[PATCH 6/6] docs: deprecate virtio-crypto

We have outstanding guest exploitable bugs in the code which is fairly
complex and needs some serious love to clean it up. As off-CPU
cryptography acceleration seems to be waning in popularity lets just
deprecate the sub-system with a view to removing it in a couple of
cycles.

Link: https://gitlab.com/qemu-project/qemu/-/work_items/3625
Signed-off-by: Alex Bennée <[email protected]>
Cc: Gonglei <[email protected]>
---
 docs/about/deprecated.rst | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 0c656a968fc..3c22981fc8a 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -276,6 +276,20 @@ future release. Where no 'dh-params.pem' file is provided, the DH
 parameters will be automatically negotiated in accordance with
 RFC7919.
 
+Devices
+-------
+
+``virtio-crypto`` (since 11.2)
+''''''''''''''''''''''''''''''
+
+The ``virtio-crypto`` device emulation is quite complex code with a
+number of known flaws. It has never been migratable so is unlikely to
+be used in any serious virtualization setting. With most modern
+systems supporting on-CPU cryptography acceleration via their
+ISAs sets the need for off-CPU acceleration is also reduced. Add to
+that the kernel has recently removed the ability to use off-CPU
+acceleration suggests the time for this sort of off-load has passed.
+
 Device options
 --------------
 

-- 
2.47.3