From: "Loftus, Ciara" <ciara.loftus@intel.com>
To: "Tan, Jianfeng" <jianfeng.tan@intel.com>,
Rich Lane <rich.lane@bigswitch.com>,
"dev@dpdk.org" <dev@dpdk.org>
Cc: Tetsuya Mukawa <mukawa@igel.co.jp>,
Yuanhan Liu <yuanhan.liu@linux.intel.com>
Subject: Re: [dpdk-dev] [PATCH] vhost: call rte_vhost_enable_guest_notification only on enabled queues
Date: Thu, 7 Apr 2016 15:29:32 +0000 [thread overview]
Message-ID: <74F120C019F4A64C9B78E802F6AD4CC24F863996@IRSMSX106.ger.corp.intel.com> (raw)
In-Reply-To: <57064914.4040703@intel.com>
> On 4/7/2016 8:29 AM, Rich Lane wrote:
> > If the vhost PMD were configured with more queues than the guest, the
> old
> > code would segfault in rte_vhost_enable_guest_notification due to a NULL
> > virtqueue pointer.
> >
> > Fixes: ee584e9710b9 ("vhost: add driver on top of the library")
> > Signed-off-by: Rich Lane <rich.lane@bigswitch.com>
> > ---
> > drivers/net/vhost/rte_eth_vhost.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/vhost/rte_eth_vhost.c
> b/drivers/net/vhost/rte_eth_vhost.c
> > index b1eb082..310cbef 100644
> > --- a/drivers/net/vhost/rte_eth_vhost.c
> > +++ b/drivers/net/vhost/rte_eth_vhost.c
> > @@ -265,7 +265,6 @@ new_device(struct virtio_net *dev)
> > vq->device = dev;
> > vq->internal = internal;
> > vq->port = eth_dev->data->port_id;
> > - rte_vhost_enable_guest_notification(dev, vq-
> >virtqueue_id, 0);
> > }
> > for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
> > vq = eth_dev->data->tx_queues[i];
> > @@ -274,9 +273,11 @@ new_device(struct virtio_net *dev)
> > vq->device = dev;
> > vq->internal = internal;
> > vq->port = eth_dev->data->port_id;
> > - rte_vhost_enable_guest_notification(dev, vq-
> >virtqueue_id, 0);
> > }
> >
> > + for (i = 0; i < dev->virt_qp_nb * VIRTIO_QNUM; i++)
> > + rte_vhost_enable_guest_notification(dev, i, 0);
> > +
> > dev->flags |= VIRTIO_DEV_RUNNING;
> > dev->priv = eth_dev;
> > eth_dev->data->dev_link.link_status = ETH_LINK_UP;
>
> Just one question, when qemu starts a vm, usually, only one queue is
> enabled, then only 1 tx and 1 rx are called
> rte_vhost_enable_guest_notification; but after system is up, we use
> "ethtool -K eth0 combined x" to enable multiqueues, there's no chance to
> call rte_vhost_enable_guest_notification for other queues, right?
As far as I know, virt_qp_nb will report the number of queues available, regardless of their state enabled/disabled. So for example if we have 4 queues, but only one enabled, virt_qp_nb should still = 4 and rte_vhost_enable_guest_notification() will be called for all of these queues.
Thanks,
Ciara
>
> Thanks,
> Jianfeng
next prev parent reply other threads:[~2016-04-07 15:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-07 0:29 Rich Lane
2016-04-07 10:40 ` Loftus, Ciara
2016-04-07 11:48 ` Tan, Jianfeng
2016-04-07 15:29 ` Loftus, Ciara [this message]
2016-04-07 15:42 ` Yuanhan Liu
2016-04-07 16:13 ` Tan, Jianfeng
2016-04-07 15:42 ` Yuanhan Liu
2016-04-07 17:20 ` Thomas Monjalon
2016-04-08 1:45 ` Tetsuya Mukawa
2016-04-08 6:14 ` Yuanhan Liu
2016-04-08 7:03 ` Tetsuya Mukawa
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