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

[Dongli Zhang <dongli.zhang@oracle.com>]

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?

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(),
>>>  };
>>>  
>>>
>