For all the examples in the next sections, the test setup is the same and is
shown here.
-First, QEMU should be started as:
+First, QEMU should be started like this:
-# /path/to/your/source/qemu [...] \
+# qemu-system-TARGET [...] \
-chardev socket,id=qmp,port=4444,host=localhost,server \
-mon chardev=qmp,mode=control,pretty=on
}
}
-You should see "Hello, world" and "we love qemu" in the terminal running qemu,
+You should see "Hello, world" and "We love qemu" in the terminal running qemu,
if you don't see these strings, then something went wrong.
=== Errors ===
}
}
-As a general rule, all QMP errors should use ERROR_CLASS_GENERIC_ERROR
-(done by default when using error_setg()). There are two exceptions to
-this rule:
+Note that error_setg() produces a "GenericError" class. In general,
+all QMP errors should have that error class. There are two exceptions
+to this rule:
- 1. A non-generic ErrorClass value exists* for the failure you want to report
- (eg. DeviceNotFound)
+ 1. To support a management application's need to recognize a specific
+ error for special handling
- 2. Management applications have to take special action on the failure you
- want to report, hence you have to add a new ErrorClass value so that they
- can check for it
+ 2. Backward compatibility
If the failure you want to report falls into one of the two cases above,
use error_set() with a second argument of an ErrorClass value.
- * All existing ErrorClass values are defined in the qapi-schema.json file
-
=== Command Documentation ===
There's only one step missing to make "hello-world"'s implementation complete,
and that's its documentation in the schema file.
-This is very important. No QMP command will be accepted in QEMU without proper
-documentation.
-
There are many examples of such documentation in the schema file already, but
here goes "hello-world"'s new entry for qapi/misc.json:
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