include/hw/virtio/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 "qemu-common.h"
  21 #include "hw/virtio/virtio_ring.h"
  22 #include "hw/virtio/virtio.h"
  23
  24 typedef struct {
  25     MemoryRegion *mr;               /* memory region containing the vring */
  26     struct vring vr;                /* virtqueue vring mapped to host memory */
  27     uint16_t last_avail_idx;        /* last processed avail ring index */
  28     uint16_t last_used_idx;         /* last processed used ring index */
  29     uint16_t signalled_used;        /* EVENT_IDX state */
  30     bool signalled_used_valid;
  31     bool broken;                    /* was there a fatal error? */
  32 } Vring;
  33
  34 static inline unsigned int vring_get_num(Vring *vring)
  35 {
  36     return vring->vr.num;
  37 }
  38
  39 /* Are there more descriptors available? */
  40 static inline bool vring_more_avail(Vring *vring)
  41 {
  42     return vring->vr.avail->idx != vring->last_avail_idx;
  43 }
  44
  45 /* Fail future vring_pop() and vring_push() calls until reset */
  46 static inline void vring_set_broken(Vring *vring)
  47 {
  48     vring->broken = true;
  49 }
  50
  51 bool vring_setup(Vring *vring, VirtIODevice *vdev, int n);
  52 void vring_teardown(Vring *vring, VirtIODevice *vdev, int n);
  53 void vring_disable_notification(VirtIODevice *vdev, Vring *vring);
  54 bool vring_enable_notification(VirtIODevice *vdev, Vring *vring);
  55 bool vring_should_notify(VirtIODevice *vdev, Vring *vring);
  56 int vring_pop(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem);
  57 void vring_push(Vring *vring, VirtQueueElement *elem, int len);
  58
  59 #endif /* VRING_H */