From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [Qemu-devel] [PATCH] qemu: Introduce VIRTIO_NET_F_STANDBY feature bit to virtio_net Date: Tue, 12 Jun 2018 05:17:26 +0300 Message-ID: <20180612051432-mutt-send-email-mst@kernel.org> References: <1525734594-11134-1-git-send-email-sridhar.samudrala@intel.com> <20180611202207-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Sridhar Samudrala , alexander.h.duyck@intel.com, virtio-dev@lists.oasis-open.org, qemu-devel@nongnu.org, jiri@resnulli.us, kubakici@wp.pl, netdev@vger.kernel.org, jesse.brandeburg@intel.com, virtualization@lists.linux-foundation.org, loseweigh@gmail.com, aaron.f.brown@intel.com To: Jason Wang Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:46318 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S935057AbeFLCR3 (ORCPT ); Mon, 11 Jun 2018 22:17:29 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Jun 12, 2018 at 09:54:44AM +0800, Jason Wang wrote: > > > On 2018年06月12日 01:26, Michael S. Tsirkin wrote: > > On Mon, May 07, 2018 at 04:09:54PM -0700, Sridhar Samudrala wrote: > > > This feature bit can be used by hypervisor to indicate virtio_net device to > > > act as a standby for another device with the same MAC address. > > > > > > I tested this with a small change to the patch to mark the STANDBY feature 'true' > > > by default as i am using libvirt to start the VMs. > > > Is there a way to pass the newly added feature bit 'standby' to qemu via libvirt > > > XML file? > > > > > > Signed-off-by: Sridhar Samudrala > > So I do not think we can commit to this interface: we > > really need to control visibility of the primary device. > > The problem is legacy guest won't use primary device at all if we do this. And that's by design - I think it's the only way to ensure the legacy guest isn't confused. > How about control the visibility of standby device? > > Thanks standy the always there to guarantee no downtime. > > However just for testing purposes, we could add a non-stable > > interface "x-standby" with the understanding that as any > > x- prefix it's unstable and will be changed down the road, > > likely in the next release. > > > > > > > --- > > > hw/net/virtio-net.c | 2 ++ > > > include/standard-headers/linux/virtio_net.h | 3 +++ > > > 2 files changed, 5 insertions(+) > > > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > index 90502fca7c..38b3140670 100644 > > > --- a/hw/net/virtio-net.c > > > +++ b/hw/net/virtio-net.c > > > @@ -2198,6 +2198,8 @@ static Property virtio_net_properties[] = { > > > true), > > > DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, SPEED_UNKNOWN), > > > DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str), > > > + DEFINE_PROP_BIT64("standby", VirtIONet, host_features, VIRTIO_NET_F_STANDBY, > > > + false), > > > DEFINE_PROP_END_OF_LIST(), > > > }; > > > diff --git a/include/standard-headers/linux/virtio_net.h b/include/standard-headers/linux/virtio_net.h > > > index e9f255ea3f..01ec09684c 100644 > > > --- a/include/standard-headers/linux/virtio_net.h > > > +++ b/include/standard-headers/linux/virtio_net.h > > > @@ -57,6 +57,9 @@ > > > * Steering */ > > > #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */ > > > +#define VIRTIO_NET_F_STANDBY 62 /* Act as standby for another device > > > + * with the same MAC. > > > + */ > > > #define VIRTIO_NET_F_SPEED_DUPLEX 63 /* Device set linkspeed and duplex */ > > > #ifndef VIRTIO_NET_NO_LEGACY > > > -- > > > 2.14.3