docs/devel: document query handle lifetimes

I forgot to document the lifetime of handles in the developer
documentation. Do so now.

Signed-off-by: Alex Bennée <[email protected]>
Reviewed-by: Robert Foley <[email protected]>
Reviewed-by: Robert Foley <[email protected]>
Message-Id: <20200225124710[email protected]>

diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst
index 718eef00f22a6fb51ebee8afaff106f15a00459f..a05990906cc09b9b764858dc0fa0fbf9d50b373f 100644 (file)
--- a/docs/devel/tcg-plugins.rst
+++ b/docs/devel/tcg-plugins.rst
@@ -51,8 +51,17 @@ about how QEMU's translation works to the plugins. While there are
 conceptions such as translation time and translation blocks the
 details are opaque to plugins. The plugin is able to query select
 details of instructions and system configuration only through the
-exported *qemu_plugin* functions. The types used to describe
-instructions and events are opaque to the plugins themselves.
+exported *qemu_plugin* functions.
+
+Query Handle Lifetime
+---------------------
+
+Each callback provides an opaque anonymous information handle which
+can usually be further queried to find out information about a
+translation, instruction or operation. The handles themselves are only
+valid during the lifetime of the callback so it is important that any
+information that is needed is extracted during the callback and saved
+by the plugin.
 
 Usage
 =====