page_cache: dup memory on insert

The page cache frees all data on finish, on resize and
if there is collision on insert. So it should be the caches
responsibility to dup the data that is stored in the cache.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NOrit Wasserman <owasserm@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

arch_init.c

@@ -293,8 +293,7 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t *current_data,
 
     if (!cache_is_cached(XBZRLE.cache, current_addr)) {
         if (!last_stage) {
-            cache_insert(XBZRLE.cache, current_addr,
-                         g_memdup(current_data, TARGET_PAGE_SIZE));
+            cache_insert(XBZRLE.cache, current_addr, current_data);
         }
         acct_info.xbzrle_cache_miss++;
         return -1;

include/migration/page_cache.h

@@ -57,7 +57,8 @@ bool cache_is_cached(const PageCache *cache, uint64_t addr);
 uint8_t *get_cached_data(const PageCache *cache, uint64_t addr);
 
 /**
- * cache_insert: insert the page into the cache. the previous value will be overwritten
+ * cache_insert: insert the page into the cache. the page cache
+ * will dup the data on insert. the previous value will be overwritten
  *
  * @cache pointer to the PageCache struct
  * @addr: page address

page_cache.c

@@ -159,7 +159,7 @@ void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata)
         cache->num_items++;
     }
 
-    it->it_data = pdata;
+    it->it_data = g_memdup(pdata, cache->page_size);
     it->it_age = ++cache->max_item_age;
     it->it_addr = addr;
 }