Don't abort on memory allocation error

It is better to fail migration in case of failure to
allocate new cache item

Signed-off-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

arch_init.c

@@ -284,7 +284,9 @@ 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, current_data);
+            if (cache_insert(XBZRLE.cache, current_addr, current_data) == -1) {
+                return -1;
+            }
         }
         acct_info.xbzrle_cache_miss++;
         return -1;

include/migration/page_cache.h

@@ -60,11 +60,13 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t addr);
  * cache_insert: insert the page into the cache. the page cache
  * will dup the data on insert. the previous value will be overwritten
  *
+ * Returns -1 on error
+ *
  * @cache pointer to the PageCache struct
  * @addr: page address
  * @pdata: pointer to the page
  */
-void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata);
+int cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata);
 
 /**
  * cache_resize: resize the page cache. In case of size reduction the extra

page_cache.c

@@ -150,7 +150,7 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t addr)
     return cache_get_by_addr(cache, addr)->it_data;
 }
 
-void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata)
+int cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata)
 {
 
     CacheItem *it = NULL;
@@ -161,16 +161,22 @@ void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata)
     /* actual update of entry */
     it = cache_get_by_addr(cache, addr);
 
-    /* free old cached data if any */
-    g_free(it->it_data);
-
+    /* allocate page */
     if (!it->it_data) {
+        it->it_data = g_try_malloc(cache->page_size);
+        if (!it->it_data) {
+            DPRINTF("Error allocating page\n");
+            return -1;
+        }
         cache->num_items++;
     }
 
-    it->it_data = g_memdup(pdata, cache->page_size);
+    memcpy(it->it_data, pdata, cache->page_size);
+
     it->it_age = ++cache->max_item_age;
     it->it_addr = addr;
+
+    return 0;
 }
 
 int64_t cache_resize(PageCache *cache, int64_t new_num_pages)