memory: add ref/unref calls

Add ref/unref calls at the following places:

- places where memory regions are stashed by a listener and
  used outside the BQL (including in Xen or KVM).

- memory_region_find callsites

- creation of aliases and containers (only the aliased/contained
  region gets a reference to avoid loops)

- around calls to del_subregion/add_subregion, where the region
  could disappear after the first call

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index 15b489620b..c06a01821d 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -606,6 +606,7 @@ static void xen_pt_region_add(MemoryListener *l, MemoryRegionSection *sec)
     XenPCIPassthroughState *s = container_of(l, XenPCIPassthroughState,
                                              memory_listener);
 
+    memory_region_ref(sec->mr);
     xen_pt_region_update(s, sec, true);
 }
 
@@ -615,6 +616,7 @@ static void xen_pt_region_del(MemoryListener *l, MemoryRegionSection *sec)
                                              memory_listener);
 
     xen_pt_region_update(s, sec, false);
+    memory_region_unref(sec->mr);
 }
 
 static void xen_pt_io_region_add(MemoryListener *l, MemoryRegionSection *sec)
@@ -622,6 +624,7 @@ static void xen_pt_io_region_add(MemoryListener *l, MemoryRegionSection *sec)
     XenPCIPassthroughState *s = container_of(l, XenPCIPassthroughState,
                                              io_listener);
 
+    memory_region_ref(sec->mr);
     xen_pt_region_update(s, sec, true);
 }
 
@@ -631,6 +634,7 @@ static void xen_pt_io_region_del(MemoryListener *l, MemoryRegionSection *sec)
                                              io_listener);
 
     xen_pt_region_update(s, sec, false);
+    memory_region_unref(sec->mr);
 }
 
 static const MemoryListener xen_pt_memory_listener = {