[PATCH v5 5/6] RFC qapi/device_add: handle the rom_order_override when cold-plugging

[Damien Hedde]

rom_set_order_override() and rom_reset_order_override() were called
in qemu_create_cli_devices() to set the rom_order_override value
once and for all when creating the devices added on CLI.

Unfortunately this won't work with qapi commands.

Move the calls inside device_add so that it will be done in every
case:
+ CLI option: -device
+ QAPI command: device_add

rom_[set|reset]_order_override() are implemented in hw/core/loader.c
They either do nothing or call fw_cfg_[set|reset]_order_override().
The later functions are implemented in hw/nvram/fw_cfg.c and only
change an integer value of a "global" variable.
In consequence, there are no complex side effects involved and we can
safely move them from outside the -device option loop to the inner
function.

Signed-off-by: Damien Hedde <damien.he...@greensocs.com>
---

I see 2 other ways to handle this:

1. Adding a new option to device_add.

We could add a new boolean (_rom_order_override_ for example) option
tot he qapi command. This flag would then be forced to "true" when
handling "-device" parameter from CLI.
The flag default could be:
- always false
- false on hot-plug, true on cold-plug.

2. Adding a new qapi command
We could add one or two commands to do the
rom_[set|reset]_order_override() operation.
---
 softmmu/qdev-monitor.c | 11 +++++++++++
 softmmu/vl.c           |  2 --
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
index d68ef883b5..7cbee2b0d8 100644
--- a/softmmu/qdev-monitor.c
+++ b/softmmu/qdev-monitor.c
@@ -43,6 +43,7 @@
 #include "hw/qdev-properties.h"
 #include "hw/clock.h"
 #include "hw/boards.h"
+#include "hw/loader.h"
 
 /*
  * Aliases were a bad idea from the start.  Let's keep them
@@ -673,6 +674,10 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts,
         return NULL;
     }
 
+    if (!is_hotplug) {
+        rom_set_order_override(FW_CFG_ORDER_OVERRIDE_DEVICE);
+    }
+
     /* create device */
     dev = qdev_new(driver);
 
@@ -714,6 +719,9 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts,
     if (!qdev_realize(DEVICE(dev), bus, errp)) {
         goto err_del_dev;
     }
+    if (!is_hotplug) {
+        rom_reset_order_override();
+    }
     return dev;
 
 err_del_dev:
@@ -721,6 +729,9 @@ err_del_dev:
         object_unparent(OBJECT(dev));
         object_unref(OBJECT(dev));
     }
+    if (!is_hotplug) {
+        rom_reset_order_override();
+    }
     return NULL;
 }
 
diff --git a/softmmu/vl.c b/softmmu/vl.c
index ea15e37973..5a0d54b595 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2635,7 +2635,6 @@ static void qemu_create_cli_devices(void)
     }
 
     /* init generic devices */
-    rom_set_order_override(FW_CFG_ORDER_OVERRIDE_DEVICE);
     qemu_opts_foreach(qemu_find_opts("device"),
                       device_init_func, NULL, &error_fatal);
     QTAILQ_FOREACH(opt, &device_opts, next) {
@@ -2652,7 +2651,6 @@ static void qemu_create_cli_devices(void)
         object_unref(OBJECT(dev));
         loc_pop(&opt->loc);
     }
-    rom_reset_order_override();
 }
 
 static void qemu_machine_creation_done(void)
-- 
2.36.1