On (Mon) Mar 22 2010 [14:16:32], Michael S. Tsirkin wrote:
> > > > I can't certainly predict how many ports might be needed, but I think
> > > > we'll have other ways of communication if we need > 200 ports.
> > >
> > > If, say, 32 bytes are sufficient, let's just reserve a fixed size
> > > array and everything will be simpler?
> >
> > Yes, 32 bytes means 256 ports. Should be OK; if not, one could add more
> > such devices and get more ports. But if I have to choose between fixing
> > the number of ports in the config space vs using the control queue for
> > the bitmap, I'll go for the latter. That's assuming we really really
> > don't want to use the config space for storing the bitmap.
>
> I guess with control queue we also simply use message per port
> state change - would that be simpler than a bitmap?
Yes, that's how hot-unplug is done currently (before this patchset).
I'll cook up a similar version like you suggest for adding ports as
well.
> > > > > > + port_bit = ffs(*map);
> > > > > > + port_bit--; /* ffs returns bit location */
>
> simple u32 port_bit = ffs(*map) - 1; not clear enough?
Well yeah; I'll just open-code it.
Amit
--
http://log.amitshah.net/
_______________________________________________
Virtualization mailing list
[email protected]
https://lists.linux-foundation.org/mailman/listinfo/virtualization
