On 6/11/20 12:02 PM, patrick...@intel.com wrote:
> From: Patrick <patrick...@intel.com>
>
> This patch implement async enqueue data path for split ring.
A bit more verbose commit message would be helpful since the cover
letter won't be in the git history. Duplicating relevant parts from
the cover letter would be sufficient.
> Signed-off-by: Patrick <patrick...@intel.com>
> ---
> lib/librte_vhost/rte_vhost_async.h | 38 +++
> lib/librte_vhost/virtio_net.c | 538
> ++++++++++++++++++++++++++++++++++++-
> 2 files changed, 574 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_vhost/rte_vhost_async.h
> b/lib/librte_vhost/rte_vhost_async.h
> index 82f2ebe..efcba0a 100644
> --- a/lib/librte_vhost/rte_vhost_async.h
> +++ b/lib/librte_vhost/rte_vhost_async.h
> @@ -131,4 +131,42 @@ int rte_vhost_async_channel_register(int vid, uint16_t
> queue_id,
> */
> int rte_vhost_async_channel_unregister(int vid, uint16_t queue_id);
>
> +/**
> + * This function submit enqueue data to DMA. This function has no
> + * guranttee to the transfer completion upon return. Applications should
> + * poll transfer status by rte_vhost_poll_enqueue_completed()
> + *
> + * @param vid
> + * id of vhost device to enqueue data
> + * @param queue_id
> + * queue id to enqueue data
> + * @param pkts
> + * array of packets to be enqueued
> + * @param count
> + * packets num to be enqueued
> + * @return
> + * num of packets enqueued
> + */
> +uint16_t rte_vhost_submit_enqueue_burst(int vid, uint16_t queue_id,
> + struct rte_mbuf **pkts, uint16_t count);
> +
> +/**
> + * This function check DMA completion status for a specific vhost
> + * device queue. Packets which finish copying (enqueue) operation
> + * will be returned in an array.
> + *
> + * @param vid
> + * id of vhost device to enqueue data
> + * @param queue_id
> + * queue id to enqueue data
> + * @param pkts
> + * blank array to get return packet pointer
> + * @param count
> + * size of the packet array
> + * @return
> + * num of packets returned
> + */
> +uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
> + struct rte_mbuf **pkts, uint16_t count);
> +
> #endif /* _RTE_VDPA_H_ */
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 751c1f3..cf9f884 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -17,14 +17,15 @@
> #include <rte_arp.h>
> #include <rte_spinlock.h>
> #include <rte_malloc.h>
> +#include <rte_vhost_async.h>
>
> #include "iotlb.h"
> #include "vhost.h"
>
> -#define MAX_PKT_BURST 32
> -
> #define MAX_BATCH_LEN 256
>
> +#define VHOST_ASYNC_BATCH_THRESHOLD 8
> +
> static __rte_always_inline bool
> rxvq_is_mergeable(struct virtio_net *dev)
> {
> @@ -117,6 +118,35 @@
> }
>
> static __rte_always_inline void
> +async_flush_shadow_used_ring_split(struct virtio_net *dev,
> + struct vhost_virtqueue *vq)
> +{
> + uint16_t used_idx = vq->last_used_idx & (vq->size - 1);
> +
> + if (used_idx + vq->shadow_used_idx <= vq->size) {
> + do_flush_shadow_used_ring_split(dev, vq, used_idx, 0,
> + vq->shadow_used_idx);
> + } else {
> + uint16_t size;
> +
> + /* update used ring interval [used_idx, vq->size] */
> + size = vq->size - used_idx;
> + do_flush_shadow_used_ring_split(dev, vq, used_idx, 0, size);
> +
> + /* update the left half used ring interval [0, left_size] */
> + do_flush_shadow_used_ring_split(dev, vq, 0, size,
> + vq->shadow_used_idx - size);
> + }
> + vq->last_used_idx += vq->shadow_used_idx;
> +
> + rte_smp_wmb();
> +
> + vhost_log_cache_sync(dev, vq);
> +
> + vq->shadow_used_idx = 0;
> +}
> +
> +static __rte_always_inline void
> update_shadow_used_ring_split(struct vhost_virtqueue *vq,
> uint16_t desc_idx, uint32_t len)
> {
> @@ -905,6 +935,199 @@
> return error;
> }
>
> +static __rte_always_inline void
> +async_fill_vec(struct iovec *v, void *base, size_t len)
> +{
> + v->iov_base = base;
> + v->iov_len = len;
> +}
> +
> +static __rte_always_inline void
> +async_fill_it(struct iov_it *it, size_t count,
> + struct iovec *vec, unsigned long nr_seg)
> +{
> + it->offset = 0;
> + it->count = count;
> +
> + if (count) {
> + it->iov = vec;
> + it->nr_segs = nr_seg;
> + } else {
> + it->iov = 0;
> + it->nr_segs = 0;
> + }
> +}
> +
> +static __rte_always_inline void
> +async_fill_des(struct dma_trans_desc *desc,
> + struct iov_it *src, struct iov_it *dst)
> +{
> + desc->src = src;
> + desc->dst = dst;
> +}
> +
> +static __rte_always_inline int
> +async_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
> + struct rte_mbuf *m, struct buf_vector *buf_vec,
> + uint16_t nr_vec, uint16_t num_buffers,
> + struct iovec *src_iovec, struct iovec *dst_iovec,
> + struct iov_it *src_it, struct iov_it *dst_it)
> +{
> + uint32_t vec_idx = 0;
> + uint32_t mbuf_offset, mbuf_avail;
> + uint32_t buf_offset, buf_avail;
> + uint64_t buf_addr, buf_iova, buf_len;
> + uint32_t cpy_len, cpy_threshold;
> + uint64_t hdr_addr;
> + struct rte_mbuf *hdr_mbuf;
> + struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
> + struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL;
> + int error = 0;
> +
> + uint32_t tlen = 0;
> + int tvec_idx = 0;
> + void *hpa;
> +
> + if (unlikely(m == NULL)) {
> + error = -1;
> + goto out;
> + }
> +
> + cpy_threshold = vq->async_threshold;
> +
> + buf_addr = buf_vec[vec_idx].buf_addr;
> + buf_iova = buf_vec[vec_idx].buf_iova;
> + buf_len = buf_vec[vec_idx].buf_len;
> +
> + if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1)) {
> + error = -1;
> + goto out;
> + }
> +
> + hdr_mbuf = m;
> + hdr_addr = buf_addr;
> + if (unlikely(buf_len < dev->vhost_hlen))
> + hdr = &tmp_hdr;
> + else
> + hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)hdr_addr;
> +
> + VHOST_LOG_DATA(DEBUG, "(%d) RX: num merge buffers %d\n",
> + dev->vid, num_buffers);
> +
> + if (unlikely(buf_len < dev->vhost_hlen)) {
> + buf_offset = dev->vhost_hlen - buf_len;
> + vec_idx++;
> + buf_addr = buf_vec[vec_idx].buf_addr;
> + buf_iova = buf_vec[vec_idx].buf_iova;
> + buf_len = buf_vec[vec_idx].buf_len;
> + buf_avail = buf_len - buf_offset;
> + } else {
> + buf_offset = dev->vhost_hlen;
> + buf_avail = buf_len - dev->vhost_hlen;
> + }
> +
> + mbuf_avail = rte_pktmbuf_data_len(m);
> + mbuf_offset = 0;
> +
> + while (mbuf_avail != 0 || m->next != NULL) {
> + /* done with current buf, get the next one */
> + if (buf_avail == 0) {
> + vec_idx++;
> + if (unlikely(vec_idx >= nr_vec)) {
> + error = -1;
> + goto out;
> + }
> +
> + buf_addr = buf_vec[vec_idx].buf_addr;
> + buf_iova = buf_vec[vec_idx].buf_iova;
> + buf_len = buf_vec[vec_idx].buf_len;
> +
> + buf_offset = 0;
> + buf_avail = buf_len;
> + }
> +
> + /* done with current mbuf, get the next one */
> + if (mbuf_avail == 0) {
> + m = m->next;
> +
> + mbuf_offset = 0;
> + mbuf_avail = rte_pktmbuf_data_len(m);
> + }
> +
> + if (hdr_addr) {
> + virtio_enqueue_offload(hdr_mbuf, &hdr->hdr);
> + if (rxvq_is_mergeable(dev))
> + ASSIGN_UNLESS_EQUAL(hdr->num_buffers,
> + num_buffers);
> +
> + if (unlikely(hdr == &tmp_hdr)) {
> + copy_vnet_hdr_to_desc(dev, vq, buf_vec, hdr);
> + } else {
> + PRINT_PACKET(dev, (uintptr_t)hdr_addr,
> + dev->vhost_hlen, 0);
> + vhost_log_cache_write_iova(dev, vq,
> + buf_vec[0].buf_iova,
> + dev->vhost_hlen);
> + }
> +
> + hdr_addr = 0;
> + }
> +
> + cpy_len = RTE_MIN(buf_avail, mbuf_avail);
> +
> + if (unlikely(cpy_len >= cpy_threshold)) {
> + hpa = (void *)(uintptr_t)gpa_to_hpa(dev,
> + buf_iova + buf_offset, cpy_len);
> +
> + if (unlikely(!hpa)) {
> + error = -1;
> + goto out;
> + }
> +
> + async_fill_vec(src_iovec + tvec_idx,
> + (void *)(uintptr_t)rte_pktmbuf_iova_offset(m,
> + mbuf_offset), cpy_len);
> +
> + async_fill_vec(dst_iovec + tvec_idx, hpa, cpy_len);
> +
> + tlen += cpy_len;
> + tvec_idx++;
> + } else {
> + if (unlikely(vq->batch_copy_nb_elems >= vq->size)) {
> + rte_memcpy(
> + (void *)((uintptr_t)(buf_addr + buf_offset)),
> + rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
> + cpy_len);
> +
> + PRINT_PACKET(dev,
> + (uintptr_t)(buf_addr + buf_offset),
> + cpy_len, 0);
> + } else {
> + batch_copy[vq->batch_copy_nb_elems].dst =
> + (void *)((uintptr_t)(buf_addr + buf_offset));
> + batch_copy[vq->batch_copy_nb_elems].src =
> + rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
> + batch_copy[vq->batch_copy_nb_elems].log_addr =
> + buf_iova + buf_offset;
> + batch_copy[vq->batch_copy_nb_elems].len =
> + cpy_len;
> + vq->batch_copy_nb_elems++;
> + }
> + }
> +
> + mbuf_avail -= cpy_len;
> + mbuf_offset += cpy_len;
> + buf_avail -= cpy_len;
> + buf_offset += cpy_len;
> + }
> +
> +out:
> + async_fill_it(src_it, tlen, src_iovec, tvec_idx);
> + async_fill_it(dst_it, tlen, dst_iovec, tvec_idx);
> +
> + return error;
> +}
> +
> static __rte_always_inline int
> vhost_enqueue_single_packed(struct virtio_net *dev,
> struct vhost_virtqueue *vq,
> @@ -1236,6 +1459,317 @@
> return virtio_dev_rx(dev, queue_id, pkts, count);
> }
>
> +static __rte_always_inline void
> +virtio_dev_rx_async_submit_split_err(struct virtio_net *dev,
> + struct vhost_virtqueue *vq, uint16_t queue_id,
> + uint16_t last_idx, uint16_t shadow_idx)
> +{
> + while (vq->async_pkts_inflight_n) {
> + int er = vq->async_ops.check_completed_copies(dev->vid,
> + queue_id, 0, MAX_PKT_BURST);
> +
> + if (er < 0) {
> + vq->async_pkts_inflight_n = 0;
> + break;
> + }
> +
> + vq->async_pkts_inflight_n -= er;
> + }
> +
> + vq->shadow_used_idx = shadow_idx;
> + vq->last_avail_idx = last_idx;
> +}
> +
> +static __rte_noinline uint32_t
> +virtio_dev_rx_async_submit_split(struct virtio_net *dev,
> + struct vhost_virtqueue *vq, uint16_t queue_id,
> + struct rte_mbuf **pkts, uint32_t count)
> +{
> + uint32_t pkt_idx = 0, pkt_burst_idx = 0;
> + uint16_t num_buffers;
> + struct buf_vector buf_vec[BUF_VECTOR_MAX];
> + uint16_t avail_head, last_idx, shadow_idx;
> +
> + struct iov_it *it_pool = vq->it_pool;
> + struct iovec *vec_pool = vq->vec_pool;
> + struct dma_trans_desc tdes[MAX_PKT_BURST];
> + struct iovec *src_iovec = vec_pool;
> + struct iovec *dst_iovec = vec_pool + (VHOST_MAX_ASYNC_VEC >> 1);
> + struct iov_it *src_it = it_pool;
> + struct iov_it *dst_it = it_pool + 1;
> + uint16_t n_free_slot, slot_idx;
> + int n_pkts = 0;
> +
> + avail_head = *((volatile uint16_t *)&vq->avail->idx);
> + last_idx = vq->last_avail_idx;
> + shadow_idx = vq->shadow_used_idx;
> +
> + /*
> + * The ordering between avail index and
> + * desc reads needs to be enforced.
> + */
> + rte_smp_rmb();
> +
> + rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
> +
> + for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
> + uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
> + uint16_t nr_vec = 0;
> +
> + if (unlikely(reserve_avail_buf_split(dev, vq,
> + pkt_len, buf_vec, &num_buffers,
> + avail_head, &nr_vec) < 0)) {
> + VHOST_LOG_DATA(DEBUG,
> + "(%d) failed to get enough desc from vring\n",
> + dev->vid);
> + vq->shadow_used_idx -= num_buffers;
> + break;
> + }
> +
> + VHOST_LOG_DATA(DEBUG, "(%d) current index %d | end index %d\n",
> + dev->vid, vq->last_avail_idx,
> + vq->last_avail_idx + num_buffers);
> +
> + if (async_mbuf_to_desc(dev, vq, pkts[pkt_idx],
> + buf_vec, nr_vec, num_buffers,
> + src_iovec, dst_iovec, src_it, dst_it) < 0) {
> + vq->shadow_used_idx -= num_buffers;
> + break;
> + }
> +
> + slot_idx = (vq->async_pkts_idx + pkt_idx) & (vq->size - 1);
> + if (src_it->count) {
> + async_fill_des(&tdes[pkt_burst_idx], src_it, dst_it);
> + pkt_burst_idx++;
> + vq->async_pending_info[slot_idx] =
> + num_buffers | (src_it->nr_segs << 16);
> + src_iovec += src_it->nr_segs;
> + dst_iovec += dst_it->nr_segs;
> + src_it += 2;
> + dst_it += 2;
> + } else {
> + vq->async_pending_info[slot_idx] = num_buffers;
> + vq->async_pkts_inflight_n++;
> + }
> +
> + vq->last_avail_idx += num_buffers;
> +
> + if (pkt_burst_idx >= VHOST_ASYNC_BATCH_THRESHOLD ||
> + (pkt_idx == count - 1 && pkt_burst_idx)) {
> + n_pkts = vq->async_ops.transfer_data(dev->vid,
> + queue_id, tdes, 0, pkt_burst_idx);
> + src_iovec = vec_pool;
> + dst_iovec = vec_pool + (VHOST_MAX_ASYNC_VEC >> 1);
> + src_it = it_pool;
> + dst_it = it_pool + 1;
> +
> + if (unlikely(n_pkts < (int)pkt_burst_idx)) {
> + vq->async_pkts_inflight_n +=
> + n_pkts > 0 ? n_pkts : 0;
> + virtio_dev_rx_async_submit_split_err(dev,
> + vq, queue_id, last_idx, shadow_idx);
> + return 0;
> + }
> +
> + pkt_burst_idx = 0;
> + vq->async_pkts_inflight_n += n_pkts;
> + }
> + }
> +
> + if (pkt_burst_idx) {
> + n_pkts = vq->async_ops.transfer_data(dev->vid,
> + queue_id, tdes, 0, pkt_burst_idx);
> + if (unlikely(n_pkts <= (int)pkt_burst_idx)) {
> + vq->async_pkts_inflight_n += n_pkts > 0 ? n_pkts : 0;
> + virtio_dev_rx_async_submit_split_err(dev, vq, queue_id,
> + last_idx, shadow_idx);
> + return 0;
> + }
> +
> + vq->async_pkts_inflight_n += n_pkts;
> + }
> +
> + do_data_copy_enqueue(dev, vq);
> +
> + n_free_slot = vq->size - vq->async_pkts_idx;
> + if (n_free_slot > pkt_idx) {
> + rte_memcpy(&vq->async_pkts_pending[vq->async_pkts_idx],
> + pkts, pkt_idx * sizeof(uintptr_t));
> + vq->async_pkts_idx += pkt_idx;
> + } else {
> + rte_memcpy(&vq->async_pkts_pending[vq->async_pkts_idx],
> + pkts, n_free_slot * sizeof(uintptr_t));
> + rte_memcpy(&vq->async_pkts_pending[0],
> + &pkts[n_free_slot],
> + (pkt_idx - n_free_slot) * sizeof(uintptr_t));
> + vq->async_pkts_idx = pkt_idx - n_free_slot;
> + }
> +
> + if (likely(vq->shadow_used_idx))
> + async_flush_shadow_used_ring_split(dev, vq);
> +
> + return pkt_idx;
> +}
> +
> +uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
> + struct rte_mbuf **pkts, uint16_t count)
> +{
> + struct virtio_net *dev = get_device(vid);
> + struct vhost_virtqueue *vq;
> + uint16_t n_pkts_cpl, n_pkts_put = 0, n_descs = 0;
> + uint16_t start_idx, pkts_idx, vq_size;
> + uint64_t *async_pending_info;
> +
> + VHOST_LOG_DATA(DEBUG, "(%d) %s\n", dev->vid, __func__);
> + if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
> + VHOST_LOG_DATA(ERR, "(%d) %s: invalid virtqueue idx %d.\n",
> + dev->vid, __func__, queue_id);
> + return 0;
> + }
> +
> + vq = dev->virtqueue[queue_id];
> +
> + rte_spinlock_lock(&vq->access_lock);
> +
> + pkts_idx = vq->async_pkts_idx;
> + async_pending_info = vq->async_pending_info;
> + vq_size = vq->size;
> + start_idx = pkts_idx > vq->async_pkts_inflight_n ?
> + pkts_idx - vq->async_pkts_inflight_n :
> + (vq_size - vq->async_pkts_inflight_n + pkts_idx) &
> + (vq_size - 1);
> +
> + n_pkts_cpl =
> + vq->async_ops.check_completed_copies(vid, queue_id, 0, count);
> +
> + rte_smp_wmb();
> +
> + while (likely(((start_idx + n_pkts_put) & (vq_size - 1)) != pkts_idx)) {
> + uint64_t info = async_pending_info[
> + (start_idx + n_pkts_put) & (vq_size - 1)];
> + uint64_t n_segs;
> + n_pkts_put++;
> + n_descs += info & ASYNC_PENDING_INFO_N_MSK;
> + n_segs = info >> ASYNC_PENDING_INFO_N_SFT;
> +
> + if (n_segs) {
> + if (!n_pkts_cpl || n_pkts_cpl < n_segs) {
> + n_pkts_put--;
> + n_descs -= info & ASYNC_PENDING_INFO_N_MSK;
> + if (n_pkts_cpl) {
> + async_pending_info[
> + (start_idx + n_pkts_put) &
> + (vq_size - 1)] =
> + ((n_segs - n_pkts_cpl) <<
> + ASYNC_PENDING_INFO_N_SFT) |
> + (info & ASYNC_PENDING_INFO_N_MSK);
> + n_pkts_cpl = 0;
> + }
> + break;
> + }
> + n_pkts_cpl -= n_segs;
> + }
> + }
> +
> + if (n_pkts_put) {
> + vq->async_pkts_inflight_n -= n_pkts_put;
> + *(volatile uint16_t *)&vq->used->idx += n_descs;
> +
> + vhost_vring_call_split(dev, vq);
> + }
> +
> + if (start_idx + n_pkts_put <= vq_size) {
> + rte_memcpy(pkts, &vq->async_pkts_pending[start_idx],
> + n_pkts_put * sizeof(uintptr_t));
> + } else {
> + rte_memcpy(pkts, &vq->async_pkts_pending[start_idx],
> + (vq_size - start_idx) * sizeof(uintptr_t));
> + rte_memcpy(&pkts[vq_size - start_idx], vq->async_pkts_pending,
> + (n_pkts_put - vq_size + start_idx) * sizeof(uintptr_t));
> + }
> +
> + rte_spinlock_unlock(&vq->access_lock);
> +
> + return n_pkts_put;
> +}
> +
> +static __rte_always_inline uint32_t
> +virtio_dev_rx_async_submit(struct virtio_net *dev, uint16_t queue_id,
> + struct rte_mbuf **pkts, uint32_t count)
> +{
> + struct vhost_virtqueue *vq;
> + uint32_t nb_tx = 0;
> + bool drawback = false;
> +
> + VHOST_LOG_DATA(DEBUG, "(%d) %s\n", dev->vid, __func__);
> + if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
> + VHOST_LOG_DATA(ERR, "(%d) %s: invalid virtqueue idx %d.\n",
> + dev->vid, __func__, queue_id);
> + return 0;
> + }
> +
> + vq = dev->virtqueue[queue_id];
> +
> + rte_spinlock_lock(&vq->access_lock);
> +
> + if (unlikely(vq->enabled == 0))
> + goto out_access_unlock;
> +
> + if (unlikely(!vq->async_registered)) {
> + drawback = true;
fallback instead?
> + goto out_access_unlock;
> + }
> +
> + if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> + vhost_user_iotlb_rd_lock(vq);
> +
> + if (unlikely(vq->access_ok == 0))
> + if (unlikely(vring_translate(dev, vq) < 0))
> + goto out;
> +
> + count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
> + if (count == 0)
> + goto out;
> +
> + /* TODO: packed queue not implemented */
> + if (vq_is_packed(dev))
> + nb_tx = 0;
> + else
> + nb_tx = virtio_dev_rx_async_submit_split(dev,
> + vq, queue_id, pkts, count);
> +
> +out:
> + if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> + vhost_user_iotlb_rd_unlock(vq);
> +
> +out_access_unlock:
> + rte_spinlock_unlock(&vq->access_lock);
> +
> + if (drawback)
> + return rte_vhost_enqueue_burst(dev->vid, queue_id, pkts, count);
> +
> + return nb_tx;
> +}
> +
> +uint16_t
> +rte_vhost_submit_enqueue_burst(int vid, uint16_t queue_id,
> + struct rte_mbuf **pkts, uint16_t count)
> +{
> + struct virtio_net *dev = get_device(vid);
> +
> + if (!dev)
> + return 0;
> +
> + if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
> + VHOST_LOG_DATA(ERR,
> + "(%d) %s: built-in vhost net backend is disabled.\n",
> + dev->vid, __func__);
> + return 0;
> + }
> +
> + return virtio_dev_rx_async_submit(dev, queue_id, pkts, count);
> +}
> +
> static inline bool
> virtio_net_with_host_offload(struct virtio_net *dev)
> {
>
