ide: Update ide_drive_get to be HBA agnostic

Instead of duplicating the logic for the if_ide
(bus,unit) mappings, rely on the blockdev layer
for managing those mappings for us, and use the
drive_get_by_index call instead.

This allows ide_drive_get to work for AHCI HBAs
as well, and can be used in the Q35 initialization.

Lastly, change the nature of the argument to
ide_drive_get so that represents the number of
total drives we can support, and not the total
number of buses. This will prevent array overflows
if the units-per-default-bus property ever needs
to be adjusted for compatibility reasons.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1412187569-23452-5-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/blockdev.c b/blockdev.c
index 1780d7723a..e595910476 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -135,6 +135,23 @@ void blockdev_auto_del(BlockDriverState *bs)
     }
 }
 
+/**
+ * Returns the current mapping of how many units per bus
+ * a particular interface can support.
+ *
+ *  A positive integer indicates n units per bus.
+ *  0 implies the mapping has not been established.
+ * -1 indicates an invalid BlockInterfaceType was given.
+ */
+int drive_get_max_devs(BlockInterfaceType type)
+{
+    if (type >= IF_IDE && type < IF_COUNT) {
+        return if_max_devs[type];
+    }
+
+    return -1;
+}
+
 static int drive_index_to_bus_id(BlockInterfaceType type, int index)
 {
     int max_devs = if_max_devs[type];