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": 90.82,
+  "coverage_score": 91.52,
   "exclude_path": "mmap_windows.rs",
-  "crate_features": "backend-mmap,backend-atomic,backend-bitmap"
+  "crate_features": "backend-mmap,backend-atomic,backend-bitmap,iommu"
 }

src/guest_memory.rs

@@ -901,6 +901,9 @@ impl<M: GuestMemory + ?Sized> IoMemory for M {
 #[cfg(test)]
 mod tests {
     #![allow(clippy::undocumented_unsafe_blocks)]
+
+    // Note that `IoMemory` is tested primarily in src/iommu.rs via `IommuMemory`.
+
     use super::*;
     #[cfg(feature = "backend-mmap")]
     use crate::bytes::ByteValued;
@@ -1141,4 +1144,57 @@ mod tests {
         let r = mem.find_region(addr).unwrap();
         assert_eq!(r.is_hugetlbfs(), None);
     }
+
+    /// 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);
+    }
+
+    /// Test `Permissions::has_write()`.
+    #[test]
+    fn test_perm_has_write() {
+        assert!(!Permissions::No.has_write());
+        assert!(!Permissions::Read.has_write());
+        assert!(Permissions::Write.has_write());
+        assert!(Permissions::ReadWrite.has_write());
+    }
 }