RE: [PATCH v2] vhost: fix madvise IOTLB entries pages overlap check

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, March 15, 2023 7:40 PM
> To: dev@dpdk.org; mkp@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>;
> david.marchand@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v2] vhost: fix madvise IOTLB entries pages overlap check
> 
> At removal time, when testing whether the IOTLB entry has
> shared pages with the previous and next entries in the
> cache, it checks whether the start address of the entry to
> be removed is on the same page as the start address of the
> next entry in the cache.
> 
> This is not correct, as an entry could cover several page
> so the end address of the entry to be remove should be
> used. This patch address this issue.
> 
> Fixes: dea092d0addb ("vhost: fix madvise arguments alignment")
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.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 11785392ac..3f45bc6061 100644
> --- a/lib/vhost/iotlb.c
> +++ b/lib/vhost/iotlb.c
> @@ -182,8 +182,8 @@ vhost_user_iotlb_cache_random_evict(struct virtio_net
> *dev, struct vhost_virtque
>  					(node->uaddr & mask) != (prev_node->uaddr &
> 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 & mask) != (next_node-
> >uaddr & mask))
> +				if (next_node == NULL || ((node->uaddr + node-
> >size - 1) & mask) !=
> +						(next_node->uaddr & mask))
>  					mem_set_dump((void *)(uintptr_t)node->uaddr,
> node->size,
>  							false, alignment);
>  			}
> @@ -287,8 +287,8 @@ vhost_user_iotlb_cache_remove(struct virtio_net *dev,
> struct vhost_virtqueue *vq
>  					(node->uaddr & mask) != (prev_node->uaddr &
> 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 & mask) != (next_node-
> >uaddr & mask))
> +				if (next_node == NULL || ((node->uaddr + node-
> >size - 1) & mask) !=
> +						(next_node->uaddr & mask))
>  					mem_set_dump((void *)(uintptr_t)node->uaddr,
> node->size,
>  							false, alignment);
>  			}
> --
> 2.39.2

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>