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@xxxxxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
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;
--
MST
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