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Date: Mon, 10 Aug 2009 16:02:36 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] Re: virtio-serial: An interface for
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: kvm@vger.kernel.org, "Richard W.M. Jones" <rjones@redhat.com>, Rusty Russell <rusty@rustcorp.com.au>, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, Amit Shah <amit.shah@redhat.com>

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