[dpdk-dev] [PATCH v2 02/17] vhost: fix return code of messages requiring replies

[Ilya Maximets]

On 03.10.2018 17:49, Maxime Coquelin wrote:
> 
> 
> On 10/03/2018 03:26 PM, Ilya Maximets wrote:
>> On 02.10.2018 12:36, Maxime Coquelin wrote:
>>> VHOST_USER_GET_PROTOCOL_FEATURES, VHOST_USER_GET_VRING_BASE
>>> and VHOST_USER_SET_LOG_BASE require replies, so their handlers
>>> should return VH_RESULT_REPLY, not VH_RESULT_OK.
>>>
>>> Fixes: 2cfbbb86c62a ("vhost: unify message handling function signature")
>>>
>>> Signed-off-by: Maxime Coquelin <maxime.coquelin at 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 060b41893..ce0ac0098 100644
>>> --- a/lib/librte_vhost/vhost_user.c
>>> +++ b/lib/librte_vhost/vhost_user.c
>>> @@ -1161,7 +1161,7 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
>>>         msg->size = sizeof(msg->payload.state);
>>>   -    return VH_RESULT_OK;
>>> +    return VH_RESULT_REPLY;
>>>   }
>>>     /*
>>> @@ -1218,7 +1218,7 @@ vhost_user_get_protocol_features(struct virtio_net **pdev,
>>>       msg->payload.u64 = protocol_features;
>>>       msg->size = sizeof(msg->payload.u64);
>>>   -    return VH_RESULT_OK;
>>> +    return VH_RESULT_REPLY;
>>>   }
>>>     static int
>>> @@ -1298,7 +1298,7 @@ vhost_user_set_log_base(struct virtio_net **pdev, struct VhostUserMsg *msg)
>>>         msg->size = sizeof(msg->payload.u64);
>>
>> Maybe we need to set size to zero? This message should not have
>> "Slave payload" according to docs and QEMU does not check it.
> 
> I agree with the fix, but it's here since the beginning, not related to
> this series. I will add it at the beginning of the series though.

OK.

> 
> I think the spec could also be updated, to clarify what payload is
> expected when VHOST_USER_PROTOCOL_F_LOG_SHMFD is negotiated.

Yeah. There was an attempt few years ago, but it wasn't merged because of
code changes, I guess:
    https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg03526.html

> 
>>
>>>   -    return VH_RESULT_OK;
>>> +    return VH_RESULT_REPLY;
>>>   }
>>>     static int vhost_user_set_log_fd(struct virtio_net **pdev __rte_unused,
>>>