mirror of https://github.com/ipxe/ipxe.git
144 lines
3.1 KiB
C
144 lines
3.1 KiB
C
/* virtio-pci.c - virtio ring management
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*
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* (c) Copyright 2008 Bull S.A.S.
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*
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* Author: Laurent Vivier <Laurent.Vivier@bull.net>
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*
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* some parts from Linux Virtio Ring
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*
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* Copyright Rusty Russell IBM Corporation 2007
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*
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*
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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#include "etherboot.h"
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#include "ipxe/io.h"
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#include "ipxe/virtio-pci.h"
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#include "ipxe/virtio-ring.h"
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#define BUG() do { \
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printf("BUG: failure at %s:%d/%s()!\n", \
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__FILE__, __LINE__, __FUNCTION__); \
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while(1); \
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} while (0)
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#define BUG_ON(condition) do { if (condition) BUG(); } while (0)
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/*
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* vring_free
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*
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* put at the begin of the free list the current desc[head]
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*/
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void vring_detach(struct vring_virtqueue *vq, unsigned int head)
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{
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struct vring *vr = &vq->vring;
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unsigned int i;
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/* find end of given descriptor */
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i = head;
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while (vr->desc[i].flags & VRING_DESC_F_NEXT)
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i = vr->desc[i].next;
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/* link it with free list and point to it */
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vr->desc[i].next = vq->free_head;
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wmb();
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vq->free_head = head;
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}
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/*
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* vring_get_buf
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*
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* get a buffer from the used list
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*
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*/
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void *vring_get_buf(struct vring_virtqueue *vq, unsigned int *len)
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{
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struct vring *vr = &vq->vring;
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struct vring_used_elem *elem;
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u32 id;
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void *opaque;
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BUG_ON(!vring_more_used(vq));
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elem = &vr->used->ring[vq->last_used_idx % vr->num];
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wmb();
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id = elem->id;
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if (len != NULL)
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*len = elem->len;
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opaque = vq->vdata[id];
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vring_detach(vq, id);
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vq->last_used_idx++;
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return opaque;
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}
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void vring_add_buf(struct vring_virtqueue *vq,
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struct vring_list list[],
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unsigned int out, unsigned int in,
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void *opaque, int num_added)
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{
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struct vring *vr = &vq->vring;
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int i, avail, head, prev;
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BUG_ON(out + in == 0);
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prev = 0;
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head = vq->free_head;
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for (i = head; out; i = vr->desc[i].next, out--) {
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vr->desc[i].flags = VRING_DESC_F_NEXT;
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vr->desc[i].addr = list->addr;
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vr->desc[i].len = list->length;
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prev = i;
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list++;
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}
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for ( ; in; i = vr->desc[i].next, in--) {
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vr->desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
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vr->desc[i].addr = list->addr;
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vr->desc[i].len = list->length;
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prev = i;
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list++;
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}
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vr->desc[prev].flags &= ~VRING_DESC_F_NEXT;
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vq->free_head = i;
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vq->vdata[head] = opaque;
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avail = (vr->avail->idx + num_added) % vr->num;
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vr->avail->ring[avail] = head;
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wmb();
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}
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void vring_kick(struct virtio_pci_modern_device *vdev, unsigned int ioaddr,
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struct vring_virtqueue *vq, int num_added)
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{
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struct vring *vr = &vq->vring;
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wmb();
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vr->avail->idx += num_added;
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mb();
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if (!(vr->used->flags & VRING_USED_F_NO_NOTIFY)) {
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if (vdev) {
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/* virtio 1.0 */
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vpm_notify(vdev, vq);
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} else {
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/* legacy virtio */
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vp_notify(ioaddr, vq->queue_index);
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}
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}
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}
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