virtio-blk: switch off scsi-passthrough by default

Devices that are compliant with virtio-1 do not support scsi
passthrough any more (and it has not been a recommended setup
anyway for quite some time). To avoid having to switch it off
explicitly in newer qemus that turn on virtio-1 by default, let's
switch the default to scsi=false for 2.5.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Message-id: 1444991154-79217-4-git-send-email-cornelia.huck@de.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

hw/block/virtio-blk.c

@@ -972,7 +972,7 @@ static Property virtio_blk_properties[] = {
     DEFINE_PROP_STRING("serial", VirtIOBlock, conf.serial),
     DEFINE_PROP_BIT("config-wce", VirtIOBlock, conf.config_wce, 0, true),
 #ifdef __linux__
-    DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, true),
+    DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, false),
 #endif
     DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,
                     true),

include/hw/compat.h

@@ -2,7 +2,11 @@
 #define HW_COMPAT_H
 
 #define HW_COMPAT_2_4 \
-        /* empty */
+        {\
+            .driver   = "virtio-blk-device",\
+            .property = "scsi",\
+            .value    = "true",\
+        },
 
 #define HW_COMPAT_2_3 \
         {\