Assuiming you have a disk image with Fedora called: "base.qcow2", launch
QEMU this way:

    $ qemu-system-x86_64 -display none -no-user-config \
        -nodefaults -monitor stdio -cpu IvyBridge \
        -machine pc,accel=kvm,usb=off -m 2048
        -blockdev node-name=node-Base,driver=qcow2,file.driver=file,file.filename=./base.qcow2 \
    	-device virtio-blk,drive=node-Base,id=virtio0 \
	-qmp unix:/tmp/qmp-sock,server,nowait

Then, from 'qemu/scripts/qmp/', invoke the 'qmp-shell' (this is just a
convenient script that lets you supply key-value pairs of input and
outputs (except when it doesn't) raw JSON):

    $ ./qmp/qmp-shell -p -v /tmp/qmp-sock
    (QEMU)

A simple example, when you type the QMP command `query-kvm` on the
'qmp-shell', you'll see it generate JSON query with arguments (there are
none in this case) and its succesful response:

    (QEMU) query-kvm
    {
        "execute": "query-kvm", 
        "arguments": {}
    }
    {
        "return": {
            "enabled": true, 
            "present": true
        }
    }


The Problem
-----------

Now, let's try a bit more complex command that I'm hoping the
'qmp-shell' will generate valid JSON.  But it doesn't:

    (QEMU) query-cpu-model-expansion type=static model={"name":"IvyBridge"}
    {
        "execute": "query-cpu-model-expansion", 
        "arguments": {
            "model": "{name:IvyBridge}", 
            "type": "static"
        }
    }
    {
        "error": {
            "class": "GenericError", 
            "desc": "Invalid parameter type for 'model', expected: object"
        }
    }
    (QEMU) 


*Ideally*, it should generate the following:

    {  
       "execute":"query-cpu-model-expansion",
       "arguments":{  
          "type":"static",
          "model":{  
             "name":"IvyBridge"
          }
       }
    }

        - - -

Looking at the code of the 'qmp-shell', its very rudimentary parser
__parse_value():

https://git.qemu.org/?p=qemu.git;a=blob;f=scripts/qmp/qmp-shell;h=770140772d07b90d8a03d54a6d570d269002cb07;hb=HEAD#l167