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, 3 insertions, 0 deletions

diff --git a/exec.c b/exec.c
index f926bd793f..e3ac1a18fd 100644
--- a/exec.c
+++ b/exec.c
@@ -763,11 +763,14 @@ static uint16_t phys_section_add(MemoryRegionSection *section)
                                 phys_sections_nb_alloc);
     }
     phys_sections[phys_sections_nb] = *section;
+    memory_region_ref(section->mr);
     return phys_sections_nb++;
 }
 
 static void phys_section_destroy(MemoryRegion *mr)
 {
+    memory_region_unref(mr);
+
     if (mr->subpage) {
         subpage_t *subpage = container_of(mr, subpage_t, iomem);
         memory_region_destroy(&subpage->iomem);