vringh: fix range used in iotlb_translate()

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")
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20221109102503.18816-2-sgarzare@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index c9f5c8ea3afbd175246bb97f7dbf84d85df55fa2..33eb941fcf154631eb32b01b42ef8ba80dc4ef34 100644 (file)
--- 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;