Index: sys/x86/iommu/busdma_dmar.c
===================================================================
--- sys/x86/iommu/busdma_dmar.c
+++ sys/x86/iommu/busdma_dmar.c
@@ -665,8 +665,8 @@
 {
 	struct bus_dma_tag_dmar *tag;
 	struct bus_dmamap_dmar *map;
-	vm_page_t *ma;
-	vm_paddr_t pstart, pend;
+	vm_page_t *ma, fma;
+	vm_paddr_t pstart, pend, paddr;
 	int error, i, ma_cnt, offset;
 
 	tag = (struct bus_dma_tag_dmar *)dmat;
@@ -679,10 +679,45 @@
 	    M_WAITOK : M_NOWAIT);
 	if (ma == NULL)
 		return (ENOMEM);
-	for (i = 0; i < ma_cnt; i++)
-		ma[i] = PHYS_TO_VM_PAGE(pstart + i * PAGE_SIZE);
+	fma = NULL;
+	for (i = 0; i < ma_cnt; i++) {
+		paddr = pstart + i * PAGE_SIZE;
+		ma[i] = PHYS_TO_VM_PAGE(paddr);
+		if (ma[i] == NULL || VM_PAGE_TO_PHYS(ma[i]) != paddr) {
+			/*
+			 * If PHYS_TO_VM_PAGE() returned NULL or the
+			 * vm_page was not initialized we'll use fake
+			 * pages to go back and fill in the holes.
+			 *
+			 * Allocate the fake page array now as an
+			 * indicator.
+			 */
+			fma = malloc(sizeof(struct vm_page) * ma_cnt, M_DEVBUF,
+			    M_ZERO | (map->cansleep ? M_WAITOK : M_NOWAIT));
+			if (fma == NULL) {
+				free(ma, M_DEVBUF);
+				return (ENOMEM);
+			}
+		}
+	}
+	if (fma != NULL) {
+		/*
+		 * For some addresses PHYS_TO_VM_PAGE() returned NULL
+		 * or the vm_page was not initialized.  Use fake pages
+		 * to fill in the holes.
+		 */
+		for (i = 0; i < ma_cnt; i++) {
+			paddr = pstart + i * PAGE_SIZE;
+			if (ma[i] == NULL || VM_PAGE_TO_PHYS(ma[i]) != paddr) {
+				vm_page_initfake(&fma[i], pstart + i * PAGE_SIZE,
+				    VM_MEMATTR_DEFAULT);
+				ma[i] = &fma[i];
+			}
+		}
+	}
 	error = dmar_bus_dmamap_load_something(tag, map, ma, offset, buflen,
 	    flags, segs, segp);
+	free(fma, M_DEVBUF);
 	free(ma, M_DEVBUF);
 	return (error);
 }
@@ -708,37 +743,43 @@
 	    M_WAITOK : M_NOWAIT);
 	if (ma == NULL)
 		return (ENOMEM);
-	if (dumping) {
+	fma = NULL;
+	for (i = 0; i < ma_cnt; i++, pstart += PAGE_SIZE) {
+		if (pmap == kernel_pmap)
+			paddr = pmap_kextract(pstart);
+		else
+			paddr = pmap_extract(pmap, pstart);
+		ma[i] = PHYS_TO_VM_PAGE(paddr);
+		if (ma[i] == NULL || VM_PAGE_TO_PHYS(ma[i]) != paddr) {
+			/*
+			 * If PHYS_TO_VM_PAGE() returned NULL or the
+			 * vm_page was not initialized we'll use fake
+			 * pages to go back and fill in the holes.
+			 *
+			 * Allocate the fake page array now as an
+			 * indicator.
+			 */
+			fma = malloc(sizeof(struct vm_page) * ma_cnt, M_DEVBUF,
+			    M_ZERO | (map->cansleep ? M_WAITOK : M_NOWAIT));
+			if (fma == NULL) {
+				free(ma, M_DEVBUF);
+				return (ENOMEM);
+			}
+		}
+	}
+	if (fma != NULL) {
 		/*
-		 * If dumping, do not attempt to call
-		 * PHYS_TO_VM_PAGE() at all.  It may return non-NULL
-		 * but the vm_page returned might be not initialized,
-		 * e.g. for the kernel itself.
+		 * For some addresses PHYS_TO_VM_PAGE() returned NULL
+		 * or the vm_page was not initialized.  Use fake pages
+		 * to fill in the holes.
 		 */
-		KASSERT(pmap == kernel_pmap, ("non-kernel address write"));
-		fma = malloc(sizeof(struct vm_page) * ma_cnt, M_DEVBUF,
-		    M_ZERO | (map->cansleep ? M_WAITOK : M_NOWAIT));
-		if (fma == NULL) {
-			free(ma, M_DEVBUF);
-			return (ENOMEM);
-		}
 		for (i = 0; i < ma_cnt; i++, pstart += PAGE_SIZE) {
-			paddr = pmap_kextract(pstart);
-			vm_page_initfake(&fma[i], paddr, VM_MEMATTR_DEFAULT);
-			ma[i] = &fma[i];
-		}
-	} else {
-		fma = NULL;
-		for (i = 0; i < ma_cnt; i++, pstart += PAGE_SIZE) {
 			if (pmap == kernel_pmap)
 				paddr = pmap_kextract(pstart);
 			else
 				paddr = pmap_extract(pmap, pstart);
-			ma[i] = PHYS_TO_VM_PAGE(paddr);
-			KASSERT(VM_PAGE_TO_PHYS(ma[i]) == paddr,
-			    ("PHYS_TO_VM_PAGE failed %jx %jx m %p",
-			    (uintmax_t)paddr, (uintmax_t)VM_PAGE_TO_PHYS(ma[i]),
-			    ma[i]));
+			vm_page_initfake(&fma[i], paddr, VM_MEMATTR_DEFAULT);
+			ma[i] = &fma[i];
 		}
 	}
 	error = dmar_bus_dmamap_load_something(tag, map, ma, offset, buflen,