6.1-stable review patch. If anyone has any objections, please let me know.
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From: Eric Auger eric.auger@redhat.com
commit ca50ec377c2e94b0a9f8735de2856cd0f13beab4 upstream.
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@redhat.com Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries") Cc: stable@vger.kernel.org # v5.17+ Acked-by: Jason Wang jasowang@redhat.com Message-Id: 20230927140544.205088-1-eric.auger@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vhost/vhost.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1176,9 +1176,7 @@ ssize_t vhost_chr_write_iter(struct vhos 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; }