[Qemu-devel] Re: virtio-serial: An interface for host-guest communication

Gerd Hoffmann kraxel at redhat.com
Mon Aug 10 07:02:36 PDT 2009


On 08/10/09 15:02, Anthony Liguori wrote:

> I think you're missing my fundamental point. Don't use the kernel as the
> guest interface.
>
> Introduce a userspace daemon that exposes a domain socket. Then we can
> have a proper protocol that uses reverse fqdns for identification.

We need nothing but (a) bidirectional byte streams and (b) name tags for 
them.

Do we really want design a daemon and a protocol for such a simple 
thing?  Especially as requiring a daemon for that adds a few problems 
you don't have without them.  Access control for example:  For device 
nodes you can just use standard unix permissions and acls.  You can 
easily do stuff like adding the logged in desktop user to the 
/dev/vmchannel/org/qemu/clipboard acl using existing solutions.  With a 
daemon you have to hop through a number of loops to archive the same.

Can't we simply have guest apps open "/dev/vmchannel/$protocol" ?

cheers,
   Gerd



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