Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
virt_to_phys - map virtual addresses to physical
SYNOPSIS
unsigned long virt_to_phys (volatile void * address);
ARGUMENTS
address
address to remap
DESCRIPTION
The returned physical address is the physical (CPU) mapping for the
memory address given. It is only valid to use this function on
addresses directly mapped or allocated via kmalloc.
This function does not give bus mappings for DMA transfers. In almost
all conceivable cases a device driver should not be using this function
AUTHORS
Matthew Wilcox <matthew@wil.cx>, Alan Cox <alan@redhat.com>.