Re: [PATCH v7 31/46] vhost: virtio 1.0 endian-ness support

Cornelia Huck
2014-12-01T12:34:09Z

On Sun, 30 Nov 2014 17:11:49 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/vhost/vhost.c | 93 +++++++++++++++++++++++++++++++--------------------
> 1 file changed, 56 insertions(+), 37 deletions(-)
>

> @@ -1113,18 +1120,19 @@ static int get_indirect(struct vhost_virtqueue *vq,
> {
> struct vring_desc desc;
> unsigned int i = 0, count, found = 0;
> + u32 len = vhost32_to_cpu(vq, indirect->len);
> int ret;
>
> /* Sanity check */
> - if (unlikely(indirect->len % sizeof desc)) {
> + if (unlikely(len % sizeof desc)) {
> vq_err(vq, "Invalid length in indirect descriptor: "
> "len 0x%llx not multiple of 0x%zx\n",
> - (unsigned long long)indirect->len,
> + (unsigned long long)vhost32_to_cpu(vq, indirect->len),

Can't you use len here?

> sizeof desc);
> return -EINVAL;
> }
>
> - ret = translate_desc(vq, indirect->addr, indirect->len, vq->indirect,
> + ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
> UIO_MAXIOV);
> if (unlikely(ret < 0)) {
> vq_err(vq, "Translation failure %d in indirect.\n", ret);

> @@ -1404,7 +1422,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
>
> /* Make sure buffer is written before we update index. */
> smp_wmb();
> - if (put_user(vq->last_used_idx, &vq->used->idx)) {
> + if (__put_user(cpu_to_vhost16(vq, vq->last_used_idx), &vq->used->idx)) {

Why s/put_user/__put_user/ - I don't see how endianness conversions
should have an influence there?

> vq_err(vq, "Failed to increment used idx");
> return -EFAULT;
> }

> @@ -1449,11 +1468,11 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
> if (unlikely(!v))
> return true;
>
> - if (get_user(event, vhost_used_event(vq))) {
> + if (__get_user(event, vhost_used_event(vq))) {

Dito: why the change?

> vq_err(vq, "Failed to get used event idx");
> return true;
> }
> - return vring_need_event(event, new, old);
> + return vring_need_event(vhost16_to_cpu(vq, event), new, old);
> }
>
> /* This actually signals the guest, using eventfd. */