diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -497,8 +497,8 @@
 	.kva_min =	KV5ADDR(NPML5EPG / 2, 0, 0, 0, 0),	/* == rec_pt */
 	.dmap_low =	KV5ADDR(DMPML5I, 0, 0, 0, 0),
 	.dmap_high =	KV5ADDR(DMPML5I + NDMPML5E, 0, 0, 0, 0),
-	.lm_low =	KV4ADDR(LMSPML4I, 0, 0, 0),
-	.lm_high =	KV4ADDR(LMEPML4I + 1, 0, 0, 0),
+	.lm_low =	KV5ADDR(LMSPML5I, 0, 0, 0, 0),
+	.lm_high =	KV5ADDR(LMEPML5I + 1, 0, 0, 0, 0),
 	.km_low =	KV4ADDR(KPML4BASE, 0, 0, 0),
 	.km_high =	KV4ADDR(KPML4BASE + NKPML4E - 1, NPDPEPG - 1,
 			    NPDEPG - 1, NPTEPG - 1),
@@ -2475,6 +2475,7 @@
 	struct pmap_preinit_mapping *ppim;
 	vm_page_t m, mpte;
 	pml4_entry_t *pml4e;
+	unsigned long lm_max;
 	int error, i, ret, skz63;
 
 	/* L1TF, reserve page @0 unconditionally */
@@ -2600,10 +2601,15 @@
 
 	lm_ents = 8;
 	TUNABLE_INT_FETCH("vm.pmap.large_map_pml4_entries", &lm_ents);
-	if (lm_ents > LMEPML4I - LMSPML4I + 1)
-		lm_ents = LMEPML4I - LMSPML4I + 1;
+	lm_max = (kva_layout.lm_high - kva_layout.lm_low) / NBPML4;
+	if (lm_ents > lm_max) {
+		printf(
+	    "pmap: shrinking large map from requested %d slots to %ld slots\n",
+		    lm_ents, lm_max);
+		lm_ents = lm_max;
+	}
 #ifdef KMSAN
-	if (lm_ents > KMSANORIGPML4I - LMSPML4I) {
+	if (!la57 && lm_ents > KMSANORIGPML4I - LMSPML4I) {
 		printf(
 	    "pmap: shrinking large map for KMSAN (%d slots to %ld slots)\n",
 		    lm_ents, KMSANORIGPML4I - LMSPML4I);
@@ -2615,12 +2621,20 @@
 		    lm_ents, (u_long)lm_ents * (NBPML4 / 1024 / 1024 / 1024));
 	if (lm_ents != 0) {
 		large_vmem = vmem_create("large", kva_layout.lm_low,
-		    (vmem_size_t)kva_layout.lm_high - kva_layout.lm_low,
-		    PAGE_SIZE, 0, M_WAITOK);
+		    (vmem_size_t)lm_ents * NBPML4, PAGE_SIZE, 0, M_WAITOK);
 		if (large_vmem == NULL) {
 			printf("pmap: cannot create large map\n");
 			lm_ents = 0;
 		}
+		if (la57) {
+			for (i = 0; i < howmany((vm_offset_t)NBPML4 *
+			    lm_ents, NBPML5); i++) {
+				m = pmap_large_map_getptp_unlocked();
+				kernel_pmap->pm_pmltop[LMSPML5I + i] = X86_PG_V |
+				    X86_PG_RW | X86_PG_A | X86_PG_M |
+				    pg_nx | VM_PAGE_TO_PHYS(m);
+			}
+		}
 		for (i = 0; i < lm_ents; i++) {
 			m = pmap_large_map_getptp_unlocked();
 			pml4e = pmap_pml4e(kernel_pmap, kva_layout.lm_low +
@@ -10763,19 +10777,28 @@
 static pdp_entry_t *
 pmap_large_map_pdpe(vm_offset_t va)
 {
+	pml4_entry_t *pm4;
 	vm_pindex_t pml4_idx;
 	vm_paddr_t mphys;
 
-	pml4_idx = pmap_pml4e_index(va);
-	KASSERT(LMSPML4I <= pml4_idx && pml4_idx < LMSPML4I + lm_ents,
-	    ("pmap_large_map_pdpe: va %#jx out of range idx %#jx LMSPML4I "
-	    "%#jx lm_ents %d",
-	    (uintmax_t)va, (uintmax_t)pml4_idx, LMSPML4I, lm_ents));
-	KASSERT((kernel_pml4[pml4_idx] & X86_PG_V) != 0,
-	    ("pmap_large_map_pdpe: invalid pml4 for va %#jx idx %#jx "
-	    "LMSPML4I %#jx lm_ents %d",
-	    (uintmax_t)va, (uintmax_t)pml4_idx, LMSPML4I, lm_ents));
-	mphys = kernel_pml4[pml4_idx] & PG_FRAME;
+	KASSERT(va >= kva_layout.lm_low && va < kva_layout.lm_low +
+	    (vm_offset_t)NBPML4 * lm_ents, ("va %#lx not in large map", va));
+	if (la57) {
+		pm4 = pmap_pml4e(kernel_pmap, va);
+		mphys = *pm4 & PG_FRAME;
+	} else {
+		pml4_idx = pmap_pml4e_index(va);
+
+		KASSERT(LMSPML4I <= pml4_idx && pml4_idx < LMSPML4I + lm_ents,
+		    ("pmap_large_map_pdpe: va %#jx out of range idx %#jx "
+		    "LMSPML4I %#jx lm_ents %d",
+		    (uintmax_t)va, (uintmax_t)pml4_idx, LMSPML4I, lm_ents));
+		KASSERT((kernel_pml4[pml4_idx] & X86_PG_V) != 0,
+		    ("pmap_large_map_pdpe: invalid pml4 for va %#jx idx %#jx "
+		    "LMSPML4I %#jx lm_ents %d",
+		    (uintmax_t)va, (uintmax_t)pml4_idx, LMSPML4I, lm_ents));
+		mphys = kernel_pml4[pml4_idx] & PG_FRAME;
+	}
 	return ((pdp_entry_t *)PHYS_TO_DMAP(mphys) + pmap_pdpe_index(va));
 }
 
@@ -12144,10 +12167,12 @@
 	for (sva = 0, i = pmap_pml4e_index(sva); i < NPML4EPG; i++) {
 		switch (i) {
 		case PML4PML4I:
-			sbuf_printf(sb, "\nRecursive map:\n");
+			if (!la57)
+				sbuf_printf(sb, "\nRecursive map:\n");
 			break;
 		case DMPML4I:
-			sbuf_printf(sb, "\nDirect map:\n");
+			if (!la57)
+				sbuf_printf(sb, "\nDirect map:\n");
 			break;
 #ifdef KASAN
 		case KASANPML4I:
@@ -12166,7 +12191,8 @@
 			sbuf_printf(sb, "\nKernel map:\n");
 			break;
 		case LMSPML4I:
-			sbuf_printf(sb, "\nLarge map:\n");
+			if (!la57)
+				sbuf_printf(sb, "\nLarge map:\n");
 			break;
 		}
 
diff --git a/sys/amd64/include/pmap.h b/sys/amd64/include/pmap.h
--- a/sys/amd64/include/pmap.h
+++ b/sys/amd64/include/pmap.h
@@ -202,9 +202,14 @@
 #define	KMSANSHADPML4I	(KPML4BASE - NKMSANSHADPML4E)
 #define	KMSANORIGPML4I	(DMPML4I - NKMSANORIGPML4E)
 
-/* Large map: index of the first and max last pml4 entry */
+/*
+ * Large map: index of the first and max last pml4/la48 and pml5/la57
+ * entry.
+ */
 #define	LMSPML4I	(PML4PML4I + 1)
 #define	LMEPML4I	(KASANPML4I - 1)
+#define	LMSPML5I	(DMPML5I + NDMPML5E)
+#define	LMEPML5I	(LMSPML5I + 32 - 1)	/* 32 slots for large map */
 
 /*
  * XXX doesn't really belong here I guess...
diff --git a/sys/amd64/include/vmparam.h b/sys/amd64/include/vmparam.h
--- a/sys/amd64/include/vmparam.h
+++ b/sys/amd64/include/vmparam.h
@@ -181,9 +181,9 @@
  * 0x0100000000000000 - 0xf0ffffffffffffff   does not exist (hole)
  * 0xff00000000000000 - 0xff00ffffffffffff   recursive page table (2048TB slot)
  * 0xff01000000000000 - 0xff20ffffffffffff   direct map (32 x 2048TB slots)
- * 0xff21000000000000 - 0xffff807fffffffff   unused
- * 0xffff808000000000 - 0xffff847fffffffff   large map (can be tuned up)
- * 0xffff848000000000 - 0xfffff77fffffffff   unused (large map extends there)
+ * 0xff21000000000000 - 0xff40ffffffffffff   large map
+ * 0xff41000000000000 - 0xffff7fffffffffff   unused
+ * 0xffff800000000000 - 0xfffff5ffffffffff   unused (start of kernel pml4 entry)
  * 0xfffff60000000000 - 0xfffff7ffffffffff   2TB KMSAN origin map, optional
  * 0xfffff78000000000 - 0xfffff7bfffffffff   512GB KASAN shadow map, optional
  * 0xfffff80000000000 - 0xfffffbffffffffff   4TB unused