| /* virtio-pci.c - virtio ring management |
| * |
| * (c) Copyright 2008 Bull S.A.S. |
| * |
| * Author: Laurent Vivier <Laurent.Vivier@bull.net> |
| * |
| * some parts from Linux Virtio Ring |
| * |
| * Copyright Rusty Russell IBM Corporation 2007 |
| * |
| * Adopted for Seabios: Gleb Natapov <gleb@redhat.com> |
| * |
| * This work is licensed under the terms of the GNU LGPLv3 |
| * See the COPYING file in the top-level directory. |
| * |
| * |
| */ |
| |
| #include "virtio-ring.h" |
| #include "virtio-pci.h" |
| #include "biosvar.h" // GET_GLOBAL |
| #include "util.h" // dprintf |
| |
| #define BUG() do { \ |
| dprintf(1, "BUG: failure at %s:%d/%s()!\n", \ |
| __FILE__, __LINE__, __func__); \ |
| while(1); \ |
| } while (0) |
| #define BUG_ON(condition) do { if (condition) BUG(); } while (0) |
| |
| /* |
| * vring_more_used |
| * |
| * is there some used buffers ? |
| * |
| */ |
| |
| int vring_more_used(struct vring_virtqueue *vq) |
| { |
| struct vring_used *used = GET_LOWFLAT(vq->vring.used); |
| int more = GET_LOWFLAT(vq->last_used_idx) != GET_LOWFLAT(used->idx); |
| /* Make sure ring reads are done after idx read above. */ |
| smp_rmb(); |
| return more; |
| } |
| |
| /* |
| * vring_free |
| * |
| * put at the begin of the free list the current desc[head] |
| */ |
| |
| void vring_detach(struct vring_virtqueue *vq, unsigned int head) |
| { |
| struct vring *vr = &vq->vring; |
| struct vring_desc *desc = GET_LOWFLAT(vr->desc); |
| unsigned int i; |
| |
| /* find end of given descriptor */ |
| |
| i = head; |
| while (GET_LOWFLAT(desc[i].flags) & VRING_DESC_F_NEXT) |
| i = GET_LOWFLAT(desc[i].next); |
| |
| /* link it with free list and point to it */ |
| |
| SET_LOWFLAT(desc[i].next, GET_LOWFLAT(vq->free_head)); |
| SET_LOWFLAT(vq->free_head, head); |
| } |
| |
| /* |
| * vring_get_buf |
| * |
| * get a buffer from the used list |
| * |
| */ |
| |
| int vring_get_buf(struct vring_virtqueue *vq, unsigned int *len) |
| { |
| struct vring *vr = &vq->vring; |
| struct vring_used_elem *elem; |
| struct vring_used *used = GET_LOWFLAT(vq->vring.used); |
| u32 id; |
| int ret; |
| |
| // BUG_ON(!vring_more_used(vq)); |
| |
| elem = &used->ring[GET_LOWFLAT(vq->last_used_idx) % GET_LOWFLAT(vr->num)]; |
| id = GET_LOWFLAT(elem->id); |
| if (len != NULL) |
| *len = GET_LOWFLAT(elem->len); |
| |
| ret = GET_LOWFLAT(vq->vdata[id]); |
| |
| vring_detach(vq, id); |
| |
| SET_LOWFLAT(vq->last_used_idx, GET_LOWFLAT(vq->last_used_idx) + 1); |
| |
| return ret; |
| } |
| |
| void vring_add_buf(struct vring_virtqueue *vq, |
| struct vring_list list[], |
| unsigned int out, unsigned int in, |
| int index, int num_added) |
| { |
| struct vring *vr = &vq->vring; |
| int i, av, head, prev; |
| struct vring_desc *desc = GET_LOWFLAT(vr->desc); |
| struct vring_avail *avail = GET_LOWFLAT(vr->avail); |
| |
| BUG_ON(out + in == 0); |
| |
| prev = 0; |
| head = GET_LOWFLAT(vq->free_head); |
| for (i = head; out; i = GET_LOWFLAT(desc[i].next), out--) { |
| SET_LOWFLAT(desc[i].flags, VRING_DESC_F_NEXT); |
| SET_LOWFLAT(desc[i].addr, (u64)virt_to_phys(list->addr)); |
| SET_LOWFLAT(desc[i].len, list->length); |
| prev = i; |
| list++; |
| } |
| for ( ; in; i = GET_LOWFLAT(desc[i].next), in--) { |
| SET_LOWFLAT(desc[i].flags, VRING_DESC_F_NEXT|VRING_DESC_F_WRITE); |
| SET_LOWFLAT(desc[i].addr, (u64)virt_to_phys(list->addr)); |
| SET_LOWFLAT(desc[i].len, list->length); |
| prev = i; |
| list++; |
| } |
| SET_LOWFLAT(desc[prev].flags, |
| GET_LOWFLAT(desc[prev].flags) & ~VRING_DESC_F_NEXT); |
| |
| SET_LOWFLAT(vq->free_head, i); |
| |
| SET_LOWFLAT(vq->vdata[head], index); |
| |
| av = (GET_LOWFLAT(avail->idx) + num_added) % GET_LOWFLAT(vr->num); |
| SET_LOWFLAT(avail->ring[av], head); |
| } |
| |
| void vring_kick(unsigned int ioaddr, struct vring_virtqueue *vq, int num_added) |
| { |
| struct vring *vr = &vq->vring; |
| struct vring_avail *avail = GET_LOWFLAT(vr->avail); |
| |
| /* Make sure idx update is done after ring write. */ |
| smp_wmb(); |
| SET_LOWFLAT(avail->idx, GET_LOWFLAT(avail->idx) + num_added); |
| |
| vp_notify(ioaddr, GET_LOWFLAT(vq->queue_index)); |
| } |