Re: [Xen-devel] [libvirt] Setting devid for emulated NICs (Xen 4.3.1 / libvirt 1.2.0) using libxl driver

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-12-18 at 14:12 +0100, Stefan Bader wrote:
> On 18.12.2013 13:27, Ian Campbell wrote:
> > On Tue, 2013-12-17 at 18:32 +0100, Stefan Bader wrote:
> >>>
> >>> Might this libxl fix be relevant:
> >>>         commit 5420f26507fc5c9853eb1076401a8658d72669da
> >>>         Author: Jim Fehlig <jfehlig@xxxxxxxx>
> >>>         Date:   Fri Jan 11 12:22:26 2013 +0000
> >>>         
> >>>             libxl: Set vfb and vkb devid if not done so by the caller
> >>>             
> >>>             Other devices set a sensible devid if the caller has not done 
> >>> so.
> >>>             Do the same for vfb and vkb.  While at it, factor out the 
> >>> common code
> >>>             used to determine a sensible devid, so it can be used by other
> >>>             libxl__device_*_add functions.
> >>>             
> >>>             Signed-off-by: Jim Fehlig <jfehlig@xxxxxxxx>
> >>>             Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> >>>             Committed-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> >>>         
> >>> and a follow up in dfeccbeaa. Although the comment implies that nic's
> >>> were already correctly assigning a devid if the caller specified -1, so
> >>> I don't know why it doesn't work for you :-(
> >>
> >> Ok, yes, the commit above indeed changes libxl__device_nic_add to call
> >> libxl__device_nextid for the devid... Just how is this actually called.
> >> Maybe not sufficient but "git grep libxl__device_nic_add" in the xen code 
> >> only
> >> shows the definition and a declaration in libxl_internal.h to me...
> > 
> > I have a feeling a macro might be involved...
> > 
> > Here we go, look for DEFINE_DEVICE_REMOVE in libxl.c. We should really
> > add the eventual function names in comments to provide grep fodder....
> 
> Oh duh, yeah. So in DEFINE_DEVICE_ADD a libxl_device_nic_add is created which
> calls to libxl__device_nic_add. When I look for the single _ version I find a
> call from xl_cmdimpl.c and its public declaration in libxl.h.
> So I guess the bug is that libvirt in the libxl driver never seems to do so

The macro creates libxl__add_nics which adds the nics from the
libxl_domain_config->nics array. I don't think libvirt needs to call
libxl_device_nic_add manually unless it is hotplugging a new nic at
runtime.

> . Ok,
> thanks a lot for digging the out the DEFINE. As nice those are to create 
> similar
> functions from template, grep and tags fail to be helpful with them.
> 
> -Stefan
> > 
> > Ian.
> > 
> > --
> > libvir-list mailing list
> > libvir-list@xxxxxxxxxx
> > https://www.redhat.com/mailman/listinfo/libvir-list
> > 
> 
> 



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