From 9253c34cfb9dd32faeb8e513f6d8fafd356a2e62 Mon Sep 17 00:00:00 2001 From: Joyce Kong Date: Mon, 21 Dec 2020 23:50:30 +0800 Subject: [PATCH] vhost: relax full barriers for desc flags Relax the full read barrier to one-way barrier for desc flags in packed vring. Signed-off-by: Joyce Kong Reviewed-by: Ruifeng Wang Reviewed-by: Maxime Coquelin --- lib/librte_vhost/virtio_net.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c index c912ae354f..b779034dca 100644 --- a/lib/librte_vhost/virtio_net.c +++ b/lib/librte_vhost/virtio_net.c @@ -222,8 +222,9 @@ vhost_flush_dequeue_shadow_packed(struct virtio_net *dev, struct vring_used_elem_packed *used_elem = &vq->shadow_used_packed[0]; vq->desc_packed[vq->shadow_last_used_idx].id = used_elem->id; - rte_smp_wmb(); - vq->desc_packed[vq->shadow_last_used_idx].flags = used_elem->flags; + /* desc flags is the synchronization point for virtio packed vring */ + __atomic_store_n(&vq->desc_packed[vq->shadow_last_used_idx].flags, + used_elem->flags, __ATOMIC_RELEASE); vhost_log_cache_used_vring(dev, vq, vq->shadow_last_used_idx * sizeof(struct vring_packed_desc), -- 2.20.1