On Wed, May 02, 2018 at 09:50:21AM +0200, Jiri Pirko wrote:

Wed, May 02, 2018 at 02:20:26AM CEST, sridhar.samudrala@intel.com wrote:

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On 4/30/2018 12:20 AM, Jiri Pirko wrote:

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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.

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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.

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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 that is easy. You allow the change of the mac and in the "failover"
mac change implementation you propagate the change down to slaves. If
one slave does not support the change, you bail out. And since VF does

I wish people would say primary/standby and not "VF" :)

not allow it as you say, once it will be enslaved, the mac change could
not be done. Seems like a correct behavior to me

what if primary does not allow mac changes and is attached after
mac is changed on standy?

and is in-sync with how
bond/team behaves.

I think in the end virtio can just block MAC changes for simplicity.

I personally don't see softmac as a must have feature in v1,
we can add it later.

What's the situation with init scripts and whether it's
possible to make them work well would be a better question.

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So for the initial implementation, do you see any issues with having this restriction
in STANDBY mode.