People asked for a pdf for a new spec, so here it is: http://userweb.kernel.org/~mst/virtio-spec-event-idx-v2.pdf Guest and host implementation can be found here: git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git vhost-net-next-event-idx-v1 git://git.kernel.org/pub/scm/linux/kernel/git/mst/qemu-kvm.git virtio-net-event-idx-v1 Description reposted below: I'm working on a patchset (to follow shortly) that modified the notificatin hand-off in virtio to be basically like Xen: each side published an index, the other side only triggers an event when it crosses that index value (Xen event indexes start at 1, ours start at 0 for backward-compatiblity, but that's minor). Especially for testing, it is very convenient to have separate feature bits for this change in used and available ring; since we've run out of bits in the 32 bit field, I added another 32 bit and bit 31 enables that. I started with using both flags and indexes in parallel, but switched to doing either-or: this means we do not need to tweak memory access ordering as index access just replaces flags access. A note on naming: the index replacing avail->flags is named used_event, the index replacing used->flags is named avail_event to stress the fact that these actually point into the other side of the ring: event is triggered when avail->idx == used->avail_event + 1 and when used->idx == avail->used_event + 1, respectively. Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> -- MST -- 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
