On Feb 13, 2005, at 3:13 PM, Manuel Bouyer wrote:

> for Xen, I need to allocate some kernel virtual address space, into 
> which I'll
> map physical pages loaned by foreign domains for I/O. The management 
> of these
> pages will be done in the backend drivers, and so will bypass pmap(9).
> It there a way to reserve some kernel virtual address space from UVM, 
> but
> without physical memory backing it ? I didn't find an obvious way to 
> do this
> in the uvm(9) man page.

Look at how the i386 bus_space does this.

-- thorpej