xref: /dpdk/drivers/net/virtio/virtqueue.c (revision 2808423a9ce42a748aed77a4b487be27d2b6acfa)
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 the elements in the used ring. */
58 void
59 virtqueue_rxvq_flush(struct virtqueue *vq)
60 {
61 	struct virtnet_rx *rxq = &vq->rxq;
62 	struct virtio_hw *hw = vq->hw;
63 	struct vring_used_elem *uep;
64 	struct vq_desc_extra *dxp;
65 	uint16_t used_idx, desc_idx;
66 	uint16_t nb_used, i;
67 
68 	nb_used = VIRTQUEUE_NUSED(vq);
69 
70 	for (i = 0; i < nb_used; i++) {
71 		used_idx = vq->vq_used_cons_idx & (vq->vq_nentries - 1);
72 		uep = &vq->vq_ring.used->ring[used_idx];
73 		if (hw->use_simple_rx) {
74 			desc_idx = used_idx;
75 			rte_pktmbuf_free(vq->sw_ring[desc_idx]);
76 			vq->vq_free_cnt++;
77 		} else if (hw->use_inorder_rx) {
78 			desc_idx = (uint16_t)uep->id;
79 			dxp = &vq->vq_descx[desc_idx];
80 			if (dxp->cookie != NULL) {
81 				rte_pktmbuf_free(dxp->cookie);
82 				dxp->cookie = NULL;
83 			}
84 			vq_ring_free_inorder(vq, desc_idx, 1);
85 		} else {
86 			desc_idx = (uint16_t)uep->id;
87 			dxp = &vq->vq_descx[desc_idx];
88 			if (dxp->cookie != NULL) {
89 				rte_pktmbuf_free(dxp->cookie);
90 				dxp->cookie = NULL;
91 			}
92 			vq_ring_free_chain(vq, desc_idx);
93 		}
94 		vq->vq_used_cons_idx++;
95 	}
96 
97 	if (hw->use_simple_rx) {
98 		while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
99 			virtio_rxq_rearm_vec(rxq);
100 			if (virtqueue_kick_prepare(vq))
101 				virtqueue_notify(vq);
102 		}
103 	}
104 }
105