Re: [PATCH 1/2] vringh: fix range used in iotlb_translate()

[Jason Wang]

On Tue, Nov 8, 2022 at 6:34 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:
>
> vhost_iotlb_itree_first() requires `start` and `last` parameters
> to search for a mapping that overlaps the range.
>
> In iotlb_translate() we cyclically call vhost_iotlb_itree_first(),
> incrementing `addr` by the amount already translated, so rightly
> we move the `start` parameter passed to vhost_iotlb_itree_first(),
> but we should hold the `last` parameter constant.
>
> Let's fix it by saving the `last` parameter value before incrementing
> `addr` in the loop.
>
> Fixes: 9ad9c49cfe97 ("vringh: IOTLB support")
> Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>

Acked-by: Jason Wang <jasowang@xxxxxxxxxx>

> ---
>  drivers/vhost/vringh.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> index 11f59dd06a74..828c29306565 100644
> --- a/drivers/vhost/vringh.c
> +++ b/drivers/vhost/vringh.c
> @@ -1102,7 +1102,7 @@ static int iotlb_translate(const struct vringh *vrh,
>         struct vhost_iotlb_map *map;
>         struct vhost_iotlb *iotlb = vrh->iotlb;
>         int ret = 0;
> -       u64 s = 0;
> +       u64 s = 0, last = addr + len - 1;
>
>         spin_lock(vrh->iotlb_lock);
>
> @@ -1114,8 +1114,7 @@ static int iotlb_translate(const struct vringh *vrh,
>                         break;
>                 }
>
> -               map = vhost_iotlb_itree_first(iotlb, addr,
> -                                             addr + len - 1);
> +               map = vhost_iotlb_itree_first(iotlb, addr, last);
>                 if (!map || map->start > addr) {
>                         ret = -EINVAL;
>                         break;
> --
> 2.38.1
>