vhost: support async packed ring dequeue

This patch implements packed ring dequeue data path
for asynchronous vhost.

Signed-off-by: Cheng Jiang <cheng1.jiang@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index c939624..229e6b3 100644 (file)
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -27,7 +27,7 @@
 #define MAX_BATCH_LEN 256
 
 static __rte_always_inline uint16_t
-async_poll_dequeue_completed_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
+async_poll_dequeue_completed(struct virtio_net *dev, struct vhost_virtqueue *vq,
                struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
                uint16_t vchan_id, bool legacy_ol_flags);
 
@@ -2207,12 +2207,7 @@ rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t queue_id,
                n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id,
                                        pkts, count, dma_id, vchan_id);
        else {
-               if (unlikely(vq_is_packed(dev)))
-                       VHOST_LOG_DATA(ERR,
-                                       "(%s) %s: async dequeue does not support packed ring.\n",
-                                       dev->ifname, __func__);
-               else
-                       n_pkts_cpl = async_poll_dequeue_completed_split(dev, vq, pkts, count,
+               n_pkts_cpl = async_poll_dequeue_completed(dev, vq, pkts, count,
                                        dma_id, vchan_id, dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS);
        }
 
@@ -2271,12 +2266,7 @@ rte_vhost_clear_queue(int vid, uint16_t queue_id, struct rte_mbuf **pkts,
                n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id,
                                pkts, count, dma_id, vchan_id);
        else {
-               if (unlikely(vq_is_packed(dev)))
-                       VHOST_LOG_DATA(ERR,
-                                       "(%s) %s: async dequeue does not support packed ring.\n",
-                                       dev->ifname, __func__);
-               else
-                       n_pkts_cpl = async_poll_dequeue_completed_split(dev, vq, pkts, count,
+               n_pkts_cpl = async_poll_dequeue_completed(dev, vq, pkts, count,
                                        dma_id, vchan_id, dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS);
        }
 
@@ -3339,7 +3329,7 @@ out_access_unlock:
 }
 
 static __rte_always_inline uint16_t
-async_poll_dequeue_completed_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
+async_poll_dequeue_completed(struct virtio_net *dev, struct vhost_virtqueue *vq,
                struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
                uint16_t vchan_id, bool legacy_ol_flags)
 {
@@ -3354,7 +3344,7 @@ async_poll_dequeue_completed_split(struct virtio_net *dev, struct vhost_virtqueu
        from = start_idx;
        while (vq->async->pkts_cmpl_flag[from] && count--) {
                vq->async->pkts_cmpl_flag[from] = false;
-               from = (from + 1) & (vq->size - 1);
+               from = (from + 1) % vq->size;
                nr_cpl_pkts++;
        }
 
@@ -3362,7 +3352,7 @@ async_poll_dequeue_completed_split(struct virtio_net *dev, struct vhost_virtqueu
                return 0;
 
        for (i = 0; i < nr_cpl_pkts; i++) {
-               from = (start_idx + i) & (vq->size - 1);
+               from = (start_idx + i) % vq->size;
                pkts[i] = pkts_info[from].mbuf;
 
                if (virtio_net_with_host_offload(dev))
@@ -3371,10 +3361,14 @@ async_poll_dequeue_completed_split(struct virtio_net *dev, struct vhost_virtqueu
        }
 
        /* write back completed descs to used ring and update used idx */
-       write_back_completed_descs_split(vq, nr_cpl_pkts);
-       __atomic_add_fetch(&vq->used->idx, nr_cpl_pkts, __ATOMIC_RELEASE);
-       vhost_vring_call_split(dev, vq);
-
+       if (vq_is_packed(dev)) {
+               write_back_completed_descs_packed(vq, nr_cpl_pkts);
+               vhost_vring_call_packed(dev, vq);
+       } else {
+               write_back_completed_descs_split(vq, nr_cpl_pkts);
+               __atomic_add_fetch(&vq->used->idx, nr_cpl_pkts, __ATOMIC_RELEASE);
+               vhost_vring_call_split(dev, vq);
+       }
        vq->async->pkts_inflight_n -= nr_cpl_pkts;
 
        return nr_cpl_pkts;
@@ -3511,8 +3505,8 @@ virtio_dev_tx_async_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 
 out:
        /* DMA device may serve other queues, unconditionally check completed. */
-       nr_done_pkts = async_poll_dequeue_completed_split(dev, vq, pkts, pkts_size,
-                                                         dma_id, vchan_id, legacy_ol_flags);
+       nr_done_pkts = async_poll_dequeue_completed(dev, vq, pkts, pkts_size,
+                                                       dma_id, vchan_id, legacy_ol_flags);
 
        return nr_done_pkts;
 }
@@ -3539,6 +3533,171 @@ virtio_dev_tx_async_split_compliant(struct virtio_net *dev,
                                pkts, count, dma_id, vchan_id, false);
 }
 
+static __rte_always_inline void
+vhost_async_shadow_dequeue_single_packed(struct vhost_virtqueue *vq, uint16_t buf_id)
+{
+       struct vhost_async *async = vq->async;
+       uint16_t idx = async->buffer_idx_packed;
+
+       async->buffers_packed[idx].id = buf_id;
+       async->buffers_packed[idx].len = 0;
+       async->buffers_packed[idx].count = 1;
+
+       async->buffer_idx_packed++;
+       if (async->buffer_idx_packed >= vq->size)
+               async->buffer_idx_packed -= vq->size;
+
+}
+
+static __rte_always_inline int
+virtio_dev_tx_async_single_packed(struct virtio_net *dev,
+                       struct vhost_virtqueue *vq,
+                       struct rte_mempool *mbuf_pool,
+                       struct rte_mbuf *pkts,
+                       uint16_t slot_idx,
+                       bool legacy_ol_flags)
+{
+       int err;
+       uint16_t buf_id, desc_count = 0;
+       uint16_t nr_vec = 0;
+       uint32_t buf_len;
+       struct buf_vector buf_vec[BUF_VECTOR_MAX];
+       static bool allocerr_warned;
+
+       if (unlikely(fill_vec_buf_packed(dev, vq, vq->last_avail_idx, &desc_count,
+                                        buf_vec, &nr_vec, &buf_id, &buf_len,
+                                        VHOST_ACCESS_RO) < 0))
+               return -1;
+
+       if (unlikely(virtio_dev_pktmbuf_prep(dev, pkts, buf_len))) {
+               if (!allocerr_warned) {
+                       VHOST_LOG_DATA(ERR, "(%s) Failed mbuf alloc of size %d from %s.\n",
+                               dev->ifname, buf_len, mbuf_pool->name);
+
+                       allocerr_warned = true;
+               }
+               return -1;
+       }
+
+       err = desc_to_mbuf(dev, vq, buf_vec, nr_vec, pkts, mbuf_pool,
+               legacy_ol_flags, slot_idx, true);
+       if (unlikely(err)) {
+               rte_pktmbuf_free(pkts);
+               if (!allocerr_warned) {
+                       VHOST_LOG_DATA(ERR, "(%s) Failed to copy desc to mbuf on.\n", dev->ifname);
+                       allocerr_warned = true;
+               }
+               return -1;
+       }
+
+       /* update async shadow packed ring */
+       vhost_async_shadow_dequeue_single_packed(vq, buf_id);
+
+       return err;
+}
+
+static __rte_always_inline uint16_t
+virtio_dev_tx_async_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
+               struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts,
+               uint16_t count, uint16_t dma_id, uint16_t vchan_id, bool legacy_ol_flags)
+{
+       uint16_t pkt_idx;
+       uint16_t slot_idx = 0;
+       uint16_t nr_done_pkts = 0;
+       uint16_t pkt_err = 0;
+       uint32_t n_xfer;
+       struct vhost_async *async = vq->async;
+       struct async_inflight_info *pkts_info = async->pkts_info;
+       struct rte_mbuf *pkts_prealloc[MAX_PKT_BURST];
+
+       VHOST_LOG_DATA(DEBUG, "(%d) about to dequeue %u buffers\n", dev->vid, count);
+
+       async_iter_reset(async);
+
+       if (rte_pktmbuf_alloc_bulk(mbuf_pool, pkts_prealloc, count))
+               goto out;
+
+       for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
+               struct rte_mbuf *pkt = pkts_prealloc[pkt_idx];
+
+               rte_prefetch0(&vq->desc_packed[vq->last_avail_idx]);
+
+               slot_idx = (async->pkts_idx + pkt_idx) % vq->size;
+               if (unlikely(virtio_dev_tx_async_single_packed(dev, vq, mbuf_pool, pkt,
+                               slot_idx, legacy_ol_flags))) {
+                       rte_pktmbuf_free_bulk(&pkts_prealloc[pkt_idx], count - pkt_idx);
+                       break;
+               }
+
+               pkts_info[slot_idx].mbuf = pkt;
+
+               vq_inc_last_avail_packed(vq, 1);
+
+       }
+
+       n_xfer = vhost_async_dma_transfer(dev, vq, dma_id, vchan_id, async->pkts_idx,
+                                       async->iov_iter, pkt_idx);
+
+       async->pkts_inflight_n += n_xfer;
+
+       pkt_err = pkt_idx - n_xfer;
+
+       if (unlikely(pkt_err)) {
+               pkt_idx -= pkt_err;
+
+               /**
+                * recover DMA-copy related structures and free pktmbuf for DMA-error pkts.
+                */
+               if (async->buffer_idx_packed >= pkt_err)
+                       async->buffer_idx_packed -= pkt_err;
+               else
+                       async->buffer_idx_packed += vq->size - pkt_err;
+
+               while (pkt_err-- > 0) {
+                       rte_pktmbuf_free(pkts_info[slot_idx % vq->size].mbuf);
+                       slot_idx--;
+               }
+
+               /* recover available ring */
+               if (vq->last_avail_idx >= pkt_err) {
+                       vq->last_avail_idx -= pkt_err;
+               } else {
+                       vq->last_avail_idx += vq->size - pkt_err;
+                       vq->avail_wrap_counter ^= 1;
+               }
+       }
+
+       async->pkts_idx += pkt_idx;
+       if (async->pkts_idx >= vq->size)
+               async->pkts_idx -= vq->size;
+
+out:
+       nr_done_pkts = async_poll_dequeue_completed(dev, vq, pkts, count,
+                                       dma_id, vchan_id, legacy_ol_flags);
+
+       return nr_done_pkts;
+}
+
+__rte_noinline
+static uint16_t
+virtio_dev_tx_async_packed_legacy(struct virtio_net *dev, struct vhost_virtqueue *vq,
+               struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts,
+               uint16_t count, uint16_t dma_id, uint16_t vchan_id)
+{
+       return virtio_dev_tx_async_packed(dev, vq, mbuf_pool,
+                               pkts, count, dma_id, vchan_id, true);
+}
+
+__rte_noinline
+static uint16_t
+virtio_dev_tx_async_packed_compliant(struct virtio_net *dev, struct vhost_virtqueue *vq,
+               struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts,
+               uint16_t count, uint16_t dma_id, uint16_t vchan_id)
+{
+       return virtio_dev_tx_async_packed(dev, vq, mbuf_pool,
+                               pkts, count, dma_id, vchan_id, false);
+}
+
 uint16_t
 rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
        struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count,
@@ -3641,25 +3800,22 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
                count -= 1;
        }
 
-       if (unlikely(vq_is_packed(dev))) {
-               static bool not_support_pack_log;
-               if (!not_support_pack_log) {
-                       VHOST_LOG_DATA(ERR,
-                               "(%s) %s: async dequeue does not support packed ring.\n",
-                               dev->ifname, __func__);
-                       not_support_pack_log = true;
-               }
-               count = 0;
-               goto out;
+       if (vq_is_packed(dev)) {
+               if (dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS)
+                       count = virtio_dev_tx_async_packed_legacy(dev, vq, mbuf_pool,
+                                       pkts, count, dma_id, vchan_id);
+               else
+                       count = virtio_dev_tx_async_packed_compliant(dev, vq, mbuf_pool,
+                                       pkts, count, dma_id, vchan_id);
+       } else {
+               if (dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS)
+                       count = virtio_dev_tx_async_split_legacy(dev, vq, mbuf_pool,
+                                       pkts, count, dma_id, vchan_id);
+               else
+                       count = virtio_dev_tx_async_split_compliant(dev, vq, mbuf_pool,
+                                       pkts, count, dma_id, vchan_id);
        }
 
-       if (dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS)
-               count = virtio_dev_tx_async_split_legacy(dev, vq, mbuf_pool, pkts,
-                                                        count, dma_id, vchan_id);
-       else
-               count = virtio_dev_tx_async_split_compliant(dev, vq, mbuf_pool, pkts,
-                                                           count, dma_id, vchan_id);
-
        *nr_inflight = vq->async->pkts_inflight_n;
 
 out: