qdev/compat: compat property infrastructure.

This add support for switching devices into a compatibility mode
using device properties.  Machine types can have a list of properties
for specific devices attached to allow the easy creation of machine
types compatible to older qemu versions.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index 8b0d0ffce7..06c25aff71 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -244,3 +244,26 @@ void qdev_prop_set_defaults(DeviceState *dev, Property *props)
     }
 }
 
+static CompatProperty *compat_props;
+
+void qdev_prop_register_compat(CompatProperty *props)
+{
+    compat_props = props;
+}
+
+void qdev_prop_set_compat(DeviceState *dev)
+{
+    CompatProperty *prop;
+
+    if (!compat_props) {
+        return;
+    }
+    for (prop = compat_props; prop->driver != NULL; prop++) {
+        if (strcmp(dev->info->name, prop->driver) != 0) {
+            continue;
+        }
+        if (qdev_prop_parse(dev, prop->property, prop->value) != 0) {
+            abort();
+        }
+    }
+}