IN  PMDL MemoryDescriptorList,

Routine Description:

    This function maps physical pages described by a memory descriptor
    list into the system virtual address space or the user portion of
    the virtual address space.


    MemoryDescriptorList - Supplies a valid Memory Descriptor List which has
                            been updated by MmProbeAndLockPages.

    AccessMode - Supplies an indicator of where to map the pages;
                 KernelMode indicates that the pages should be mapped in the
                 system part of the address space, UserMode indicates the
                 pages should be mapped in the user part of the address space.

Return Value:

    Returns the base address where the pages are mapped.  The base address
    has the same offset as the virtual address in the MDL.

    This routine will raise an exception if the processor mode is USER_MODE
    and quota limits or VM limits are exceeded.


    Kernel mode.  DISPATCH_LEVEL or below if access mode is KernelMode,
                  APC_LEVEL or below if access mode is UserMode.