Index: head/sys/arm64/arm64/pmap.c
===================================================================
--- head/sys/arm64/arm64/pmap.c
+++ head/sys/arm64/arm64/pmap.c
@@ -221,6 +221,8 @@
 static struct rwlock_padalign pvh_global_lock;
 
 vm_paddr_t dmap_phys_base;	/* The start of the dmap region */
+vm_paddr_t dmap_phys_max;	/* The limit of the dmap region */
+vm_offset_t dmap_max_addr;	/* The virtual address limit of the dmap */
 
 /* This code assumes all L1 DMAP entries will be used */
 CTASSERT((DMAP_MIN_ADDRESS  & ~L0_OFFSET) == DMAP_MIN_ADDRESS);
@@ -550,15 +552,15 @@
 }
 
 static void
-pmap_bootstrap_dmap(vm_offset_t kern_l1, vm_paddr_t kernstart)
+pmap_bootstrap_dmap(vm_offset_t kern_l1, vm_paddr_t min_pa, vm_paddr_t max_pa)
 {
 	vm_offset_t va;
 	vm_paddr_t pa;
 	u_int l1_slot;
 
-	pa = dmap_phys_base = kernstart & ~L1_OFFSET;
+	pa = dmap_phys_base = min_pa & ~L1_OFFSET;
 	va = DMAP_MIN_ADDRESS;
-	for (; va < DMAP_MAX_ADDRESS;
+	for (; va < DMAP_MAX_ADDRESS && pa < max_pa;
 	    pa += L1_SIZE, va += L1_SIZE, l1_slot++) {
 		l1_slot = ((va - DMAP_MIN_ADDRESS) >> L1_SHIFT);
 
@@ -567,6 +569,10 @@
 		    ATTR_IDX(CACHED_MEMORY) | L1_BLOCK);
 	}
 
+	/* Set the upper limit of the DMAP region */
+	dmap_phys_max = pa;
+	dmap_max_addr = va;
+
 	cpu_dcache_wb_range((vm_offset_t)pagetable_dmap,
 	    PAGE_SIZE * DMAP_TABLES);
 	cpu_tlb_flushID();
@@ -651,7 +657,7 @@
 	pt_entry_t *l2;
 	vm_offset_t va, freemempos;
 	vm_offset_t dpcpu, msgbufpv;
-	vm_paddr_t pa, min_pa;
+	vm_paddr_t pa, max_pa, min_pa;
 	int i;
 
 	kern_delta = KERNBASE - kernstart;
@@ -671,7 +677,7 @@
 	rw_init(&pvh_global_lock, "pmap pv global");
 
 	/* Assume the address we were loaded to is a valid physical address */
-	min_pa = KERNBASE - kern_delta;
+	min_pa = max_pa = KERNBASE - kern_delta;
 
 	/*
 	 * Find the minimum physical address. physmap is sorted,
@@ -682,11 +688,12 @@
 			continue;
 		if (physmap[i] <= min_pa)
 			min_pa = physmap[i];
-		break;
+		if (physmap[i + 1] > max_pa)
+			max_pa = physmap[i + 1];
 	}
 
 	/* Create a direct map region early so we can use it for pa -> va */
-	pmap_bootstrap_dmap(l1pt, min_pa);
+	pmap_bootstrap_dmap(l1pt, min_pa, max_pa);
 
 	va = KERNBASE;
 	pa = KERNBASE - kern_delta;
Index: head/sys/arm64/include/vmparam.h
===================================================================
--- head/sys/arm64/include/vmparam.h
+++ head/sys/arm64/include/vmparam.h
@@ -162,19 +162,19 @@
 #define	VM_MIN_KERNEL_ADDRESS	(0xffff000000000000UL)
 #define	VM_MAX_KERNEL_ADDRESS	(0xffff008000000000UL)
 
-/* 2TiB for the direct map region */
+/* 2 TiB maximum for the direct map region */
 #define	DMAP_MIN_ADDRESS	(0xfffffd0000000000UL)
 #define	DMAP_MAX_ADDRESS	(0xffffff0000000000UL)
 
 #define	DMAP_MIN_PHYSADDR	(dmap_phys_base)
-#define	DMAP_MAX_PHYSADDR	(dmap_phys_base + (DMAP_MAX_ADDRESS - DMAP_MIN_ADDRESS))
+#define	DMAP_MAX_PHYSADDR	(dmap_phys_max)
 
 /* True if pa is in the dmap range */
 #define	PHYS_IN_DMAP(pa)	((pa) >= DMAP_MIN_PHYSADDR && \
     (pa) < DMAP_MAX_PHYSADDR)
 /* True if va is in the dmap range */
 #define	VIRT_IN_DMAP(va)	((va) >= DMAP_MIN_ADDRESS && \
-    (va) < DMAP_MAX_ADDRESS)
+    (va) < (dmap_max_addr))
 
 #define	PHYS_TO_DMAP(pa)						\
 ({									\
@@ -237,6 +237,8 @@
 #ifndef LOCORE
 
 extern vm_paddr_t dmap_phys_base;
+extern vm_paddr_t dmap_phys_max;
+extern vm_offset_t dmap_max_addr;
 extern u_int tsb_kernel_ldd_phys;
 extern vm_offset_t vm_max_kernel_address;
 extern vm_offset_t init_pt_va;