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dataplane: endianness-aware accesses

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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>
This commit is contained in:
Cornelia Huck 2015-01-26 17:26:42 +01:00 • committed by Stefan Hajnoczi
parent 9a75b0a037
commit b0e5d90ebc
7 changed files with 117 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

14
include/hw/virtio/dataplane/vring.h
View file

@ -31,17 +31,6 @@ typedef struct {
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)
{
@ -54,6 +43,7 @@ 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(Vring *vring, VirtQueueElement *elem, int len);
void vring_push(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem,
int len);
#endif /* VRING_H */