Re: [PATCH] virtio-spec: clarify ro/rw bits and updating rule of virtio-net status field

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


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@xxxxxxxxxx> 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@xxxxxxxxxx> 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@xxxxxxxxxx>
> > > 
> > > 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
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization


[KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Photo]     [Yosemite]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]     [Find Someone Nice]     [Video 4 Linux]     [Linux Resources]
Add to Google Powered by Linux