On Mon, 13 Aug 2012 10:56:38 +0200, Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote: > On Wed, 08 Aug 2012 13:52:57 +0930 > Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote: > > > On Tue, 7 Aug 2012 16:52:47 +0200, Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote: > > 1) Please don't limit yourself to 32 feature bits! If you look at how > > virtio_mmio does it, they use a selector to index into a > > theoretically-infinite array of feature bits: > > It should be easy to extend the data processed by the feature ccws to a > feature/index combination. Would it be practical to limit the index to > an 8 bit value? 256 feature bits? That seems like it could one day be limiting. Or an 8 bit accessor into feature words? 8192 seems enough for anyone sane. > > Note that we're also speculating a move to a new vring format, which > > will probably be little-endian. But you probably want a completely new > > ccw code for that anyway. > > Do you have a pointer to that discussion handy? > > If the host may support different vring formats, I'll probably want to > add some kind of discovery mechanism for that as well (what discovery > mechanism depends on whether this would be per-device or per-machine). It would be per-machine; per-device would be a bit crazy. We'd deprecate the old ring format. There's been no consistent thread on the ideas for a ring change, unfortunately, but you can find interesting parts here, off this thread: Message-ID: <8762gj6q5r.fsf@xxxxxxxxxxxxxxx> Subject: Re: [RFC 7/11] virtio_pci: new, capability-aware driver. Cheers, Rusty. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
