seems I finally found what upset kqemu on amd64 SMP... shared gdt! (please test patch :)

[Teufel]

>  Okay I _think_ I know a little more about this now...  kqemu itself
> doesn't use the fpu, but the guest code it runs can, and in that case the
> DNA trap is just used for (host) lazy fpu context switching like as if the
> code was running in userland regularly.  And I just tested the following
> patch that should get rid of the message by calling fpudna/npxdna directly
> (files/patch-fpucontext is the interesting part:)
Applied the patch today and I can confirm, there are no more dna 
messages as expected. A win2k3 guest runs now couple of hours with some 
stress test and the kernel is still fine. I think this patch solves the 
broken kqemu on amd64. Great work.