Subject: Re: [virtio-dev] Re: [Qemu-devel] [PATCH] qemu: Introduce VIRTIO_NET_F_STANDBY feature bit to virtio_net

From: "Michael S. Tsirkin" <[email-masked]>
Date: Tue, 19 Jun 2018 23:32:06 +0300

On Tue, Jun 19, 2018 at 12:54:53PM +0200, Cornelia Huck wrote:
> Sorry about dragging mainframes into this, but this will only work for
> homogenous device coupling, not for heterogenous. Consider my vfio-pci
> + virtio-net-ccw example again: The guest cannot find out that the two
> belong together by checking some group ID, it has to either use the MAC
> or some needs-to-be-architectured property.
> 
> Alternatively, we could propose that mechanism as pci-only, which means
> we can rely on mechanisms that won't necessarily work on non-pci
> transports. (FWIW, I don't see a use case for using vfio-ccw to pass
> through a network card anytime in the near future, due to the nature of
> network cards currently in use on s390.)

That's what it boils down to, yes.  If there's need to have this for
non-pci devices, then we should put it in config space.
Cornelia, what do you think?

-- 
MST