Add tests for IOMMU functionality

This commit also adds the iommu feature to the coverage_config feature
list.  (I left the aarch64 coverage value unchanged; I cannot find out
how to get the current value on my system, and it isn’t include in CI.)

Signed-off-by: Hanna Czenczek <hreitz@redhat.com>

Author: XanClic

coverage_config_aarch64.json

@@ -1,5 +1,5 @@
 {
   "coverage_score": 85.2,
   "exclude_path": "mmap/windows.rs",
-  "crate_features": "backend-mmap,backend-atomic,backend-bitmap"
+  "crate_features": "backend-mmap,backend-atomic,backend-bitmap,iommu"
 }

coverage_config_x86_64.json

@@ -1,5 +1,5 @@
 {
-  "coverage_score": 91.78,
+  "coverage_score": 92.68,
   "exclude_path": "mmap_windows.rs",
-  "crate_features": "backend-mmap,backend-atomic,backend-bitmap"
+  "crate_features": "backend-mmap,backend-atomic,backend-bitmap,iommu"
 }

src/io_memory.rs

@@ -181,3 +181,54 @@ impl<M: GuestMemory> IoMemory for M {
         Some(self)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Permissions;
+
+    // Note that `IoMemory` is tested primarily in src/iommu.rs via `IommuMemory`.
+
+    /// Test `Permissions & Permissions`.
+    #[test]
+    fn test_perm_and() {
+        use Permissions::*;
+
+        for p in [No, Read, Write, ReadWrite] {
+            assert_eq!(p & p, p);
+        }
+        for p1 in [No, Read, Write, ReadWrite] {
+            for p2 in [No, Read, Write, ReadWrite] {
+                assert_eq!(p1 & p2, p2 & p1);
+            }
+        }
+        for p in [No, Read, Write, ReadWrite] {
+            assert_eq!(No & p, No);
+        }
+        for p in [No, Read, Write, ReadWrite] {
+            assert_eq!(ReadWrite & p, p);
+        }
+        assert_eq!(Read & Write, No);
+    }
+
+    /// Test `Permissions | Permissions`.
+    #[test]
+    fn test_perm_or() {
+        use Permissions::*;
+
+        for p in [No, Read, Write, ReadWrite] {
+            assert_eq!(p | p, p);
+        }
+        for p1 in [No, Read, Write, ReadWrite] {
+            for p2 in [No, Read, Write, ReadWrite] {
+                assert_eq!(p1 | p2, p2 | p1);
+            }
+        }
+        for p in [No, Read, Write, ReadWrite] {
+            assert_eq!(No | p, p);
+        }
+        for p in [No, Read, Write, ReadWrite] {
+            assert_eq!(ReadWrite | p, ReadWrite);
+        }
+        assert_eq!(Read | Write, ReadWrite);
+    }
+}