diff mbox

[dpdk-dev,v2,1/3] net/virtio_user: fix queue pair not enabled

Message ID 1475003466-146063-2-git-send-email-jianfeng.tan@intel.com (mailing list archive)
State Accepted, archived
Delegated to: Yuanhan Liu
Headers

Commit Message

Jianfeng Tan Sept. 27, 2016, 7:11 p.m. UTC 
  When virtio_user is used with OVS-DPDK (with mq disabled), it cannot
receive any packets.

It's because when vhost provides VHOST_USER_GET_PROTOCOL_FEATURES,
all queue pairs are initialized in the disabled state. Quote
QEMU/docs/specs/vhost-user.txt:
    If VHOST_USER_F_PROTOCOL_FEATURES has not been negotiated, the
    ring is initialized in an enabled state.
    If VHOST_USER_F_PROTOCOL_FEATURES has been negotiated, the ring
    is initialized in a disabled state.

In OVS-DPDK, all queue pairs are in the disabled state by default.
When used with QEMU, QEMU will set it as enabled in the process of
initialization. So this patch is to add similar logic in virtio_user.

Fixes: 37a7eb2ae816 ("net/virtio-user: add device emulation layer")

Reported-by: Ning Li <lining18@jd.com>
Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
---
 drivers/net/virtio/virtio_user/virtio_user_dev.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Yuanhan Liu Sept. 28, 2016, 12:05 a.m. UTC | #1 
On Tue, Sep 27, 2016 at 07:11:04PM +0000, Jianfeng Tan wrote:
> When virtio_user is used with OVS-DPDK (with mq disabled), it cannot
> receive any packets.
> 
> It's because when vhost provides VHOST_USER_GET_PROTOCOL_FEATURES,
> all queue pairs are initialized in the disabled state. Quote
> QEMU/docs/specs/vhost-user.txt:
>     If VHOST_USER_F_PROTOCOL_FEATURES has not been negotiated, the
>     ring is initialized in an enabled state.
>     If VHOST_USER_F_PROTOCOL_FEATURES has been negotiated, the ring
>     is initialized in a disabled state.

As stated before, it has nothing to do with VHOST_USER_F_PROTOCOL_FEATURES.
You seems forgot to change the commit log.
>
> In OVS-DPDK, all queue pairs are in the disabled state by default.
> When used with QEMU, QEMU will set it as enabled in the process of
> initialization. So this patch is to add similar logic in virtio_user.

I would reword the commit log to someting like following:

    When virtio_user is used with OVS-DPDK (with mq disabled), it cannot
    receive any packets. This is because no queue is enabled at all when
    mq is disabled.
    
    To fix it, we should consistently make sure the 1st queue is
    enabled,which is also the behaviour QEMU takes.
 
> Fixes: 37a7eb2ae816 ("net/virtio-user: add device emulation layer")
> 
> Reported-by: Ning Li <lining18@jd.com>
> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>

Series applied to dpdk-next-virtio, with above commit reword.

Thanks.

	--yliu
diff mbox

Patch

diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 376c9cf..bf1155c 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -131,6 +131,9 @@  virtio_user_start_device(struct virtio_user_dev *dev)
 		}
 	}
 
+	/* we enable the 1st queue pair by default. */
+	vhost_user_enable_queue_pair(dev->vhostfd, 0, 1);
+
 	/* After setup all virtqueues, we need to set_features so that these
 	 * features can be set into each virtqueue in vhost side. And before
 	 * that, make sure VHOST_USER_F_PROTOCOL_FEATURES is added if mq is