By default, we assume that server need to wait all inflight IO on
GET_VRING_BASE. However, this fact is not recorded anywhere in the
documentation.
So, add this info in rst.

Signed-off-by: Alexandr Moshkov <dtalexundeer@yandex-team.ru>
---
 docs/interop/vhost-user.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 2e50f2ddfa..02908b48fa 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -1243,7 +1243,8 @@ Front-end message types
 
   When and as long as all of a device's vrings are stopped, it is
   *suspended*, see :ref:`Suspended device state
-  <suspended_device_state>`.
+  <suspended_device_state>`. The back-end must complete all inflight I/O
+  requests for the specified vring before stopping it.
 
   The request payload's *num* field is currently reserved and must be
   set to 0.
-- 
2.34.1