[PATCH 0/0][RFC] KVM use of vringfd

[Mark McLoughlin <markmc@redhat.com>]

Hey,
        Since this came up at the KVM forum, I thought I'd post these
patches here for discussion.

        The first issue with making KVM use vringfd is that the mmap()
interface doesn't work for KVM since it is the guest that allocates
the ring descriptor, so it doesn't make much sense for the host to
remap those pages.

        The second issue is a little more tricky; QEMU's networking
implementation is based around the notion of connecting a number
of interfaces to a VLAN. So, in less common cases where you don't
just have a tap interface and a virtio interface connected to the
VLAN, you can't take just lguest's simple approach of sharing the
same vrings between the tap driver in the host and the virtio driver
in the guest and having the host userspace notify each side of buffers
as they come and go. I know Anthony has ideas here, so I'll just let
him outline them.

Cheers,
Mark.