On Mon, Jul 16, 2018 at 11:28:09AM +0800, Jason Wang wrote:
[...]
> @@ -1367,10 +1397,48 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned
> int ioctl, void __user *arg
> vq->last_avail_idx = s.num;
> /* Forget the cached index value. */
> vq->avail_idx = vq->last_avail_idx;
> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
> + vq->last_avail_wrap_counter = wrap_counter;
> + vq->avail_wrap_counter = vq->last_avail_wrap_counter;
> + }
> break;
> case VHOST_GET_VRING_BASE:
> s.index = idx;
> s.num = vq->last_avail_idx;
> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
> + s.num |= vq->last_avail_wrap_counter << 31;
> + if (copy_to_user(argp, &s, sizeof(s)))
> + r = -EFAULT;
> + break;
> + case VHOST_SET_VRING_USED_BASE:
> + /* Moving base with an active backend?
> + * You don't want to do that.
> + */
> + if (vq->private_data) {
> + r = -EBUSY;
> + break;
> + }
> + if (copy_from_user(&s, argp, sizeof(s))) {
> + r = -EFAULT;
> + break;
> + }
> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
> + wrap_counter = s.num >> 31;
> + s.num &= ~(1 << 31);
> + }
> + if (s.num > 0xffff) {
> + r = -EINVAL;
> + break;
> + }
Do we want to put wrap_counter at bit 15?
If put wrap_counter at bit 31, the check (s.num > 0xffff)
won't be able to catch the illegal index 0x8000~0xffff for
packed ring.
> + vq->last_used_idx = s.num;
> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
> + vq->last_used_wrap_counter = wrap_counter;
> + break;
> + case VHOST_GET_VRING_USED_BASE:
Do we need the new VHOST_GET_VRING_USED_BASE and
VHOST_SET_VRING_USED_BASE ops?
We are going to merge below series in DPDK:
http://patches.dpdk.org/patch/45874/
We may need to reach an agreement first.
> + s.index = idx;
> + s.num = vq->last_used_idx;
> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
> + s.num |= vq->last_used_wrap_counter << 31;
> if (copy_to_user(argp, &s, sizeof s))
> r = -EFAULT;
> break;
[...]
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