From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Samudrala, Sridhar" Subject: Re: [PATCH net-next v9 3/4] virtio_net: Extend virtio to use VF datapath when available Date: Tue, 1 May 2018 17:20:26 -0700 Message-ID: <9c6f055c-c665-0601-3973-bce74d72544b@intel.com> References: <1524848820-42258-1-git-send-email-sridhar.samudrala@intel.com> <1524848820-42258-4-git-send-email-sridhar.samudrala@intel.com> <20180428094205.GM5632@nanopsycho.orion> <638e52c7-64db-9d8d-7530-f6b000d3e292@intel.com> <20180430072034.GH23854@nanopsycho.orion> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: mst@redhat.com, stephen@networkplumber.org, davem@davemloft.net, netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, virtio-dev@lists.oasis-open.org, jesse.brandeburg@intel.com, alexander.h.duyck@intel.com, kubakici@wp.pl, jasowang@redhat.com, loseweigh@gmail.com, aaron.f.brown@intel.com To: Jiri Pirko Return-path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: In-Reply-To: <20180430072034.GH23854@nanopsycho.orion> Content-Language: en-US List-Id: netdev.vger.kernel.org On 4/30/2018 12:20 AM, Jiri Pirko wrote: > >>> Now I try to change mac of the failover master: >>> [root@test1 ~]# ip link set ens3 addr 52:54:00:b2:a7:f3 >>> RTNETLINK answers: Operation not supported >>> >>> That I did expect to work. I would expect this would change the mac of >>> the master and both standby and primary slaves. >> If a VF is untrusted, a VM will not able to change its MAC and moreover > Note that at this point, I have no VF. So I'm not sure why you mention > that. > > >> in this mode we are assuming that the hypervisor has assigned the MAC and >> guest is not expected to change the MAC. > Wait, for ordinary old-fashioned virtio_net, as a VM user, I can change > mac and all works fine. How is this different? Change mac on "failover > instance" should work and should propagate the mac down to its slaves. > > >> For the initial implementation, i would propose not allowing the guest to >> change the MAC of failover or standby dev. > I see no reason for such restriction. > It is true that a VM user can change mac address of a normal virtio-net interface, however when it is in STANDBY mode i think we should not allow this change specifically because we are creating a failover instance based on a MAC that is assigned by the hypervisor. Moreover,  in a cloud environment i would think that PF/hypervisor assigns a MAC to the VF and it cannot be changed by the guest. So for the initial implementation, do you see any issues with having this restriction in STANDBY mode.