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

[Laine Stump]

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.)