Linux-libre 4.5-gnu

2 files changed, 56 insertions, 8 deletions

diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
index c33e1c489..8b8cfadf7 100644
--- a/include/xen/interface/io/blkif.h
+++ b/include/xen/interface/io/blkif.h
@@ -28,6 +28,54 @@ typedef uint16_t blkif_vdev_t;
 typedef uint64_t blkif_sector_t;
 
 /*
+ * Multiple hardware queues/rings:
+ * If supported, the backend will write the key "multi-queue-max-queues" to
+ * the directory for that vbd, and set its value to the maximum supported
+ * number of queues.
+ * Frontends that are aware of this feature and wish to use it can write the
+ * key "multi-queue-num-queues" with the number they wish to use, which must be
+ * greater than zero, and no more than the value reported by the backend in
+ * "multi-queue-max-queues".
+ *
+ * For frontends requesting just one queue, the usual event-channel and
+ * ring-ref keys are written as before, simplifying the backend processing
+ * to avoid distinguishing between a frontend that doesn't understand the
+ * multi-queue feature, and one that does, but requested only one queue.
+ *
+ * Frontends requesting two or more queues must not write the toplevel
+ * event-channel and ring-ref keys, instead writing those keys under sub-keys
+ * having the name "queue-N" where N is the integer ID of the queue/ring for
+ * which those keys belong. Queues are indexed from zero.
+ * For example, a frontend with two queues must write the following set of
+ * queue-related keys:
+ *
+ * /local/domain/1/device/vbd/0/multi-queue-num-queues = "2"
+ * /local/domain/1/device/vbd/0/queue-0 = ""
+ * /local/domain/1/device/vbd/0/queue-0/ring-ref = "<ring-ref#0>"
+ * /local/domain/1/device/vbd/0/queue-0/event-channel = "<evtchn#0>"
+ * /local/domain/1/device/vbd/0/queue-1 = ""
+ * /local/domain/1/device/vbd/0/queue-1/ring-ref = "<ring-ref#1>"
+ * /local/domain/1/device/vbd/0/queue-1/event-channel = "<evtchn#1>"
+ *
+ * It is also possible to use multiple queues/rings together with
+ * feature multi-page ring buffer.
+ * For example, a frontend requests two queues/rings and the size of each ring
+ * buffer is two pages must write the following set of related keys:
+ *
+ * /local/domain/1/device/vbd/0/multi-queue-num-queues = "2"
+ * /local/domain/1/device/vbd/0/ring-page-order = "1"
+ * /local/domain/1/device/vbd/0/queue-0 = ""
+ * /local/domain/1/device/vbd/0/queue-0/ring-ref0 = "<ring-ref#0>"
+ * /local/domain/1/device/vbd/0/queue-0/ring-ref1 = "<ring-ref#1>"
+ * /local/domain/1/device/vbd/0/queue-0/event-channel = "<evtchn#0>"
+ * /local/domain/1/device/vbd/0/queue-1 = ""
+ * /local/domain/1/device/vbd/0/queue-1/ring-ref0 = "<ring-ref#2>"
+ * /local/domain/1/device/vbd/0/queue-1/ring-ref1 = "<ring-ref#3>"
+ * /local/domain/1/device/vbd/0/queue-1/event-channel = "<evtchn#1>"
+ *
+ */
+
+/*
  * REQUEST CODES.
  */
 #define BLKIF_OP_READ              0
diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h
index 7dc685b40..21f4fbd55 100644
--- a/include/xen/interface/io/ring.h
+++ b/include/xen/interface/io/ring.h
@@ -208,12 +208,12 @@ struct __name##_back_ring {						\
 
 
 #define RING_PUSH_REQUESTS(_r) do {					\
-    wmb(); /* back sees requests /before/ updated producer index */	\
+    virt_wmb(); /* back sees requests /before/ updated producer index */	\
     (_r)->sring->req_prod = (_r)->req_prod_pvt;				\
 } while (0)
 
 #define RING_PUSH_RESPONSES(_r) do {					\
-    wmb(); /* front sees responses /before/ updated producer index */	\
+    virt_wmb(); /* front sees responses /before/ updated producer index */	\
     (_r)->sring->rsp_prod = (_r)->rsp_prod_pvt;				\
 } while (0)
 
@@ -250,9 +250,9 @@ struct __name##_back_ring {						\
 #define RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(_r, _notify) do {		\
     RING_IDX __old = (_r)->sring->req_prod;				\
     RING_IDX __new = (_r)->req_prod_pvt;				\
-    wmb(); /* back sees requests /before/ updated producer index */	\
+    virt_wmb(); /* back sees requests /before/ updated producer index */	\
     (_r)->sring->req_prod = __new;					\
-    mb(); /* back sees new requests /before/ we check req_event */	\
+    virt_mb(); /* back sees new requests /before/ we check req_event */	\
     (_notify) = ((RING_IDX)(__new - (_r)->sring->req_event) <		\
 		 (RING_IDX)(__new - __old));				\
 } while (0)
@@ -260,9 +260,9 @@ struct __name##_back_ring {						\
 #define RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(_r, _notify) do {		\
     RING_IDX __old = (_r)->sring->rsp_prod;				\
     RING_IDX __new = (_r)->rsp_prod_pvt;				\
-    wmb(); /* front sees responses /before/ updated producer index */	\
+    virt_wmb(); /* front sees responses /before/ updated producer index */	\
     (_r)->sring->rsp_prod = __new;					\
-    mb(); /* front sees new responses /before/ we check rsp_event */	\
+    virt_mb(); /* front sees new responses /before/ we check rsp_event */	\
     (_notify) = ((RING_IDX)(__new - (_r)->sring->rsp_event) <		\
 		 (RING_IDX)(__new - __old));				\
 } while (0)
@@ -271,7 +271,7 @@ struct __name##_back_ring {						\
     (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r);			\
     if (_work_to_do) break;						\
     (_r)->sring->req_event = (_r)->req_cons + 1;			\
-    mb();								\
+    virt_mb();								\
     (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r);			\
 } while (0)
 
@@ -279,7 +279,7 @@ struct __name##_back_ring {						\
     (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r);			\
     if (_work_to_do) break;						\
     (_r)->sring->rsp_event = (_r)->rsp_cons + 1;			\
-    mb();								\
+    virt_mb();								\
     (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r);			\
 } while (0)