vfio-user: make flags more ergonomic

There are two issues with DmaMapFlags:

1. `READ_ONLY` being set doesn't mean that the mapping is read-only.
   This is confusing in code that uses these constants (same for
   `WRITE_ONLY`).

2. Due to some bitflags update the type doesn't derive standard traits
   anymore. Manually annotate those.

Fix both of these issues. While I was here, I also added the necessary
traits to DmaUnmapFlags.

Signed-off-by: Julian Stecklina <[email protected]>

Author: blitz

vfio-user/src/lib.rs

@@ -102,14 +102,14 @@ fn default_migration_capabilities() -> MigrationCapabilities {
 }
 
 bitflags! {
-    #[derive(Debug)]
+    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
     pub struct DmaMapFlags: u32 {
-        const READ_ONLY = 1 << 0;
-        const WRITE_ONLY = 1 << 1;
-        const READ_WRITE = Self::READ_ONLY.bits() | Self::WRITE_ONLY.bits();
+        const READ = 1 << 0;
+        const WRITE = 1 << 1;
+        const READ_WRITE = Self::READ.bits() | Self::WRITE.bits();
     }
 
-    #[derive(Debug)]
+    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
     pub struct DmaUnmapFlags: u32 {
         const GET_DIRTY_PAGE_INFO = 1 << 1;
         const UNMAP_ALL = 1 << 2;