VMCALL to KVM userspace?

[Florian Pester <florian.pester@tu-dresden.de>]

Hi,

for a uni project I'm trying to write a userspace for KVM that can run
ELF binaries without a full blown OS in the guest. The idea is to handle
any syscalls made by the binary running inside the guest in the
userspace of the host. In the simplest case you could forward them to
the host Linux kernel.

In any case, I've gotten pretty far, setting up IDTs, the VCPU, Page
Tables and whatnot, but right now I'm stuck. I setup my syscall handler
to do a VMCALL, which according to the Intel manual is supposed to
return control to the host. However this seems to be handled by KVM
without an exit into userspace?

If this is correct, is there any way to make a call to the host VMM,
that will be transfered to userspace by KVM?

Thanks
Florian