hmp: Add support for coroutine command handlers

Often, QMP command handlers are not only called to handle QMP commands,
but also from a corresponding HMP command handler. In order to give them
a consistent environment, optionally run HMP command handlers in a
coroutine, too.

The implementation is a lot simpler than in QMP because for HMP, we
still block the VM while the coroutine is running.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201005155855.256490-11-kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt
index 4a41e36a75..c6438c6aa9 100644
--- a/docs/devel/qapi-code-gen.txt
+++ b/docs/devel/qapi-code-gen.txt
@@ -617,8 +617,8 @@ pitfalls are:
 
 Since the command handler may assume coroutine context, any callers
 other than the QMP dispatcher must also call it in coroutine context.
-In particular, HMP commands calling such a QMP command handler must
-enter coroutine context before calling the handler.
+In particular, HMP commands calling such a QMP command handler must be
+marked .coroutine = true in hmp-commands.hx.
 
 It is an error to specify both 'coroutine': true and 'allow-oob': true
 for a command.  We don't currently have a use case for both together and