[PATCH v3 03/28] vhost: fix IOTLB entries overlap check with previous entry

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Commit 22b6d0ac691a ("vhost: fix madvise IOTLB entries pages overlap check")
fixed the check to ensure the entry to be removed does not
overlap with the next one in the IOTLB cache before marking
it as DONTDUMP with madvise(). This is not enough, because
the same issue is present when comparing with the previous
entry in the cache, where the end address of the previous
entry should be used, not the start one.

Fixes: dea092d0addb ("vhost: fix madvise arguments alignment")
Cc: stable@dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Mike Pattrick <mkp@redhat.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
---
 lib/vhost/iotlb.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/vhost/iotlb.c b/lib/vhost/iotlb.c
index 3f45bc6061..870c8acb88 100644
--- a/lib/vhost/iotlb.c
+++ b/lib/vhost/iotlb.c
@@ -178,8 +178,8 @@ vhost_user_iotlb_cache_random_evict(struct virtio_net *dev, struct vhost_virtque
 			mask = ~(alignment - 1);
 
 			/* Don't disable coredump if the previous node is in the same page */
-			if (prev_node == NULL ||
-					(node->uaddr & mask) != (prev_node->uaddr & mask)) {
+			if (prev_node == NULL || (node->uaddr & mask) !=
+					((prev_node->uaddr + prev_node->size - 1) & mask)) {
 				next_node = RTE_TAILQ_NEXT(node, next);
 				/* Don't disable coredump if the next node is in the same page */
 				if (next_node == NULL || ((node->uaddr + node->size - 1) & mask) !=
@@ -283,8 +283,8 @@ vhost_user_iotlb_cache_remove(struct virtio_net *dev, struct vhost_virtqueue *vq
 			mask = ~(alignment-1);
 
 			/* Don't disable coredump if the previous node is in the same page */
-			if (prev_node == NULL ||
-					(node->uaddr & mask) != (prev_node->uaddr & mask)) {
+			if (prev_node == NULL || (node->uaddr & mask) !=
+					((prev_node->uaddr + prev_node->size - 1) & mask)) {
 				next_node = RTE_TAILQ_NEXT(node, next);
 				/* Don't disable coredump if the next node is in the same page */
 				if (next_node == NULL || ((node->uaddr + node->size - 1) & mask) !=
-- 
2.40.1