Re: [Qemu-devel] [PATCH v2] net: Fix hotplug with pci_add

[Amit Shah]

On (Wed) Jun 09 2010 [15:28:11], Amit Shah wrote:
> > Let me rephrase: Behavior changes for -net types without an init()
> > method.  The only one without an init() method is "none".  Before,
> > net_client_init() succeeded for it.  Now it fails.  What's the impact of
> > that change?  And why does it make sense?
> 
> It makes sense because we don't actually initialise anything. We don't
> place anything in the nd_table[] array. That means callers shouldn't
> poke in the array for any values. Returning -1 makes sense for that
> reason. If we continued to return 0, callers might just assume that init
> was successful and that nd_table[0] was set up for use appropriately.
> 
> The thing is that the code doesn't go this far in case of '-net none'
> anyway. This was just a potential bug lurking around for any new -net
> method which didn't have an init.

Hm, I only tested -net none from the monitor, using pci_add. Looks like
I skipped testing it from the cmd line. I did that today and found out
the VM doesn't start. I've sent a patch to revert to the original
behaviour of returning 0, and we'll have to find another way of fixing
the 'success or index' return problem.

                Amit