Index: head/sys/arm64/arm64/pmap.c
===================================================================
--- head/sys/arm64/arm64/pmap.c
+++ head/sys/arm64/arm64/pmap.c
@@ -178,8 +178,32 @@
 #endif
 
 #define	pmap_l2_pindex(v)	((v) >> L2_SHIFT)
-#define	pa_to_pvh(pa)		(&pv_table[pmap_l2_pindex(pa)])
 
+static struct md_page *
+pa_to_pvh(vm_paddr_t pa)
+{
+	struct vm_phys_seg *seg;
+	int segind;
+
+	for (segind = 0; segind < vm_phys_nsegs; segind++) {
+		seg = &vm_phys_segs[segind];
+		if (pa >= seg->start && pa < seg->end)
+			return ((struct md_page *)seg->md_first +
+			    pmap_l2_pindex(pa) - pmap_l2_pindex(seg->start));
+	}
+	panic("pa 0x%jx not within vm_phys_segs", (uintmax_t)pa);
+}
+
+static struct md_page *
+page_to_pvh(vm_page_t m)
+{
+	struct vm_phys_seg *seg;
+
+	seg = &vm_phys_segs[m->segind];
+	return ((struct md_page *)seg->md_first +
+	    pmap_l2_pindex(VM_PAGE_TO_PHYS(m)) - pmap_l2_pindex(seg->start));
+}
+
 #define	NPV_LIST_LOCKS	MAXCPU
 
 #define	PHYS_TO_PV_LIST_LOCK(pa)	\
@@ -1049,6 +1073,8 @@
 void
 pmap_init(void)
 {
+	struct vm_phys_seg *seg, *next_seg;
+	struct md_page *pvh;
 	vm_size_t s;
 	uint64_t mmfr1;
 	int i, pv_npg, vmid_bits;
@@ -1093,7 +1119,12 @@
 	/*
 	 * Calculate the size of the pv head table for superpages.
 	 */
-	pv_npg = howmany(vm_phys_segs[vm_phys_nsegs - 1].end, L2_SIZE);
+	pv_npg = 0;
+	for (i = 0; i < vm_phys_nsegs; i++) {
+		seg = &vm_phys_segs[i];
+		pv_npg += pmap_l2_pindex(roundup2(seg->end, L2_SIZE)) -
+		    pmap_l2_pindex(seg->start);
+	}
 
 	/*
 	 * Allocate memory for the pv head table for superpages.
@@ -1105,6 +1136,31 @@
 		TAILQ_INIT(&pv_table[i].pv_list);
 	TAILQ_INIT(&pv_dummy.pv_list);
 
+	/*
+	 * Set pointers from vm_phys_segs to pv_table.
+	 */
+	for (i = 0, pvh = pv_table; i < vm_phys_nsegs; i++) {
+		seg = &vm_phys_segs[i];
+		seg->md_first = pvh;
+		pvh += pmap_l2_pindex(roundup2(seg->end, L2_SIZE)) -
+		    pmap_l2_pindex(seg->start);
+
+		/*
+		 * If there is a following segment, and the final
+		 * superpage of this segment and the initial superpage
+		 * of the next segment are the same then adjust the
+		 * pv_table entry for that next segment down by one so
+		 * that the pv_table entries will be shared.
+		 */
+		if (i + 1 < vm_phys_nsegs) {
+			next_seg = &vm_phys_segs[i + 1];
+			if (pmap_l2_pindex(roundup2(seg->end, L2_SIZE)) - 1 ==
+			    pmap_l2_pindex(next_seg->start)) {
+				pvh--;
+			}
+		}
+	}
+
 	vm_initialized = 1;
 }
 
@@ -2247,7 +2303,7 @@
 				m->md.pv_gen++;
 				if (TAILQ_EMPTY(&m->md.pv_list) &&
 				    (m->flags & PG_FICTITIOUS) == 0) {
-					pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
+					pvh = page_to_pvh(m);
 					if (TAILQ_EMPTY(&pvh->pv_list)) {
 						vm_page_aflag_clear(m,
 						    PGA_WRITEABLE);
@@ -2788,7 +2844,7 @@
 		pmap_pvh_free(&m->md, pmap, va);
 		if (TAILQ_EMPTY(&m->md.pv_list) &&
 		    (m->flags & PG_FICTITIOUS) == 0) {
-			pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
+			pvh = page_to_pvh(m);
 			if (TAILQ_EMPTY(&pvh->pv_list))
 				vm_page_aflag_clear(m, PGA_WRITEABLE);
 		}
@@ -2858,7 +2914,7 @@
 			pmap_pvh_free(&m->md, pmap, sva);
 			if (TAILQ_EMPTY(&m->md.pv_list) &&
 			    (m->flags & PG_FICTITIOUS) == 0) {
-				pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
+				pvh = page_to_pvh(m);
 				if (TAILQ_EMPTY(&pvh->pv_list))
 					vm_page_aflag_clear(m, PGA_WRITEABLE);
 			}
@@ -2997,8 +3053,7 @@
 	    ("pmap_remove_all: page %p is not managed", m));
 	SLIST_INIT(&free);
 	lock = VM_PAGE_TO_PV_LIST_LOCK(m);
-	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy :
-	    pa_to_pvh(VM_PAGE_TO_PHYS(m));
+	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : page_to_pvh(m);
 retry:
 	rw_wlock(lock);
 	while ((pv = TAILQ_FIRST(&pvh->pv_list)) != NULL) {
@@ -4480,7 +4535,7 @@
 			break;
 	}
 	if (!rv && loops < 16 && (m->flags & PG_FICTITIOUS) == 0) {
-		pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
+		pvh = page_to_pvh(m);
 		TAILQ_FOREACH(pv, &pvh->pv_list, pv_next) {
 			if (PV_PMAP(pv) == pmap) {
 				rv = TRUE;
@@ -4535,7 +4590,7 @@
 		PMAP_UNLOCK(pmap);
 	}
 	if ((m->flags & PG_FICTITIOUS) == 0) {
-		pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
+		pvh = page_to_pvh(m);
 		TAILQ_FOREACH(pv, &pvh->pv_list, pv_next) {
 			pmap = PV_PMAP(pv);
 			if (!PMAP_TRYLOCK(pmap)) {
@@ -4577,7 +4632,7 @@
 	rw_rlock(lock);
 	rv = !TAILQ_EMPTY(&m->md.pv_list) ||
 	    ((m->flags & PG_FICTITIOUS) == 0 &&
-	    !TAILQ_EMPTY(&pa_to_pvh(VM_PAGE_TO_PHYS(m))->pv_list));
+	    !TAILQ_EMPTY(&page_to_pvh(m)->pv_list));
 	rw_runlock(lock);
 	return (rv);
 }
@@ -4740,8 +4795,7 @@
 					if ((m->a.flags & PGA_WRITEABLE) != 0 &&
 					    TAILQ_EMPTY(&m->md.pv_list) &&
 					    (m->flags & PG_FICTITIOUS) == 0) {
-						pvh = pa_to_pvh(
-						    VM_PAGE_TO_PHYS(m));
+						pvh = page_to_pvh(m);
 						if (TAILQ_EMPTY(&pvh->pv_list))
 							vm_page_aflag_clear(m,
 							    PGA_WRITEABLE);
@@ -4818,7 +4872,7 @@
 			goto out;
 	}
 	if ((m->flags & PG_FICTITIOUS) == 0) {
-		pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
+		pvh = page_to_pvh(m);
 		TAILQ_FOREACH(pv, &pvh->pv_list, pv_next) {
 			pmap = PV_PMAP(pv);
 			PMAP_ASSERT_STAGE1(pmap);
@@ -4938,8 +4992,7 @@
 	if (!pmap_page_is_write_mapped(m))
 		return;
 	lock = VM_PAGE_TO_PV_LIST_LOCK(m);
-	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy :
-	    pa_to_pvh(VM_PAGE_TO_PHYS(m));
+	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : page_to_pvh(m);
 retry_pv_loop:
 	rw_wlock(lock);
 	TAILQ_FOREACH_SAFE(pv, &pvh->pv_list, pv_next, next_pv) {
@@ -5035,7 +5088,7 @@
 	cleared = 0;
 	pa = VM_PAGE_TO_PHYS(m);
 	lock = PHYS_TO_PV_LIST_LOCK(pa);
-	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : pa_to_pvh(pa);
+	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : page_to_pvh(m);
 	rw_wlock(lock);
 retry:
 	not_cleared = 0;
@@ -5312,8 +5365,7 @@
 
 	if (!pmap_page_is_write_mapped(m))
 		return;
-	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy :
-	    pa_to_pvh(VM_PAGE_TO_PHYS(m));
+	pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy : page_to_pvh(m);
 	lock = VM_PAGE_TO_PV_LIST_LOCK(m);
 	rw_wlock(lock);
 restart:
Index: head/sys/vm/vm_phys.h
===================================================================
--- head/sys/vm/vm_phys.h
+++ head/sys/vm/vm_phys.h
@@ -72,6 +72,7 @@
 #if VM_NRESERVLEVEL > 0
 	vm_reserv_t	first_reserv;
 #endif
+	void		*md_first;
 	int		domain;
 	struct vm_freelist (*free_queues)[VM_NFREEPOOL][VM_NFREEORDER_MAX];
 };