Re: pci passthrough - VF reset at boot is dropping assigned MAC

[David Ahern <dsahern@gmail.com>]

On 04/25/11 14:29, David Ahern wrote:
> 
> 
> On 04/25/11 13:18, Alex Williamson wrote:
>>>> I don't see this happening on my system, once manually set the mac never
>>>> changes.  I can restart and reset the VM and the host and guest both
>>>> continue seeing the set mac address.  I tested it with both a recent
>>>> rhel6.1 host kernel as well as upstream 2.6.39-rc4.  If I switch to a VF
>>>> with an unset mac, those will change on each VM reset or restart.
>>>
>>> Blacklist igbvf in the host and you will. That must be the difference: I
>>> was preventing the vf driver from loading in the host -- it's not needed
>>> there, so why load it?
>>
>> I already have it blacklisted.  It's not needed if you're using the VFs
>> they way we are, but there are other uses.
>>
>>> I rebooted for a fresh run. Loaded the igbvf driver before starting the
>>> VM using my tools. With the igbvf driver loaded in the host the MAC
>>> address for the VF was not reset.
>>>
>>> As for why I blacklisted it -- udev. What a PITA with VFs. I saw the
>>> feature for Fedora 15 which should address this.
>>
>> Yes, my VM is up to renaming the VFs eth1340 since the mac changes every
>> boot.  I'm still confused though as I did a whole round of testing after
>> a reboot where igbvf was never loaded and the set mac address stuck
>> across VM restarts and resets.
>>
>> Alex
>>
> 
> The resetting of the VM MAC address is fixed in 2.6.39-rc4, so it's a
> Fedora 14, 2.6.35.12 problem.

Just to finish this off. This is the patch that fixed the MAC address
reset problem:

commit a6b5ea353845b3f3d9ac4317c0b3be9cc37c259b
Author: Greg Rose <gregory.v.rose@intel.com>
Date:   Sat Nov 6 05:42:59 2010 +0000

    igb: Warn on attempt to override administratively set MAC/VLAN

    Print a warning message to the system log when the VF attempts to
    override administratively set MAC/VLAN configuration.

    Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
    Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

David