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

On Thu, 2013-12-19 at 11:39 -0700, Jim Fehlig wrote: > Stefan Bader wrote: > >> Oh, just while talking about setdefault. Jim, this is one of the odd things when >> moving from xm to xl stack from libvirt: libvirt defaults to the netfront NIC >> when no model is specified and sets the type. The libxl setdefault function sets >> the model to rtl8139 but leaves the type untouched. >> > The xend toolstack always creates both emulated and vif devices unless > 'type=netfront' is explicitly specified. As you say, the guest gets to > choose what to do with them. E.g. PXE boot using the emulated device, > or have the driver for the PV device unplug the emulated one. I don't > think libxl supports this right? > On my 4.3.1 setup, I changed the above to if (hvm) { x_nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU; if (l_nic->model) { if (VIR_STRDUP(x_nic->model, l_nic->model) < 0) return -1; if (STREQ(l_nic->model, "netfront")) x_nic->nictype = LIBXL_NIC_TYPE_VIF; } } else { x_nic->nictype = LIBXL_NIC_TYPE_VIF; } which is better initialization logic IMO. If the domain is hvm, set nictype to LIBXL_NIC_TYPE_VIF_IOEMU, unless model 'netfront' is specified. This behavior is consistent with the legacy xen driver. The change seems to work fine and resolves the PXE issue Stefan noted - as long as I initialize devid in libvirt. So we'll need the above fix in libvirt, as well as a resolution to the nic devid initialization in libxl that started this thread. Regards, Jim It should do, in fact I thought it was the default. How are you initialising the libxl_device_nic?

Type == VIF_IOEMU (which is the default for a VIF on an HVM guest) means both emulated and pv. (there were bugs in the semantics here in very early versions of libxl, but I thought they were fixed even before 4.2)