[ovs-dev] [PATCH 2/4] xenserver: Restore XS5.5 compatibility for vif script.

Ian Campbell Ian.Campbell at citrix.com
Wed Mar 17 17:42:03 UTC 2010


On Wed, 2010-03-17 at 17:12 +0000, Ben Pfaff wrote:
> On Wed, Mar 17, 2010 at 04:53:01PM +0000, Ian Campbell wrote:
> > One thing to note is that $DEVID is not valid for tap devices on 5.5 (it
> > erroneously counts from 0 the number of emulated devices instead of
> > reflecting VIF.device from the XenAPI).
> 
> As far as I can tell the vif script doesn't get called at all for tap
> devices on 5.5.

Oh, yes, that was another change made in the 5.6 branch, I'd forgotten.

> 
> > $DEVID is correct from 5.6 onwards.
> > 
> > It may be that you aren't worried about this field for a tap device and
> > we should only call this stuff for vif devices?
> 
> Really what we need is a way to figure out what VIF UUID (etc.) a given
> vif or tap device corresponds to.  On any XS version we have a solution
> for vifs.  For taps, on 5.6+ it appears that we can get it by s/tap/vif/
> and looking at the vif's information.  On 5.5 I used to think it was the
> same but now I know that it isn't.  I don't have a good solution yet.  I
> think earlier you suggested essentially this for a given $DOMID:
> 
>         * Sort all the tap$DOMID.x devices in order by x.
> 
>         * Sort all the vif$DOMID.x devices in order by x.
> 
>         * Match up the first device in the tap list to the first device
>           in the vif list, the second to the second, and so on.  (There
>           should be the same number.)
> 
> Does that work?

I _think_ it should. For the second list you could also consult the list
of VIF devices in the data model for that domain.

>   I guess that hotplug is not an issue because there is
> no network hotplug without paravirt.

Correct.

Ian.






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