Messages in this thread | | | Date | Wed, 21 Mar 2012 08:37:46 +0200 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH] virtio-spec: clarify ro/rw bits and updating rule of virtio-net status field |
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On Wed, Mar 21, 2012 at 10:10:52AM +1030, Rusty Russell wrote: > On Wed, 21 Mar 2012 00:48:05 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote: > > On Tue, Mar 20, 2012 at 09:35:18PM +1030, Rusty Russell wrote: > > > On Tue, 20 Mar 2012 14:20:21 +0800, Jason Wang <jasowang@redhat.com> wrote: > > > > This patch clarifies VIRTIO_NET_S_LINK_UP as a read-only bit and > > > > VIRTIO_NET_S_ANNOUNCE as a read-writable bit. Also introduce the write 1 to > > > > clear semantics for all read-writable bits of config status field. This could > > > > help to reduce the config status field updating race between host and guest and > > > > also simplify the implementation. > > > > > > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > > > > > This approach assumes an active config field, which neither lguest nor > > > S/390 have. > > > > > > Thanks, > > > Rusty. > > > > What does 'active' mean in this context? > > It means you are assuming that writes to the config field trap to the > host. > > Rusty.
Ah. Right, we need to trap for host to clear the bit. OK, so let's make the bit RO, and add VIRTIO_NET_CTRL_ANNOUNCED to acknowledge that we've seen VIRTIO_NET_S_ANNOUNCE using the control VQ?
If there's no ctrl VQ, we won't acknowledge the feature bit ...
> -- > How could I marry someone with more hair than me? http://baldalex.org
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