Re: VIF network definition does not work with backend=domnet

[Jason Andryuk <jandryuk@xxxxxxxxx>]

On Sat, Mar 22, 2025 at 8:51 AM Shen Long
<xen-mailinglist@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,

Hi Shen,

> Here the test.cfg domu which "works":
>
> name = "test"
> builder = "hvm"
> vcpus = 1
> memory = 4096
> #vif = [ 'backend=netbackend,bridge=dmz' ]

Try:
vif = [ 'backend=netbackend,bridge=dmz,type=vif' ]

This will give "test" just a PV nic (and not an emulated nic).

> disk = [ 'file:/isos/systemrescue-11.03-amd64.iso,hda:cdrom,r' ]
> usbdevice = [ "tablet" ]
> serial = "pty"
> on_poweroff = "destroy"
> on_reboot = "restart"
> on_crash = "restart"
>
> It does not have a proper disk yet, because testing.
> The Problem is, if i remove the hash from the vif spec, i get this error
> on `xl create test.cfg`:
>
> # xl create /etc/xen/domuconfig/test.cnf
> Parsing config from /etc/xen/domuconfig/test.cnf
> libxl: error: libxl_dm.c:3157:device_model_spawn_outcome: Domain
> 89:domain 89 device model: spawn failed (rc=-3)

/var/log/xen/qemu-dm-test.log probably reports an error about bridge
dmz not existing.

qemu runs in dom0, but your bridge "dmz" is in the driver domain,
"netbackend".  By using type=vif, xl skips creating the emulated nic
with qemu.  I think `xl network-attach` uses type=vif by default,
which also avoids the emulated nic issue.

Regards,
Jason