diff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulated-alloc.c
new file mode 100644
index 0000000..87e6b7d
--- /dev/null
+++ b/drivers/xen/unpopulated-alloc.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/errno.h>
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/memremap.h>
+#include <linux/slab.h>
+
+#include <asm/page.h>
+
+#include <xen/page.h>
+#include <xen/xen.h>
+
+static DEFINE_MUTEX(list_lock);
+static struct page *page_list;
+static unsigned int list_count;
+
+static int fill_list(unsigned int nr_pages)
+{
+	struct dev_pagemap *pgmap;
+	struct resource *res;
+	void *vaddr;
+	unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION);
+	int ret = -ENOMEM;
+
+	res = kzalloc(sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return -ENOMEM;
+
+	res->name = "Xen scratch";
+	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+
+	ret = allocate_resource(&iomem_resource, res,
+				alloc_pages * PAGE_SIZE, 0, -1,
+				PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
+	if (ret < 0) {
+		pr_err("Cannot allocate new IOMEM resource\n");
+		goto err_resource;
+	}
+
+	pgmap = kzalloc(sizeof(*pgmap), GFP_KERNEL);
+	if (!pgmap) {
+		ret = -ENOMEM;
+		goto err_pgmap;
+	}
+
+	pgmap->type = MEMORY_DEVICE_GENERIC;
+	pgmap->range = (struct range) {
+		.start = res->start,
+		.end = res->end,
+	};
+	pgmap->nr_range = 1;
+	pgmap->owner = res;
+
+#ifdef CONFIG_XEN_HAVE_PVMMU
+        /*
+         * memremap will build page tables for the new memory so
+         * the p2m must contain invalid entries so the correct
+         * non-present PTEs will be written.
+         *
+         * If a failure occurs, the original (identity) p2m entries
+         * are not restored since this region is now known not to
+         * conflict with any devices.
+         */
+	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+		xen_pfn_t pfn = PFN_DOWN(res->start);
+
+		for (i = 0; i < alloc_pages; i++) {
+			if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
+				pr_warn("set_phys_to_machine() failed, no memory added\n");
+				ret = -ENOMEM;
+				goto err_memremap;
+			}
+                }
+	}
+#endif
+
+	vaddr = memremap_pages(pgmap, NUMA_NO_NODE);
+	if (IS_ERR(vaddr)) {
+		pr_err("Cannot remap memory range\n");
+		ret = PTR_ERR(vaddr);
+		goto err_memremap;
+	}
+
+	for (i = 0; i < alloc_pages; i++) {
+		struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);
+
+		BUG_ON(!virt_addr_valid(vaddr + PAGE_SIZE * i));
+		pg->zone_device_data = page_list;
+		page_list = pg;
+		list_count++;
+	}
+
+	return 0;
+
+err_memremap:
+	kfree(pgmap);
+err_pgmap:
+	release_resource(res);
+err_resource:
+	kfree(res);
+	return ret;
+}
+
+/**
+ * xen_alloc_unpopulated_pages - alloc unpopulated pages
+ * @nr_pages: Number of pages
+ * @pages: pages returned
+ * @return 0 on success, error otherwise
+ */
+int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
+{
+	unsigned int i;
+	int ret = 0;
+
+	mutex_lock(&list_lock);
+	if (list_count < nr_pages) {
+		ret = fill_list(nr_pages - list_count);
+		if (ret)
+			goto out;
+	}
+
+	for (i = 0; i < nr_pages; i++) {
+		struct page *pg = page_list;
+
+		BUG_ON(!pg);
+		page_list = pg->zone_device_data;
+		list_count--;
+		pages[i] = pg;
+
+#ifdef CONFIG_XEN_HAVE_PVMMU
+		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+			ret = xen_alloc_p2m_entry(page_to_pfn(pg));
+			if (ret < 0) {
+				unsigned int j;
+
+				for (j = 0; j <= i; j++) {
+					pages[j]->zone_device_data = page_list;
+					page_list = pages[j];
+					list_count++;
+				}
+				goto out;
+			}
+		}
+#endif
+	}
+
+out:
+	mutex_unlock(&list_lock);
+	return ret;
+}
+EXPORT_SYMBOL(xen_alloc_unpopulated_pages);
+
+/**
+ * xen_free_unpopulated_pages - return unpopulated pages
+ * @nr_pages: Number of pages
+ * @pages: pages to return
+ */
+void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)
+{
+	unsigned int i;
+
+	mutex_lock(&list_lock);
+	for (i = 0; i < nr_pages; i++) {
+		pages[i]->zone_device_data = page_list;
+		page_list = pages[i];
+		list_count++;
+	}
+	mutex_unlock(&list_lock);
+}
+EXPORT_SYMBOL(xen_free_unpopulated_pages);
+
+#ifdef CONFIG_XEN_PV
+static int __init init(void)
+{
+	unsigned int i;
+
+	if (!xen_domain())
+		return -ENODEV;
+
+	if (!xen_pv_domain())
+		return 0;
+
+	/*
+	 * Initialize with pages from the extra memory regions (see
+	 * arch/x86/xen/setup.c).
+	 */
+	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
+		unsigned int j;
+
+		for (j = 0; j < xen_extra_mem[i].n_pfns; j++) {
+			struct page *pg =
+				pfn_to_page(xen_extra_mem[i].start_pfn + j);
+
+			pg->zone_device_data = page_list;
+			page_list = pg;
+			list_count++;
+		}
+	}
+
+	return 0;
+}
+subsys_initcall(init);
+#endif