[dpdk-stable] [PATCH 19.11] net/virtio: fix refill order in packed ring datapath
Christian Ehrhardt
christian.ehrhardt at canonical.com
Tue Aug 17 11:44:26 CEST 2021
On Tue, Aug 17, 2021 at 4:30 AM Marvin Liu <yong.liu at intel.com> wrote:
>
> [ upstream commit 2d91b28730a945def257bc372a525c9b5dbf181c ]
Thanks, applied
> The front-end should refill the descriptor with the mbuf indicated by
> the buff_id rather then the index of used descriptor. Back-end may
> return buffers out of order if async copy mode is enabled.
>
> When initializing rxq, refill the descriptors in order as buff_id is
> not available at that time.
>
> Fixes: a76290c8f1cf ("net/virtio: implement Rx path for packed queues")
>
> Signed-off-by: Marvin Liu <yong.liu at intel.com>
> Signed-off-by: Cheng Jiang <cheng1.jiang at intel.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 5211736d2..421e4847e 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -474,13 +474,35 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf **cookie,
> return 0;
> }
>
> +static inline void
> +virtqueue_refill_single_packed(struct virtqueue *vq,
> + struct vring_packed_desc *dp,
> + struct rte_mbuf *cookie)
> +{
> + uint16_t flags = vq->vq_packed.cached_flags;
> + struct virtio_hw *hw = vq->hw;
> +
> + dp->addr = VIRTIO_MBUF_ADDR(cookie, vq) +
> + RTE_PKTMBUF_HEADROOM - hw->vtnet_hdr_size;
> + dp->len = cookie->buf_len -
> + RTE_PKTMBUF_HEADROOM + hw->vtnet_hdr_size;
> +
> + virtqueue_store_flags_packed(dp, flags,
> + hw->weak_barriers);
> +
> + if (++vq->vq_avail_idx >= vq->vq_nentries) {
> + vq->vq_avail_idx -= vq->vq_nentries;
> + vq->vq_packed.cached_flags ^=
> + VRING_PACKED_DESC_F_AVAIL_USED;
> + flags = vq->vq_packed.cached_flags;
> + }
> +}
> +
> static inline int
> -virtqueue_enqueue_recv_refill_packed(struct virtqueue *vq,
> +virtqueue_enqueue_recv_refill_packed_init(struct virtqueue *vq,
> struct rte_mbuf **cookie, uint16_t num)
> {
> struct vring_packed_desc *start_dp = vq->vq_packed.ring.desc;
> - uint16_t flags = vq->vq_packed.cached_flags;
> - struct virtio_hw *hw = vq->hw;
> struct vq_desc_extra *dxp;
> uint16_t idx;
> int i;
> @@ -496,24 +518,34 @@ virtqueue_enqueue_recv_refill_packed(struct virtqueue *vq,
> dxp->cookie = (void *)cookie[i];
> dxp->ndescs = 1;
>
> - start_dp[idx].addr = VIRTIO_MBUF_ADDR(cookie[i], vq) +
> - RTE_PKTMBUF_HEADROOM - hw->vtnet_hdr_size;
> - start_dp[idx].len = cookie[i]->buf_len - RTE_PKTMBUF_HEADROOM
> - + hw->vtnet_hdr_size;
> + virtqueue_refill_single_packed(vq, &start_dp[idx], cookie[i]);
> + }
> + vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - num);
> + return 0;
> +}
>
> - vq->vq_desc_head_idx = dxp->next;
> - if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
> - vq->vq_desc_tail_idx = vq->vq_desc_head_idx;
> +static inline int
> +virtqueue_enqueue_recv_refill_packed(struct virtqueue *vq,
> + struct rte_mbuf **cookie, uint16_t num)
> +{
> + struct vring_packed_desc *start_dp = vq->vq_packed.ring.desc;
> + struct vq_desc_extra *dxp;
> + uint16_t idx, did;
> + int i;
>
> - virtqueue_store_flags_packed(&start_dp[idx], flags,
> - hw->weak_barriers);
> + if (unlikely(vq->vq_free_cnt == 0))
> + return -ENOSPC;
> + if (unlikely(vq->vq_free_cnt < num))
> + return -EMSGSIZE;
>
> - if (++vq->vq_avail_idx >= vq->vq_nentries) {
> - vq->vq_avail_idx -= vq->vq_nentries;
> - vq->vq_packed.cached_flags ^=
> - VRING_PACKED_DESC_F_AVAIL_USED;
> - flags = vq->vq_packed.cached_flags;
> - }
> + for (i = 0; i < num; i++) {
> + idx = vq->vq_avail_idx;
> + did = start_dp[idx].id;
> + dxp = &vq->vq_descx[did];
> + dxp->cookie = (void *)cookie[i];
> + dxp->ndescs = 1;
> +
> + virtqueue_refill_single_packed(vq, &start_dp[idx], cookie[i]);
> }
> vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - num);
> return 0;
> @@ -1022,7 +1054,7 @@ virtio_dev_rx_queue_setup_finish(struct rte_eth_dev *dev, uint16_t queue_idx)
>
> /* Enqueue allocated buffers */
> if (vtpci_packed_queue(vq->hw))
> - error = virtqueue_enqueue_recv_refill_packed(vq,
> + error = virtqueue_enqueue_recv_refill_packed_init(vq,
> &m, 1);
> else
> error = virtqueue_enqueue_recv_refill(vq,
> --
> 2.17.1
>
--
Christian Ehrhardt
Staff Engineer, Ubuntu Server
Canonical Ltd
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