On 4/7/2016 11:29 PM, Loftus, Ciara wrote:
>> 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 at 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.
Oh, yes. I failed to really get multiqueue configured right, which leads
to the wrong conclusion. Sorry.
Thanks,
Jianfeng
>
> Thanks,
> Ciara
>
>> Thanks,
>> Jianfeng
