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

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(a)suse.com&gt; >>>> 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(a)suse.com&gt; >>>> Acked-by: Ian Campbell <ian.campbell(a)citrix.com&gt; >>>> Committed-by: Ian Campbell <ian.campbell(a)citrix.com&gt; >>>> >>>> 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.