diff options
authorHalil Pasic <pasic@linux.vnet.ibm.com>2017-01-30 11:09:36 +0100
committerMichael S. Tsirkin <mst@redhat.com>2017-02-03 23:38:57 +0200
commitcda8bba0f99d25d2061c531113c14fa41effc3ae (patch)
parent0d5415b489f68b58e1983a53793d25d53098ed4b (diff)
vhost: fix initialization for vq->is_le
Currently, under certain circumstances vhost_init_is_le does just a part of the initialization job, and depends on vhost_reset_is_le being called too. For this reason vhost_vq_init_access used to call vhost_reset_is_le when vq->private_data is NULL. This is not only counter intuitive, but also real a problem because it breaks vhost_net. The bug was introduced to vhost_net with commit 2751c9882b94 ("vhost: cross-endian support for legacy devices"). The symptom is corruption of the vq's used.idx field (virtio) after VHOST_NET_SET_BACKEND was issued as a part of the vhost shutdown on a vq with pending descriptors. Let us make sure the outcome of vhost_init_is_le never depend on the state it is actually supposed to initialize, and fix virtio_net by removing the reset from vhost_vq_init_access. With the above, there is no reason for vhost_reset_is_le to do just half of the job. Let us make vhost_reset_is_le reinitialize is_le. Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com> Reported-by: Michael A. Tebolt <miket@us.ibm.com> Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Fixes: commit 2751c9882b94 ("vhost: cross-endian support for legacy devices") Cc: <stable@vger.kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Tested-by: Michael A. Tebolt <miket@us.ibm.com>
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index d6432603880c..8f99fe08de02 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -130,14 +130,14 @@ static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
static void vhost_init_is_le(struct vhost_virtqueue *vq)
- if (vhost_has_feature(vq, VIRTIO_F_VERSION_1))
- vq->is_le = true;
+ vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
+ || virtio_legacy_is_little_endian();
static void vhost_reset_is_le(struct vhost_virtqueue *vq)
- vq->is_le = virtio_legacy_is_little_endian();
+ vhost_init_is_le(vq);
struct vhost_flush_struct {
@@ -1714,10 +1714,8 @@ int vhost_vq_init_access(struct vhost_virtqueue *vq)
int r;
bool is_le = vq->is_le;
- if (!vq->private_data) {
- vhost_reset_is_le(vq);
+ if (!vq->private_data)
return 0;
- }