From: "Tan, Jianfeng" <jianfeng.tan@intel.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: dev@dpdk.org, zhihong.wang@intel.com, lining18@jd.com
Subject: Re: [dpdk-dev] [PATCH 2/3] net/virtio_user: fix wrong sequence of messages
Date: Tue, 6 Sep 2016 15:54:30 +0800 [thread overview]
Message-ID: <bac1d3e5-7643-3eb5-2515-d4a8f745c94d@intel.com> (raw)
In-Reply-To: <20160906064246.GQ30752@yliu-dev.sh.intel.com>
Hi Yuanhan,
On 9/6/2016 2:42 PM, Yuanhan Liu wrote:
> On Fri, Aug 05, 2016 at 11:36:42AM +0000, Jianfeng Tan wrote:
>> When virtio_user is used with VPP's native vhost user, it cannot
>> send/receive any packets.
>>
>> The root cause is that vpp-vhost-user translates the message
>> VHOST_USER_SET_FEATURES as puting this device into init state,
>> aka, zero all related structures. However, previous code
>> puts this message at last in the whole initialization process,
>> which leads to all previous information are zeroed.
>>
>> To fix this issue, we rearrange the sequence of those messages.
>> - step 0, send VHOST_USER_SET_VRING_CALL so that vhost allocates
>> virtqueue structures;
> Yes, it is. However, it's not that right to do that (you see there is
> a FIXME in vhost_user_set_vring_call()).
I suppose you are specifying vhost_set_vring_call().
>
> That means it need be fixed: we should not rely on fact that it's the
> first per-vring message we will get in the current QEMU implementation
> as the truth.
>
> That also means, naming a function like virtio_user_create_queue() based
> on above behaviour is wrong.
It's actually a good catch. After a light thought, I think in DPDK
vhost, we may need to create those virtqueues once unix socket gets
connected, just like in vhost-net, virtqueues are created on char file
open. Right?
>
>> - step 1, send VHOST_USER_SET_FEATURES to confirm the features;
>> - step 2, send VHOST_USER_SET_MEM_TABLE to share mem regions;
>> - step 3, send VHOST_USER_SET_VRING_NUM, VHOST_USER_SET_VRING_BASE,
>> VHOST_USER_SET_VRING_ADDR, VHOST_USER_SET_VRING_KICK for each
>> queue;
>> - ...
>>
>> Fixes: 37a7eb2ae816 ("net/virtio-user: add device emulation layer")
>>
>> Reported-by: Zhihong Wang <zhihong.wang@intel.com>
>> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
>> ---
>> drivers/net/virtio/virtio_user/virtio_user_dev.c | 120 ++++++++++++++---------
>> 1 file changed, 72 insertions(+), 48 deletions(-)
> That's too much of code for a bug fix. I'm wondering how about just
> moving VHOST_USER_GET_PROTOCOL_FEATURES ahead, to the begining of
> virtio_user_start_device()? It should fix this issue.
Why does VHOST_USER_GET_PROTOCOL_FEATURES care? Do you mean shifting
VHOST_USER_SET_FEATURES earlier?
Thanks,
Jianfeng
>
> --yliu
next prev parent reply other threads:[~2016-09-06 7:54 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-05 11:36 [dpdk-dev] [PATCH 0/3] fix virtio_user issues Jianfeng Tan
2016-08-05 11:36 ` [dpdk-dev] [PATCH 1/3] net/virtio_user: fix queue pair not enabled Jianfeng Tan
2016-09-06 6:30 ` Yuanhan Liu
2016-08-05 11:36 ` [dpdk-dev] [PATCH 2/3] net/virtio_user: fix wrong sequence of messages Jianfeng Tan
2016-08-05 16:36 ` Stephen Hemminger
2016-08-08 1:19 ` Tan, Jianfeng
2016-09-06 6:42 ` Yuanhan Liu
2016-09-06 7:54 ` Tan, Jianfeng [this message]
2016-09-06 8:20 ` Yuanhan Liu
2016-09-08 8:53 ` Tan, Jianfeng
2016-09-08 12:18 ` Yuanhan Liu
2016-09-09 3:59 ` Tan, Jianfeng
2016-09-09 4:19 ` Yuanhan Liu
2016-09-09 5:50 ` Tan, Jianfeng
2016-09-09 6:03 ` Yuanhan Liu
2016-09-09 6:24 ` Tan, Jianfeng
2016-09-09 6:31 ` Yuanhan Liu
2016-08-05 11:36 ` [dpdk-dev] [PATCH 3/3] net/virtio_user: fix dev not freed after init error Jianfeng Tan
2016-08-05 16:34 ` Stephen Hemminger
2016-08-08 1:07 ` Tan, Jianfeng
2016-08-29 7:01 ` [dpdk-dev] [PATCH 0/3] fix virtio_user issues Christian Ehrhardt
2016-09-27 19:11 ` [dpdk-dev] [PATCH v2 " Jianfeng Tan
2016-09-27 19:11 ` [dpdk-dev] [PATCH v2 1/3] net/virtio_user: fix queue pair not enabled Jianfeng Tan
2016-09-28 0:05 ` Yuanhan Liu
2016-09-27 19:11 ` [dpdk-dev] [PATCH v2 2/3] net/virtio_user: fix wrong sequence of messages Jianfeng Tan
2016-09-27 19:11 ` [dpdk-dev] [PATCH v2 3/3] net/virtio_user: fix dev not freed after init error Jianfeng Tan
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