diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 43e612bc2bcd..8d9a60ccb777 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -281,9 +281,6 @@ int arch_add_memory(int nid, u64 start, u64 size,
 	unsigned long size_pages = PFN_DOWN(size);
 	int rc;
 
-	if (WARN_ON_ONCE(params->altmap))
-		return -EINVAL;
-
 	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
 		return -EINVAL;
 
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 186a020857cf..eb100479f7be 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -33,8 +33,12 @@ static void __ref *vmem_alloc_pages(unsigned int order)
 	return memblock_alloc(size, size);
 }
 
-static void vmem_free_pages(unsigned long addr, int order)
+static void vmem_free_pages(unsigned long addr, int order, struct vmem_altmap *altmap)
 {
+	if (altmap) {
+		vmem_altmap_free(altmap, 1 << order);
+		return;
+	}
 	/* We don't expect boot memory to be removed ever. */
 	if (!slab_is_available() ||
 	    WARN_ON_ONCE(PageReserved(virt_to_page((void *)addr))))
@@ -156,7 +160,8 @@ static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
 
 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
 static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
-				  unsigned long end, bool add, bool direct)
+				  unsigned long end, bool add, bool direct,
+				  struct vmem_altmap *altmap)
 {
 	unsigned long prot, pages = 0;
 	int ret = -ENOMEM;
@@ -172,11 +177,11 @@ static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
 			if (pte_none(*pte))
 				continue;
 			if (!direct)
-				vmem_free_pages((unsigned long) pfn_to_virt(pte_pfn(*pte)), 0);
+				vmem_free_pages((unsigned long)pfn_to_virt(pte_pfn(*pte)), get_order(PAGE_SIZE), altmap);
 			pte_clear(&init_mm, addr, pte);
 		} else if (pte_none(*pte)) {
 			if (!direct) {
-				void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+				void *new_page = vmemmap_alloc_block_buf(PAGE_SIZE, NUMA_NO_NODE, altmap);
 
 				if (!new_page)
 					goto out;
@@ -213,7 +218,8 @@ static void try_free_pte_table(pmd_t *pmd, unsigned long start)
 
 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
 static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
-				  unsigned long end, bool add, bool direct)
+				  unsigned long end, bool add, bool direct,
+				  struct vmem_altmap *altmap)
 {
 	unsigned long next, prot, pages = 0;
 	int ret = -ENOMEM;
@@ -234,11 +240,11 @@ static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
 				if (IS_ALIGNED(addr, PMD_SIZE) &&
 				    IS_ALIGNED(next, PMD_SIZE)) {
 					if (!direct)
-						vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
+						vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE), altmap);
 					pmd_clear(pmd);
 					pages++;
 				} else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
-					vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
+					vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE), altmap);
 					pmd_clear(pmd);
 				}
 				continue;
@@ -261,7 +267,7 @@ static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
 				 * page tables since vmemmap_populate gets
 				 * called for each section separately.
 				 */
-				new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE);
+				new_page = vmemmap_alloc_block_buf(PMD_SIZE, NUMA_NO_NODE, altmap);
 				if (new_page) {
 					set_pmd(pmd, __pmd(__pa(new_page) | prot));
 					if (!IS_ALIGNED(addr, PMD_SIZE) ||
@@ -280,7 +286,7 @@ static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
 				vmemmap_use_sub_pmd(addr, next);
 			continue;
 		}
-		ret = modify_pte_table(pmd, addr, next, add, direct);
+		ret = modify_pte_table(pmd, addr, next, add, direct, altmap);
 		if (ret)
 			goto out;
 		if (!add)
@@ -302,12 +308,12 @@ static void try_free_pmd_table(pud_t *pud, unsigned long start)
 	for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
 		if (!pmd_none(*pmd))
 			return;
-	vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER);
+	vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER, NULL);
 	pud_clear(pud);
 }
 
 static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
-			    bool add, bool direct)
+			    bool add, bool direct, struct vmem_altmap *altmap)
 {
 	unsigned long next, prot, pages = 0;
 	int ret = -ENOMEM;
@@ -347,7 +353,7 @@ static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
 		} else if (pud_large(*pud)) {
 			continue;
 		}
-		ret = modify_pmd_table(pud, addr, next, add, direct);
+		ret = modify_pmd_table(pud, addr, next, add, direct, altmap);
 		if (ret)
 			goto out;
 		if (!add)
@@ -370,12 +376,12 @@ static void try_free_pud_table(p4d_t *p4d, unsigned long start)
 		if (!pud_none(*pud))
 			return;
 	}
-	vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER);
+	vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER, NULL);
 	p4d_clear(p4d);
 }
 
 static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
-			    bool add, bool direct)
+			    bool add, bool direct, struct vmem_altmap *altmap)
 {
 	unsigned long next;
 	int ret = -ENOMEM;
@@ -394,7 +400,7 @@ static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
 				goto out;
 			p4d_populate(&init_mm, p4d, pud);
 		}
-		ret = modify_pud_table(p4d, addr, next, add, direct);
+		ret = modify_pud_table(p4d, addr, next, add, direct, altmap);
 		if (ret)
 			goto out;
 		if (!add)
@@ -415,12 +421,12 @@ static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
 		if (!p4d_none(*p4d))
 			return;
 	}
-	vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER);
+	vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER, NULL);
 	pgd_clear(pgd);
 }
 
 static int modify_pagetable(unsigned long start, unsigned long end, bool add,
-			    bool direct)
+			    bool direct, struct vmem_altmap *altmap)
 {
 	unsigned long addr, next;
 	int ret = -ENOMEM;
@@ -445,7 +451,7 @@ static int modify_pagetable(unsigned long start, unsigned long end, bool add,
 				goto out;
 			pgd_populate(&init_mm, pgd, p4d);
 		}
-		ret = modify_p4d_table(pgd, addr, next, add, direct);
+		ret = modify_p4d_table(pgd, addr, next, add, direct, altmap);
 		if (ret)
 			goto out;
 		if (!add)
@@ -458,14 +464,16 @@ static int modify_pagetable(unsigned long start, unsigned long end, bool add,
 	return ret;
 }
 
-static int add_pagetable(unsigned long start, unsigned long end, bool direct)
+static int add_pagetable(unsigned long start, unsigned long end, bool direct,
+			 struct vmem_altmap *altmap)
 {
-	return modify_pagetable(start, end, true, direct);
+	return modify_pagetable(start, end, true, direct, altmap);
 }
 
-static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
+static int remove_pagetable(unsigned long start, unsigned long end, bool direct,
+			    struct vmem_altmap *altmap)
 {
-	return modify_pagetable(start, end, false, direct);
+	return modify_pagetable(start, end, false, direct, altmap);
 }
 
 /*
@@ -474,7 +482,7 @@ static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
 static int vmem_add_range(unsigned long start, unsigned long size)
 {
 	start = (unsigned long)__va(start);
-	return add_pagetable(start, start + size, true);
+	return add_pagetable(start, start + size, true, NULL);
 }
 
 /*
@@ -483,7 +491,7 @@ static int vmem_add_range(unsigned long start, unsigned long size)
 static void vmem_remove_range(unsigned long start, unsigned long size)
 {
 	start = (unsigned long)__va(start);
-	remove_pagetable(start, start + size, true);
+	remove_pagetable(start, start + size, true, NULL);
 }
 
 /*
@@ -496,9 +504,9 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 
 	mutex_lock(&vmem_mutex);
 	/* We don't care about the node, just use NUMA_NO_NODE on allocations */
-	ret = add_pagetable(start, end, false);
+	ret = add_pagetable(start, end, false, altmap);
 	if (ret)
-		remove_pagetable(start, end, false);
+		remove_pagetable(start, end, false, altmap);
 	mutex_unlock(&vmem_mutex);
 	return ret;
 }
@@ -509,7 +517,7 @@ void vmemmap_free(unsigned long start, unsigned long end,
 		  struct vmem_altmap *altmap)
 {
 	mutex_lock(&vmem_mutex);
-	remove_pagetable(start, end, false);
+	remove_pagetable(start, end, false, altmap);
 	mutex_unlock(&vmem_mutex);
 }