MTU on a virtio-net device?

[Michael Tokarev <mjt@tls.msk.ru>]

Right now (2.6.27), there's no way to change MTU of a
virtio-net interface, since the mtu-changing method is
not provided.  Is there a simple way to add such a
beast?

I'm asking because I'm not familiar with the internals,
and because, I think, increasing MTU (so that the
resulting skb still fits in a single page) will increase
performance significantly, at least on a internal/virtual
network -- currently there are just way too many context
switches and the like while copying data from one guest
to another or between guest and host.

Thanks!

/mjt