[PATCH RFC 11/11] vl: Enter main loop in phase @machine-initialized

[Markus Armbruster <armbru@redhat.com>]

The previous commit demonstrated how you can interleave QMP-over-CLI
with startup.  We want the same for real QMP.

QMP-over-CLI starts in phase @no-machine, and may advance the phase.

We then advance to phase @machine-ready, and enter the main loop, and
real QMP becomes available.

If we skip the phase advance, real QMP becomes exactly as expressive
as QMP-over-CLI.  Except the main loop crashes.

If we skip to phase @machine-created, it doesn't crash, but it doesn't
give me a QMP monitor either.  Same for phase @accel-created.

Skipping to @machine-initialized works, and suffices to let me
demonstrate cold plug via QMP:

    $ qemu-system-x86_64
    {"QMP": {"version": {"qemu": {"micro": 92, "minor": 1, "major": 6}, "package": "v6.2.0-rc2-39-g8c7f07732b"}, "capabilities": ["oob"]}}
    {"execute": "qmp_capabilities", "arguments": {"enable": ["oob"]}}
    {"return": {}}
    {"execute": "device_add", "arguments": {"driver": "isa-serial"}}
    {"return": {}}

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 softmmu/vl.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/softmmu/vl.c b/softmmu/vl.c
index 9406368338..01f87aec07 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -1038,7 +1038,12 @@ void qemu_init(int argc, char **argv, char **envp)
         }
     }
 
-    qemu_until_phase(PHASE_MACHINE_READY);
+    /*
+     * FIXME need to force phase, because staying in PHASE_NO_MACHINE
+     * crashes, and going only to PHASE_MACHINE_CREATED or
+     * PHASE_ACCEL_CREATED gives no monitor.
+     */
+    qemu_until_phase(PHASE_MACHINE_INITIALIZED);
 }
 
 void qemu_until_phase(MachineInitPhase phase)
-- 
2.31.1