On Sat, Apr 22, 2023 at 3:57 AM Shannon Nelson <shannon.nelson@xxxxxxx> wrote:
>
> Use the right structs for PACKED or split vqs when setting and
> getting the vring base.
>
> Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxx>
> ---
> drivers/vhost/vhost.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index f11bdbe4c2c5..f64efda48f21 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1633,17 +1633,25 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
> r = -EFAULT;
> break;
> }
> - if (s.num > 0xffff) {
> - r = -EINVAL;
> - break;
> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
> + vq->last_avail_idx = s.num & 0xffff;
> + vq->last_used_idx = (s.num >> 16) & 0xffff;
I think we need to tweak the comment around last_avail_idx and last_used_idx:
/* Last available index we saw. */
u16 last_avail_idx;
/* Last index we used. */
u16 last_used_idx;
To describe that it contains wrap counters as well in the case of
packed virtqueue or maybe it's time to rename them (since they are
invented for split virtqueue).
Thanks
> + } else {
> + if (s.num > 0xffff) {
> + r = -EINVAL;
> + break;
> + }
> + vq->last_avail_idx = s.num;
> }
> - vq->last_avail_idx = s.num;
> /* Forget the cached index value. */
> vq->avail_idx = vq->last_avail_idx;
> 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 = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16);
> + else
> + s.num = vq->last_avail_idx;
> if (copy_to_user(argp, &s, sizeof s))
> r = -EFAULT;
> break;
> --
> 2.17.1
>
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