus() as usize) {
             Some(Some(bus_addr)) => bus_addr,
             Some(None) | None => return f(None),