block/qdev: Allow configuring WCE with qdev properties

As cache.writeback is a BlockBackend property and as such more related
to the guest device than the BlockDriverState, we already removed it
from the blockdev-add interface. This patch adds the new way to set it,
as a qdev property of the corresponding guest device.

For example: -drive if=none,file=test.img,node-name=img
             -device ide-hd,drive=img,write-cache=off

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/hw/block/block.c b/hw/block/block.c
index 97a59d4fa2..396b0d5de1 100644
--- a/hw/block/block.c
+++ b/hw/block/block.c
@@ -51,6 +51,22 @@ void blkconf_blocksizes(BlockConf *conf)
     }
 }
 
+void blkconf_apply_backend_options(BlockConf *conf)
+{
+    BlockBackend *blk = conf->blk;
+    bool wce;
+
+    switch (conf->wce) {
+    case ON_OFF_AUTO_ON:    wce = true; break;
+    case ON_OFF_AUTO_OFF:   wce = false; break;
+    case ON_OFF_AUTO_AUTO:  wce = blk_enable_write_cache(blk); break;
+    default:
+        abort();
+    }
+
+    blk_set_enable_write_cache(blk, wce);
+}
+
 void blkconf_geometry(BlockConf *conf, int *ptrans,
                       unsigned cyls_max, unsigned heads_max, unsigned secs_max,
                       Error **errp)