From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Coquelin Subject: Re: [PATCH v4 04/19] vhost: fix payload size of reply Date: Tue, 9 Oct 2018 12:30:45 +0200 Message-ID: References: <20181008152557.14275-1-maxime.coquelin@redhat.com> <20181008152557.14275-5-maxime.coquelin@redhat.com> <20181009102125.GA27427@debian> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit 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 To: Tiwei Bie Return-path: In-Reply-To: <20181009102125.GA27427@debian> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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 > 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 >>