[dpdk-dev] [PATCH v11 3/9] net/virtio: add packed virtqueue helpers

[Jens Freimann <jfreimann@redhat.com>]

Add helper functions to set/clear and check descriptor flags.

Signed-off-by: Jens Freimann <jfreimann@redhat.com>
---
 drivers/net/virtio/virtio_ethdev.c |  2 +
 drivers/net/virtio/virtqueue.h     | 73 +++++++++++++++++++++++++++++-
 2 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index fdcb7ecaa..48707b7b8 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -310,6 +310,7 @@ virtio_init_vring(struct virtqueue *vq)
 	if (vtpci_packed_queue(vq->hw)) {
 		vring_init_packed(&vq->ring_packed, ring_mem, VIRTIO_PCI_VRING_ALIGN, size);
 		vring_desc_init_packed(vq, size);
+		virtqueue_disable_intr_packed(vq);
 	} else {
 		vring_init_split(vr, ring_mem, VIRTIO_PCI_VRING_ALIGN, size);
 		vring_desc_init_split(vr->desc, size);
@@ -383,6 +384,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t vtpci_queue_idx)
 	vq->hw = hw;
 	vq->vq_queue_index = vtpci_queue_idx;
 	vq->vq_nentries = vq_size;
+	vq->event_flags_shadow = 0;
 	if (vtpci_packed_queue(hw)) {
 		vq->avail_wrap_counter = 1;
 		vq->used_wrap_counter = 1;
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 1401a9844..20b42f5fb 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -170,6 +170,7 @@ struct virtqueue {
 	struct vring_packed ring_packed;  /**< vring keeping desc, used and avail */
 	bool avail_wrap_counter;
 	bool used_wrap_counter;
+	uint16_t event_flags_shadow;
 
 	/**
 	 * Last consumed descriptor in the used table,
@@ -250,6 +251,32 @@ struct virtio_tx_region {
 			   __attribute__((__aligned__(16)));
 };
 
+static inline void
+_set_desc_avail(struct vring_packed_desc *desc, int wrap_counter)
+{
+	desc->flags |= VRING_DESC_F_AVAIL(wrap_counter) |
+		       VRING_DESC_F_USED(!wrap_counter);
+}
+
+static inline void
+set_desc_avail(struct virtqueue *vq, struct vring_packed_desc *desc)
+{
+	_set_desc_avail(desc, vq->avail_wrap_counter);
+}
+
+static inline int
+desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)
+{
+	uint16_t used, avail, flags;
+
+	flags = desc->flags;
+	used = !!(flags & VRING_DESC_F_USED(1));
+	avail = !!(flags & VRING_DESC_F_AVAIL(1));
+
+	return avail == used && used == vq->used_wrap_counter;
+}
+
+
 static inline void
 vring_desc_init_packed(struct virtqueue *vq, int n)
 {
@@ -273,22 +300,64 @@ vring_desc_init_split(struct vring_desc *dp, uint16_t n)
 	dp[i].next = VQ_RING_DESC_CHAIN_END;
 }
 
+/**
+ * Tell the backend not to interrupt us.
+ */
+static inline void
+virtqueue_disable_intr_packed(struct virtqueue *vq)
+{
+	uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
+
+	if (*event_flags != RING_EVENT_FLAGS_DISABLE) {
+		*event_flags = RING_EVENT_FLAGS_DISABLE;
+	}
+}
+
+
 /**
  * Tell the backend not to interrupt us.
  */
 static inline void
 virtqueue_disable_intr(struct virtqueue *vq)
 {
-	vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+	if (vtpci_packed_queue(vq->hw))
+		virtqueue_disable_intr_packed(vq);
+	else
+		vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+}
+
+/**
+ * Tell the backend to interrupt us.
+ */
+static inline void
+virtqueue_enable_intr_packed(struct virtqueue *vq)
+{
+	uint16_t *off_wrap = &vq->ring_packed.driver_event->desc_event_off_wrap;
+	uint16_t *event_flags = &vq->ring_packed.driver_event->desc_event_flags;
+
+	*off_wrap = vq->vq_used_cons_idx |
+		((uint16_t)(vq->used_wrap_counter << 15));
+
+	if (vq->event_flags_shadow == RING_EVENT_FLAGS_DISABLE) {
+		virtio_wmb();
+		vq->event_flags_shadow =
+			vtpci_with_feature(vq->hw, VIRTIO_RING_F_EVENT_IDX) ?
+				RING_EVENT_FLAGS_DESC : RING_EVENT_FLAGS_ENABLE;
+		*event_flags = vq->event_flags_shadow;
+	}
 }
 
+
 /**
  * Tell the backend to interrupt us.
  */
 static inline void
 virtqueue_enable_intr(struct virtqueue *vq)
 {
-	vq->vq_ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
+	if (vtpci_packed_queue(vq->hw))
+		virtqueue_enable_intr_packed(vq);
+	else
+		vq->vq_ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
 }
 
 /**
-- 
2.17.2