On a x64 Windows 7 I want to get the limits of non paged pool. I know that _KDDEBUGGER_DATA64 structure has this information (fields like MmNonPagedPoolStart and MmNonPagedPoolEnd). On x86 systems this structure was obtained from KPCR.KdVersionBlock, but looking with WinDbg at KPCR's on x64 systems, KdVersionBlock seems to always be null. Is there a way of getting this structure? Or another way of getting what I want? Maybe I'm not looking in the right place. 
Obtaining MmNonPagedPoolStart on x64 systems
windows;memory
nt!KdDebuggerDatablock used to be a public global symbol in NTlkd> x/v nt!KdDebuggerDataBlockpub global 80545b60             0 nt!KdDebuggerDataBlock = <no type information> dpS  nt!KdDebuggerDataBlock lxxxx should fetch the NonPagedPoolStart lkd> !grep -i -c dpS nt!KdDebuggerDataBlock la5 -e pool 8055b5a0 nt!ExpPagedPoolDescriptor 8054ab2c nt!ExpNumberOfPagedPools nt!MmMaximumNonPagedPoolInBytes 80553cb8 nt!MmNonPagedPoolStartThis should get the complete structurelkd> .printf %ma\t%08x\n , nt!KdDebuggerDataBlock+10,poi(nt!KdDebuggerDataBlock+14)KDBG    00000290lkd> .for (r $t0=0 ; @$t0 <poi(nt!KdDebuggerDataBlock + 14) ; r $t0 = @$t0+4) { .printf %08x\t%08x\t%y\n, (nt!KdDebuggerDataBlock + @$t0) ,poi(nt!KdDebuggerDataBlock + @$t0) ,poi(nt!KdDebuggerDataBlock + @$t0) }