[ovirt-users] macvlan + IPv6

[Edward Haas]

----- Original Message -----
| From: "Jay Turner" <jkt at iix.net>
| To: users at ovirt.org
| Sent: Tuesday, February 23, 2016 5:13:21 PM
| Subject: Re: [ovirt-users] macvlan + IPv6
| 
| As a follow-up to this, I made some headway in sorting out the source of the
| issue, but hoping someone can give me a pointer to where this is happening
| in the code, as well as some understanding for why.
| 
| In oVirt, when I allocate a virtual function to a guest, a new MAC address is
| generated for the VF (as it should be) from the MAC address pool in oVirt,
| and then that MAC address is written to the VF on the hypervisor. Thus I end
| up with something like:
| 
| : ens11: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master i40e
| state UP mode DEFAULT qlen 1000
| link/ether 3c:fd:fe:9d:a1:38 brd ff:ff:ff:ff:ff:ff
| vf 0 MAC 00:1a:4a:16:01:52, spoof checking on, link-state auto
| 
| This *is not* how it happens under libvirt/virt-manager, however. When
| allocating a VF to a guest under libvirt, a random MAC address is generated
| and associated with the VF under the guest, but it is not written back to
| the hypervisor, and is instead left as 00:00:00:00:00:00.
| 
| I am pretty sure this writing of the MAC address at the hypervisor is causing
| at least some of the issues I'm seeing, as with the Intel cards, that
| prevents the guest from changing/adding a new MAC address, which is what
| happens with the instantiation of a macvlan interface.
| 
| So can anyone point me to where in the oVirt code this MAC address assignment
| is occurring? Also curious why oVirt does this assignment, but libvirt does
| not.
| 
| Thanks!
| 
| - jkt
| 
| On Mon, Feb 22, 2016 at 2:51 PM Jay Turner < jkt at iix.net > wrote:
| 
| 
| 
| Hoping someone can help with a problem my team is seeing under oVirt.
| 
| We are making heavy use of macvlan interfaces (in VEPA mode) on-top of
| virtual functions, under VMs being managed by oVirt. In this scenario IPv6
| is not playing nicely, with no traffic going through, and messages about
| neighbor solicitation. There are some pointers out there indicating the
| issue stems from the fact IPv6 utilizing multicast for neighbor
| solicitation, but nothing we have tried seems to work around this issue.
| 
| The problem is made all the most bizarre by the fact that on the same
| hardware libvirt + virt-manager works perfectly fine. I have looked at the
| corresponding xml for the guests, and nothing seems to point to the
| underlying cause for oVirt to fail, but libvirt to succeed.
| 
| * Intel XL710 40G NICs (i40e/i40evf drivers)
| * CentOS 7.1 (fully up-to-date)
| * oVirt 3.6
| * libvirt-1.2.17
| * virt-manager-1.2.1-8
| 
| Thanks for any pointers folks can provide.
| 
| - jkt
| 
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| 

Could you please provide the dumpxml for both setups (oVirt and non-oVirt)?
(sudo virsh -r dumpxml <domain>)

Thanks,
Edy.