add functions to provide direct access to guest memory as vmd addresses

iovec_mem() populates an iovec array based on guest physical
addresses. this allows the use of things like readv and writev for
moving data between the guest and a disk image file without having
to bounce the memory.

vaddr_mem() provides a vmd usable pointer based on a guests physical
address. this makes it possible to directly reference things like
virtio rings without having to bounce that memory either. however,
it assumes that a contiguous range of guest physical memory will
sit in a single vm memory range. mlarkin@ says this is right.

ok mlarkin@

0 files changed, 0 insertions, 0 deletions