Re: [Qemu-devel] [PATCH v4 10/47] Return path: Open a return path on QEMUFile for sockets

[Dr. David Alan Gilbert]

* David Gibson (address@hidden) wrote:
> On Fri, Oct 03, 2014 at 06:47:16PM +0100, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> > 
> > Postcopy needs a method to send messages from the destination back to
> > the source, this is the 'return path'.
> > 
> > Wire it up for 'socket' QEMUFile's using a dup'd fd.
> 
> This doesn't seem like the right abstraction to me.  In particular I
> can't really see how you'd implement this for anything other than
> socket.
> 
> I'd suggest instead creating new "open" helper functions (within the
> QEMUFile code) that open both a forward and return path
> simultaneously.

Can you give an example of a transport where it would be a problem,
so I can look at how that works?

It's a little tricky since, on the destination, at the time we create
the connection we don't know that we're going to need the return path.

Dave

> -- 
> David Gibson                  | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au        | minimalist, thank you.  NOT _the_ 
> _other_
>                               | _way_ _around_!
> http://www.ozlabs.org/~dgibson


--
Dr. David Alan Gilbert / address@hidden / Manchester, UK