On 08.07.2019 20:13, Marvin Liu wrote:
> In fast enqueue function, will first check whether descriptors are
> cache aligned. Fast enqueue function will check prerequisites in the
> beginning. Fast enqueue function do not support chained mbufs, normal
> function will handle that.
>
> Signed-off-by: Marvin Liu <yong....@intel.com>
>
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 884befa85..f24026acd 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -39,6 +39,8 @@
>
> #define VHOST_LOG_CACHE_NR 32
>
> +/* Used in fast packed ring functions */
> +#define PACKED_DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct
> vring_packed_desc))
> /**
> * Structure contains buffer address, length and descriptor index
> * from vring to do scatter RX.
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 003aec1d4..b877510da 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -897,6 +897,115 @@ virtio_dev_rx_split(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
> return pkt_idx;
> }
>
> +static __rte_always_inline uint16_t
> +virtio_dev_rx_fast_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
> + struct rte_mbuf **pkts)
> +{
> + bool wrap_counter = vq->avail_wrap_counter;
> + struct vring_packed_desc *descs = vq->desc_packed;
> + uint16_t avail_idx = vq->last_avail_idx;
> + uint64_t desc_addr, desc_addr1, desc_addr2, desc_addr3, len, len1,
> + len2, len3;
> + struct virtio_net_hdr_mrg_rxbuf *hdr, *hdr1, *hdr2, *hdr3;
> + uint32_t buf_offset = dev->vhost_hlen;
> +
> + if (unlikely(avail_idx & 0x3))
> + return -1;
> +
> + if (unlikely(avail_idx < (vq->size - PACKED_DESC_PER_CACHELINE)))
Doe it makes sense to check this?
If this condition is not 'true', all the code below will access incorrect
memory.
> + rte_prefetch0((void *)(uintptr_t)&descs[avail_idx +
> + PACKED_DESC_PER_CACHELINE]);
> + else
> + rte_prefetch0((void *)(uintptr_t)&descs[0]);
> +
> + if (unlikely((pkts[0]->next != NULL) |
> + (pkts[1]->next != NULL) |
> + (pkts[2]->next != NULL) |
> + (pkts[3]->next != NULL)))
> + return -1;
> +
> + if (unlikely(!desc_is_avail(&descs[avail_idx], wrap_counter)) |
> + unlikely(!desc_is_avail(&descs[avail_idx + 1], wrap_counter)) |
> + unlikely(!desc_is_avail(&descs[avail_idx + 2], wrap_counter)) |
> + unlikely(!desc_is_avail(&descs[avail_idx + 3], wrap_counter)))
> + return 1;
> +
> + rte_smp_rmb();
> +
> + len = descs[avail_idx].len;
> + len1 = descs[avail_idx + 1].len;
> + len2 = descs[avail_idx + 2].len;
> + len3 = descs[avail_idx + 3].len;
> +
> + if (unlikely((pkts[0]->pkt_len > (len - buf_offset)) |
> + (pkts[1]->pkt_len > (len1 - buf_offset)) |
> + (pkts[2]->pkt_len > (len2 - buf_offset)) |
> + (pkts[3]->pkt_len > (len3 - buf_offset))))
> + return -1;
> +
> + desc_addr = vhost_iova_to_vva(dev, vq,
> + descs[avail_idx].addr,
> + &len,
> + VHOST_ACCESS_RW);
> +
> + desc_addr1 = vhost_iova_to_vva(dev, vq,
> + descs[avail_idx + 1].addr,
> + &len1,
> + VHOST_ACCESS_RW);
> +
> + desc_addr2 = vhost_iova_to_vva(dev, vq,
> + descs[avail_idx + 2].addr,
> + &len2,
> + VHOST_ACCESS_RW);
> +
> + desc_addr3 = vhost_iova_to_vva(dev, vq,
> + descs[avail_idx + 3].addr,
> + &len3,
> + VHOST_ACCESS_RW);
> +
> + if (unlikely((len != descs[avail_idx].len) |
> + (len1 != descs[avail_idx + 1].len) |
> + (len2 != descs[avail_idx + 2].len) |
> + (len3 != descs[avail_idx + 3].len)))
> + return -1;
> +
> + hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr;
> + hdr1 = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr1;
> + hdr2 = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr2;
> + hdr3 = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr3;
> +
> + virtio_enqueue_offload(pkts[0], &hdr->hdr);
> + virtio_enqueue_offload(pkts[1], &hdr1->hdr);
> + virtio_enqueue_offload(pkts[2], &hdr2->hdr);
> + virtio_enqueue_offload(pkts[3], &hdr3->hdr);
> +
> + len = pkts[0]->pkt_len + dev->vhost_hlen;
> + len1 = pkts[1]->pkt_len + dev->vhost_hlen;
> + len2 = pkts[2]->pkt_len + dev->vhost_hlen;
> + len3 = pkts[3]->pkt_len + dev->vhost_hlen;
> +
> + vq->last_avail_idx += PACKED_DESC_PER_CACHELINE;
The whole function assumes that PACKED_DESC_PER_CACHELINE equals to 4,
but if it's not, it will not work correctly.
> + if (vq->last_avail_idx >= vq->size) {
> + vq->last_avail_idx -= vq->size;
> + vq->avail_wrap_counter ^= 1;
> + }
> +
> + rte_memcpy((void *)(uintptr_t)(desc_addr + buf_offset),
> + rte_pktmbuf_mtod_offset(pkts[0], void *, 0),
> + pkts[0]->pkt_len);
> + rte_memcpy((void *)(uintptr_t)(desc_addr1 + buf_offset),
> + rte_pktmbuf_mtod_offset(pkts[1], void *, 0),
> + pkts[1]->pkt_len);
> + rte_memcpy((void *)(uintptr_t)(desc_addr2 + buf_offset),
> + rte_pktmbuf_mtod_offset(pkts[2], void *, 0),
> + pkts[2]->pkt_len);
> + rte_memcpy((void *)(uintptr_t)(desc_addr3 + buf_offset),
> + rte_pktmbuf_mtod_offset(pkts[3], void *, 0),
> + pkts[3]->pkt_len);
> +
> + return 0;
> +}
> +
> static __rte_always_inline uint16_t
> virtio_dev_rx_normal_packed(struct virtio_net *dev, struct vhost_virtqueue
> *vq,
> struct rte_mbuf *pkt)
>
