Commit e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb
entries") Forbade vhost iotlb msg with null size to prevent entries
with size = start = 0 and last = ULONG_MAX to end up in the iotlb.
Then commit 95932ab2ea07 ("vhost: allow batching hint without size")
only applied the check for VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE
message types to fix a regression observed with batching hit.
Still, the introduction of that check introduced a regression for
some users attempting to invalidate the whole ULONG_MAX range by
setting the size to 0. This is the case with qemu/smmuv3/vhost
integration which does not work anymore. It Looks safe to partially
revert the original commit and allow VHOST_IOTLB_INVALIDATE messages
with null size. vhost_iotlb_del_range() will compute a correct end
iova. Same for vhost_vdpa_iotlb_unmap().
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries")
Cc: stable@xxxxxxxxxxxxxxx # v5.17+
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c71d573f1c94..e0c181ad17e3 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1458,9 +1458,7 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
goto done;
}
- if ((msg.type == VHOST_IOTLB_UPDATE ||
- msg.type == VHOST_IOTLB_INVALIDATE) &&
- msg.size == 0) {
+ if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) {
ret = -EINVAL;
goto done;
}
--
2.41.0
