qapi: Document some missing details of RTC_CHANGE event

The RTC_CHANGE event's documentation is missing some details:
 * the offset argument is in units of seconds
 * it isn't guaranteed that the RTC will implement the event

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20220221192123.749970-3-peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

diff --git a/qapi/misc.json b/qapi/misc.json
index 7a70eaa3ffc80662ea1590e7b8332c7e6b04ea74..0ab235e41f732641920b6501523876918c33ffa3 100644 (file)
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -533,10 +533,12 @@
 #
 # Emitted when the guest changes the RTC time.
 #
-# @offset: offset between base RTC clock (as specified by -rtc base), and
-#          new RTC clock value
+# @offset: offset in seconds between base RTC clock (as specified
+#          by -rtc base), and new RTC clock value
 #
 # Note: This event is rate-limited.
+#       It is not guaranteed that the RTC in the system implements
+#       this event, or even that the system has an RTC at all.
 #
 # Since: 0.13
 #