drivers/net/virtio/virtqueue.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2015 Intel Corporation
   3  */
   4 #include <stdint.h>
   5
   6 #include <rte_mbuf.h>
   7
   8 #include "virtqueue.h"
   9 #include "virtio_logs.h"
  10 #include "virtio_pci.h"
  11 #include "virtio_rxtx_simple.h"
  12
  13 /*
  14  * Two types of mbuf to be cleaned:
  15  * 1) mbuf that has been consumed by backend but not used by virtio.
  16  * 2) mbuf that hasn't been consued by backend.
  17  */
  18 struct rte_mbuf *
  19 virtqueue_detach_unused(struct virtqueue *vq)
  20 {
  21         struct rte_mbuf *cookie;
  22         struct virtio_hw *hw;
  23         uint16_t start, end;
  24         int type, idx;
  25
  26         if (vq == NULL)
  27                 return NULL;
  28
  29         hw = vq->hw;
  30         type = virtio_get_queue_type(hw, vq->vq_queue_index);
  31         start = vq->vq_avail_idx & (vq->vq_nentries - 1);
  32         end = (vq->vq_avail_idx + vq->vq_free_cnt) & (vq->vq_nentries - 1);
  33
  34         for (idx = 0; idx < vq->vq_nentries; idx++) {
  35                 if (hw->use_simple_rx && type == VTNET_RQ) {
  36                         if (start <= end && idx >= start && idx < end)
  37                                 continue;
  38                         if (start > end && (idx >= start || idx < end))
  39                                 continue;
  40                         cookie = vq->sw_ring[idx];
  41                         if (cookie != NULL) {
  42                                 vq->sw_ring[idx] = NULL;
  43                                 return cookie;
  44                         }
  45                 } else {
  46                         cookie = vq->vq_descx[idx].cookie;
  47                         if (cookie != NULL) {
  48                                 vq->vq_descx[idx].cookie = NULL;
  49                                 return cookie;
  50                         }
  51                 }
  52         }
  53
  54         return NULL;
  55 }
  56
  57 /* Flush used descs */
  58 static void
  59 virtqueue_rxvq_flush_packed(struct virtqueue *vq)
  60 {
  61         struct vq_desc_extra *dxp;
  62         uint16_t i;
  63
  64         struct vring_packed_desc *descs = vq->ring_packed.desc_packed;
  65         int cnt = 0;
  66
  67         i = vq->vq_used_cons_idx;
  68         while (desc_is_used(&descs[i], vq) && cnt++ < vq->vq_nentries) {
  69                 dxp = &vq->vq_descx[descs[i].id];
  70                 if (dxp->cookie != NULL) {
  71                         rte_pktmbuf_free(dxp->cookie);
  72                         dxp->cookie = NULL;
  73                 }
  74                 vq->vq_free_cnt++;
  75                 vq->vq_used_cons_idx++;
  76                 if (vq->vq_used_cons_idx >= vq->vq_nentries) {
  77                         vq->vq_used_cons_idx -= vq->vq_nentries;
  78                         vq->used_wrap_counter ^= 1;
  79                 }
  80                 i = vq->vq_used_cons_idx;
  81         }
  82 }
  83
  84 /* Flush the elements in the used ring. */
  85 static void
  86 virtqueue_rxvq_flush_split(struct virtqueue *vq)
  87 {
  88         struct virtnet_rx *rxq = &vq->rxq;
  89         struct virtio_hw *hw = vq->hw;
  90         struct vring_used_elem *uep;
  91         struct vq_desc_extra *dxp;
  92         uint16_t used_idx, desc_idx;
  93         uint16_t nb_used, i;
  94
  95         nb_used = VIRTQUEUE_NUSED(vq);
  96
  97         for (i = 0; i < nb_used; i++) {
  98                 used_idx = vq->vq_used_cons_idx & (vq->vq_nentries - 1);
  99                 uep = &vq->vq_ring.used->ring[used_idx];
 100                 if (hw->use_simple_rx) {
 101                         desc_idx = used_idx;
 102                         rte_pktmbuf_free(vq->sw_ring[desc_idx]);
 103                         vq->vq_free_cnt++;
 104                 } else if (hw->use_inorder_rx) {
 105                         desc_idx = (uint16_t)uep->id;
 106                         dxp = &vq->vq_descx[desc_idx];
 107                         if (dxp->cookie != NULL) {
 108                                 rte_pktmbuf_free(dxp->cookie);
 109                                 dxp->cookie = NULL;
 110                         }
 111                         vq_ring_free_inorder(vq, desc_idx, 1);
 112                 } else {
 113                         desc_idx = (uint16_t)uep->id;
 114                         dxp = &vq->vq_descx[desc_idx];
 115                         if (dxp->cookie != NULL) {
 116                                 rte_pktmbuf_free(dxp->cookie);
 117                                 dxp->cookie = NULL;
 118                         }
 119                         vq_ring_free_chain(vq, desc_idx);
 120                 }
 121                 vq->vq_used_cons_idx++;
 122         }
 123
 124         if (hw->use_simple_rx) {
 125                 while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
 126                         virtio_rxq_rearm_vec(rxq);
 127                         if (virtqueue_kick_prepare(vq))
 128                                 virtqueue_notify(vq);
 129                 }
 130         }
 131 }
 132
 133 /* Flush the elements in the used ring. */
 134 void
 135 virtqueue_rxvq_flush(struct virtqueue *vq)
 136 {
 137         struct virtio_hw *hw = vq->hw;
 138
 139         if (vtpci_packed_queue(hw))
 140                 virtqueue_rxvq_flush_packed(vq);
 141         else
 142                 virtqueue_rxvq_flush_split(vq);
 143 }