This patch implements the vhost logic from scratch into a single function
designed for high performance and better maintainability.
---
Changes in v3:
1. Rewrite enqueue and delete the obsolete in the same patch.
Signed-off-by: Zhihong Wang <zhihong.wang at intel.com>
---
lib/librte_vhost/vhost_rxtx.c | 537 +++++++++++++-----------------------------
1 file changed, 160 insertions(+), 377 deletions(-)
diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
index 08a73fd..b09a9c3 100644
--- a/lib/librte_vhost/vhost_rxtx.c
+++ b/lib/librte_vhost/vhost_rxtx.c
@@ -91,7 +91,7 @@ is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t
qp_nb)
return (is_tx ^ (idx & 1)) == 0 && idx < qp_nb * VIRTIO_QNUM;
}
-static void
+static inline void __attribute__((always_inline))
virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
{
if (m_buf->ol_flags & PKT_TX_L4_MASK) {
@@ -125,427 +125,210 @@ virtio_enqueue_offload(struct rte_mbuf *m_buf, struct
virtio_net_hdr *net_hdr)
}
}
-static inline void
-copy_virtio_net_hdr(struct virtio_net *dev, uint64_t desc_addr,
- struct virtio_net_hdr_mrg_rxbuf hdr)
+static inline uint32_t __attribute__((always_inline))
+loop_check(struct vhost_virtqueue *vq, uint16_t avail_idx, uint32_t pkt_left)
{
- if (dev->vhost_hlen == sizeof(struct virtio_net_hdr_mrg_rxbuf))
- *(struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr = hdr;
- else
- *(struct virtio_net_hdr *)(uintptr_t)desc_addr = hdr.hdr;
+ if (pkt_left == 0 || avail_idx == vq->last_used_idx)
+ return 1;
+
+ return 0;
}
-static inline int __attribute__((always_inline))
-copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
- struct rte_mbuf *m, uint16_t desc_idx)
+static inline uint32_t __attribute__((always_inline))
+enqueue_packet(struct virtio_net *dev, struct vhost_virtqueue *vq,
+ uint16_t avail_idx, struct rte_mbuf *mbuf,
+ uint32_t is_mrg_rxbuf)
{
- uint32_t desc_avail, desc_offset;
- uint32_t mbuf_avail, mbuf_offset;
- uint32_t cpy_len;
+ struct virtio_net_hdr_mrg_rxbuf *virtio_hdr;
struct vring_desc *desc;
- uint64_t desc_addr;
- struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
-
- desc = &vq->desc[desc_idx];
+ uint64_t desc_addr = 0;
+ uint32_t desc_chain_head = 0;
+ uint32_t desc_chain_len = 0;
+ uint32_t desc_current = 0;
+ uint32_t desc_offset = 0;
+ uint32_t mbuf_len = 0;
+ uint32_t mbuf_avail = 0;
+ uint32_t copy_len = 0;
+ uint32_t extra_buffers = 0;
+ uint32_t used_idx_round = 0;
+
+ /* start with the first mbuf of the packet */
+ mbuf_len = rte_pktmbuf_data_len(mbuf);
+ mbuf_avail = mbuf_len;
+
+ /* get the current desc */
+ desc_current = vq->avail->ring[(vq->last_used_idx) & (vq->size - 1)];
+ desc_chain_head = desc_current;
+ desc = &vq->desc[desc_current];
desc_addr = gpa_to_vva(dev, 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);
+ if (unlikely(!desc_addr))
+ goto error;
- virtio_enqueue_offload(m, &virtio_hdr.hdr);
- copy_virtio_net_hdr(dev, desc_addr, virtio_hdr);
+ /* handle virtio header */
+ virtio_hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr;
+ virtio_enqueue_offload(mbuf, &(virtio_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;
+ desc_chain_len = desc_offset;
+ desc_addr += desc_offset;
+ if (is_mrg_rxbuf)
+ virtio_hdr->num_buffers = 1;
- 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);
+ /* start copy from mbuf to desc */
+ while (1) {
+ /* get the next mbuf if the current done */
+ if (!mbuf_avail) {
+ if (mbuf->next) {
+ mbuf = mbuf->next;
+ mbuf_len = rte_pktmbuf_data_len(mbuf);
+ mbuf_avail = mbuf_len;
+ } else
+ break;
}
- /* 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;
- }
- if (unlikely(desc->next >= vq->size))
- return -1;
-
- desc = &vq->desc[desc->next];
- desc_addr = gpa_to_vva(dev, desc->addr);
- if (unlikely(!desc_addr))
- return -1;
-
- desc_offset = 0;
- desc_avail = desc->len;
+ /* get the next desc if the current done */
+ if (desc->len <= desc_offset) {
+ if (desc->flags & VRING_DESC_F_NEXT) {
+ /* go on with the current desc chain */
+ desc_offset = 0;
+ desc_current = desc->next;
+ desc = &vq->desc[desc_current];
+ desc_addr = gpa_to_vva(dev, desc->addr);
+ if (unlikely(!desc_addr))
+ goto rollback;
+ } else if (is_mrg_rxbuf) {
+ /* start with the next desc chain */
+ used_idx_round = vq->last_used_idx
+ & (vq->size - 1);
+ vq->used->ring[used_idx_round].id =
+ desc_chain_head;
+ vq->used->ring[used_idx_round].len =
+ desc_chain_len;
+ vhost_log_used_vring(dev, vq,
+ offsetof(struct vring_used,
+ ring[used_idx_round]),
+ sizeof(vq->used->ring[
+ used_idx_round]));
+ vq->last_used_idx++;
+ extra_buffers++;
+ virtio_hdr->num_buffers++;
+ if (avail_idx == vq->last_used_idx)
+ goto rollback;
+
+ desc_current =
+ vq->avail->ring[(vq->last_used_idx) &
+ (vq->size - 1)];
+ desc_chain_head = desc_current;
+ desc = &vq->desc[desc_current];
+ desc_addr = gpa_to_vva(dev, desc->addr);
+ if (unlikely(!desc_addr))
+ goto rollback;
+
+ desc_chain_len = 0;
+ desc_offset = 0;
+ } else
+ goto rollback;
}
- 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;
-}
-
-/**
- * This function adds buffers to the virtio devices RX virtqueue. Buffers can
- * be received from the physical port or from another virtio device. A packet
- * count is returned to indicate the number of packets that are succesfully
- * added to the RX queue. This function works when the mbuf is scattered, but
- * it doesn't support the mergeable feature.
- */
-static inline uint32_t __attribute__((always_inline))
-virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
- struct rte_mbuf **pkts, uint32_t count)
-{
- struct vhost_virtqueue *vq;
- uint16_t avail_idx, free_entries, start_idx;
- uint16_t desc_indexes[MAX_PKT_BURST];
- uint16_t used_idx;
- uint32_t i;
-
- LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
- if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
- RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
- dev->vid, __func__, queue_id);
- return 0;
+ /* copy mbuf data */
+ copy_len = RTE_MIN(desc->len - desc_offset, mbuf_avail);
+ rte_memcpy((void *)(uintptr_t)desc_addr,
+ rte_pktmbuf_mtod_offset(mbuf, void *,
+ mbuf_len - mbuf_avail),
+ copy_len);
+ vhost_log_write(dev, desc->addr + desc_offset, copy_len);
+ mbuf_avail -= copy_len;
+ desc_offset += copy_len;
+ desc_addr += copy_len;
+ desc_chain_len += copy_len;
}
- vq = dev->virtqueue[queue_id];
- if (unlikely(vq->enabled == 0))
- return 0;
-
- avail_idx = *((volatile uint16_t *)&vq->avail->idx);
- start_idx = vq->last_used_idx;
- free_entries = avail_idx - start_idx;
- count = RTE_MIN(count, free_entries);
- count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
- if (count == 0)
- return 0;
-
- LOG_DEBUG(VHOST_DATA, "(%d) start_idx %d | end_idx %d\n",
- dev->vid, start_idx, start_idx + count);
-
- /* Retrieve all of the desc indexes first to avoid caching issues. */
- rte_prefetch0(&vq->avail->ring[start_idx & (vq->size - 1)]);
- for (i = 0; i < count; i++) {
- used_idx = (start_idx + i) & (vq->size - 1);
- desc_indexes[i] = vq->avail->ring[used_idx];
- vq->used->ring[used_idx].id = desc_indexes[i];
- vq->used->ring[used_idx].len = pkts[i]->pkt_len +
- dev->vhost_hlen;
- vhost_log_used_vring(dev, vq,
- offsetof(struct vring_used, ring[used_idx]),
- sizeof(vq->used->ring[used_idx]));
- }
+ used_idx_round = vq->last_used_idx & (vq->size - 1);
+ vq->used->ring[used_idx_round].id = desc_chain_head;
+ vq->used->ring[used_idx_round].len = desc_chain_len;
+ vhost_log_used_vring(dev, vq,
+ offsetof(struct vring_used, ring[used_idx_round]),
+ sizeof(vq->used->ring[used_idx_round]));
+ vq->last_used_idx++;
- rte_prefetch0(&vq->desc[desc_indexes[0]]);
- for (i = 0; i < count; i++) {
- uint16_t desc_idx = desc_indexes[i];
- int err;
+ return 0;
- err = copy_mbuf_to_desc(dev, vq, pkts[i], desc_idx);
- if (unlikely(err)) {
- used_idx = (start_idx + i) & (vq->size - 1);
- vq->used->ring[used_idx].len = dev->vhost_hlen;
- vhost_log_used_vring(dev, vq,
- offsetof(struct vring_used, ring[used_idx]),
- sizeof(vq->used->ring[used_idx]));
- }
+rollback:
+ /* rollback on any error if last_used_idx update on-the-fly */
+ if (is_mrg_rxbuf)
+ vq->last_used_idx -= extra_buffers;
- if (i + 1 < count)
- rte_prefetch0(&vq->desc[desc_indexes[i+1]]);
- }
+error:
+ return 1;
+}
+static inline void __attribute__((always_inline))
+notify_guest(struct virtio_net *dev, struct vhost_virtqueue *vq)
+{
rte_smp_wmb();
-
- *(volatile uint16_t *)&vq->used->idx += count;
- vq->last_used_idx += count;
- vhost_log_used_vring(dev, vq,
- offsetof(struct vring_used, idx),
- sizeof(vq->used->idx));
-
- /* flush used->idx update before we read avail->flags. */
+ vq->used->idx = vq->last_used_idx;
+ vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
+ sizeof(vq->used->idx));
rte_mb();
-
- /* Kick the guest if necessary. */
if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
&& (vq->callfd >= 0))
eventfd_write(vq->callfd, (eventfd_t)1);
- return count;
-}
-
-static inline int
-fill_vec_buf(struct vhost_virtqueue *vq, uint32_t avail_idx,
- uint32_t *allocated, uint32_t *vec_idx,
- struct buf_vector *buf_vec)
-{
- uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
- uint32_t vec_id = *vec_idx;
- uint32_t len = *allocated;
-
- while (1) {
- if (unlikely(vec_id >= BUF_VECTOR_MAX || idx >= vq->size))
- return -1;
-
- len += vq->desc[idx].len;
- buf_vec[vec_id].buf_addr = vq->desc[idx].addr;
- buf_vec[vec_id].buf_len = vq->desc[idx].len;
- buf_vec[vec_id].desc_idx = idx;
- vec_id++;
-
- if ((vq->desc[idx].flags & VRING_DESC_F_NEXT) == 0)
- break;
-
- idx = vq->desc[idx].next;
- }
-
- *allocated = len;
- *vec_idx = vec_id;
-
- return 0;
-}
-
-/*
- * Returns -1 on fail, 0 on success
- */
-static inline int
-reserve_avail_buf_mergeable(struct vhost_virtqueue *vq, uint32_t size,
- uint16_t *end, struct buf_vector *buf_vec)
-{
- uint16_t cur_idx;
- uint16_t avail_idx;
- uint32_t allocated = 0;
- uint32_t vec_idx = 0;
- uint16_t tries = 0;
-
- cur_idx = vq->last_used_idx;
-
- while (1) {
- avail_idx = *((volatile uint16_t *)&vq->avail->idx);
- if (unlikely(cur_idx == avail_idx))
- return -1;
-
- if (unlikely(fill_vec_buf(vq, cur_idx, &allocated,
- &vec_idx, buf_vec) < 0))
- return -1;
-
- cur_idx++;
- tries++;
-
- if (allocated >= size)
- break;
-
- /*
- * if we tried all available ring items, and still
- * can't get enough buf, it means something abnormal
- * happened.
- */
- if (unlikely(tries >= vq->size))
- return -1;
- }
-
- *end = cur_idx;
- return 0;
}
-static inline uint32_t __attribute__((always_inline))
-copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
- uint16_t end_idx, struct rte_mbuf *m,
- struct buf_vector *buf_vec)
+uint16_t
+rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
+ struct rte_mbuf **pkts, uint16_t count)
{
- struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
- uint32_t vec_idx = 0;
- uint16_t start_idx = vq->last_used_idx;
- uint16_t cur_idx = start_idx;
- uint64_t desc_addr;
- uint32_t mbuf_offset, mbuf_avail;
- uint32_t desc_offset, desc_avail;
- uint32_t cpy_len;
- uint16_t desc_idx, used_idx;
-
- if (unlikely(m == NULL))
+ struct vhost_virtqueue *vq;
+ struct virtio_net *dev;
+ uint32_t pkt_idx = 0;
+ uint32_t pkt_left = 0;
+ uint32_t pkt_sent = 0;
+ uint32_t is_mrg_rxbuf = 0;
+ uint16_t avail_idx = 0;
+
+ /* precheck */
+ if (unlikely(count == 0))
return 0;
- LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n",
- dev->vid, cur_idx, end_idx);
+ count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
- desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
- if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr)
+ dev = get_device(vid);
+ if (unlikely(!dev))
return 0;
- rte_prefetch0((void *)(uintptr_t)desc_addr);
-
- virtio_hdr.num_buffers = end_idx - start_idx;
- LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n",
- dev->vid, virtio_hdr.num_buffers);
-
- virtio_enqueue_offload(m, &virtio_hdr.hdr);
- copy_virtio_net_hdr(dev, desc_addr, virtio_hdr);
- vhost_log_write(dev, buf_vec[vec_idx].buf_addr, dev->vhost_hlen);
- PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
-
- desc_avail = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
- desc_offset = dev->vhost_hlen;
-
- mbuf_avail = rte_pktmbuf_data_len(m);
- mbuf_offset = 0;
- while (mbuf_avail != 0 || m->next != NULL) {
- /* done with current desc buf, get the next one */
- if (desc_avail == 0) {
- desc_idx = buf_vec[vec_idx].desc_idx;
-
- if (!(vq->desc[desc_idx].flags & VRING_DESC_F_NEXT)) {
- /* Update used ring with desc information */
- used_idx = cur_idx++ & (vq->size - 1);
- vq->used->ring[used_idx].id = desc_idx;
- vq->used->ring[used_idx].len = desc_offset;
- vhost_log_used_vring(dev, vq,
- offsetof(struct vring_used,
- ring[used_idx]),
- sizeof(vq->used->ring[used_idx]));
- }
-
- vec_idx++;
- desc_addr = gpa_to_vva(dev, buf_vec[vec_idx].buf_addr);
- if (unlikely(!desc_addr))
- return 0;
-
- /* Prefetch buffer address. */
- rte_prefetch0((void *)(uintptr_t)desc_addr);
- desc_offset = 0;
- desc_avail = buf_vec[vec_idx].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);
- }
-
- 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, buf_vec[vec_idx].buf_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;
- }
-
- used_idx = cur_idx & (vq->size - 1);
- vq->used->ring[used_idx].id = buf_vec[vec_idx].desc_idx;
- vq->used->ring[used_idx].len = desc_offset;
- vhost_log_used_vring(dev, vq,
- offsetof(struct vring_used, ring[used_idx]),
- sizeof(vq->used->ring[used_idx]));
-
- return end_idx - start_idx;
-}
-
-static inline uint32_t __attribute__((always_inline))
-virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
- struct rte_mbuf **pkts, uint32_t count)
-{
- struct vhost_virtqueue *vq;
- uint32_t pkt_idx = 0, nr_used = 0;
- uint16_t end;
- struct buf_vector buf_vec[BUF_VECTOR_MAX];
-
- LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
- if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
- RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
- dev->vid, __func__, queue_id);
+ if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb)))
return 0;
- }
vq = dev->virtqueue[queue_id];
- if (unlikely(vq->enabled == 0))
+ if (unlikely(!vq->enabled))
return 0;
- count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
- if (count == 0)
- return 0;
+ if (dev->features & (1ULL << VIRTIO_NET_F_MRG_RXBUF))
+ is_mrg_rxbuf = 1;
- for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
- uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
-
- if (unlikely(reserve_avail_buf_mergeable(vq, pkt_len,
- &end, buf_vec) < 0)) {
- LOG_DEBUG(VHOST_DATA,
- "(%d) failed to get enough desc from vring\n",
- dev->vid);
+ /* start enqueuing packets 1 by 1 */
+ pkt_idx = 0;
+ pkt_left = count;
+ avail_idx = *((volatile uint16_t *)&vq->avail->idx);
+ while (1) {
+ if (loop_check(vq, avail_idx, pkt_left))
break;
- }
-
- nr_used = copy_mbuf_to_desc_mergeable(dev, vq, end,
- pkts[pkt_idx], buf_vec);
- rte_smp_wmb();
- *(volatile uint16_t *)&vq->used->idx += nr_used;
- vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
- sizeof(vq->used->idx));
- vq->last_used_idx += nr_used;
- }
-
- if (likely(pkt_idx)) {
- /* flush used->idx update before we read avail->flags. */
- rte_mb();
+ if (enqueue_packet(dev, vq, avail_idx, pkts[pkt_idx],
+ is_mrg_rxbuf))
+ break;
- /* Kick the guest if necessary. */
- if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
- && (vq->callfd >= 0))
- eventfd_write(vq->callfd, (eventfd_t)1);
+ pkt_idx++;
+ pkt_sent++;
+ pkt_left--;
}
- return pkt_idx;
-}
-
-uint16_t
-rte_vhost_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;
+ /* update used idx and kick the guest if necessary */
+ if (pkt_sent)
+ notify_guest(dev, vq);
- 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);
+ return pkt_sent;
}
static void
--
2.7.4
