[PATCH] softmmu/memory: fix memory_region_ioeventfd_equal()

[Elena Afanasova <eafanasova@gmail.com>]

Eventfd can be registered with a zero length when fast_mmio is true.
Handle this case properly when dispatching through QEMU.

Signed-off-by: Elena Afanasova <eafanasova@gmail.com>
---
 softmmu/memory.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/softmmu/memory.c b/softmmu/memory.c
index 403ff3abc9..3ca2154a64 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -203,10 +203,17 @@ static bool memory_region_ioeventfd_before(MemoryRegionIoeventfd *a,
 }
 
 static bool memory_region_ioeventfd_equal(MemoryRegionIoeventfd *a,
-                                          MemoryRegionIoeventfd *b)
-{
-    return !memory_region_ioeventfd_before(a, b)
-        && !memory_region_ioeventfd_before(b, a);
+                                          MemoryRegionIoeventfd *mrb)
+{
+    if (int128_eq(a->addr.start, mrb->addr.start) &&
+            (!int128_nz(mrb->addr.size) ||
+             int128_eq(a->addr.size, mrb->addr.size)) &&
+            (a->match_data == mrb->match_data) &&
+            ((mrb->match_data && (a->data == mrb->data)) || !mrb->match_data) &&
+            (a->e == mrb->e))
+        return true;
+
+    return false;
 }
 
 /* Range of memory in the global map.  Addresses are absolute. */
-- 
2.25.1