QMP command set-vcpu-dirty-limit hangs

[Markus Armbruster]

Watch this:

    $ qemu-system-x86_64 -S -display none -qmp stdio -accel 
kvm,dirty-ring-size=1024
    {"QMP": {"version": {"qemu": {"micro": 90, "minor": 2, "major": 7}, 
"package": "v8.0.0-rc0-15-g918ee397b6-dirty"}, "capabilities": ["oob"]}}
    {"execute": "qmp_capabilities"}
    {"return": {}}
    {"execute": "set-vcpu-dirty-limit","arguments": {"dirty-rate": 200}

Hangs.

If I'm using it incorrectly (I have no idea), it should fail, not hang.