hw/dataplane/vring.h

   1 /* Copyright 2012 Red Hat, Inc. and/or its affiliates
   2  * Copyright IBM, Corp. 2012
   3  *
   4  * Based on Linux 2.6.39 vhost code:
   5  * Copyright (C) 2009 Red Hat, Inc.
   6  * Copyright (C) 2006 Rusty Russell IBM Corporation
   7  *
   8  * Author: Michael S. Tsirkin <mst@redhat.com>
   9  *         Stefan Hajnoczi <stefanha@redhat.com>
  10  *
  11  * Inspiration, some code, and most witty comments come from
  12  * Documentation/virtual/lguest/lguest.c, by Rusty Russell
  13  *
  14  * This work is licensed under the terms of the GNU GPL, version 2.
  15  */
  16
  17 #ifndef VRING_H
  18 #define VRING_H
  19
  20 #include <linux/virtio_ring.h>
  21 #include "qemu-common.h"
  22 #include "hostmem.h"
  23 #include "hw/virtio.h"
  24
  25 typedef struct {
  26     HostMem hostmem;                /* guest memory mapper */
  27     struct vring vr;                /* virtqueue vring mapped to host memory */
  28     uint16_t last_avail_idx;        /* last processed avail ring index */
  29     uint16_t last_used_idx;         /* last processed used ring index */
  30     uint16_t signalled_used;        /* EVENT_IDX state */
  31     bool signalled_used_valid;
  32     bool broken;                    /* was there a fatal error? */
  33 } Vring;
  34
  35 static inline unsigned int vring_get_num(Vring *vring)
  36 {
  37     return vring->vr.num;
  38 }
  39
  40 /* Are there more descriptors available? */
  41 static inline bool vring_more_avail(Vring *vring)
  42 {
  43     return vring->vr.avail->idx != vring->last_avail_idx;
  44 }
  45
  46 /* Fail future vring_pop() and vring_push() calls until reset */
  47 static inline void vring_set_broken(Vring *vring)
  48 {
  49     vring->broken = true;
  50 }
  51
  52 bool vring_setup(Vring *vring, VirtIODevice *vdev, int n);
  53 void vring_teardown(Vring *vring);
  54 void vring_disable_notification(VirtIODevice *vdev, Vring *vring);
  55 bool vring_enable_notification(VirtIODevice *vdev, Vring *vring);
  56 bool vring_should_notify(VirtIODevice *vdev, Vring *vring);
  57 int vring_pop(VirtIODevice *vdev, Vring *vring,
  58               struct iovec iov[], struct iovec *iov_end,
  59               unsigned int *out_num, unsigned int *in_num);
  60 void vring_push(Vring *vring, unsigned int head, int len);
  61
  62 #endif /* VRING_H */