qapi: introduce new cmd option "allow-preconfig"

New option will be used to allow commands, which are prepared/need
to run, during preconfig state. Other commands that should be able
to run in preconfig state, should be amended to not expect machine
in initialized state or deal with it.

For compatibility reasons, commands that don't use new flag
'allow-preconfig' explicitly are not permitted to run in
preconfig state but allowed in all other states like they used
to be.

Within this patch allow following commands in preconfig state:
   qmp_capabilities
   query-qmp-schema
   query-commands
   query-command-line-options
   query-status
   exit-preconfig
to allow qmp connection, basic introspection and moving to the next
state.

PS:
set-numa-node and query-hotpluggable-cpus will be enabled later in
a separate patches.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1526057503-39287-1-git-send-email-imammedo@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[ehabkost: Changed "since 2.13" to "since 3.0"]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt
index b9b6eabd08..1366228b2a 100644
--- a/docs/devel/qapi-code-gen.txt
+++ b/docs/devel/qapi-code-gen.txt
@@ -559,7 +559,7 @@ following example objects:
 Usage: { 'command': STRING, '*data': COMPLEX-TYPE-NAME-OR-DICT,
          '*returns': TYPE-NAME, '*boxed': true,
          '*gen': false, '*success-response': false,
-         '*allow-oob': true }
+         '*allow-oob': true, '*allow-preconfig': true }
 
 Commands are defined by using a dictionary containing several members,
 where three members are most common.  The 'command' member is a
@@ -683,6 +683,15 @@ OOB command handlers must satisfy the following conditions:
 
 If in doubt, do not implement OOB execution support.
 
+A command may use the optional 'allow-preconfig' key to permit its execution
+at early runtime configuration stage (preconfig runstate).
+If not specified then a command defaults to 'allow-preconfig': false.
+
+An example of declaring a command that is enabled during preconfig:
+ { 'command': 'qmp_capabilities',
+   'data': { '*enable': [ 'QMPCapability' ] },
+   'allow-preconfig': true }
+
 === Events ===
 
 Usage: { 'event': STRING, '*data': COMPLEX-TYPE-NAME-OR-DICT,