diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
index 843ae71fc6..47f84be8e0 100644
--- a/docs/system/deprecated.rst
+++ b/docs/system/deprecated.rst
@@ -404,6 +404,17 @@ The above, converted to the current supported format::
 
   json:{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"}
 
+linux-user mode CPUs
+--------------------
+
+``tilegx`` CPUs (since 5.1.0)
+'''''''''''''''''''''''''''''
+
+The ``tilegx`` guest CPU support (which was only implemented in
+linux-user mode) is deprecated and will be removed in a future version
+of QEMU. Support for this CPU was removed from the upstream Linux
+kernel in 2018, and has also been dropped from glibc.
+
 Related binaries
 ----------------