From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: "Yang, Zhiyong" <zhiyong.yang@intel.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "yuanhan.liu@linux.intel.com" <yuanhan.liu@linux.intel.com>,
"Loftus, Ciara" <ciara.loftus@intel.com>,
"Marc-André Lureau" <mlureau@redhat.com>
Subject: Re: [dpdk-dev] [PATCH] vhost: fix MQ fails to startup
Date: Thu, 27 Apr 2017 10:32:40 +0200 [thread overview]
Message-ID: <a97b6d6d-48e0-c70f-79c8-f4676db8c865@redhat.com> (raw)
In-Reply-To: <E182254E98A5DA4EB1E657AC7CB9BD2A3EBA7E7D@BGSMSX101.gar.corp.intel.com>
On 04/27/2017 10:24 AM, Yang, Zhiyong wrote:
> Hi, Maxime:
>
>> -----Original Message-----
>> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
>> Sent: Thursday, April 27, 2017 4:05 PM
>> To: Yang, Zhiyong <zhiyong.yang@intel.com>; dev@dpdk.org
>> Cc: yuanhan.liu@linux.intel.com; Loftus, Ciara <ciara.loftus@intel.com>; Marc-
>> André Lureau <mlureau@redhat.com>
>> Subject: Re: [PATCH] vhost: fix MQ fails to startup
>>
>>
>>
>> On 04/27/2017 09:56 AM, Maxime Coquelin wrote:
>>> Hi Zhiyong,
>>>
>>> +Marc-André
>>>
>>> On 04/27/2017 08:34 AM, Zhiyong Yang wrote:
>>>> vhost since dpdk17.02 + qemu2.7 and above will cause failures of new
>>>> connection when negotiating to set MQ. (one queue pair works
>>>> well).Because there exist some bugs in qemu code when introducing
>>>> VHOST_USER_PROTOCOL_F_REPLY_ACK to qemu. when dealing with the
>> vhost
>>>> message VHOST_USER_SET_MEM_TABLE for the second time, qemu indeed
>>>> doesn't send the messge (The message needs to be sent only once)but
>>>> still will be waiting for dpdk's reply ack, then, qemu is always
>>>> freezing. DPDK code works in the right way.
>>>
>>> I'm looking at Qemu's vhost_user_set_mem_table() function, but fail to
>>> see how it could wait for the reply-ack if it didn't send the
>>> VHOST_USER_SET_MEM_TABLE request before.
>>
>> Oh, sorry, I get it now.
>> Are you working for a fix in Qemu, or have you already reported the problem?
>
> I will send bug fix patch to Qemu.
> The same wrong code has also been used when Qemu2.9 introduce the MTU negotiation with DPDK.
> I will fix them at the same time in qemu.
I think the problem must be fixed generally and not per request.
Maybe in vhost_user_write() if one-time request, just clear the
VHOST_USER_NEED_REPLY flag. Then, in process_message_reply(), return
early if this flag isn't set.
But that is not enough because as said, even if fixed, the backend has
no way to know about it.
> Thanks
> Zhiyong
>
>>
>> Thanks,
>> Maxime
next prev parent reply other threads:[~2017-04-27 8:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-27 6:34 Zhiyong Yang
2017-04-27 7:41 ` Loftus, Ciara
2017-04-27 7:56 ` Maxime Coquelin
2017-04-27 8:05 ` Maxime Coquelin
2017-04-27 8:24 ` Yang, Zhiyong
2017-04-27 8:32 ` Maxime Coquelin [this message]
2017-04-27 8:20 ` Yuanhan Liu
2017-04-27 8:52 ` Maxime Coquelin
2017-04-28 2:25 ` Yuanhan Liu
2017-04-28 7:23 ` Maxime Coquelin
2017-04-28 7:35 ` Yuanhan Liu
2017-04-28 7:39 ` Yuanhan Liu
2017-04-28 7:57 ` Maxime Coquelin
2017-04-28 8:00 ` Yuanhan Liu
2017-04-27 8:12 ` Yuanhan Liu
2017-04-27 8:32 ` Yang, Zhiyong
2017-04-27 9:41 ` [dpdk-dev] [PATCH v2] vhost: workaround " Zhiyong Yang
2017-04-27 10:00 ` Maxime Coquelin
2017-04-28 4:29 ` Yuanhan Liu
2017-05-10 2:07 ` Yang, Zhiyong
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