Re: [Qemu-devel] emulated lance device crashes in debian-sparc32

[Mark Glines <mark@glines.org>]

On Sun, 20 May 2007 11:25:25 +0100
Paul Brook <paul@codesourcery.com> wrote:
> > In my past experience, -net user implies -net nic. 
> 
> You are mistaken. -net user does not imply -net nic.

I just tested this.  You are absolutely right, I was wrong about the
behavior on x86.


> > Hmm.  -net performs 2 separate functions.  First, it sets up the
> > network card in the guest machine (nic, model, and macaddr).
> > Second, it specifies how that card behaves on the host side of
> > things (vlan, user, tap, or socket).
> 
> -net creates devices and attaches them to the virtual network,
> whether they be emulated devices on the host, or devices for
> communication with the "real" world.

Thanks for explaining.

So the issue on sparc was that the device is relied on by the
SS-5 platform code (it sounds like sun4m has this device on-board at
a fixed offset, non-pci), but not initialized properly due to the lack
of -net nic?  Should sun4m imply -net nic,model=lance then?  It doesn't
make much sense to me to ever turn the lance port off, if its
integrated into the platform itself (not a daughter card).

I apologize for the additional confusion; I guess I was confused by the
fact that "-net nic -net user" is the default when no -net options are
provided, and passing "-net user" on the cmdline disabled the implicit
-net nic.

Mark