From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id B3F9D1B484; Tue, 9 Oct 2018 12:34:39 +0200 (CEST) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 051C130820DD; Tue, 9 Oct 2018 10:34:39 +0000 (UTC) Received: from [10.36.112.57] (ovpn-112-57.ams2.redhat.com [10.36.112.57]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9A6C66EE3C; Tue, 9 Oct 2018 10:34:30 +0000 (UTC) From: Maxime Coquelin To: Tiwei Bie Cc: dev@dpdk.org, zhihong.wang@intel.com, jfreimann@redhat.com, nicknickolaev@gmail.com, i.maximets@samsung.com, bruce.richardson@intel.com, alejandro.lucero@netronome.com, dgilbert@redhat.com, stable@dpdk.org References: <20181008152557.14275-1-maxime.coquelin@redhat.com> <20181008152557.14275-5-maxime.coquelin@redhat.com> <20181009102125.GA27427@debian> Message-ID: Date: Tue, 9 Oct 2018 12:34:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Tue, 09 Oct 2018 10:34:39 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH v4 04/19] vhost: fix payload size of reply X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Oct 2018 10:34:40 -0000 On 10/09/2018 12:30 PM, Maxime Coquelin wrote: > > > On 10/09/2018 12:21 PM, Tiwei Bie wrote: >> On Mon, Oct 08, 2018 at 05:25:42PM +0200, Maxime Coquelin wrote: >>> QEMU doesn't expect any payload for the reply of >>> VHOST_USER_SET_LOG_BASE request, so don't send any. >>> Note that the Vhost-user specification isn't clear about >>> it and would need to be fixed. >>> >>> Fixes: 54f9e32305d4 ("vhost: handle dirty pages logging request") >>> Cc: stable@dpdk.org >>> >>> Reported-by: Ilya Maximets >>> Signed-off-by: Maxime Coquelin >>> Acked-by: Ilya Maximets >>> --- >>>   lib/librte_vhost/vhost_user.c | 6 +++++- >>>   1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/lib/librte_vhost/vhost_user.c >>> b/lib/librte_vhost/vhost_user.c >>> index 7f3e86778..71a0e7dd7 100644 >>> --- a/lib/librte_vhost/vhost_user.c >>> +++ b/lib/librte_vhost/vhost_user.c >>> @@ -1296,7 +1296,11 @@ vhost_user_set_log_base(struct virtio_net >>> **pdev, struct VhostUserMsg *msg) >>>       dev->log_base = dev->log_addr + off; >>>       dev->log_size = size; >>> -    msg->size = sizeof(msg->payload.u64); >>> +    /* >>> +     * The spec is not clear about it (yet), but QEMU doesn't expect >>> +     * any payload in the reply. >>> +     */ >>> +    msg->size = 0; >> >> I think the spec is clear about it that no payload is >> expected in the reply: >> >> https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L496 >> > It isn't really clear because there are two cases[0]: > 1. VHOST_USER_PROTOCOL_F_LOG_SHMFD not negotiated: In this case no reply >    has to be sent. > 2. VHOST_USER_PROTOCOL_F_LOG_SHMFD negotiated: In this case reply with >    empty payload hsa to be sent. > > [0]: > https://github.com/qemu/qemu/blob/7c69b7c849641a39ba3defa40d384a2ba24cd7a2/docs/interop/vhost-user.txt#L177 > And I would add that N/A isn't clear, because SET_VRING_ADDR specifies N/A as slave payload, whereas the implementation does not implement a reply. >> But below line in the spec needs to be fixed: >> >> https://github.com/qemu/qemu/blob/7c69b7c84964/docs/interop/vhost-user.txt#L495 >> > > Indeed. > >> >>>       return VH_RESULT_REPLY; >>>   } >>> -- >>> 2.17.1 >>>