[dpdk-dev] [RFC 14/29] vhost: a rough implementation on enqueue code path
Tiwei Bie
tiwei.bie at intel.com
Wed Jun 21 04:57:50 CEST 2017
From: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
---
lib/librte_vhost/virtio_net.c | 124 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 123 insertions(+), 1 deletion(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index b4d9031..f7dd4eb 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -583,6 +583,126 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
return pkt_idx;
}
+static inline int __attribute__((always_inline))
+enqueue_pkt(struct virtio_net *dev, struct vring_desc_1_1 *descs,
+ uint16_t desc_idx, struct rte_mbuf *m)
+{
+ uint32_t desc_avail, desc_offset;
+ uint32_t mbuf_avail, mbuf_offset;
+ uint32_t cpy_len;
+ struct vring_desc_1_1 *desc;
+ uint64_t desc_addr;
+ struct virtio_net_hdr_mrg_rxbuf *hdr;
+
+ desc = &descs[desc_idx];
+ desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
+ /*
+ * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
+ * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
+ * otherwise stores offset on the stack instead of in a register.
+ */
+ if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr)
+ return -1;
+
+ rte_prefetch0((void *)(uintptr_t)desc_addr);
+
+ hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr;
+ virtio_enqueue_offload(m, &hdr->hdr);
+ vhost_log_write(dev, desc->addr, dev->vhost_hlen);
+ PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
+
+ desc_offset = dev->vhost_hlen;
+ desc_avail = desc->len - dev->vhost_hlen;
+
+ 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 */
+ return -1;
+ }
+
+ /** NOTE: we should not come here with current
+ virtio-user implementation **/
+ desc_idx = (desc_idx + 1); // & (vq->size - 1);
+ desc = &descs[desc_idx];
+ if (unlikely(!(desc->flags & DESC_HW)))
+ return -1;
+
+ desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
+ if (unlikely(!desc_addr))
+ return -1;
+
+ desc_offset = 0;
+ desc_avail = desc->len;
+ }
+
+ cpy_len = RTE_MIN(desc_avail, mbuf_avail);
+ rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
+ rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
+ cpy_len);
+ vhost_log_write(dev, desc->addr + desc_offset, cpy_len);
+ PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
+ cpy_len, 0);
+
+ mbuf_avail -= cpy_len;
+ mbuf_offset += cpy_len;
+ desc_avail -= cpy_len;
+ desc_offset += cpy_len;
+ }
+
+ return 0;
+}
+
+static inline uint32_t __attribute__((always_inline))
+vhost_enqueue_burst_1_1(struct virtio_net *dev, uint16_t queue_id,
+ struct rte_mbuf **pkts, uint32_t count)
+{
+ struct vhost_virtqueue *vq;
+ uint16_t i;
+ uint16_t idx;
+ struct vring_desc_1_1 *desc;
+ uint16_t head_idx;
+
+ vq = dev->virtqueue[queue_id];
+ if (unlikely(vq->enabled == 0))
+ return 0;
+
+ head_idx = vq->last_used_idx;
+ desc = vq->desc_1_1;
+ for (i = 0; i < count; i++) {
+ /* XXX: there is an assumption that no desc will be chained */
+ idx = vq->last_used_idx & (vq->size - 1);
+ if (!(desc[idx].flags & DESC_HW))
+ break;
+
+ if (enqueue_pkt(dev, desc, idx, pkts[i]) < 0)
+ break;
+
+ vq->last_used_idx++;
+ }
+ count = i;
+
+ rte_smp_wmb();
+ for (i = 0; i < count; i++) {
+ idx = (head_idx + i) & (vq->size - 1);
+ desc[idx].flags &= ~DESC_HW;
+ desc[idx].len = pkts[i]->pkt_len;
+ }
+
+ return count;
+}
+
uint16_t
rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
struct rte_mbuf **pkts, uint16_t count)
@@ -592,7 +712,9 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
if (!dev)
return 0;
- if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
+ if (dev->features & (1ULL << VIRTIO_F_VERSION_1_1))
+ return vhost_enqueue_burst_1_1(dev, queue_id, pkts, count);
+ else if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
return virtio_dev_merge_rx(dev, queue_id, pkts, count);
else
return virtio_dev_rx(dev, queue_id, pkts, count);
--
2.7.4
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