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/* Copyright 2012 Red Hat, Inc. and/or its affiliates

 * Copyright IBM, Corp. 2012

 *

 * Based on Linux 2.6.39 vhost code:

 * Copyright (C) 2009 Red Hat, Inc.

 * Copyright (C) 2006 Rusty Russell IBM Corporation

 *

 * Author: Michael S. Tsirkin <mst@redhat.com>

 *         Stefan Hajnoczi <stefanha@redhat.com>

 *

 * Inspiration, some code, and most witty comments come from

 * Documentation/virtual/lguest/lguest.c, by Rusty Russell

 *

 * This work is licensed under the terms of the GNU GPL, version 2.

 */

#ifndef VRING_H

#define VRING_H

#include <linux/virtio_ring.h>

#include "qemu-common.h"

#include "hostmem.h"

#include "hw/virtio/virtio.h"

typedef struct {

    HostMem hostmem;                /* guest memory mapper */

    struct vring vr;                /* virtqueue vring mapped to host memory */

    uint16_t last_avail_idx;        /* last processed avail ring index */

    uint16_t last_used_idx;         /* last processed used ring index */

    uint16_t signalled_used;        /* EVENT_IDX state */

    bool signalled_used_valid;

    bool broken;                    /* was there a fatal error? */

} Vring;

static inline unsigned int vring_get_num(Vring *vring)

{

    return vring->vr.num;

}

/* Are there more descriptors available? */

static inline bool vring_more_avail(Vring *vring)

{

    return vring->vr.avail->idx != vring->last_avail_idx;

}

/* Fail future vring_pop() and vring_push() calls until reset */

static inline void vring_set_broken(Vring *vring)

{

    vring->broken = true;

}

bool vring_setup(Vring *vring, VirtIODevice *vdev, int n);

void vring_teardown(Vring *vring, VirtIODevice *vdev, int n);

void vring_disable_notification(VirtIODevice *vdev, Vring *vring);

bool vring_enable_notification(VirtIODevice *vdev, Vring *vring);

bool vring_should_notify(VirtIODevice *vdev, Vring *vring);

int vring_pop(VirtIODevice *vdev, Vring *vring,

              struct iovec iov[], struct iovec *iov_end,

              unsigned int *out_num, unsigned int *in_num);

void vring_push(Vring *vring, unsigned int head, int len);

#endif /* VRING_H */