Re: [dpdk-dev] [PATCH v2 2/3] net/vhost: fix queue update

["Wang, Yinan" <yinan.wang@intel.com>]

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia@intel.com>
> Sent: 2020?7?29? 10:53
> To: Maxime Coquelin <maxime.coquelin@redhat.com>; dev@dpdk.org;
> matan@mellanox.com; Liu, Yong <yong.liu@intel.com>; Wang, Yinan
> <yinan.wang@intel.com>
> Cc: thomas@monjalon.net; Yigit, Ferruh <ferruh.yigit@intel.com>;
> david.marchand@redhat.com
> Subject: RE: [PATCH v2 2/3] net/vhost: fix queue update
> 
> 
> > -----Original Message-----
> > From: Maxime Coquelin <maxime.coquelin@redhat.com>
> > Sent: Wednesday, July 29, 2020 12:50 AM
> > To: dev@dpdk.org; matan@mellanox.com; Xia, Chenbo
> > <chenbo.xia@intel.com>; Liu, Yong <yong.liu@intel.com>; Wang, Yinan
> > <yinan.wang@intel.com>
> > Cc: thomas@monjalon.net; Yigit, Ferruh <ferruh.yigit@intel.com>;
> > david.marchand@redhat.com; Maxime Coquelin
> > <maxime.coquelin@redhat.com>
> > Subject: [PATCH v2 2/3] net/vhost: fix queue update
> >
> > Now that the vhost library saves the guest notifications enablement value
> in its
> > virtqueues metadata, it is not necessary to do it in the vring_state_changed
> > callback.
> >
> > One effect of the patch is also to prevent possible deadlock happening in
> vhost
> > library.
> >
> > Fixes: 604052ae5395 ("net/vhost: support queue update")
> >
> > Reported-by: Yinan Wang <yinan.wang@intel.com>
> > Tested-by: Yinan Wang <yinan.wang@intel.com>
> > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> > ---
> >  drivers/net/vhost/rte_eth_vhost.c | 28 +++++++++-------------------
> >  1 file changed, 9 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/net/vhost/rte_eth_vhost.c
> > b/drivers/net/vhost/rte_eth_vhost.c
> > index bbf79b2c0e..951929c663 100644
> > --- a/drivers/net/vhost/rte_eth_vhost.c
> > +++ b/drivers/net/vhost/rte_eth_vhost.c
> > @@ -94,7 +94,6 @@ struct vhost_queue {
> >  	struct rte_mempool *mb_pool;
> >  	uint16_t port;
> >  	uint16_t virtqueue_id;
> > -	bool intr_en;
> >  	struct vhost_stats stats;
> >  };
> >
> > @@ -547,8 +546,6 @@ eth_rxq_intr_enable(struct rte_eth_dev *dev,
> uint16_t
> > qid)
> >  	rte_vhost_enable_guest_notification(vq->vid, (qid << 1) + 1, 1);
> >  	rte_wmb();
> >
> > -	vq->intr_en = true;
> > -
> >  	return ret;
> >  }
> >
> > @@ -574,8 +571,6 @@ eth_rxq_intr_disable(struct rte_eth_dev *dev,
> uint16_t
> > qid)
> >  	rte_vhost_enable_guest_notification(vq->vid, (qid << 1) + 1, 0);
> >  	rte_wmb();
> >
> > -	vq->intr_en = false;
> > -
> >  	return 0;
> >  }
> >
> > @@ -841,7 +836,6 @@ vring_conf_update(int vid, struct rte_eth_dev
> *eth_dev,
> > uint16_t vring_id)
> >  	struct rte_eth_conf *dev_conf = &eth_dev->data->dev_conf;
> >  	struct pmd_internal *internal = eth_dev->data->dev_private;
> >  	struct rte_vhost_vring vring;
> > -	struct vhost_queue *vq;
> >  	int rx_idx = vring_id % 2 ? (vring_id - 1) >> 1 : -1;
> >  	int ret = 0;
> >
> > @@ -853,21 +847,17 @@ vring_conf_update(int vid, struct rte_eth_dev
> > *eth_dev, uint16_t vring_id)
> >  	    rte_atomic32_read(&internal->dev_attached) &&
> >  	    rte_atomic32_read(&internal->started) &&
> >  	    dev_conf->intr_conf.rxq) {
> > -		vq = eth_dev->data->rx_queues[rx_idx];
> >  		ret = rte_vhost_get_vhost_vring(vid, vring_id, &vring);
> > -		if (!ret) {
> > -			if (vring.kickfd !=
> > -			    eth_dev->intr_handle->efds[rx_idx]) {
> > -				VHOST_LOG(INFO,
> > -					  "kickfd for rxq-%d was changed.\n",
> > -					  rx_idx);
> > -				eth_dev->intr_handle->efds[rx_idx] =
> > -								   vring.kickfd;
> > -			}
> > +		if (ret) {
> > +			VHOST_LOG(ERR, "Failed to get vring %d
> > information.\n",
> > +					vring_id);
> > +			return ret;
> > +		}
> >
> > -			rte_vhost_enable_guest_notification(vid, vring_id,
> > -							    vq->intr_en);
> > -			rte_wmb();
> > +		if (vring.kickfd != eth_dev->intr_handle->efds[rx_idx]) {
> > +			VHOST_LOG(INFO, "kickfd for rxq-%d was
> changed.\n",
> > +					  rx_idx);
> > +			eth_dev->intr_handle->efds[rx_idx] = vring.kickfd;
> >  		}
> >  	}
> >
> > --
> > 2.26.2
> 
> Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Tested-by: Yinan Wang <yinan.wang@intel.com>