From 11d5253a3e93a38be14da65328dd19960fd8cb14 Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Thu, 28 Feb 2019 18:57:04 +0100 Subject: [PATCH] vhost: prevent disabled rings to be processed with zero-copy The vhost-user spec says that once the vring is disabled, the client has to stop processing it. But it can happen when dequeue zero-copy is enabled if outstanding descriptors buffers are still being processed by an external NIC or another guest. The fix consists in draining the zmbufs list to ensure no more descriptors buffers are in the wild. Note that this fix is only working in the case REPLY_ACK protocol feature is enabled, which is not the case by default for now (it is only enabled when IOMMU feature is enabled in the vhost library). Fixes: b0a985d1f340 ("vhost: add dequeue zero copy") Cc: stable@dpdk.org Signed-off-by: Maxime Coquelin Reviewed-by: Tiwei Bie --- lib/librte_vhost/vhost_user.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c index 36c0c676db..555d09ad9e 100644 --- a/lib/librte_vhost/vhost_user.c +++ b/lib/librte_vhost/vhost_user.c @@ -1345,6 +1345,10 @@ vhost_user_set_vring_enable(struct virtio_net **pdev, dev->notify_ops->vring_state_changed(dev->vid, index, enable); + /* On disable, rings have to be stopped being processed. */ + if (!enable && dev->dequeue_zero_copy) + drain_zmbuf_list(dev->virtqueue[index]); + dev->virtqueue[index]->enabled = enable; return RTE_VHOST_MSG_RESULT_OK; -- 2.20.1