diff --git a/xen/common/bitops.c b/xen/common/bitops.c
index 9e532f0d87..b504dd1308 100644
--- a/xen/common/bitops.c
+++ b/xen/common/bitops.c
@@ -112,9 +112,32 @@ static void __init test_for_each_set_bit(void)
         panic("for_each_set_bit(uint64) expected %#"PRIx64", got %#"PRIx64"\n", ull, ull_res);
 }
 
+static void __init test_multiple_bits_set(void)
+{
+    /*
+     * multiple_bits_set() is generic on the type of it's parameter, as the
+     * internal expression is so simple.
+     */
+
+    CHECK(multiple_bits_set, 0, false);
+    CHECK(multiple_bits_set, 1, false);
+    CHECK(multiple_bits_set, 2, false);
+    CHECK(multiple_bits_set, 3, true);
+
+    CHECK(multiple_bits_set, 1 | (1UL << (BITS_PER_LONG - 1)), true);
+#if BITS_PER_LONG > 32
+    CHECK(multiple_bits_set, 1 | (1UL << 32), true);
+#endif
+
+    CHECK(multiple_bits_set, 0x8000000000000001ULL, true);
+    CHECK(multiple_bits_set, 0xc000000000000000ULL, true);
+}
+
 static void __init __constructor test_bitops(void)
 {
     test_ffs();
     test_fls();
     test_for_each_set_bit();
+
+    test_multiple_bits_set();
 }
diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h
index 94af6da18b..4d51708c4a 100644
--- a/xen/include/xen/bitops.h
+++ b/xen/include/xen/bitops.h
@@ -296,6 +296,16 @@ static always_inline attr_const unsigned int fls64(uint64_t x)
               __v && ((iter) = ffs_g(__v) - 1, true);   \
               __v &= __v - 1 )
 
+/*
+ * Calculate if a value has two or more bits set.  Always use this in
+ * preference to an expression of the form 'hweight(x) > 1'.
+ */
+#define multiple_bits_set(x)                    \
+    ({                                          \
+        typeof(x) _v = (x);                     \
+        (_v & (_v - 1)) != 0;                   \
+    })
+
 /* --------------------- Please tidy below here --------------------- */
 
 #ifndef find_next_bit
diff --git a/xen/include/xen/self-tests.h b/xen/include/xen/self-tests.h
index e9a8794893..bd8a4867aa 100644
--- a/xen/include/xen/self-tests.h
+++ b/xen/include/xen/self-tests.h
@@ -15,11 +15,14 @@
  *
  * Clang < 8 can't fold constants through static inlines, causing this to
  * fail.  Simply skip it for incredibly old compilers.
+ *
+ * N.B. fn is intentionally not bracketed to allow us to test function-like
+ * macros too.
  */
 #if !defined(CONFIG_CC_IS_CLANG) || CONFIG_CLANG_VERSION >= 80000
 #define COMPILE_CHECK(fn, val, res)                                     \
     do {                                                                \
-        typeof((fn)(val)) real = (fn)(val);                             \
+        typeof(fn(val)) real = fn(val);                                 \
                                                                         \
         if ( !__builtin_constant_p(real) )                              \
             BUILD_ERROR("'" STR(fn(val)) "' not compile-time constant"); \
@@ -34,10 +37,13 @@
  * Check that Xen's runtime logic for fn(val) gives the expected answer.  This
  * requires using HIDE() to prevent the optimiser from collapsing the logic
  * into a constant.
+ *
+ * N.B. fn is intentionally not bracketed to allow us to test function-like
+ * macros too.
  */
 #define RUNTIME_CHECK(fn, val, res)                     \
     do {                                                \
-        typeof((fn)(val)) real = (fn)(HIDE(val));       \
+        typeof(fn(val)) real = fn(HIDE(val));           \
                                                         \
         if ( real != (res) )                            \
             panic("%s: %s(%s) expected %u, got %u\n",   \