diff --git a/qemu/include/qemu/range.h b/qemu/include/qemu/range.h
index 6add664e..1dd1b0e0 100644
--- a/qemu/include/qemu/range.h
+++ b/qemu/include/qemu/range.h
@@ -38,12 +38,93 @@ struct Range {
     uint64_t end;   /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */
 };
 
+static inline void range_invariant(Range *range)
+{
+    assert((!range->begin && !range->end) /* empty */
+           || range->begin <= range->end - 1); /* non-empty */
+}
+
+/* Compound literal encoding the empty range */
+// Unicorn: MSVC is in the stone-age and not C99/C11 compliant
+//#define range_empty ((Range){ .begin = 0, .end = 0 })
+
+/* Is @range empty? */
+static inline bool range_is_empty(Range *range)
+{
+    range_invariant(range);
+    return !range->begin && !range->end;
+}
+
+/* Does @range contain @val? */
+static inline bool range_contains(Range *range, uint64_t val)
+{
+    return !range_is_empty(range)
+        && val >= range->begin && val <= range->end - 1;
+}
+
+/* Initialize @range to the empty range */
+static inline void range_make_empty(Range *range)
+{
+    range->begin = 0;
+    range->end = 0;
+    assert(range_is_empty(range));
+}
+
+/*
+ * Initialize @range to span the interval [@lob,@upb].
+ * Both bounds are inclusive.
+ * The interval must not be empty, i.e. @lob must be less than or
+ * equal @upb.
+ * The interval must not be [0,UINT64_MAX], because Range can't
+ * represent that.
+ */
+static inline void range_set_bounds(Range *range, uint64_t lob, uint64_t upb)
+{
+    assert(lob <= upb);
+    range->begin = lob;
+    range->end = upb + 1;       /* may wrap to zero, that's okay */
+    assert(!range_is_empty(range));
+}
+
+/*
+ * Initialize @range to span the interval [@lob,@upb_plus1).
+ * The lower bound is inclusive, the upper bound is exclusive.
+ * Zero @upb_plus1 is special: if @lob is also zero, set @range to the
+ * empty range.  Else, set @range to [@lob,UINT64_MAX].
+ */
+static inline void range_set_bounds1(Range *range,
+                                     uint64_t lob, uint64_t upb_plus1)
+{
+    range->begin = lob;
+    range->end = upb_plus1;
+    range_invariant(range);
+}
+
+/* Return @range's lower bound.  @range must not be empty. */
+static inline uint64_t range_lob(Range *range)
+{
+    assert(!range_is_empty(range));
+    return range->begin;
+}
+
+/* Return @range's upper bound.  @range must not be empty. */
+static inline uint64_t range_upb(Range *range)
+{
+    assert(!range_is_empty(range));
+    return range->end - 1;
+}
+
+/*
+ * Extend @range to the smallest interval that includes @extend_by, too.
+ * This must not extend @range to cover the interval [0,UINT64_MAX],
+ * because Range can't represent that.
+ */
 static inline void range_extend(Range *range, Range *extend_by)
 {
-    if (!extend_by->begin && !extend_by->end) {
+    if (range_is_empty(extend_by)) {
         return;
     }
-    if (!range->begin && !range->end) {
+    if (range_is_empty(range)) {
         *range = *extend_by;
         return;
     }
@@ -54,6 +135,8 @@ static inline void range_extend(Range *range, Range *extend_by)
     if (range->end - 1 < extend_by->end - 1) {
         range->end = extend_by->end;
     }
+    /* Must not extend to { .begin = 0, .end = 0 }: */
+    assert(!range_is_empty(range));
 }
 
 /* Get last byte of a range from offset + length.
diff --git a/qemu/qapi/string-input-visitor.c b/qemu/qapi/string-input-visitor.c
index a01140a8..dd132459 100644
--- a/qemu/qapi/string-input-visitor.c
+++ b/qemu/qapi/string-input-visitor.c
@@ -59,8 +59,7 @@ static int parse_str(StringInputVisitor *siv, const char *name, Error **errp)
         if (errno == 0 && endptr > str) {
             if (*endptr == '\0') {
                 cur = g_malloc0(sizeof(*cur));
-                cur->begin = start;
-                cur->end = start + 1;
+                range_set_bounds(cur, start, start);
                 siv->ranges = range_list_insert(siv->ranges, cur);
                 cur = NULL;
                 str = NULL;
@@ -73,16 +72,14 @@ static int parse_str(StringInputVisitor *siv, const char *name, Error **errp)
                      end < start + 65536)) {
                     if (*endptr == '\0') {
                         cur = g_malloc0(sizeof(*cur));
-                        cur->begin = start;
-                        cur->end = end + 1;
+                        range_set_bounds(cur, start, end);
                         siv->ranges = range_list_insert(siv->ranges, cur);
                         cur = NULL;
                         str = NULL;
                     } else if (*endptr == ',') {
                         str = endptr + 1;
                         cur = g_malloc0(sizeof(*cur));
-                        cur->begin = start;
-                        cur->end = end + 1;
+                        range_set_bounds(cur, start, end);
                         siv->ranges = range_list_insert(siv->ranges, cur);
                         cur = NULL;
                     } else {
@@ -94,8 +91,7 @@ static int parse_str(StringInputVisitor *siv, const char *name, Error **errp)
             } else if (*endptr == ',') {
                 str = endptr + 1;
                 cur = g_malloc0(sizeof(*cur));
-                cur->begin = start;
-                cur->end = start + 1;
+                range_set_bounds(cur, start, start);
                 siv->ranges = range_list_insert(siv->ranges, cur);
                 cur = NULL;
             } else {
@@ -134,7 +130,7 @@ start_list(Visitor *v, const char *name, GenericList **list, size_t size,
     if (siv->cur_range) {
         Range *r = siv->cur_range->data;
         if (r) {
-            siv->cur = r->begin;
+            siv->cur = range_lob(r);
         }
         *list = g_malloc0(size);
     } else {
@@ -156,7 +152,7 @@ static GenericList *next_list(Visitor *v, GenericList *tail, size_t size)
         return NULL;
     }
 
-    if ((uint64_t)siv->cur < r->begin || (uint64_t)siv->cur >= r->end) {
+    if (!range_contains(r, siv->cur)) {
         siv->cur_range = g_list_next(siv->cur_range);
         if (!siv->cur_range) {
             return NULL;
@@ -165,7 +161,7 @@ static GenericList *next_list(Visitor *v, GenericList *tail, size_t size)
         if (!r) {
             return NULL;
         }
-        siv->cur = r->begin;
+        siv->cur = range_lob(r);
     }
 
     tail->next = g_malloc0(size);
@@ -208,7 +204,7 @@ static void parse_type_int64(Visitor *v, const char *name, int64_t *obj,
             goto error;
         }
 
-        siv->cur = r->begin;
+        siv->cur = range_lob(r);
     }
 
     *obj = siv->cur;
diff --git a/qemu/util/range.c b/qemu/util/range.c
index e90c988d..e5f2e711 100644
--- a/qemu/util/range.c
+++ b/qemu/util/range.c
@@ -46,8 +46,7 @@ GList *range_list_insert(GList *list, Range *data)
 {
     GList *l;
 
-    /* Range lists require no empty ranges */
-    assert(data->begin < data->end || (data->begin && !data->end));
+    assert(!range_is_empty(data));
 
     /* Skip all list elements strictly less than data */
     for (l = list; l && range_compare(l->data, data) < 0; l = l->next) {