From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Xu Subject: Re: [PATCH v2 5/6] vhost: claim that we support GUEST_ANNOUNCE feature Date: Tue, 22 Dec 2015 16:11:08 +0800 Message-ID: <20151222081108.GF7532@pxdev.xzpeter.org> References: <1449027793-30975-1-git-send-email-yuanhan.liu@linux.intel.com> <1450321921-27799-1-git-send-email-yuanhan.liu@linux.intel.com> <1450321921-27799-6-git-send-email-yuanhan.liu@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: "Michael S. Tsirkin" , dev@dpdk.org, Victor Kaplansky To: Yuanhan Liu Return-path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 5F79DF72 for ; Tue, 22 Dec 2015 09:11:23 +0100 (CET) Content-Disposition: inline In-Reply-To: <1450321921-27799-6-git-send-email-yuanhan.liu@linux.intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Thu, Dec 17, 2015 at 11:12:00AM +0800, Yuanhan Liu wrote: > It's actually a feature already enabled in Linux kernel. What we need to > do is simply to claim that we support such feature, and nothing else. > > With that, the guest will send GARP messages after live migration. > > Signed-off-by: Yuanhan Liu > --- > lib/librte_vhost/virtio-net.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c > index 03044f6..0ba5045 100644 > --- a/lib/librte_vhost/virtio-net.c > +++ b/lib/librte_vhost/virtio-net.c > @@ -74,6 +74,7 @@ static struct virtio_net_config_ll *ll_root; > #define VHOST_SUPPORTED_FEATURES ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | \ > (1ULL << VIRTIO_NET_F_CTRL_VQ) | \ > (1ULL << VIRTIO_NET_F_CTRL_RX) | \ > + (1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE) | \ Do we really need this? I can understand when guest declare with this VIRTIO_NET_F_GUEST_ANNOUNCE flag. With that, guest itself will handle the announcement after migration. However, how could I understand if it's declared by a vhost-user backend? What does it mean? In vhost-user.txt (in QEMU repo docs/specs/), the only place that mentioned this is SEND_RARP: * VHOST_USER_SEND_RARP Id: 19 Equivalent ioctl: N/A Master payload: u64 Ask vhost user backend to broadcast a fake RARP to notify the migration is terminated for guest that does not support GUEST_ANNOUNCE. ... Here, it mention the GUEST_ANNOUNCE since when guest support this, we do not need to send SEND_RARP to vhost-user backend again. It never explain what does it mean when vhost-user declaring to have this flag... Thanks. Peter > (VHOST_SUPPORTS_MQ) | \ > (1ULL << VIRTIO_F_VERSION_1) | \ > (1ULL << VHOST_F_LOG_ALL) | \ > -- > 1.9.0 >