/* SPDX-License-Identifier: BSD-3-Clause * Copyright(c) 2010-2016 Intel Corporation */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "iotlb.h" #include "vhost.h" #define MAX_PKT_BURST 32 #define MAX_BATCH_LEN 256 static bool is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring) { return (is_tx ^ (idx & 1)) == 0 && idx < nr_vring; } static __rte_always_inline struct vring_desc * alloc_copy_ind_table(struct virtio_net *dev, struct vhost_virtqueue *vq, struct vring_desc *desc) { struct vring_desc *idesc; uint64_t src, dst; uint64_t len, remain = desc->len; uint64_t desc_addr = desc->addr; idesc = rte_malloc(__func__, desc->len, 0); if (unlikely(!idesc)) return 0; dst = (uint64_t)(uintptr_t)idesc; while (remain) { len = remain; src = vhost_iova_to_vva(dev, vq, desc_addr, &len, VHOST_ACCESS_RO); if (unlikely(!src || !len)) { rte_free(idesc); return 0; } rte_memcpy((void *)(uintptr_t)dst, (void *)(uintptr_t)src, len); remain -= len; dst += len; desc_addr += len; } return idesc; } static __rte_always_inline void free_ind_table(struct vring_desc *idesc) { rte_free(idesc); } static __rte_always_inline void do_flush_shadow_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq, uint16_t to, uint16_t from, uint16_t size) { rte_memcpy(&vq->used->ring[to], &vq->shadow_used_ring[from], size * sizeof(struct vring_used_elem)); vhost_log_used_vring(dev, vq, offsetof(struct vring_used, ring[to]), size * sizeof(struct vring_used_elem)); } static __rte_always_inline void flush_shadow_used_ring(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(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(dev, vq, used_idx, 0, size); /* update the left half used ring interval [0, left_size] */ do_flush_shadow_used_ring(dev, vq, 0, size, vq->shadow_used_idx - size); } vq->last_used_idx += vq->shadow_used_idx; rte_smp_wmb(); *(volatile uint16_t *)&vq->used->idx += vq->shadow_used_idx; vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx), sizeof(vq->used->idx)); } static __rte_always_inline void update_shadow_used_ring(struct vhost_virtqueue *vq, uint16_t desc_idx, uint16_t len) { uint16_t i = vq->shadow_used_idx++; vq->shadow_used_ring[i].id = desc_idx; vq->shadow_used_ring[i].len = len; } static inline void do_data_copy_enqueue(struct virtio_net *dev, struct vhost_virtqueue *vq) { struct batch_copy_elem *elem = vq->batch_copy_elems; uint16_t count = vq->batch_copy_nb_elems; int i; for (i = 0; i < count; i++) { rte_memcpy(elem[i].dst, elem[i].src, elem[i].len); vhost_log_write(dev, elem[i].log_addr, elem[i].len); PRINT_PACKET(dev, (uintptr_t)elem[i].dst, elem[i].len, 0); } } static inline void do_data_copy_dequeue(struct vhost_virtqueue *vq) { struct batch_copy_elem *elem = vq->batch_copy_elems; uint16_t count = vq->batch_copy_nb_elems; int i; for (i = 0; i < count; i++) rte_memcpy(elem[i].dst, elem[i].src, elem[i].len); } /* avoid write operation when necessary, to lessen cache issues */ #define ASSIGN_UNLESS_EQUAL(var, val) do { \ if ((var) != (val)) \ (var) = (val); \ } while (0) static void virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr) { uint64_t csum_l4 = m_buf->ol_flags & PKT_TX_L4_MASK; if (m_buf->ol_flags & PKT_TX_TCP_SEG) csum_l4 |= PKT_TX_TCP_CKSUM; if (csum_l4) { net_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; net_hdr->csum_start = m_buf->l2_len + m_buf->l3_len; switch (csum_l4) { case PKT_TX_TCP_CKSUM: net_hdr->csum_offset = (offsetof(struct tcp_hdr, cksum)); break; case PKT_TX_UDP_CKSUM: net_hdr->csum_offset = (offsetof(struct udp_hdr, dgram_cksum)); break; case PKT_TX_SCTP_CKSUM: net_hdr->csum_offset = (offsetof(struct sctp_hdr, cksum)); break; } } else { ASSIGN_UNLESS_EQUAL(net_hdr->csum_start, 0); ASSIGN_UNLESS_EQUAL(net_hdr->csum_offset, 0); ASSIGN_UNLESS_EQUAL(net_hdr->flags, 0); } /* IP cksum verification cannot be bypassed, then calculate here */ if (m_buf->ol_flags & PKT_TX_IP_CKSUM) { struct ipv4_hdr *ipv4_hdr; ipv4_hdr = rte_pktmbuf_mtod_offset(m_buf, struct ipv4_hdr *, m_buf->l2_len); ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr); } if (m_buf->ol_flags & PKT_TX_TCP_SEG) { if (m_buf->ol_flags & PKT_TX_IPV4) net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else net_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; net_hdr->gso_size = m_buf->tso_segsz; net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len + m_buf->l4_len; } else if (m_buf->ol_flags & PKT_TX_UDP_SEG) { net_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; net_hdr->gso_size = m_buf->tso_segsz; net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len + m_buf->l4_len; } else { ASSIGN_UNLESS_EQUAL(net_hdr->gso_type, 0); ASSIGN_UNLESS_EQUAL(net_hdr->gso_size, 0); ASSIGN_UNLESS_EQUAL(net_hdr->hdr_len, 0); } } static __rte_always_inline int copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq, struct vring_desc *descs, struct rte_mbuf *m, uint16_t desc_idx, uint32_t size) { uint32_t desc_avail, desc_offset; uint32_t mbuf_avail, mbuf_offset; uint32_t cpy_len; uint64_t desc_chunck_len; struct vring_desc *desc; uint64_t desc_addr, desc_gaddr; /* A counter to avoid desc dead loop chain */ uint16_t nr_desc = 1; struct batch_copy_elem *batch_copy = vq->batch_copy_elems; uint16_t copy_nb = vq->batch_copy_nb_elems; int error = 0; desc = &descs[desc_idx]; desc_chunck_len = desc->len; desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); /* * 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) { error = -1; goto out; } rte_prefetch0((void *)(uintptr_t)desc_addr); if (likely(desc_chunck_len >= dev->vhost_hlen)) { virtio_enqueue_offload(m, (struct virtio_net_hdr *)(uintptr_t)desc_addr); PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0); vhost_log_write(dev, desc_gaddr, dev->vhost_hlen); } else { struct virtio_net_hdr vnet_hdr; uint64_t remain = dev->vhost_hlen; uint64_t len; uint64_t src = (uint64_t)(uintptr_t)&vnet_hdr, dst; uint64_t guest_addr = desc_gaddr; virtio_enqueue_offload(m, &vnet_hdr); while (remain) { len = remain; dst = vhost_iova_to_vva(dev, vq, guest_addr, &len, VHOST_ACCESS_RW); if (unlikely(!dst || !len)) { error = -1; goto out; } rte_memcpy((void *)(uintptr_t)dst, (void *)(uintptr_t)src, len); PRINT_PACKET(dev, (uintptr_t)dst, (uint32_t)len, 0); vhost_log_write(dev, guest_addr, len); remain -= len; guest_addr += len; dst += len; } } desc_avail = desc->len - dev->vhost_hlen; if (unlikely(desc_chunck_len < dev->vhost_hlen)) { desc_chunck_len = desc_avail; desc_gaddr = desc->addr + dev->vhost_hlen; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; } else { desc_offset = dev->vhost_hlen; desc_chunck_len -= dev->vhost_hlen; } 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); } /* 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 */ error = -1; goto out; } if (unlikely(desc->next >= size || ++nr_desc > size)) { error = -1; goto out; } desc = &descs[desc->next]; desc_chunck_len = desc->len; desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; desc_avail = desc->len; } else if (unlikely(desc_chunck_len == 0)) { desc_chunck_len = desc_avail; desc_gaddr += desc_offset; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; } cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail); if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size)) { rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)), rte_pktmbuf_mtod_offset(m, void *, mbuf_offset), cpy_len); vhost_log_write(dev, desc_gaddr + desc_offset, cpy_len); PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), cpy_len, 0); } else { batch_copy[copy_nb].dst = (void *)((uintptr_t)(desc_addr + desc_offset)); batch_copy[copy_nb].src = rte_pktmbuf_mtod_offset(m, void *, mbuf_offset); batch_copy[copy_nb].log_addr = desc_gaddr + desc_offset; batch_copy[copy_nb].len = cpy_len; copy_nb++; } mbuf_avail -= cpy_len; mbuf_offset += cpy_len; desc_avail -= cpy_len; desc_offset += cpy_len; desc_chunck_len -= cpy_len; } out: vq->batch_copy_nb_elems = copy_nb; return error; } /** * 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 successfully * added to the RX queue. This function works when the mbuf is scattered, but * it doesn't support the mergeable feature. */ static __rte_always_inline uint32_t 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]; struct vring_desc *descs; uint16_t used_idx; uint32_t i, sz; VHOST_LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__); if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) { RTE_LOG(ERR, VHOST_DATA, "(%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 (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)) { count = 0; goto out; } } 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) goto out; VHOST_LOG_DEBUG(VHOST_DATA, "(%d) start_idx %d | end_idx %d\n", dev->vid, start_idx, start_idx + count); vq->batch_copy_nb_elems = 0; /* 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])); } rte_prefetch0(&vq->desc[desc_indexes[0]]); for (i = 0; i < count; i++) { struct vring_desc *idesc = NULL; uint16_t desc_idx = desc_indexes[i]; int err; if (vq->desc[desc_idx].flags & VRING_DESC_F_INDIRECT) { uint64_t dlen = vq->desc[desc_idx].len; descs = (struct vring_desc *)(uintptr_t) vhost_iova_to_vva(dev, vq, vq->desc[desc_idx].addr, &dlen, VHOST_ACCESS_RO); if (unlikely(!descs)) { count = i; break; } if (unlikely(dlen < vq->desc[desc_idx].len)) { /* * The indirect desc table is not contiguous * in process VA space, we have to copy it. */ idesc = alloc_copy_ind_table(dev, vq, &vq->desc[desc_idx]); if (unlikely(!idesc)) break; descs = idesc; } desc_idx = 0; sz = vq->desc[desc_idx].len / sizeof(*descs); } else { descs = vq->desc; sz = vq->size; } err = copy_mbuf_to_desc(dev, vq, descs, pkts[i], desc_idx, sz); if (unlikely(err)) { count = i; free_ind_table(idesc); break; } if (i + 1 < count) rte_prefetch0(&vq->desc[desc_indexes[i+1]]); if (unlikely(!!idesc)) free_ind_table(idesc); } do_data_copy_enqueue(dev, 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)); vhost_vring_call(dev, vq); out: if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) vhost_user_iotlb_rd_unlock(vq); out_access_unlock: rte_spinlock_unlock(&vq->access_lock); return count; } static __rte_always_inline int fill_vec_buf(struct virtio_net *dev, struct vhost_virtqueue *vq, uint32_t avail_idx, uint32_t *vec_idx, struct buf_vector *buf_vec, uint16_t *desc_chain_head, uint16_t *desc_chain_len) { uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)]; uint32_t vec_id = *vec_idx; uint32_t len = 0; uint64_t dlen; struct vring_desc *descs = vq->desc; struct vring_desc *idesc = NULL; *desc_chain_head = idx; if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) { dlen = vq->desc[idx].len; descs = (struct vring_desc *)(uintptr_t) vhost_iova_to_vva(dev, vq, vq->desc[idx].addr, &dlen, VHOST_ACCESS_RO); if (unlikely(!descs)) return -1; if (unlikely(dlen < vq->desc[idx].len)) { /* * The indirect desc table is not contiguous * in process VA space, we have to copy it. */ idesc = alloc_copy_ind_table(dev, vq, &vq->desc[idx]); if (unlikely(!idesc)) return -1; descs = idesc; } idx = 0; } while (1) { if (unlikely(vec_id >= BUF_VECTOR_MAX || idx >= vq->size)) { free_ind_table(idesc); return -1; } len += descs[idx].len; buf_vec[vec_id].buf_addr = descs[idx].addr; buf_vec[vec_id].buf_len = descs[idx].len; buf_vec[vec_id].desc_idx = idx; vec_id++; if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0) break; idx = descs[idx].next; } *desc_chain_len = len; *vec_idx = vec_id; if (unlikely(!!idesc)) free_ind_table(idesc); return 0; } /* * Returns -1 on fail, 0 on success */ static inline int reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq, uint32_t size, struct buf_vector *buf_vec, uint16_t *num_buffers, uint16_t avail_head) { uint16_t cur_idx; uint32_t vec_idx = 0; uint16_t tries = 0; uint16_t head_idx = 0; uint16_t len = 0; *num_buffers = 0; cur_idx = vq->last_avail_idx; while (size > 0) { if (unlikely(cur_idx == avail_head)) return -1; if (unlikely(fill_vec_buf(dev, vq, cur_idx, &vec_idx, buf_vec, &head_idx, &len) < 0)) return -1; len = RTE_MIN(len, size); update_shadow_used_ring(vq, head_idx, len); size -= len; cur_idx++; tries++; *num_buffers += 1; /* * 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; } return 0; } static __rte_always_inline int copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq, struct rte_mbuf *m, struct buf_vector *buf_vec, uint16_t num_buffers) { uint32_t vec_idx = 0; uint64_t desc_addr, desc_gaddr; uint32_t mbuf_offset, mbuf_avail; uint32_t desc_offset, desc_avail; uint32_t cpy_len; uint64_t desc_chunck_len; uint64_t hdr_addr, hdr_phys_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; uint16_t copy_nb = vq->batch_copy_nb_elems; int error = 0; if (unlikely(m == NULL)) { error = -1; goto out; } desc_chunck_len = buf_vec[vec_idx].buf_len; desc_gaddr = buf_vec[vec_idx].buf_addr; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); if (buf_vec[vec_idx].buf_len < dev->vhost_hlen || !desc_addr) { error = -1; goto out; } hdr_mbuf = m; hdr_addr = desc_addr; if (unlikely(desc_chunck_len < dev->vhost_hlen)) hdr = &tmp_hdr; else hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)hdr_addr; hdr_phys_addr = desc_gaddr; rte_prefetch0((void *)(uintptr_t)hdr_addr); VHOST_LOG_DEBUG(VHOST_DATA, "(%d) RX: num merge buffers %d\n", dev->vid, num_buffers); desc_avail = buf_vec[vec_idx].buf_len - dev->vhost_hlen; if (unlikely(desc_chunck_len < dev->vhost_hlen)) { desc_chunck_len = desc_avail; desc_gaddr += dev->vhost_hlen; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; } else { desc_offset = dev->vhost_hlen; desc_chunck_len -= 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) { vec_idx++; desc_chunck_len = buf_vec[vec_idx].buf_len; desc_gaddr = buf_vec[vec_idx].buf_addr; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); if (unlikely(!desc_addr)) { error = -1; goto out; } /* Prefetch buffer address. */ rte_prefetch0((void *)(uintptr_t)desc_addr); desc_offset = 0; desc_avail = buf_vec[vec_idx].buf_len; } else if (unlikely(desc_chunck_len == 0)) { desc_chunck_len = desc_avail; desc_gaddr += desc_offset; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RW); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; } /* 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); ASSIGN_UNLESS_EQUAL(hdr->num_buffers, num_buffers); if (unlikely(hdr == &tmp_hdr)) { uint64_t len; uint64_t remain = dev->vhost_hlen; uint64_t src = (uint64_t)(uintptr_t)hdr, dst; uint64_t guest_addr = hdr_phys_addr; while (remain) { len = remain; dst = vhost_iova_to_vva(dev, vq, guest_addr, &len, VHOST_ACCESS_RW); if (unlikely(!dst || !len)) { error = -1; goto out; } rte_memcpy((void *)(uintptr_t)dst, (void *)(uintptr_t)src, len); PRINT_PACKET(dev, (uintptr_t)dst, (uint32_t)len, 0); vhost_log_write(dev, guest_addr, len); remain -= len; guest_addr += len; dst += len; } } else { PRINT_PACKET(dev, (uintptr_t)hdr_addr, dev->vhost_hlen, 0); vhost_log_write(dev, hdr_phys_addr, dev->vhost_hlen); } hdr_addr = 0; } cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail); if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size)) { rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)), rte_pktmbuf_mtod_offset(m, void *, mbuf_offset), cpy_len); vhost_log_write(dev, desc_gaddr + desc_offset, cpy_len); PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), cpy_len, 0); } else { batch_copy[copy_nb].dst = (void *)((uintptr_t)(desc_addr + desc_offset)); batch_copy[copy_nb].src = rte_pktmbuf_mtod_offset(m, void *, mbuf_offset); batch_copy[copy_nb].log_addr = desc_gaddr + desc_offset; batch_copy[copy_nb].len = cpy_len; copy_nb++; } mbuf_avail -= cpy_len; mbuf_offset += cpy_len; desc_avail -= cpy_len; desc_offset += cpy_len; desc_chunck_len -= cpy_len; } out: vq->batch_copy_nb_elems = copy_nb; return error; } static __rte_always_inline uint32_t 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; uint16_t num_buffers; struct buf_vector buf_vec[BUF_VECTOR_MAX]; uint16_t avail_head; VHOST_LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__); if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) { RTE_LOG(ERR, VHOST_DATA, "(%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 (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; vq->batch_copy_nb_elems = 0; rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]); vq->shadow_used_idx = 0; avail_head = *((volatile uint16_t *)&vq->avail->idx); 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(dev, vq, pkt_len, buf_vec, &num_buffers, avail_head) < 0)) { VHOST_LOG_DEBUG(VHOST_DATA, "(%d) failed to get enough desc from vring\n", dev->vid); vq->shadow_used_idx -= num_buffers; break; } VHOST_LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index %d\n", dev->vid, vq->last_avail_idx, vq->last_avail_idx + num_buffers); if (copy_mbuf_to_desc_mergeable(dev, vq, pkts[pkt_idx], buf_vec, num_buffers) < 0) { vq->shadow_used_idx -= num_buffers; break; } vq->last_avail_idx += num_buffers; } do_data_copy_enqueue(dev, vq); if (likely(vq->shadow_used_idx)) { flush_shadow_used_ring(dev, vq); vhost_vring_call(dev, vq); } out: if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) vhost_user_iotlb_rd_unlock(vq); out_access_unlock: rte_spinlock_unlock(&vq->access_lock); 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; if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) { RTE_LOG(ERR, VHOST_DATA, "(%d) %s: built-in vhost net backend is disabled.\n", dev->vid, __func__); return 0; } 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); } static inline bool virtio_net_with_host_offload(struct virtio_net *dev) { if (dev->features & ((1ULL << VIRTIO_NET_F_CSUM) | (1ULL << VIRTIO_NET_F_HOST_ECN) | (1ULL << VIRTIO_NET_F_HOST_TSO4) | (1ULL << VIRTIO_NET_F_HOST_TSO6) | (1ULL << VIRTIO_NET_F_HOST_UFO))) return true; return false; } static void parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr) { struct ipv4_hdr *ipv4_hdr; struct ipv6_hdr *ipv6_hdr; void *l3_hdr = NULL; struct ether_hdr *eth_hdr; uint16_t ethertype; eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *); m->l2_len = sizeof(struct ether_hdr); ethertype = rte_be_to_cpu_16(eth_hdr->ether_type); if (ethertype == ETHER_TYPE_VLAN) { struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1); m->l2_len += sizeof(struct vlan_hdr); ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto); } l3_hdr = (char *)eth_hdr + m->l2_len; switch (ethertype) { case ETHER_TYPE_IPv4: ipv4_hdr = l3_hdr; *l4_proto = ipv4_hdr->next_proto_id; m->l3_len = (ipv4_hdr->version_ihl & 0x0f) * 4; *l4_hdr = (char *)l3_hdr + m->l3_len; m->ol_flags |= PKT_TX_IPV4; break; case ETHER_TYPE_IPv6: ipv6_hdr = l3_hdr; *l4_proto = ipv6_hdr->proto; m->l3_len = sizeof(struct ipv6_hdr); *l4_hdr = (char *)l3_hdr + m->l3_len; m->ol_flags |= PKT_TX_IPV6; break; default: m->l3_len = 0; *l4_proto = 0; *l4_hdr = NULL; break; } } static __rte_always_inline void vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m) { uint16_t l4_proto = 0; void *l4_hdr = NULL; struct tcp_hdr *tcp_hdr = NULL; if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE) return; parse_ethernet(m, &l4_proto, &l4_hdr); if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) { if (hdr->csum_start == (m->l2_len + m->l3_len)) { switch (hdr->csum_offset) { case (offsetof(struct tcp_hdr, cksum)): if (l4_proto == IPPROTO_TCP) m->ol_flags |= PKT_TX_TCP_CKSUM; break; case (offsetof(struct udp_hdr, dgram_cksum)): if (l4_proto == IPPROTO_UDP) m->ol_flags |= PKT_TX_UDP_CKSUM; break; case (offsetof(struct sctp_hdr, cksum)): if (l4_proto == IPPROTO_SCTP) m->ol_flags |= PKT_TX_SCTP_CKSUM; break; default: break; } } } if (l4_hdr && hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { case VIRTIO_NET_HDR_GSO_TCPV4: case VIRTIO_NET_HDR_GSO_TCPV6: tcp_hdr = l4_hdr; m->ol_flags |= PKT_TX_TCP_SEG; m->tso_segsz = hdr->gso_size; m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2; break; case VIRTIO_NET_HDR_GSO_UDP: m->ol_flags |= PKT_TX_UDP_SEG; m->tso_segsz = hdr->gso_size; m->l4_len = sizeof(struct udp_hdr); break; default: RTE_LOG(WARNING, VHOST_DATA, "unsupported gso type %u.\n", hdr->gso_type); break; } } } static __rte_always_inline void put_zmbuf(struct zcopy_mbuf *zmbuf) { zmbuf->in_use = 0; } static __rte_always_inline int copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, struct vring_desc *descs, uint16_t max_desc, struct rte_mbuf *m, uint16_t desc_idx, struct rte_mempool *mbuf_pool) { struct vring_desc *desc; uint64_t desc_addr, desc_gaddr; uint32_t desc_avail, desc_offset; uint32_t mbuf_avail, mbuf_offset; uint32_t cpy_len; uint64_t desc_chunck_len; struct rte_mbuf *cur = m, *prev = m; struct virtio_net_hdr tmp_hdr; struct virtio_net_hdr *hdr = NULL; /* A counter to avoid desc dead loop chain */ uint32_t nr_desc = 1; struct batch_copy_elem *batch_copy = vq->batch_copy_elems; uint16_t copy_nb = vq->batch_copy_nb_elems; int error = 0; desc = &descs[desc_idx]; if (unlikely((desc->len < dev->vhost_hlen)) || (desc->flags & VRING_DESC_F_INDIRECT)) { error = -1; goto out; } desc_chunck_len = desc->len; desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RO); if (unlikely(!desc_addr)) { error = -1; goto out; } if (virtio_net_with_host_offload(dev)) { if (unlikely(desc_chunck_len < sizeof(struct virtio_net_hdr))) { uint64_t len = desc_chunck_len; uint64_t remain = sizeof(struct virtio_net_hdr); uint64_t src = desc_addr; uint64_t dst = (uint64_t)(uintptr_t)&tmp_hdr; uint64_t guest_addr = desc_gaddr; /* * No luck, the virtio-net header doesn't fit * in a contiguous virtual area. */ while (remain) { len = remain; src = vhost_iova_to_vva(dev, vq, guest_addr, &len, VHOST_ACCESS_RO); if (unlikely(!src || !len)) { error = -1; goto out; } rte_memcpy((void *)(uintptr_t)dst, (void *)(uintptr_t)src, len); guest_addr += len; remain -= len; dst += len; } hdr = &tmp_hdr; } else { hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr); rte_prefetch0(hdr); } } /* * A virtio driver normally uses at least 2 desc buffers * for Tx: the first for storing the header, and others * for storing the data. */ if (likely((desc->len == dev->vhost_hlen) && (desc->flags & VRING_DESC_F_NEXT) != 0)) { desc = &descs[desc->next]; if (unlikely(desc->flags & VRING_DESC_F_INDIRECT)) { error = -1; goto out; } desc_chunck_len = desc->len; desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RO); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; desc_avail = desc->len; nr_desc += 1; } else { desc_avail = desc->len - dev->vhost_hlen; if (unlikely(desc_chunck_len < dev->vhost_hlen)) { desc_chunck_len = desc_avail; desc_gaddr += dev->vhost_hlen; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RO); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; } else { desc_offset = dev->vhost_hlen; desc_chunck_len -= dev->vhost_hlen; } } rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset)); PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), (uint32_t)desc_chunck_len, 0); mbuf_offset = 0; mbuf_avail = m->buf_len - RTE_PKTMBUF_HEADROOM; while (1) { uint64_t hpa; cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail); /* * A desc buf might across two host physical pages that are * not continuous. In such case (gpa_to_hpa returns 0), data * will be copied even though zero copy is enabled. */ if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev, desc_gaddr + desc_offset, cpy_len)))) { cur->data_len = cpy_len; cur->data_off = 0; cur->buf_addr = (void *)(uintptr_t)(desc_addr + desc_offset); cur->buf_iova = hpa; /* * In zero copy mode, one mbuf can only reference data * for one or partial of one desc buff. */ mbuf_avail = cpy_len; } else { if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size || (hdr && cur == m) || desc->len != desc_chunck_len)) { rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *, mbuf_offset), (void *)((uintptr_t)(desc_addr + desc_offset)), cpy_len); } else { batch_copy[copy_nb].dst = rte_pktmbuf_mtod_offset(cur, void *, mbuf_offset); batch_copy[copy_nb].src = (void *)((uintptr_t)(desc_addr + desc_offset)); batch_copy[copy_nb].len = cpy_len; copy_nb++; } } mbuf_avail -= cpy_len; mbuf_offset += cpy_len; desc_avail -= cpy_len; desc_chunck_len -= cpy_len; desc_offset += cpy_len; /* This desc reaches to its end, get the next one */ if (desc_avail == 0) { if ((desc->flags & VRING_DESC_F_NEXT) == 0) break; if (unlikely(desc->next >= max_desc || ++nr_desc > max_desc)) { error = -1; goto out; } desc = &descs[desc->next]; if (unlikely(desc->flags & VRING_DESC_F_INDIRECT)) { error = -1; goto out; } desc_chunck_len = desc->len; desc_gaddr = desc->addr; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RO); if (unlikely(!desc_addr)) { error = -1; goto out; } rte_prefetch0((void *)(uintptr_t)desc_addr); desc_offset = 0; desc_avail = desc->len; PRINT_PACKET(dev, (uintptr_t)desc_addr, (uint32_t)desc_chunck_len, 0); } else if (unlikely(desc_chunck_len == 0)) { desc_chunck_len = desc_avail; desc_gaddr += desc_offset; desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr, &desc_chunck_len, VHOST_ACCESS_RO); if (unlikely(!desc_addr)) { error = -1; goto out; } desc_offset = 0; PRINT_PACKET(dev, (uintptr_t)desc_addr, (uint32_t)desc_chunck_len, 0); } /* * This mbuf reaches to its end, get a new one * to hold more data. */ if (mbuf_avail == 0) { cur = rte_pktmbuf_alloc(mbuf_pool); if (unlikely(cur == NULL)) { RTE_LOG(ERR, VHOST_DATA, "Failed to " "allocate memory for mbuf.\n"); error = -1; goto out; } if (unlikely(dev->dequeue_zero_copy)) rte_mbuf_refcnt_update(cur, 1); prev->next = cur; prev->data_len = mbuf_offset; m->nb_segs += 1; m->pkt_len += mbuf_offset; prev = cur; mbuf_offset = 0; mbuf_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM; } } prev->data_len = mbuf_offset; m->pkt_len += mbuf_offset; if (hdr) vhost_dequeue_offload(hdr, m); out: vq->batch_copy_nb_elems = copy_nb; return error; } static __rte_always_inline void update_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq, uint32_t used_idx, uint32_t desc_idx) { vq->used->ring[used_idx].id = desc_idx; vq->used->ring[used_idx].len = 0; vhost_log_used_vring(dev, vq, offsetof(struct vring_used, ring[used_idx]), sizeof(vq->used->ring[used_idx])); } static __rte_always_inline void update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq, uint32_t count) { if (unlikely(count == 0)) return; rte_smp_wmb(); rte_smp_rmb(); vq->used->idx += count; vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx), sizeof(vq->used->idx)); vhost_vring_call(dev, vq); } static __rte_always_inline struct zcopy_mbuf * get_zmbuf(struct vhost_virtqueue *vq) { uint16_t i; uint16_t last; int tries = 0; /* search [last_zmbuf_idx, zmbuf_size) */ i = vq->last_zmbuf_idx; last = vq->zmbuf_size; again: for (; i < last; i++) { if (vq->zmbufs[i].in_use == 0) { vq->last_zmbuf_idx = i + 1; vq->zmbufs[i].in_use = 1; return &vq->zmbufs[i]; } } tries++; if (tries == 1) { /* search [0, last_zmbuf_idx) */ i = 0; last = vq->last_zmbuf_idx; goto again; } return NULL; } static __rte_always_inline bool mbuf_is_consumed(struct rte_mbuf *m) { while (m) { if (rte_mbuf_refcnt_read(m) > 1) return false; m = m->next; } return true; } static __rte_always_inline void restore_mbuf(struct rte_mbuf *m) { uint32_t mbuf_size, priv_size; while (m) { priv_size = rte_pktmbuf_priv_size(m->pool); mbuf_size = sizeof(struct rte_mbuf) + priv_size; /* start of buffer is after mbuf structure and priv data */ m->buf_addr = (char *)m + mbuf_size; m->buf_iova = rte_mempool_virt2iova(m) + mbuf_size; m = m->next; } } uint16_t rte_vhost_dequeue_burst(int vid, uint16_t queue_id, struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count) { struct virtio_net *dev; struct rte_mbuf *rarp_mbuf = NULL; struct vhost_virtqueue *vq; uint32_t desc_indexes[MAX_PKT_BURST]; uint32_t used_idx; uint32_t i = 0; uint16_t free_entries; uint16_t avail_idx; dev = get_device(vid); if (!dev) return 0; if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) { RTE_LOG(ERR, VHOST_DATA, "(%d) %s: built-in vhost net backend is disabled.\n", dev->vid, __func__); return 0; } if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->nr_vring))) { RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n", dev->vid, __func__, queue_id); return 0; } vq = dev->virtqueue[queue_id]; if (unlikely(rte_spinlock_trylock(&vq->access_lock) == 0)) return 0; if (unlikely(vq->enabled == 0)) goto out_access_unlock; vq->batch_copy_nb_elems = 0; 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; if (unlikely(dev->dequeue_zero_copy)) { struct zcopy_mbuf *zmbuf, *next; int nr_updated = 0; for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list); zmbuf != NULL; zmbuf = next) { next = TAILQ_NEXT(zmbuf, next); if (mbuf_is_consumed(zmbuf->mbuf)) { used_idx = vq->last_used_idx++ & (vq->size - 1); update_used_ring(dev, vq, used_idx, zmbuf->desc_idx); nr_updated += 1; TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next); restore_mbuf(zmbuf->mbuf); rte_pktmbuf_free(zmbuf->mbuf); put_zmbuf(zmbuf); vq->nr_zmbuf -= 1; } } update_used_idx(dev, vq, nr_updated); } /* * Construct a RARP broadcast packet, and inject it to the "pkts" * array, to looks like that guest actually send such packet. * * Check user_send_rarp() for more information. * * broadcast_rarp shares a cacheline in the virtio_net structure * with some fields that are accessed during enqueue and * rte_atomic16_cmpset() causes a write if using cmpxchg. This could * result in false sharing between enqueue and dequeue. * * Prevent unnecessary false sharing by reading broadcast_rarp first * and only performing cmpset if the read indicates it is likely to * be set. */ if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) && rte_atomic16_cmpset((volatile uint16_t *) &dev->broadcast_rarp.cnt, 1, 0))) { rarp_mbuf = rte_net_make_rarp_packet(mbuf_pool, &dev->mac); if (rarp_mbuf == NULL) { RTE_LOG(ERR, VHOST_DATA, "Failed to make RARP packet.\n"); return 0; } count -= 1; } free_entries = *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx; if (free_entries == 0) goto out; VHOST_LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__); /* Prefetch available and used ring */ avail_idx = vq->last_avail_idx & (vq->size - 1); used_idx = vq->last_used_idx & (vq->size - 1); rte_prefetch0(&vq->avail->ring[avail_idx]); rte_prefetch0(&vq->used->ring[used_idx]); count = RTE_MIN(count, MAX_PKT_BURST); count = RTE_MIN(count, free_entries); VHOST_LOG_DEBUG(VHOST_DATA, "(%d) about to dequeue %u buffers\n", dev->vid, count); /* Retrieve all of the head indexes first to avoid caching issues. */ for (i = 0; i < count; i++) { avail_idx = (vq->last_avail_idx + i) & (vq->size - 1); used_idx = (vq->last_used_idx + i) & (vq->size - 1); desc_indexes[i] = vq->avail->ring[avail_idx]; if (likely(dev->dequeue_zero_copy == 0)) update_used_ring(dev, vq, used_idx, desc_indexes[i]); } /* Prefetch descriptor index. */ rte_prefetch0(&vq->desc[desc_indexes[0]]); for (i = 0; i < count; i++) { struct vring_desc *desc, *idesc = NULL; uint16_t sz, idx; uint64_t dlen; int err; if (likely(i + 1 < count)) rte_prefetch0(&vq->desc[desc_indexes[i + 1]]); if (vq->desc[desc_indexes[i]].flags & VRING_DESC_F_INDIRECT) { dlen = vq->desc[desc_indexes[i]].len; desc = (struct vring_desc *)(uintptr_t) vhost_iova_to_vva(dev, vq, vq->desc[desc_indexes[i]].addr, &dlen, VHOST_ACCESS_RO); if (unlikely(!desc)) break; if (unlikely(dlen < vq->desc[desc_indexes[i]].len)) { /* * The indirect desc table is not contiguous * in process VA space, we have to copy it. */ idesc = alloc_copy_ind_table(dev, vq, &vq->desc[desc_indexes[i]]); if (unlikely(!idesc)) break; desc = idesc; } rte_prefetch0(desc); sz = vq->desc[desc_indexes[i]].len / sizeof(*desc); idx = 0; } else { desc = vq->desc; sz = vq->size; idx = desc_indexes[i]; } pkts[i] = rte_pktmbuf_alloc(mbuf_pool); if (unlikely(pkts[i] == NULL)) { RTE_LOG(ERR, VHOST_DATA, "Failed to allocate memory for mbuf.\n"); free_ind_table(idesc); break; } err = copy_desc_to_mbuf(dev, vq, desc, sz, pkts[i], idx, mbuf_pool); if (unlikely(err)) { rte_pktmbuf_free(pkts[i]); free_ind_table(idesc); break; } if (unlikely(dev->dequeue_zero_copy)) { struct zcopy_mbuf *zmbuf; zmbuf = get_zmbuf(vq); if (!zmbuf) { rte_pktmbuf_free(pkts[i]); free_ind_table(idesc); break; } zmbuf->mbuf = pkts[i]; zmbuf->desc_idx = desc_indexes[i]; /* * Pin lock the mbuf; we will check later to see * whether the mbuf is freed (when we are the last * user) or not. If that's the case, we then could * update the used ring safely. */ rte_mbuf_refcnt_update(pkts[i], 1); vq->nr_zmbuf += 1; TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next); } if (unlikely(!!idesc)) free_ind_table(idesc); } vq->last_avail_idx += i; if (likely(dev->dequeue_zero_copy == 0)) { do_data_copy_dequeue(vq); vq->last_used_idx += i; update_used_idx(dev, vq, i); } 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 (unlikely(rarp_mbuf != NULL)) { /* * Inject it to the head of "pkts" array, so that switch's mac * learning table will get updated first. */ memmove(&pkts[1], pkts, i * sizeof(struct rte_mbuf *)); pkts[0] = rarp_mbuf; i += 1; } return i; }