OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.

 


Help: OASIS Mailing Lists Help | MarkMail Help

virtio-comment message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]


Subject: Re: [virtio-comment] virtio and endian-ness


On Mon, 19 Aug 2013 16:24:35 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Mon, Aug 19, 2013 at 03:20:49PM +0200, Cornelia Huck wrote:
> > On Mon, 19 Aug 2013 16:05:43 +0300
> > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > 
> > > > One idea might be that all devices start out in 'legacy mode' and we
> > > > add either a feature bit or a new channel command that switches to
> > > > 'standard mode'. Old hosts would reject that command, while old guests
> > > > would simply not issue it.
> > > > 
> > > > Another idea is to look at the read_conf/write_conf channel commands
> > > > and introduce a new pair of read_conf_le/write_conf_le commands. Again,
> > > > compatibility would be achived via the host doing command rejects.
> > > > 
> > > > We also have the possibility to convey extra information about the
> > > > control unit (the device) in the 'extended sense id data' via the sense
> > > > id command. Basically, we can encode some supported channel commands in
> > > > there, but we would need a new command type for that architectured.
> > > > We'd still need to rely on the command rejects mentioned above, though.
> > > 
> > > If guest can discover whether host supports the new layout,
> > > why would there be any rejects?
> > 
> > If we want to support old guests on new hosts, we'll have to rely on
> > this.
> 
> I would expect old guests not to issue old commands, if new
> host supports that why would there be rejects?
> 

Thinko, of course you are right.



[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]