Re: [PATCH 13/17] vhost: packed queue enqueue path

On Fri, Mar 16, 2018 at 04:21:16PM +0100, Jens Freimann wrote:
[...]

+static inline uint32_t __attribute__((always_inline))
+vhost_enqueue_burst_packed(struct virtio_net *dev, uint16_t queue_id,
+	      struct rte_mbuf **pkts, uint32_t count)
+{
+	struct vhost_virtqueue *vq;
+	struct vring_desc_packed *descs;
+	uint16_t idx;
+	uint16_t mask;
+	uint16_t i;
+
+	vq = dev->virtqueue[queue_id];
+
+	rte_spinlock_lock(&vq->access_lock);
+
+	if (unlikely(vq->enabled == 0)) {
+		i = 0;
+		goto out_access_unlock;
+	}
+
+	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
+		vhost_user_iotlb_rd_lock(vq);
+
+	descs = vq->desc_packed;
+	mask = vq->size - 1;

Queue size may not be a power of 2 in packed ring.

+
+	for (i = 0; i < count; i++) {

[...]

+		mbuf_avail  = rte_pktmbuf_data_len(m);
+		mbuf_offset = 0;
+		while (mbuf_avail != 0 || m->next != NULL) {
+			/* done with current mbuf, fetch next */
+			if (mbuf_avail == 0) {
+				m = m->next;
+
+				mbuf_offset = 0;
+				mbuf_avail  = rte_pktmbuf_data_len(m);
+			}
+
+			/* done with current desc buf, fetch next */
+			if (desc_avail == 0) {
+				if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
+					/* Room in vring buffer is not enough */
+					goto out;
+				}
+
+				idx = (idx + 1);
+				desc = &descs[idx];

Need to check whether idx >= queue size.

Thanks