exec: always call qemu_get_ram_ptr within rcu_read_lock

[mirror_qemu.git] / include / exec / memory.h

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 0f07159bb43bae92dc0d0b2fe29becf853833498..9bbd247c38cd5cce7b4f68446ea778de4522311b 100644 (file)
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -656,8 +656,13 @@ int memory_region_get_fd(MemoryRegion *mr);
  * memory_region_get_ram_ptr: Get a pointer into a RAM memory region.
  *
  * Returns a host pointer to a RAM memory region (created with
- * memory_region_init_ram() or memory_region_init_ram_ptr()).  Use with
- * care.
+ * memory_region_init_ram() or memory_region_init_ram_ptr()).
+ *
+ * Use with care; by the time this function returns, the returned pointer is
+ * not protected by RCU anymore.  If the caller is not within an RCU critical
+ * section and does not hold the iothread lock, it must have other means of
+ * protecting the pointer, such as a reference to the region that includes
+ * the incoming ram_addr_t.
  *
  * @mr: the memory region being queried.
  */