net/virtio: add missing read barrier for packed dequeue

[dpdk.git] / drivers / net / virtio / virtqueue.h

diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 53aeac2..ca9d8e6 100644 (file)
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -19,15 +19,40 @@
 struct rte_mbuf;
 
 /*
- * Per virtio_config.h in Linux.
+ * Per virtio_ring.h in Linux.
  *     For virtio_pci on SMP, we don't need to order with respect to MMIO
  *     accesses through relaxed memory I/O windows, so smp_mb() et al are
  *     sufficient.
  *
+ *     For using virtio to talk to real devices (eg. vDPA) we do need real
+ *     barriers.
  */
-#define virtio_mb()    rte_smp_mb()
-#define virtio_rmb()   rte_smp_rmb()
-#define virtio_wmb()   rte_smp_wmb()
+static inline void
+virtio_mb(uint8_t weak_barriers)
+{
+       if (weak_barriers)
+               rte_smp_mb();
+       else
+               rte_mb();
+}
+
+static inline void
+virtio_rmb(uint8_t weak_barriers)
+{
+       if (weak_barriers)
+               rte_smp_rmb();
+       else
+               rte_cio_rmb();
+}
+
+static inline void
+virtio_wmb(uint8_t weak_barriers)
+{
+       if (weak_barriers)
+               rte_smp_wmb();
+       else
+               rte_cio_wmb();
+}
 
 #ifdef RTE_PMD_PACKET_PREFETCH
 #define rte_packet_prefetch(p)  rte_prefetch1(p)
@@ -267,7 +292,6 @@ desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)
        return avail == used && used == vq->used_wrap_counter;
 }
 
-
 static inline void
 vring_desc_init_packed(struct virtqueue *vq, int n)
 {
@@ -323,9 +347,8 @@ virtqueue_enable_intr_packed(struct virtqueue *vq)
 {
        uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
 
-
        if (vq->event_flags_shadow == RING_EVENT_FLAGS_DISABLE) {
-               virtio_wmb();
+               virtio_wmb(vq->hw->weak_barriers);
                vq->event_flags_shadow = RING_EVENT_FLAGS_ENABLE;
                *event_flags = vq->event_flags_shadow;
        }
@@ -391,7 +414,7 @@ void vq_ring_free_inorder(struct virtqueue *vq, uint16_t desc_idx,
 static inline void
 vq_update_avail_idx(struct virtqueue *vq)
 {
-       virtio_wmb();
+       virtio_wmb(vq->hw->weak_barriers);
        vq->vq_ring.avail->idx = vq->vq_avail_idx;
 }
 
@@ -419,7 +442,7 @@ virtqueue_kick_prepare(struct virtqueue *vq)
         * Ensure updated avail->idx is visible to vhost before reading
         * the used->flags.
         */
-       virtio_mb();
+       virtio_mb(vq->hw->weak_barriers);
        return !(vq->vq_ring.used->flags & VRING_USED_F_NO_NOTIFY);
 }
 
@@ -431,7 +454,7 @@ virtqueue_kick_prepare_packed(struct virtqueue *vq)
        /*
         * Ensure updated data is visible to vhost before reading the flags.
         */
-       virtio_mb();
+       virtio_mb(vq->hw->weak_barriers);
        flags = vq->ring_packed.device_event->desc_event_flags;
 
        return flags != RING_EVENT_FLAGS_DISABLE;