svn commit: r290130 - head/sys/dev/ntb/ntb_hw

[Conrad E. Meyer]

Author: cem
Date: Thu Oct 29 04:16:28 2015
New Revision: 290130
URL: https://svnweb.freebsd.org/changeset/base/290130

Log:
  ntb: Do not attempt to set write-combining on MWs
  
  AMD64 pmap assumes ranges will be in the DMAP, which isn't necessarily
  true for NTB memory windows (especially 64-bit BARs).
  
  Suggested by:	pmap_change_attr_locked -> kassert_panic
  Sponsored by:	EMC / Isilon Storage Division

Modified:
  head/sys/dev/ntb/ntb_hw/ntb_hw.c

Modified: head/sys/dev/ntb/ntb_hw/ntb_hw.c
==============================================================================
--- head/sys/dev/ntb/ntb_hw/ntb_hw.c	Thu Oct 29 04:16:16 2015	(r290129)
+++ head/sys/dev/ntb/ntb_hw/ntb_hw.c	Thu Oct 29 04:16:28 2015	(r290130)
@@ -755,9 +755,13 @@ map_memory_window_bar(struct ntb_softc *
 		save_bar_parameters(bar);
 	}
 
+#if 0	/* XXX: amd64 pmap_change_attr() assumes region lies in DMAP. */
 	/* Mark bar region as write combining to improve performance. */
 	rc = pmap_change_attr((vm_offset_t)bar->vbase, bar->size,
 	    VM_MEMATTR_WRITE_COMBINING);
+#else
+	rc = EINVAL;
+#endif
 	print_map_success(ntb, bar, "mw");
 	if (rc == 0)
 		device_printf(ntb->device,