diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
index f6993a8fb1..a6ac188188 100644
--- a/include/qemu/atomic.h
+++ b/include/qemu/atomic.h
@@ -99,9 +99,10 @@
  * those few cases by hand.
  *
  * Note that x32 is fully detected with __x86_64__ + _ILP32, and that for
- * Sparc we always force the use of sparcv9 in configure.
+ * Sparc we always force the use of sparcv9 in configure. MIPS n32 (ILP32) &
+ * n64 (LP64) ABIs are both detected using __mips64.
  */
-#if defined(__x86_64__) || defined(__sparc__)
+#if defined(__x86_64__) || defined(__sparc__) || defined(__mips64)
 # define ATOMIC_REG_SIZE  8
 #else
 # define ATOMIC_REG_SIZE  sizeof(void *)