qemu/include/hw/virtio/dataplane/vring.h
Cornelia Huck b0e5d90ebc dataplane: endianness-aware accesses
The vring.c code currently assumes that guest and host endianness match,
which is not true for a number of cases:

- emulating targets with a different endianness than the host
- bi-endian targets, where the correct endianness depends on the virtio
  device
- upcoming support for the virtio-1 standard mandates little-endian
  accesses even for big-endian targets and hosts

Make sure to use accessors that depend on the virtio device.

Note that dataplane now needs to be built per-target.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Fam Zheng <famz@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1422289602-17874-2-git-send-email-cornelia.huck@de.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-02-16 15:07:16 +00:00

49 lines
1.7 KiB
C

/* 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 "qemu-common.h"
#include "hw/virtio/virtio_ring.h"
#include "hw/virtio/virtio.h"
typedef struct {
MemoryRegion *mr; /* memory region containing the vring */
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;
/* 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, VirtQueueElement *elem);
void vring_push(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem,
int len);
#endif /* VRING_H */