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/* Copyright 2012 Red Hat, Inc. and/or its affiliates
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* Copyright IBM, Corp. 2012
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* Based on Linux 2.6.39 vhost code:
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* Copyright (C) 2009 Red Hat, Inc.
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* Copyright (C) 2006 Rusty Russell IBM Corporation
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* Author: Michael S. Tsirkin <mst@redhat.com>
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* Stefan Hajnoczi <stefanha@redhat.com>
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* Inspiration, some code, and most witty comments come from
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* Documentation/virtual/lguest/lguest.c, by Rusty Russell
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* This work is licensed under the terms of the GNU GPL, version 2.
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#include <linux/virtio_ring.h>
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#include "qemu-common.h"
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#include "hw/dataplane/hostmem.h"
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#include "hw/virtio.h"
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HostMem hostmem; /* guest memory mapper */
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struct vring vr; /* virtqueue vring mapped to host memory */
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uint16_t last_avail_idx; /* last processed avail ring index */
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uint16_t last_used_idx; /* last processed used ring index */
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uint16_t signalled_used; /* EVENT_IDX state */
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bool signalled_used_valid;
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bool broken; /* was there a fatal error? */
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static inline unsigned int vring_get_num(Vring *vring)
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/* Are there more descriptors available? */
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static inline bool vring_more_avail(Vring *vring)
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return vring->vr.avail->idx != vring->last_avail_idx;
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/* Fail future vring_pop() and vring_push() calls until reset */
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static inline void vring_set_broken(Vring *vring)
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bool vring_setup(Vring *vring, VirtIODevice *vdev, int n);
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void vring_teardown(Vring *vring);
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void vring_disable_notification(VirtIODevice *vdev, Vring *vring);
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bool vring_enable_notification(VirtIODevice *vdev, Vring *vring);
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bool vring_should_notify(VirtIODevice *vdev, Vring *vring);
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int vring_pop(VirtIODevice *vdev, Vring *vring,
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struct iovec iov[], struct iovec *iov_end,
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unsigned int *out_num, unsigned int *in_num);
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void vring_push(Vring *vring, unsigned int head, int len);