> console message: "dvma_mapin: null page frame".  This crash was easily 

This bug was found and fixed a couple of weeks ago.

The patch is small so I'll just include it below.

-pk


Index: iommureg.h
===================================================================
RCS file: /cvsroot/src/sys/arch/sparc/sparc/iommureg.h,v
retrieving revision 1.3
retrieving revision 1.4
diff -r1.3 -r1.4
1c1
< /*    $NetBSD: iommureg.h,v 1.3 1997/09/14 19:16:04 pk Exp $ */
---
> /*    $NetBSD: iommureg.h,v 1.4 1998/01/24 16:22:47 pk Exp $ */
61a62,67
> /*
>  * Read something back from the IOMMU control space after writing
>  * to a flush register to drain write buffers (?).   This seems to
>  * avoid utter lossage on some machines (SS4s & SS5s) where our caller
>  * would see some of its local (`%lx') registers trashed.
>  */
63a70
> 	(*(volatile u_int32_t *)&(sc)->sc_reg->io_bar);		\
66a74
> 	(*(volatile u_int32_t *)&(sc)->sc_reg->io_bar);		\