@@ -133,6 +133,20 @@
* This option doesn't require a backend to use O_DIRECT, so it
* should not be used to try to control the caching behaviour.
*
+ * require
+ *
+ * The directory "require" maybe be created by tools domain to
+ * override the maximum feature set that backend provides to the
+ * frontend. The children entries within this directory are
+ * features names and its correspondent value e.g.:
+ *
+ * /local/domain/X/backend/vbd/<domid>/<devno>/require
+ * /local/domain/X/backend/vbd/<domid>/<devno>/require/multi-queue-max-queues = "2"
+ * /local/domain/X/backend/vbd/<domid>/<devno>/require/feature-persistent = "0"
+ *
+ * In the example above, block backend will negotiate up to a maximum of
+ * two queues with frontend plus disabling persistent grants.
+ *
*--------------------------------- Features ---------------------------------
*
* feature-barrier
The proposed directory provides a mechanism for tools to control the maximum feature set of the device being provisioned by backends. Examples include max ring page order, persistent grants, number of queues etc. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> --- xen/include/public/io/blkif.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+)