Re: [libvirt] Setting devid for emulated NICs (Xen 4.3.1 / libvirt 1.2.0) using libxl driver
On Tue, 2013-12-17 at 17:34 +0100, Stefan Bader wrote:
Using virt-manager "hypervisor default" type:
<interface type='bridge'>
<mac address='00:16:3e:5e:09:9d'/>
<source bridge='br0'/>
<script path='vif-bridge'/>
</interface>
This causes the qemu call to have "-net none" which removes PXE boot
abilities. A linux kernel has network through the xen pv-driver.
Changing in virt-manager to "e1000" type:
<interface type='bridge'>
<mac address='00:16:3e:5e:09:9d'/>
<source bridge='br0'/>
<script path='vif-bridge'/>
<model type='e1000'/>
</interface>
This currently (Xen 4.3.1 + libvirt 1.2.0) fails and the qemu arguments
in the log look suspicious:
-device e1000,id=nic-1,netdev=net-1,mac=00:16:3e:5e:09:9d
-netdev type=tap,id=net-1,ifname=vif1.-1-emu,script=no,downscript=no
Looking through git I found ba64b97134a6129a48684f22f31be92c3b6eef96
libxl: Allow libxl to set NIC devid
Is that a libvirt commit? Not seeing it in xen.git.
Might this libxl fix be relevant:
commit 5420f26507fc5c9853eb1076401a8658d72669da
Author: Jim Fehlig <jfehlig(a)suse.com>
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>
Acked-by: Ian Campbell <ian.campbell(a)citrix.com>
Committed-by: Ian Campbell <ian.campbell(a)citrix.com>
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 :-(
which removes a line that sets the devid of new NICs. I assume the comment
says (sorry I always seem to get confused reading it) that devid should
be auto-set by the libxl library provided by Xen.
Correct.
But I could not find where that would be done.
I expect the above commits have pointed you to the right line, but the
code should be quite near the top of libxl__device_nic_add in libxl.c
Even the xl command implementation sets it
explicitly.
The caller is also allowed to do this if it cares what number is used.
libxl_device_nic_init sets it to -1 which would explain the
wrong qemu arguments above.
Right, libxl_device_nic_init sets everything to "the defaults please"
and __device_nic_add will instantiate any defaults which the application
didn't supply.
For testing I re-added the following after the libxlMakeNic call:
--- libvirt-1.2.0.orig/src/libxl/libxl_conf.c 2013-12-11 17:04:17.000000000 +0
+++ libvirt-1.2.0/src/libxl/libxl_conf.c 2013-12-16 19:08:46.830016646 +0
@@ -907,6 +907,8 @@ libxlMakeNicList(virDomainDefPtr def, l
for (i = 0; i < nnics; i++) {
if (libxlMakeNic(l_nics[i], &x_nics[i]))
goto error;
+ if (x_nics[i].devid < 0)
+ x_nics[i].devid = i;
}
d_config->nics = x_nics;
And with that I get a working PXE boot when I set the device type
in the config. (Side note that I think not using a type defaults to
rtl8139 in the old xend driver. Maybe this should be the same for the
xl driver).
I am not sure how the right fix for it should look like as I am unsure
which part was supposed to set the devid. Just right now it does not
seem to be done.
-Stefan