1 /* virtio-pci.c - virtio ring management
3 * (c) Copyright 2008 Bull S.A.S.
5 * Author: Laurent Vivier <Laurent.Vivier@bull.net>
7 * some parts from Linux Virtio Ring
9 * Copyright Rusty Russell IBM Corporation 2007
11 * Adopted for Seabios: Gleb Natapov <gleb@redhat.com>
13 * This work is licensed under the terms of the GNU LGPLv3
14 * See the COPYING file in the top-level directory.
19 #include "virtio-ring.h"
20 #include "virtio-pci.h"
21 #include "biosvar.h" // GET_GLOBAL
22 #include "util.h" // dprintf
25 dprintf(1, "BUG: failure at %s:%d/%s()!\n", \
26 __FILE__, __LINE__, __func__); \
29 #define BUG_ON(condition) do { if (condition) BUG(); } while (0)
34 * is there some used buffers ?
38 int vring_more_used(struct vring_virtqueue *vq)
40 struct vring_used *used = GET_FLATPTR(vq->vring.used);
41 int more = GET_FLATPTR(vq->last_used_idx) != GET_FLATPTR(used->idx);
42 /* Make sure ring reads are done after idx read above. */
50 * put at the begin of the free list the current desc[head]
53 void vring_detach(struct vring_virtqueue *vq, unsigned int head)
55 struct vring *vr = &vq->vring;
56 struct vring_desc *desc = GET_FLATPTR(vr->desc);
59 /* find end of given descriptor */
62 while (GET_FLATPTR(desc[i].flags) & VRING_DESC_F_NEXT)
63 i = GET_FLATPTR(desc[i].next);
65 /* link it with free list and point to it */
67 SET_FLATPTR(desc[i].next, GET_FLATPTR(vq->free_head));
68 SET_FLATPTR(vq->free_head, head);
74 * get a buffer from the used list
78 int vring_get_buf(struct vring_virtqueue *vq, unsigned int *len)
80 struct vring *vr = &vq->vring;
81 struct vring_used_elem *elem;
82 struct vring_used *used = GET_FLATPTR(vq->vring.used);
86 // BUG_ON(!vring_more_used(vq));
88 elem = &used->ring[GET_FLATPTR(vq->last_used_idx) % GET_FLATPTR(vr->num)];
89 id = GET_FLATPTR(elem->id);
91 *len = GET_FLATPTR(elem->len);
93 ret = GET_FLATPTR(vq->vdata[id]);
97 SET_FLATPTR(vq->last_used_idx, GET_FLATPTR(vq->last_used_idx) + 1);
102 void vring_add_buf(struct vring_virtqueue *vq,
103 struct vring_list list[],
104 unsigned int out, unsigned int in,
105 int index, int num_added)
107 struct vring *vr = &vq->vring;
108 int i, av, head, prev;
109 struct vring_desc *desc = GET_FLATPTR(vr->desc);
110 struct vring_avail *avail = GET_FLATPTR(vr->avail);
112 BUG_ON(out + in == 0);
115 head = GET_FLATPTR(vq->free_head);
116 for (i = head; out; i = GET_FLATPTR(desc[i].next), out--) {
117 SET_FLATPTR(desc[i].flags, VRING_DESC_F_NEXT);
118 SET_FLATPTR(desc[i].addr, (u64)virt_to_phys(list->addr));
119 SET_FLATPTR(desc[i].len, list->length);
123 for ( ; in; i = GET_FLATPTR(desc[i].next), in--) {
124 SET_FLATPTR(desc[i].flags, VRING_DESC_F_NEXT|VRING_DESC_F_WRITE);
125 SET_FLATPTR(desc[i].addr, (u64)virt_to_phys(list->addr));
126 SET_FLATPTR(desc[i].len, list->length);
130 SET_FLATPTR(desc[prev].flags,
131 GET_FLATPTR(desc[prev].flags) & ~VRING_DESC_F_NEXT);
133 SET_FLATPTR(vq->free_head, i);
135 SET_FLATPTR(vq->vdata[head], index);
137 av = (GET_FLATPTR(avail->idx) + num_added) % GET_FLATPTR(vr->num);
138 SET_FLATPTR(avail->ring[av], head);
141 void vring_kick(unsigned int ioaddr, struct vring_virtqueue *vq, int num_added)
143 struct vring *vr = &vq->vring;
144 struct vring_avail *avail = GET_FLATPTR(vr->avail);
146 /* Make sure idx update is done after ring write. */
148 SET_FLATPTR(avail->idx, GET_FLATPTR(avail->idx) + num_added);
150 vp_notify(ioaddr, GET_FLATPTR(vq->queue_index));