Re: [Qemu-devel] [PATCH v3 2/2] net: introduce command to query rx-filter information

[Amos Kong]

On Tue, Jul 02, 2013 at 03:27:12PM +0200, Markus Armbruster wrote:
> Amos Kong <address@hidden> writes:
> 
> > On Tue, Jul 02, 2013 at 11:05:56AM +0200, Markus Armbruster wrote:
> >> Amos Kong <address@hidden> writes:
> [...]
> >> >> This interface is abstract in the sense that it applies to all NICs.  At
> >> >> this time, it's implemented only virtio-net implements it.  I'm
> >> >> habitually wary of abstractions based on just one concrete instance,
> >> >> which makes me ask:
> >> >> 
> >> >> 1. Ignorant question first: could the feature make sense for other NICs,
> >> >> too, or is it specific to virtio-net?
> >> >
> >> > We will not. 
> >> >
> >> > It's ugly to check if nic is virtio-net nic in net/net.c, so I
> >> > register the query function to NetClientInfo. Traversal the net
> >> > client list in net/net.c, and execute query of each virtio-net
> >> > instance in virtio-net.c
> >> 
> >> Implementing the feature as an optional callback is fine.
> >> 
> >> Let me rephrase my question: could this feature be implemented for other
> >> NICs?  I'm *not* asking you to do that, just whether it would be
> >> possible.
> >> 
> >> I'm asking because my review of the QAPI schema depends on the answer.
> >> 
> >> >> 2. If the former, are you reasonably sure this object will do for other
> >> >> NICs?
> >> >
> >> > No.
> >> 
> >> I'm not sure I understand you.  Do you mean to say that the feature
> >> could be implemented for other NICs, but RxFilterInfo would probably not
> >> fit for them?
> >
> > We will not implement the feature to other NICs, no request.
> >
> > We notify the management of virtio-net rx-filter change, because
> > we want to sync the the rx-filter change to macvtap device.
> 
> I understand there are no plans to implement this feature for other
> NICs.  But I'm not asking whether we *want* to implement it for other
> NICs, I'm asking whether we *could*.
 
In theory, we can.

> Or rephrased yet another way: what exactly makes this feature applicable
> to virtio-net only?

Macvtap can only be used by virtio-net, not other emulated nic.
It's meaningless for management to know the rx-filter change of
non-virtio-net NICs.
 
> If the answer is "nothing", then we *could* implement it for other NICs.
> Else, implementing it for other NICs would be impossible.
> 
> Once again, I'm not asking because I want it implemented for other
> NICs.  I'm asking because the answer affects my review of the schema.

-- 
                        Amos.