[Qemu-devel] [PATCH] qdev-monitor: Avoid exiting when hot-plugging two devices with the same bootindex value

[Marcel Apfelbaum <marcel.a@redhat.com>]

Qemu is expected to quit if the same boot index value is used by two devices.
However, hot-plugging a device with a bootindex value already used should
fail with a friendly message rather than quitting a running VM.

Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
---
 qdev-monitor.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/qdev-monitor.c b/qdev-monitor.c
index 410cdcb..654d086 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -24,6 +24,7 @@
 #include "qmp-commands.h"
 #include "sysemu/arch_init.h"
 #include "qemu/config-file.h"
+#include "sysemu/sysemu.h"
 
 /*
  * Aliases were a bad idea from the start.  Let's keep them
@@ -442,6 +443,31 @@ static BusState *qbus_find(const char *path)
     }
 }
 
+#define OBJ_PROP_BOOTINDEX "bootindex"
+
+static bool bootindex_colision(Object *obj, QemuOpts *opts)
+{
+    int32_t bootindex;
+
+    if (!object_property_find(obj, OBJ_PROP_BOOTINDEX, NULL)) {
+        return false;
+    }
+
+    /* avoid parsing by setting the property and then getting it typed */
+    object_property_parse(obj, qemu_opt_get(opts, OBJ_PROP_BOOTINDEX),
+                          OBJ_PROP_BOOTINDEX, NULL);
+    bootindex = (int32_t)object_property_get_int(obj, OBJ_PROP_BOOTINDEX,
+                                                 NULL);
+
+    if (bootindex >= 0) {
+        if (get_boot_device(bootindex)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
 DeviceState *qdev_device_add(QemuOpts *opts)
 {
     ObjectClass *obj;
@@ -502,6 +528,13 @@ DeviceState *qdev_device_add(QemuOpts *opts)
     /* create device, set properties */
     qdev = DEVICE(object_new(driver));
 
+    if (qdev_hotplug && bootindex_colision(OBJECT(qdev), opts)) {
+        qerror_report(QERR_INVALID_PARAMETER_VALUE,
+                      "bootindex", "an unused boot index value");
+        qdev_free(qdev);
+        return NULL;
+    }
+
     if (bus) {
         qdev_set_parent_bus(qdev, bus);
     }
-- 
1.8.3.1