Re: [Qemu-devel] [PATCH v3 1/5] virtio_net: Add VIRTIO_NET_F_STANDBY feature bit.

["Samudrala, Sridhar" <sridhar.samudrala@intel.com>]

On 1/8/2019 4:14 PM, Dongli Zhang wrote:
> Hi Venu,
>
> On 2019/1/9 上午1:25, Venu Busireddy wrote:
>> On 2019-01-09 00:56:38 +0800, Dongli Zhang wrote:
>>> I am not familiar with libvirt and I would like to play with this only with qemu.
>>>
>>> With failover, we need to hotplug the VF on destination server to VM after live
>>> migration. However, the VF on destination server would have different mac address.
>>>
>>> How can we specify the mac for the new VF to hotplug via qemu, as VF is only a
>>> vfio pci device?
>> How is the VF device on the destination host any different from the VF
>> on the source host?
>>
>> As you do on the source host, you first assign the MAC address of
>> 00:00:00:00:00:00 to the VF. After the migration, you assign the same
>> MAC address as that of the virtio_net device to the VF, and hotadd the VF
> This was what I was wondering.
>
> How the mac address is configured for VF (or any NIC like PF) after it is
> assigned to vfio?

ip link set <pf> vf  <vf-num>  mac <MAC>

See https://www.kernel.org/doc/html/latest/networking/net_failover.html
for a sample script that shows the steps to initiate live migration with VF
and virtio-net in standby mode.


>
> Thank you very much!
>
> Dongli Zhang
>
>
>> device to the VM. And then, after you receive the FAILOVER_PRIMARY_CHANGED
>> event, set the macvtap device to down state.
>>
>> Venu
>>
>>> I am trying to play with this with only qemu (w/o libvirt).
>>>
>>> Thank you very much!
>>>
>>> Dongli Zhang
>>>
>>> On 01/08/2019 06:29 AM, Venu Busireddy wrote:
>>>> From: Sridhar Samudrala <sridhar.samudrala@intel.com>
>>>>
>>>> This feature bit can be used by a hypervisor to indicate to the virtio_net
>>>> device that it can act as a standby for another device with the same MAC
>>>> address.
>>>>
>>>> Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
>>>> Signed-off-by: Venu Busireddy <venu.busireddy@oracle.com>
>>>> ---
>>>>   hw/net/virtio-net.c | 2 ++
>>>>   1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>>>> index 385b1a0..411f8fb 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(),
>>>>   };
>>>>   
>>>>