shutdown: Prepare for use of an enum in reset/shutdown_request

We want to track why a guest was shutdown; in particular, being able
to tell the difference between a guest request (such as ACPI request)
and host request (such as SIGINT) will prove useful to libvirt.
Since all requests eventually end up changing shutdown_requested in
vl.c, the logical change is to make that value track the reason,
rather than its current 0/1 contents.

Since command-line options control whether a reset request is turned
into a shutdown request instead, the same treatment is given to
reset_requested.

This patch adds an internal enum ShutdownCause that describes reasons
that a shutdown can be requested, and changes qemu_system_reset() to
pass the reason through, although for now nothing is actually changed
with regards to what gets reported.  The enum could be exported via
QAPI at a later date, if deemed necessary, but for now, there has not
been a request to expose that much detail to end clients.

For the most part, we turn 0 into SHUTDOWN_CAUSE_NONE, and 1 into
SHUTDOWN_CAUSE_HOST_ERROR; the only specific case where we have enough
information right now to use a different value is when we are reacting
to a host signal.  It will take a further patch to edit all call-sites
that can trigger a reset or shutdown request to properly pass in any
other reasons; this patch includes TODOs to point such places out.

qemu_system_reset() trades its 'bool report' parameter for a
'ShutdownCause reason', with all non-zero values having the same
effect; this lets us get rid of the weird #defines for VMRESET_*
as synonyms for bools.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170515214114.15442-3-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/migration/colo.c b/migration/colo.c
index 963c80256d..12d355a657 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -623,7 +623,7 @@ void *colo_process_incoming_thread(void *opaque)
         }
 
         qemu_mutex_lock_iothread();
-        qemu_system_reset(VMRESET_SILENT);
+        qemu_system_reset(SHUTDOWN_CAUSE_NONE);
         vmstate_loading = true;
         if (qemu_loadvm_state(fb) < 0) {
             error_report("COLO: loadvm failed");
diff --git a/migration/savevm.c b/migration/savevm.c
index f5e81948e6..752bf6483f 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2285,7 +2285,7 @@ int load_vmstate(const char *name, Error **errp)
         return -EINVAL;
     }
 
-    qemu_system_reset(VMRESET_SILENT);
+    qemu_system_reset(SHUTDOWN_CAUSE_NONE);
     mis->from_src_file = f;
 
     aio_context_acquire(aio_context);