Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices

[Laine Stump <laine@redhat.com>]

On 5/28/19 10:54 PM, Michael S. Tsirkin wrote:
> On Tue, May 28, 2019 at 05:14:22PM -0700, si-wei liu wrote:
>>
>>
>> On 5/21/2019 11:49 AM, Jens Freimann wrote:
>>> On Tue, May 21, 2019 at 07:37:19AM -0400, Michael S. Tsirkin wrote:
>>>> On Tue, May 21, 2019 at 09:21:57AM +0200, Jens Freimann wrote:
>>>>> On Mon, May 20, 2019 at 04:56:57PM -0600, Alex Williamson wrote:

>>>> Actually is there a list of devices for which this has been tested
>>>> besides mlx5? I think someone said some old intel cards
>>>> don't support this well, we might need to blacklist these ...
>>>
>>> So far I've tested mlx5 and XL710 which both worked, but I'm
>>> working on testing with more devices. But of course help with testing
>>> is greatly appreciated.
 >>
>> It won't work on Intel ixgbe and Broadcom bnxt_en, which requires toggling
>> the state of tap backing the virtio-net in order to release/reprogram MAC
>> filter. Actually, it's very few NICs that could work with this - even some
>> works by chance the behavior is undefined. Instead of blacklisting it makes
>> more sense to whitelist the NIC that supports it - with some new sysfs
>> attribute claiming the support presumably.
>>
>> -Siwei
> 
> I agree for many cards we won't know how they behave until we try.  One
> can consider this a bug in Linux that cards don't behave in a consistent
> way.  The best thing to do IMHO would be to write a tool that people can
> run to test the behaviour.

Is the "bad behavior" something due to the hardware of the cards, or 
their drivers? If it's the latter, then at least initially having a 
whitelist would be counterproductive, since it would make it difficult 
for relative outsiders to test and report success/failure of various cards.

(It's probably just a pipe dream, but it would be nice if it eventually 
could work with old igb cards - I have several of them that I use for 
SRIOV testing, and would rather avoid having to buy new hardware.)