Index: head/sys/dev/bge/if_bgereg.h
===================================================================
--- head/sys/dev/bge/if_bgereg.h
+++ head/sys/dev/bge/if_bgereg.h
@@ -3067,3 +3067,11 @@
 #define	BGE_LOCK_ASSERT(_sc)	mtx_assert(&(_sc)->bge_mtx, MA_OWNED)
 #define	BGE_UNLOCK(_sc)		mtx_unlock(&(_sc)->bge_mtx)
 #define	BGE_LOCK_DESTROY(_sc)	mtx_destroy(&(_sc)->bge_mtx)
+
+#ifdef BUS_SPACE_MAXADDR
+#if (BUS_SPACE_MAXADDR > 0xFFFFFFFF)
+#define	BGE_DMA_BOUNDARY	(0x100000000)
+#else
+#define	BGE_DMA_BOUNDARY	0
+#endif
+#endif
Index: head/sys/dev/pci/pci.c
===================================================================
--- head/sys/dev/pci/pci.c
+++ head/sys/dev/pci/pci.c
@@ -4343,9 +4343,6 @@
 {
 	struct pci_softc *sc;
 	int busno, domain;
-#ifdef PCI_DMA_BOUNDARY
-	int error, tag_valid;
-#endif
 #ifdef PCI_RES_BUS
 	int rid;
 #endif
@@ -4365,23 +4362,7 @@
 	if (bootverbose)
 		device_printf(dev, "domain=%d, physical bus=%d\n",
 		    domain, busno);
-#ifdef PCI_DMA_BOUNDARY
-	tag_valid = 0;
-	if (device_get_devclass(device_get_parent(device_get_parent(dev))) !=
-	    devclass_find("pci")) {
-		error = bus_dma_tag_create(bus_get_dma_tag(dev), 1,
-		    PCI_DMA_BOUNDARY, BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR,
-		    NULL, NULL, BUS_SPACE_MAXSIZE, BUS_SPACE_UNRESTRICTED,
-		    BUS_SPACE_MAXSIZE, 0, NULL, NULL, &sc->sc_dma_tag);
-		if (error)
-			device_printf(dev, "Failed to create DMA tag: %d\n",
-			    error);
-		else
-			tag_valid = 1;
-	}
-	if (!tag_valid)
-#endif
-		sc->sc_dma_tag = bus_get_dma_tag(dev);
+	sc->sc_dma_tag = bus_get_dma_tag(dev);
 	return (0);
 }
 
Index: head/sys/dev/pci/pcivar.h
===================================================================
--- head/sys/dev/pci/pcivar.h
+++ head/sys/dev/pci/pcivar.h
@@ -693,14 +693,6 @@
 
 void	pci_print_faulted_dev(void);
 
-#ifdef BUS_SPACE_MAXADDR
-#if (BUS_SPACE_MAXADDR > 0xFFFFFFFF)
-#define	PCI_DMA_BOUNDARY	0x100000000
-#else
-#define	PCI_DMA_BOUNDARY	0
-#endif
-#endif
-
 #endif	/* _SYS_BUS_H_ */
 
 /*
Index: head/sys/dev/twa/tw_osl.h
===================================================================
--- head/sys/dev/twa/tw_osl.h
+++ head/sys/dev/twa/tw_osl.h
@@ -57,6 +57,12 @@
 #define TW_OSLI_MAX_NUM_IOS		(TW_OSLI_MAX_NUM_REQUESTS - 2)
 #define TW_OSLI_MAX_NUM_AENS		0x100
 
+#ifdef PAE
+#define	TW_OSLI_DMA_BOUNDARY		(1u << 31)
+#else
+#define	TW_OSLI_DMA_BOUNDARY		((bus_size_t)((uint64_t)1 << 32))
+#endif
+
 /* Possible values of req->state. */
 #define TW_OSLI_REQ_STATE_INIT		0x0	/* being initialized */
 #define TW_OSLI_REQ_STATE_BUSY		0x1	/* submitted to CL */
Index: head/sys/dev/twa/tw_osl_freebsd.c
===================================================================
--- head/sys/dev/twa/tw_osl_freebsd.c
+++ head/sys/dev/twa/tw_osl_freebsd.c
@@ -551,7 +551,7 @@
 	/* Create the parent dma tag. */
 	if (bus_dma_tag_create(bus_get_dma_tag(sc->bus_dev), /* parent */
 				sc->alignment,		/* alignment */
-				0,			/* boundary */
+				TW_OSLI_DMA_BOUNDARY,	/* boundary */
 				BUS_SPACE_MAXADDR,	/* lowaddr */
 				BUS_SPACE_MAXADDR, 	/* highaddr */
 				NULL, NULL, 		/* filter, filterarg */
Index: head/sys/x86/iommu/intel_ctx.c
===================================================================
--- head/sys/x86/iommu/intel_ctx.c
+++ head/sys/x86/iommu/intel_ctx.c
@@ -130,7 +130,7 @@
 	maxaddr = MIN(ctx->domain->end, BUS_SPACE_MAXADDR);
 	ctx->ctx_tag.common.ref_count = 1; /* Prevent free */
 	ctx->ctx_tag.common.impl = &bus_dma_dmar_impl;
-	ctx->ctx_tag.common.boundary = PCI_DMA_BOUNDARY;
+	ctx->ctx_tag.common.boundary = 0;
 	ctx->ctx_tag.common.lowaddr = maxaddr;
 	ctx->ctx_tag.common.highaddr = maxaddr;
 	ctx->ctx_tag.common.maxsize = maxaddr;