Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com>
---
docs/memory.txt | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/docs/memory.txt b/docs/memory.txt
index 5bbee8e..3f88812 100644
--- a/docs/memory.txt
+++ b/docs/memory.txt
@@ -170,3 +170,8 @@ various constraints can be supplied to control how these
callbacks are called:
- .old_portio and .old_mmio can be used to ease porting from code using
cpu_register_io_memory() and register_ioport(). They should not be used
in new code.
+
+MMIO regions are provided with ->ref() and ->unref() callbacks; This pair
callbacks
+are optional. When ref() return non-zero, Both MemoryRegion and its opaque are
+safe to use.
+
--
1.7.4.4
