From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Ilya Maximets <i.maximets@samsung.com>,
dev@dpdk.org, tiwei.bie@intel.com, zhihong.wang@intel.com,
jfreimann@redhat.com, nicknickolaev@gmail.com,
bruce.richardson@intel.com, alejandro.lucero@netronome.com
Cc: dgilbert@redhat.com, stable@dpdk.org,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [dpdk-stable] [PATCH v2 01/17] vhost: fix messages error checks
Date: Wed, 3 Oct 2018 10:02:54 +0200 [thread overview]
Message-ID: <cdccf1e7-36ca-dbef-6abd-aa22bba2ac2c@redhat.com> (raw)
In-Reply-To: <20181003075530eucas1p1dd7191a728c1129fd5d9dbaed5fa1047~aChpN_6wn1404114041eucas1p1H@eucas1p1.samsung.com>
On 10/03/2018 09:57 AM, Ilya Maximets wrote:
> On 03.10.2018 10:50, Maxime Coquelin wrote:
>>
>>
>> On 10/02/2018 04:15 PM, Ilya Maximets wrote:
>>> On 02.10.2018 12:36, Maxime Coquelin wrote:
>>>> Return of message handling has now changed to an enum that can
>>>> take non-negative value that is not zero in case a reply is
>>>> needed. But the code checking the variable afterwards has not
>>>> been updated, leading to success messages handling being
>>>> treated as errors.
>>>>
>>>> Fixes: 4e601952cae6 ("vhost: message handling implemented as a callback array")
>>>>
>>>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>>>> ---
>>>> lib/librte_vhost/vhost_user.c | 6 +++---
>>>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>>>> index 7ef3fb4a4..060b41893 100644
>>>> --- a/lib/librte_vhost/vhost_user.c
>>>> +++ b/lib/librte_vhost/vhost_user.c
>>>> @@ -1783,7 +1783,7 @@ vhost_user_msg_handler(int vid, int fd)
>>>> }
>>>> skip_to_post_handle:
>>>> - if (!ret && dev->extern_ops.post_msg_handle) {
>>>> + if (ret != VH_RESULT_ERR && dev->extern_ops.post_msg_handle) {
>>>> uint32_t need_reply;
>>>> ret = (*dev->extern_ops.post_msg_handle)(
>>>> @@ -1800,10 +1800,10 @@ vhost_user_msg_handler(int vid, int fd)
>>>> vhost_user_unlock_all_queue_pairs(dev);
>>>> if (msg.flags & VHOST_USER_NEED_REPLY) {
>>>
>>> Maybe we need to reply here only if we didn't reply
>>> already (not VH_RESULT_REPLY) ? Otherwise, we could
>>> reply twice (with payload and with return code).
>>
>> Well, if the master sets this bit, it means it is waiting for
>> a "reply-ack", so not sending it would cause the master to wait
>> forever.
>>
>> It is the master responsibility to not set this bit for requests
>> already expecting a non "reply-ack" reply (as you fixed it for
>> postcopy's set mem table case).
>
> vhost-user docs in QEMU says:
> "
> For the message types that already solicit a reply from the client, the
> presence of VHOST_USER_PROTOCOL_F_REPLY_ACK or need_reply bit being set brings
> no behavioural change.
> "
> i.e. even if QEMU sets the need_reply flag, vhost should not reply twice.
> Am I missing something?
Oh, right. Thanks for pointing it out.
So coming back to the DPDK implementation, I just had a look again, and
it seems that we don't send a reply twice, as send_vhost_reply takes
care of clearing the VHOST_USER_NEED_REPLY flag.
Do you confirm my understanding is correct?
>>
>>>> - msg.payload.u64 = !!ret;
>>>> + msg.payload.u64 = ret == VH_RESULT_ERR;
>>>> msg.size = sizeof(msg.payload.u64);
>>>> send_vhost_reply(fd, &msg);
>>>> - } else if (ret) {
>>>> + } else if (ret == VH_RESULT_ERR) {
>>>> RTE_LOG(ERR, VHOST_CONFIG,
>>>> "vhost message handling failed.\n");
>>>> return -1;
>>>>
>>
>>
next prev parent reply other threads:[~2018-10-03 8:03 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-02 9:36 [dpdk-stable] [PATCH v2 00/17] vhost: add postcopy live-migration support Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 01/17] vhost: fix messages error checks Maxime Coquelin
2018-10-02 14:15 ` Ilya Maximets
2018-10-03 7:50 ` Maxime Coquelin
2018-10-03 7:57 ` Ilya Maximets
2018-10-03 8:02 ` Maxime Coquelin [this message]
2018-10-03 8:32 ` Ilya Maximets
2018-10-03 9:07 ` Ilya Maximets
2018-10-03 14:39 ` Maxime Coquelin
2018-10-04 5:42 ` Ilya Maximets
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 02/17] vhost: fix return code of messages requiring replies Maxime Coquelin
2018-10-03 13:26 ` Ilya Maximets
2018-10-03 14:49 ` Maxime Coquelin
2018-10-04 5:49 ` Ilya Maximets
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 03/17] vhost: fix error handling when mem table gets updated Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 04/17] vhost: define postcopy protocol flag Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 05/17] vhost: add number of fds to vhost-user messages and use it Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 06/17] vhost: pass socket fd to message handling callbacks Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 07/17] vhost: enable fds passing when sending vhost-user messages Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 08/17] vhost: add config flag for postcopy feature Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 09/17] vhost: introduce postcopy's advise message Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 10/17] vhost: add support for postcopy's listen message Maxime Coquelin
2018-10-02 14:11 ` Ilya Maximets
2018-10-03 7:46 ` Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 11/17] vhost: register new regions with userfaultfd Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 12/17] vhost: avoid useless VhostUserMemory copy Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 13/17] vhost: send userfault range addresses back to qemu Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 14/17] vhost: add support to postcopy's end request Maxime Coquelin
2018-10-02 14:18 ` Ilya Maximets
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 15/17] vhost: enable postcopy protocol feature Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 16/17] vhost: add flag to enable postcopy live-migration Maxime Coquelin
2018-10-02 9:36 ` [dpdk-stable] [PATCH v2 17/17] net/vhost: add parameter to enable postcopy support Maxime Coquelin
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