| Message ID | 1503344576-8141-1-git-send-email-mst@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2017-08-21 at 22:45 +0300, Michael S. Tsirkin wrote: > During access_ok checks, addr increases as we iterate over the data > structure, thus addr + len - 1 will point beyond the end of region we > are translating. Harmless since we then verify that the region covers > addr, but let's not waste cpu cycles. > > Reported-by: Koichiro Den <den@klaipeden.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > > Lightly tested, would appreciate an ack from reporter. > > drivers/vhost/vhost.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index e4613a3..ecd70e4 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1176,7 +1176,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq, > { > const struct vhost_umem_node *node; > struct vhost_umem *umem = vq->iotlb; > - u64 s = 0, size, orig_addr = addr; > + u64 s = 0, size, orig_addr = addr, last = addr + len - 1; > > if (vhost_vq_meta_fetch(vq, addr, len, type)) > return true; > @@ -1184,7 +1184,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq, > while (len > s) { > node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, > addr, > - addr + len - 1); > + last); > if (node == NULL || node->start > addr) { > vhost_iotlb_miss(vq, addr, access); > return false; Michael, Thank you for this one. Acked-by: Koichiro Den <den@klaipeden.com>
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index e4613a3..ecd70e4 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1176,7 +1176,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq, { const struct vhost_umem_node *node; struct vhost_umem *umem = vq->iotlb; - u64 s = 0, size, orig_addr = addr; + u64 s = 0, size, orig_addr = addr, last = addr + len - 1; if (vhost_vq_meta_fetch(vq, addr, len, type)) return true; @@ -1184,7 +1184,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq, while (len > s) { node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, addr, - addr + len - 1); + last); if (node == NULL || node->start > addr) { vhost_iotlb_miss(vq, addr, access); return false;
During access_ok checks, addr increases as we iterate over the data structure, thus addr + len - 1 will point beyond the end of region we are translating. Harmless since we then verify that the region covers addr, but let's not waste cpu cycles. Reported-by: Koichiro Den <den@klaipeden.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- Lightly tested, would appreciate an ack from reporter. drivers/vhost/vhost.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)