Re: [PATCH v2] net/virtio-user: fix multiple queues fail in server mode

["Yang, Zhiyong" <zhiyong.yang@intel.com>]

Hi tiwei,

Thanks for your review firstly.  Reply inline.

> -----Original Message-----
> From: Bie, Tiwei
> Sent: Thursday, May 10, 2018 6:23 PM
> To: Yang, Zhiyong <zhiyong.yang@intel.com>
> Cc: dev@dpdk.org; stable@dpdk.org; maxime.coquelin@redhat.com; Yigit,
> Ferruh <ferruh.yigit@intel.com>
> Subject: Re: [PATCH v2] net/virtio-user: fix multiple queues fail in server
> mode
> 
> On Thu, May 10, 2018 at 05:36:23PM +0800, zhiyong.yang@intel.com wrote:
> > This patch fixes multiple queues failure when virtio-user works in
> > server mode.
> >
> > This patch adds feature negotiation in the processing of virtio-user
> > reccnnection.
> 
> typo: reccnnection
> 

Fix it.

> >
> > Fixes: bd8f50a45d0f ("net/virtio-user: support server mode")
> >
> > Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
> > ---
> >
> > Changes in V2:
> > 1. fix a comment typo.
> > 2. add feature negotiation in the processing of reconnection.
> >
> >  drivers/net/virtio/virtio_user/vhost_user.c      |  3 +++
> >  drivers/net/virtio/virtio_user/virtio_user_dev.c | 14 ++++++++++----
> >  drivers/net/virtio/virtio_user_ethdev.c          | 20
> ++++++++++++++++++++
> >  3 files changed, 33 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/virtio/virtio_user/vhost_user.c
> > b/drivers/net/virtio/virtio_user/vhost_user.c
> > index a6df97a..93e4d92 100644
> > --- a/drivers/net/virtio/virtio_user/vhost_user.c
> > +++ b/drivers/net/virtio/virtio_user/vhost_user.c
> > @@ -263,6 +263,9 @@ struct hugepage_file_info {
> >
> >  	PMD_DRV_LOG(INFO, "%s", vhost_msg_strings[req]);
> >
> > +	if (dev->is_server && vhostfd < 0)
> > +		return -1;
> > +
> >  	msg.request = req;
> >  	msg.flags = VHOST_USER_VERSION;
> >  	msg.size = 0;
> > diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > index 38b8bc9..b7e1915 100644
> > --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > @@ -447,10 +447,16 @@ int virtio_user_stop_device(struct
> virtio_user_dev *dev)
> >  		return -1;
> >  	}
> >
> > -	for (i = 0; i < q_pairs; ++i)
> > -		ret |= dev->ops->enable_qp(dev, i, 1);
> > -	for (i = q_pairs; i < dev->max_queue_pairs; ++i)
> > -		ret |= dev->ops->enable_qp(dev, i, 0);
> > +	/* Server mode can't enable queue pairs if vhostfd is invalid,
> > +	 * always return 0 in this case.
> > +	 */
> > +	if (dev->vhostfd >= 0)  {
> > +		for (i = 0; i < q_pairs; ++i)
> > +			ret |= dev->ops->enable_qp(dev, i, 1);
> > +		for (i = q_pairs; i < dev->max_queue_pairs; ++i)
> > +			ret |= dev->ops->enable_qp(dev, i, 0);
> > +	} else if (!dev->is_server)
> > +		ret = ~0;
> 
> You need to find a chance to enable these queue pairs when the connection
> is established.
> 
Enable only one queue pairs in virtio_user_start_device.
 I want to call virtio_user_handle_mq after virtio_user_start_device in virtio_user_server_reconnect. How about ?

> >
> >  	dev->queue_pairs = q_pairs;
> >
> > diff --git a/drivers/net/virtio/virtio_user_ethdev.c
> > b/drivers/net/virtio/virtio_user_ethdev.c
> > index 4e7b3c3..91a0c44 100644
> > --- a/drivers/net/virtio/virtio_user_ethdev.c
> > +++ b/drivers/net/virtio/virtio_user_ethdev.c
> > @@ -30,6 +30,7 @@
> >  	int ret;
> >  	int flag;
> >  	int connectfd;
> > +	uint64_t features = dev->device_features, status;
> >  	struct rte_eth_dev *eth_dev = &rte_eth_devices[dev->port_id];
> >
> >  	connectfd = accept(dev->listenfd, NULL, NULL); @@ -37,6 +38,25
> @@
> >  		return -1;
> >
> >  	dev->vhostfd = connectfd;
> > +	if (dev->ops->send_request(dev, VHOST_USER_GET_FEATURES,
> > +				   &dev->device_features) < 0) {
> > +		PMD_INIT_LOG(ERR, "get_features failed: %s",
> > +			     strerror(errno));
> > +		return -1;
> > +	}
> > +
> > +	status = features & ~dev->device_features;
> 
> There is no need to introduce `status`.
> 
Ok, remove it.

> > +	/* For following bits, vhost-user doesn't really need to know */
> > +	status &= ~(1ull << VIRTIO_NET_F_MAC);
> > +	status &= ~(1ull << VIRTIO_NET_F_CTRL_VLAN);
> > +	status &= ~(1ull << VIRTIO_NET_F_CTRL_MAC_ADDR);
> > +	status &= ~(1ull << VIRTIO_NET_F_STATUS);
> > +	if (status)
> > +		PMD_INIT_LOG(ERR, "WARNING: Some features (0x%lx) are
> not supported
> > +by vhost-user!",
> 
> You will want to use PRIx64 here.
> 
Ok.

Thanks
Zhiyong