Re: [dpdk-dev] [PATCH v2 06/10] net/virtio: fix queue setup consistency

[Olivier Matz <olivier.matz@6wind.com>]

Hi Lei,

It's on my todo list, I'll check this as soon as possible.

Olivier


On Thu, Feb 01, 2018 at 03:14:15AM +0000, Yao, Lei A wrote:
> Hi, Olivier
> 
> This is Lei from DPDK validation team in Intel. During our DPDK 18.02-rc1 test,
> I find the following patch will cause one serious issue with virtio vector path: 
> the traffic can't resume after stop/start the virtio device. 
> 
> The step like following:
> 1. Launch vhost-user port using testpmd at Host 
> 2. Launch VM with virtio device, mergeable is off
> 3. Bind the virtio device to pmd driver, launch testpmd, let the tx/rx use vector path
>     virtio_xmit_pkts_simple 
>     virtio_recv_pkts_vec     
> 4. Send traffic to virtio device from vhost side, then stop the virtio device
> 5. Start the virtio device again
> After step 5, the traffic can't resume. 
> 
> Could you help check this and give a fix? This issue will impact the virtio pmd user 
> experience heavily. By the way, this patch is already included into V17.11. Looks like
> we need give a patch to this LTS version.  Thanks a lot!
> 
> BRs
> Lei
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Olivier Matz
> > Sent: Thursday, September 7, 2017 8:14 PM
> > To: dev@dpdk.org; yliu@fridaylinux.org; maxime.coquelin@redhat.com
> > Cc: stephen@networkplumber.org; stable@dpdk.org
> > Subject: [dpdk-dev] [PATCH v2 06/10] net/virtio: fix queue setup consistency
> > 
> > In rx/tx queue setup functions, some code is executed only if
> > use_simple_rxtx == 1. The value of this variable can change depending on
> > the offload flags or sse support. If Rx queue setup is called before Tx
> > queue setup, it can result in an invalid configuration:
> > 
> > - dev_configure is called: use_simple_rxtx is initialized to 0
> > - rx queue setup is called: queues are initialized without simple path
> >   support
> > - tx queue setup is called: use_simple_rxtx switch to 1, and simple
> >   Rx/Tx handlers are selected
> > 
> > Fix this by postponing a part of Rx/Tx queue initialization in
> > dev_start(), as it was the case in the initial implementation.
> > 
> > Fixes: 48cec290a3d2 ("net/virtio: move queue configure code to proper
> > place")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> > ---
> >  drivers/net/virtio/virtio_ethdev.c | 13 +++++++++++++
> >  drivers/net/virtio/virtio_ethdev.h |  6 ++++++
> >  drivers/net/virtio/virtio_rxtx.c   | 40 ++++++++++++++++++++++++++++++-
> > -------
> >  3 files changed, 51 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/net/virtio/virtio_ethdev.c
> > b/drivers/net/virtio/virtio_ethdev.c
> > index 8eee3ff80..c7888f103 100644
> > --- a/drivers/net/virtio/virtio_ethdev.c
> > +++ b/drivers/net/virtio/virtio_ethdev.c
> > @@ -1737,6 +1737,19 @@ virtio_dev_start(struct rte_eth_dev *dev)
> >  	struct virtnet_rx *rxvq;
> >  	struct virtnet_tx *txvq __rte_unused;
> >  	struct virtio_hw *hw = dev->data->dev_private;
> > +	int ret;
> > +
> > +	/* Finish the initialization of the queues */
> > +	for (i = 0; i < dev->data->nb_rx_queues; i++) {
> > +		ret = virtio_dev_rx_queue_setup_finish(dev, i);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +	for (i = 0; i < dev->data->nb_tx_queues; i++) {
> > +		ret = virtio_dev_tx_queue_setup_finish(dev, i);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > 
> >  	/* check if lsc interrupt feature is enabled */
> >  	if (dev->data->dev_conf.intr_conf.lsc) {
> > diff --git a/drivers/net/virtio/virtio_ethdev.h
> > b/drivers/net/virtio/virtio_ethdev.h
> > index c3413c6d9..2039bc547 100644
> > --- a/drivers/net/virtio/virtio_ethdev.h
> > +++ b/drivers/net/virtio/virtio_ethdev.h
> > @@ -92,10 +92,16 @@ int  virtio_dev_rx_queue_setup(struct rte_eth_dev
> > *dev, uint16_t rx_queue_id,
> >  		const struct rte_eth_rxconf *rx_conf,
> >  		struct rte_mempool *mb_pool);
> > 
> > +int virtio_dev_rx_queue_setup_finish(struct rte_eth_dev *dev,
> > +				uint16_t rx_queue_id);
> > +
> >  int  virtio_dev_tx_queue_setup(struct rte_eth_dev *dev, uint16_t
> > tx_queue_id,
> >  		uint16_t nb_tx_desc, unsigned int socket_id,
> >  		const struct rte_eth_txconf *tx_conf);
> > 
> > +int virtio_dev_tx_queue_setup_finish(struct rte_eth_dev *dev,
> > +				uint16_t tx_queue_id);
> > +
> >  uint16_t virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
> >  		uint16_t nb_pkts);
> > 
> > diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> > index e30377c51..a32e3229f 100644
> > --- a/drivers/net/virtio/virtio_rxtx.c
> > +++ b/drivers/net/virtio/virtio_rxtx.c
> > @@ -421,9 +421,6 @@ virtio_dev_rx_queue_setup(struct rte_eth_dev *dev,
> >  	struct virtio_hw *hw = dev->data->dev_private;
> >  	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
> >  	struct virtnet_rx *rxvq;
> > -	int error, nbufs;
> > -	struct rte_mbuf *m;
> > -	uint16_t desc_idx;
> > 
> >  	PMD_INIT_FUNC_TRACE();
> > 
> > @@ -440,10 +437,24 @@ virtio_dev_rx_queue_setup(struct rte_eth_dev
> > *dev,
> >  	}
> >  	dev->data->rx_queues[queue_idx] = rxvq;
> > 
> > +	return 0;
> > +}
> > +
> > +int
> > +virtio_dev_rx_queue_setup_finish(struct rte_eth_dev *dev, uint16_t
> > queue_idx)
> > +{
> > +	uint16_t vtpci_queue_idx = 2 * queue_idx +
> > VTNET_SQ_RQ_QUEUE_IDX;
> > +	struct virtio_hw *hw = dev->data->dev_private;
> > +	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
> > +	struct virtnet_rx *rxvq = &vq->rxq;
> > +	struct rte_mbuf *m;
> > +	uint16_t desc_idx;
> > +	int error, nbufs;
> > +
> > +	PMD_INIT_FUNC_TRACE();
> > 
> >  	/* Allocate blank mbufs for the each rx descriptor */
> >  	nbufs = 0;
> > -	error = ENOSPC;
> > 
> >  	if (hw->use_simple_rxtx) {
> >  		for (desc_idx = 0; desc_idx < vq->vq_nentries;
> > @@ -534,7 +545,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> >  	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
> >  	struct virtnet_tx *txvq;
> >  	uint16_t tx_free_thresh;
> > -	uint16_t desc_idx;
> > 
> >  	PMD_INIT_FUNC_TRACE();
> > 
> > @@ -563,9 +573,24 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev
> > *dev,
> > 
> >  	vq->vq_free_thresh = tx_free_thresh;
> > 
> > -	if (hw->use_simple_rxtx) {
> > -		uint16_t mid_idx  = vq->vq_nentries >> 1;
> > +	dev->data->tx_queues[queue_idx] = txvq;
> > +	return 0;
> > +}
> > +
> > +int
> > +virtio_dev_tx_queue_setup_finish(struct rte_eth_dev *dev,
> > +				uint16_t queue_idx)
> > +{
> > +	uint8_t vtpci_queue_idx = 2 * queue_idx +
> > VTNET_SQ_TQ_QUEUE_IDX;
> > +	struct virtio_hw *hw = dev->data->dev_private;
> > +	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
> > +	uint16_t mid_idx = vq->vq_nentries >> 1;
> > +	struct virtnet_tx *txvq = &vq->txq;
> > +	uint16_t desc_idx;
> > 
> > +	PMD_INIT_FUNC_TRACE();
> > +
> > +	if (hw->use_simple_rxtx) {
> >  		for (desc_idx = 0; desc_idx < mid_idx; desc_idx++) {
> >  			vq->vq_ring.avail->ring[desc_idx] =
> >  				desc_idx + mid_idx;
> > @@ -587,7 +612,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> > 
> >  	VIRTQUEUE_DUMP(vq);
> > 
> > -	dev->data->tx_queues[queue_idx] = txvq;
> >  	return 0;
> >  }
> > 
> > --
> > 2.11.0
>