MmGetSystemAddressForMdl macro

The MmGetSystemAddressForMdl routine is obsolete for Windows 2000 and later versions of Windows, and for Windows Me. It is supported only for WDM drivers that must run on Windows 98. Otherwise, use MmGetSystemAddressForMdlSafe.

MmGetSystemAddressForMdl is a macro that returns a nonpaged system-space virtual address for the buffer described by the MDL. It maps the physical pages described by a given MDL into system space, if they are not already mapped to system space.

Syntax

PVOID MmGetSystemAddressForMdl(
   MDL
);

Parameters

MDL

Pointer to a buffer whose corresponding base virtual address is to be mapped.

Return Value

None

Remarks

MmGetSystemAddressForMdl returns the base system-space virtual address that maps the physical pages described by the given MDL.

Drivers of PIO devices call this routine to translate a virtual address range, described by the MDL at Irp->MdlAddress, for a user buffer to a system-space address range.

The MDL must describe nonpageable memory. In other words, the input MDL must describe an already locked-down user-space buffer returned by MmProbeAndLockPages, a locked-down buffer returned by MmBuildMdlForNonPagedPool, or system-space memory allocated from nonpaged pool, contiguous memory, or noncached memory.

The returned base address has the same offset as the virtual address in the MDL.

Windows 2000 issues a bug check if the attempt to map to system space fails. (Therefore, you should use MmGetSystemAddressForMdlSafe instead). In Windows 98, this routine returns NULL in case of failure.

Requirements

   
Minimum supported client Obsolete for Windows 2000 and later versions of Windows, and for Windows Me. This routine is supported only for WDM drivers that must run on Windows 98. Otherwise, use MmGetSystemAddressForMdlSafe.
Target Platform Desktop
Header wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
IRQL <=DISPATCH_LEVEL

See Also

MmBuildMdlForNonPagedPool

MmGetSystemAddressForMdlSafe

MmProbeAndLockPages