Kernel mode memory is not accessible from usermode.
You could use memory mapped files, to "share memory". Memory mapping a file can be done in a user mode application or in the kernel using the ZwCreateSection, ZwMapViewOfSection, and MmMapViewInSystemSpace operations. Subsequent access to the file contents are done using this memory mapped data region; when data must be fetched from the file it is done so.
More on this in the Platform SDK and the DDK.