Hello,
On Friday 16 March 2012 11:34:37 Stefan Bader wrote:
When using the xm/xend stack to manage instances there is a bug that
causes
the emulated interfaces to be unusable when the vif config contains
type=ioemu.
I had a look at a similar problem some time ago, so some gereral comments:
Xens point of view:
If you specify model=XXX in Xen, you get that emulated NIC and also a second
Xen-PV netfront interface as well.
When you specify type=ioemu, you only get the emulated NIC, netfront is
skipped.
libvirts point of view:
If you explicitly specify a model for the interface, you get exactly that
model without the Xen-PV-companion interface, that is type=ioemu is added.
Without an explicit model, you get the default rtl8139 and netfront.
The problem with modern Linux kernels is, that unless you
specify "xen_emul_unplug=never" on the Kernel command line, the kernel
detects that you're running on Xen and disabled the emulated NIC leaving you
without any network.
So currently with libvirt you can't specify the type of the emulated NIC (for
example to get a more modern e1000) and also get the Xen-PV-interface as
well. If I remeber corrently that forces you to change the NIC model when
installing the Windows GPLPV drivers,
I hope that little bit is helpful to others, since it cost my some time to
find that out myself the hard way. Corrections are appreciated.
Sincerely
Philipp
--
Philipp Hahn Open Source Software Engineer hahn(a)univention.de
Univention GmbH be open. fon: +49 421 22 232- 0
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