[libvirt] [PATCH 14/14] Add support for network device detach

[Mark McLoughlin]

On Mon, 2009-07-20 at 15:05 +0200, Daniel Veillard wrote:
> On Mon, Jul 20, 2009 at 12:51:24PM +0100, Mark McLoughlin wrote:
> > qemu network devices are hot-unplugged in two stages - first the PCI NIC
> > is removed using 'pci_del <pci_addr>' and then the backend is removed
> > using 'host_net_remove <vlan> <name>'.
> > 
> > In order to perform these operations we need to have retained the
> > PCI address, backend name and vlan number.
> [...]
> > +    DEBUG("%s: pci_del reply: %s", vm->def->name,  reply);
> > +
> > +    /* If the command fails due to a wrong PCI address qemu prints
> > +     * 'invalid pci address'; nothing is printed on success */
> > +    if (strstr(reply, "Invalid pci address")) {
> > +        qemudReportError(conn, NULL, NULL, VIR_ERR_OPERATION_FAILED,
> > +                         _("failed to detach network device: invalid PCI address %s: %s"),
> > +                         detach->pci_addr, reply);
> > +        goto cleanup;
> > +    }
> 
>   Hum, is that the only possible source of error ? Seems trying to
> detect failure and then possibly 'invalid pci address' as a reason
> would be more reliable.

Looking at the code, I think the only other possible error currently is
"empty slot". I'll address that in a follow up patch.

The current monitor protocol sucks because we don't actually have an
error indication. For this command, we could probably say that any
response indicates an error but you can be sure some future version of
qemu would then add a success message :-)

Cheers,
Mark.