8622 panic in PTE_set_all()
8623 IMMU_CONTIG_PADDR is broken for cookies with more than one page
8625 nvme causes bad free panic in IOMMU
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>

@@ -23,10 +23,11 @@
  */
 /*
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2011 Bayard G. Bell.  All rights reserved.
  * Copyright 2012 Garrett D'Amore <garrett@damore.org>.  All rights reserved.
+ * Copyright 2017 Joyent, Inc.
  */
 
 /*
  * x86 root nexus driver
  */

@@ -2334,11 +2335,11 @@
          */
         rootnex_teardown_copybuf(dma);
         rootnex_teardown_windows(dma);
 
 #if defined(__amd64) && !defined(__xpv)
-        if (IOMMU_USED(rdip))
+        if (IOMMU_USED(rdip) && dma->dp_dvma_used)
                 (void) iommulib_nexdma_unmapobject(dip, rdip, handle,
                     &dma->dp_dvma);
 #endif
 
         /*