QMP: Update spec file

- Remove "draft" status
- Change default success response to be json-object
- Change error and event data member to be a json-object
- Update examples
- Add new section "Compatibility Considerations"
- Other fixes and clarifications

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

QMP/qmp-spec.txt

@@ -1,4 +1,4 @@
-           QEMU Monitor Protocol Draft Specification - Version 0.1
+           QEMU Monitor Protocol Specification - Version 0.1
 
 1. Introduction
 ===============
@@ -27,9 +27,9 @@ the JSON standard:
 
 http://www.ietf.org/rfc/rfc4627.txt
 
-For convenience, json-objects mentioned in this document will have its members
-in a certain order. However, in real protocol usage json-objects members can
-be in ANY order, thus no particular order should be assumed.
+For convenience, json-object members and json-array elements mentioned in
+this document will be in a certain order. However, in real protocol usage
+they can be in ANY order, thus no particular order should be assumed.
 
 2.1 General Definitions
 -----------------------
@@ -85,12 +85,13 @@ without errors.
 
 The format is:
 
-{ "return": json-value, "id": json-value }
+{ "return": json-object, "id": json-value }
 
  Where,
 
 - The "return" member contains the command returned data, which is defined
-  in a per-command basis or "OK" if the command does not return data
+  in a per-command basis or an empty json-object if the command does not
+  return data
 - The "id" member contains the transaction identification associated
   with the command execution (if issued by the Client)
 
@@ -102,7 +103,7 @@ completed because of an error condition.
 
 The format is:
 
-{ "error": { "class": json-string, "data": json-value, "desc": json-string },
+{ "error": { "class": json-string, "data": json-object, "desc": json-string },
   "id": json-value }
 
  Where,
@@ -110,7 +111,7 @@ The format is:
 - The "class" member contains the error class name (eg. "ServiceUnavailable")
 - The "data" member contains specific error data and is defined in a
   per-command basis, it will be an empty json-object if the error has no data
-- The "desc" member is a human-readable error message.  Clients should
+- The "desc" member is a human-readable error message. Clients should
   not attempt to parse this message.
 - The "id" member contains the transaction identification associated with
   the command execution (if issued by the Client)
@@ -127,7 +128,7 @@ to the Client at any time. They are called 'asynchronous events'.
 
 The format is:
 
-{ "event": json-string, "data": json-value,
+{ "event": json-string, "data": json-object,
   "timestamp": { "seconds": json-number, "microseconds": json-number } }
 
  Where,
@@ -135,7 +136,7 @@ The format is:
 - The "event" member contains the event's name
 - The "data" member contains event specific data, which is defined in a
   per-event basis, it is optional
-- The "timestamp" member contains the exact time of when the event ocurred
+- The "timestamp" member contains the exact time of when the event occurred
   in the Server. It is a fixed json-object with time in seconds and
   microseconds
 
@@ -157,19 +158,20 @@ S: {"QMP": {"capabilities": []}}
 ---------------------------
 
 C: { "execute": "stop" }
-S: {"return": "OK"}
+S: {"return": {}}
 
 3.3 KVM information
 -------------------
 
-C: {"execute": "query-kvm", "id": "example"}
-S: {"return": "enabled", "id": "example"}
+C: { "execute": "query-kvm", "id": "example" }
+S: {"return": {"enabled": true, "present": true}, "id": "example"}
 
 3.4 Parsing error
 ------------------
 
 C: { "execute": }
-S: {"error": {"class": "JSONParsing", "data": {}}}
+S: {"error": {"class": "JSONParsing", "desc": "Invalid JSON syntax", "data":
+{}}}
 
 3.5 Powerdown event
 -------------------
@@ -177,19 +179,25 @@ S: {"error": {"class": "JSONParsing", "data": {}}}
 S: {"timestamp": {"seconds": 1258551470, "microseconds": 802384}, "event":
 "POWERDOWN"}
 
-4. Notes to Client implementors
--------------------------------
+4. Compatibility Considerations
+--------------------------------
 
-4.1 It is recommended to always start the Server in pause mode, thus the
-    Client is able to perform any setup procedure without the risk of
-    race conditions and related problems
+In order to achieve maximum compatibility between versions, Clients must not 
+assume any particular:
 
-4.2 It is recommended to always check the capabilities json-array, issued
-    with the greeting message, at connection time
+- Size of json-objects or length of json-arrays
+- Order of json-object members or json-array elements
+- Amount of errors generated by a command, that is, new errors can be added
+  to any existing command in newer versions of the Server
 
-4.3 Json-objects or json-arrays mentioned in this document are not fixed
-    and no particular size or number of members/elements should be assumed.
-    New members/elements can be added at any time.
+Additionally, Clients should always:
 
-4.4 No particular order of json-objects members should be assumed, they
-    can change at any time
+- Check the capabilities json-array at connection time
+- Check the availability of commands with 'query-commands' before issuing them
+
+5. Recommendations to Client implementors
+-----------------------------------------
+
+5.1 The Server should be always started in pause mode, thus the Client is
+    able to perform any setup procedure without the risk of race conditions
+    and related problems