diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 95d360805f8a..0ff2ec634a58 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1340,6 +1340,11 @@ void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
 	__remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size);
 }
 
+bool mhp_supports_memmap_on_memory(unsigned long size)
+{
+	return __mhp_supports_memmap_on_memory(size);
+}
+
 /*
  * This memory hotplug notifier helps prevent boot memory from being
  * inadvertently removed as it blocks pfn range offlining process in
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a190aae8ceaf..b318d26a70d4 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1264,6 +1264,12 @@ void __ref arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
 	__remove_pages(start_pfn, nr_pages, altmap);
 	kernel_physical_mapping_remove(start, start + size);
 }
+
+bool mhp_supports_memmap_on_memory(unsigned long size)
+{
+	return __mhp_supports_memmap_on_memory(size);
+}
+
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 static struct kcore_list kcore_vsyscall;
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 013c69753c91..a769f44b8368 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -354,7 +354,8 @@ extern struct zone *zone_for_pfn_range(int online_type, int nid,
 extern int arch_create_linear_mapping(int nid, u64 start, u64 size,
 				      struct mhp_params *params);
 void arch_remove_linear_mapping(u64 start, u64 size);
-extern bool mhp_supports_memmap_on_memory(unsigned long size);
+bool mhp_supports_memmap_on_memory(unsigned long size);
+bool __mhp_supports_memmap_on_memory(unsigned long size);
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 #endif /* __LINUX_MEMORY_HOTPLUG_H */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index c4bac38cc147..423f96dd5481 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1247,7 +1247,8 @@ static int online_memory_block(struct memory_block *mem, void *arg)
 	return device_online(&mem->dev);
 }
 
-bool mhp_supports_memmap_on_memory(unsigned long size)
+/* Helper function for architecture to use. */
+bool __mhp_supports_memmap_on_memory(unsigned long size)
 {
 	unsigned long nr_vmemmap_pages = size / PAGE_SIZE;
 	unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page);
@@ -1285,6 +1286,20 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
 	       IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT));
 }
 
+bool __weak mhp_supports_memmap_on_memory(unsigned long size)
+{
+	return false;
+}
+
+/*
+ * Architectures may want to override the altmap reserve details based
+ * on the alignment requirement for vmemmap mapping.
+ */
+unsigned __weak long memory_block_align_base(struct resource *res)
+{
+	return 0;
+}
+
 /*
  * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
  * and online/offline operations (triggered e.g. by sysfs).
@@ -1295,7 +1310,11 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
 {
 	struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
 	enum memblock_flags memblock_flags = MEMBLOCK_NONE;
-	struct vmem_altmap mhp_altmap = {};
+	struct vmem_altmap mhp_altmap = {
+		.base_pfn =  PHYS_PFN(res->start),
+		.end_pfn  =  PHYS_PFN(res->end),
+		.reserve  = memory_block_align_base(res),
+	};
 	struct memory_group *group = NULL;
 	u64 start, size;
 	bool new_node = false;
@@ -1339,13 +1358,11 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
 	 * Self hosted memmap array
 	 */
 	if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
-		if (!mhp_supports_memmap_on_memory(size)) {
-			ret = -EINVAL;
-			goto error;
+		if (mhp_supports_memmap_on_memory(size)) {
+			mhp_altmap.free	= PHYS_PFN(size) - mhp_altmap.reserve;
+			params.altmap = &mhp_altmap;
 		}
-		mhp_altmap.free = PHYS_PFN(size);
-		mhp_altmap.base_pfn = PHYS_PFN(start);
-		params.altmap = &mhp_altmap;
+		/* if not supported don't use altmap */
 	}
 
 	/* call arch's memory hotadd */
@@ -1354,8 +1371,7 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
 		goto error;
 
 	/* create memory block devices after memory was added */
-	ret = create_memory_block_devices(start, size, &mhp_altmap,
-					  group);
+	ret = create_memory_block_devices(start, size, &mhp_altmap, group);
 	if (ret) {
 		arch_remove_memory(start, size, NULL);
 		goto error;
