[PATCH v2] mem/cxl_type3: Fix overlapping region validation error

[Yao Xingtao]

When injecting a new poisoned region through qmp_cxl_inject_poison(),
the newly injected region should not overlap with existing poisoned
regions.

The current validation method does not consider the following
overlapping region:
+---+-------+---+
| a | b(a)  | a |
+---+-------+---+

(a is a newly added region, b is an existing region, and b is a
 subregion of a)

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huwei.com>
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>

---
V1[1] -> V2:
 - Use ranges_overlap() to improve code readability
 - Replace the ASCII extended graph to ASCII basic in comment.

[1] 
20240718090753.59163-1-yaoxt.fnst@fujitsu.com">https://lore.kernel.org/qemu-devel/20240718090753.59163-1-yaoxt.fnst@fujitsu.com
---
 hw/mem/cxl_type3.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 35ac59883a5b..b2f3e2090b57 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -1331,9 +1331,7 @@ void qmp_cxl_inject_poison(const char *path, uint64_t 
start, uint64_t length,
     ct3d = CXL_TYPE3(obj);
 
     QLIST_FOREACH(p, &ct3d->poison_list, node) {
-        if (((start >= p->start) && (start < p->start + p->length)) ||
-            ((start + length > p->start) &&
-             (start + length <= p->start + p->length))) {
+        if (ranges_overlap(start, length, p->start, p->length)) {
             error_setg(errp,
                        "Overlap with existing poisoned region not supported");
             return;
-- 
2.37.3