diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 451e833f5931..3c87b0c3aca6 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -2,6 +2,7 @@
obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o
obj-$(CONFIG_X86) += fallback.o
obj-y += grant-table.o features.o balloon.o manage.o preempt.o time.o
+obj-y += mem-reservation.o
obj-y += events/
obj-y += xenbus/
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 065f0b607373..57b482d67a3a 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -71,6 +71,7 @@
#include <xen/balloon.h>
#include <xen/features.h>
#include <xen/page.h>
+#include <xen/mem_reservation.h>
static int xen_hotplug_unpopulated;
@@ -157,13 +158,6 @@ static DECLARE_DELAYED_WORK(balloon_worker, balloon_process);
#define GFP_BALLOON \
(GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC)
-static void scrub_page(struct page *page)
-{
-#ifdef CONFIG_XEN_SCRUB_PAGES
- clear_highpage(page);
-#endif
-}
-
/* balloon_append: add the given page to the balloon. */
static void __balloon_append(struct page *page)
{
@@ -463,11 +457,6 @@ static enum bp_state increase_reservation(unsigned long
nr_pages)
int rc;
unsigned long i;
struct page *page;
- struct xen_memory_reservation reservation = {
- .address_bits = 0,
- .extent_order = EXTENT_ORDER,
- .domid = DOMID_SELF
- };
if (nr_pages > ARRAY_SIZE(frame_list))
nr_pages = ARRAY_SIZE(frame_list);
@@ -486,9 +475,7 @@ static enum bp_state increase_reservation(unsigned long
nr_pages)
page = balloon_next_page(page);
}
- set_xen_guest_handle(reservation.extent_start, frame_list);
- reservation.nr_extents = nr_pages;
- rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
+ rc = xenmem_reservation_increase(nr_pages, frame_list);
if (rc <= 0)
return BP_EAGAIN;
@@ -496,29 +483,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
page = balloon_retrieve(false);
BUG_ON(page == NULL);
-#ifdef CONFIG_XEN_HAVE_PVMMU
- /*
- * We don't support PV MMU when Linux and Xen is using
- * different page granularity.
- */
- BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
-
- if (!xen_feature(XENFEAT_auto_translated_physmap)) {
- unsigned long pfn = page_to_pfn(page);
-
- set_phys_to_machine(pfn, frame_list[i]);
-
- /* Link back into the page tables if not highmem. */
- if (!PageHighMem(page)) {
- int ret;
- ret = HYPERVISOR_update_va_mapping(
- (unsigned long)__va(pfn <<
PAGE_SHIFT),
- mfn_pte(frame_list[i],
PAGE_KERNEL),
- 0);
- BUG_ON(ret);
- }
- }
-#endif
+ xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]);
/* Relinquish the page back to the allocator. */
free_reserved_page(page);
@@ -535,11 +500,6 @@ static enum bp_state decrease_reservation(unsigned long
nr_pages, gfp_t gfp)
unsigned long i;
struct page *page, *tmp;
int ret;
- struct xen_memory_reservation reservation = {
- .address_bits = 0,
- .extent_order = EXTENT_ORDER,
- .domid = DOMID_SELF
- };
LIST_HEAD(pages);
if (nr_pages > ARRAY_SIZE(frame_list))
@@ -553,7 +513,7 @@ static enum bp_state decrease_reservation(unsigned long
nr_pages, gfp_t gfp)
break;
}
adjust_managed_page_count(page, -1);
- scrub_page(page);
+ xenmem_reservation_scrub_page(page);
list_add(&page->lru, &pages);
}
@@ -575,25 +535,8 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
/* XENMEM_decrease_reservation requires a GFN */
frame_list[i++] = xen_page_to_gfn(page);
-#ifdef CONFIG_XEN_HAVE_PVMMU
- /*
- * We don't support PV MMU when Linux and Xen is using
- * different page granularity.
- */
- BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
-
- if (!xen_feature(XENFEAT_auto_translated_physmap)) {
- unsigned long pfn = page_to_pfn(page);
+ xenmem_reservation_va_mapping_reset(1, &page);
- if (!PageHighMem(page)) {
- ret = HYPERVISOR_update_va_mapping(
- (unsigned long)__va(pfn <<
PAGE_SHIFT),
- __pte_ma(0), 0);
- BUG_ON(ret);
- }
- __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
- }
-#endif
list_del(&page->lru);
balloon_append(page);
@@ -601,9 +544,7 @@ static enum bp_state decrease_reservation(unsigned long
nr_pages, gfp_t gfp)
flush_tlb_all();
- set_xen_guest_handle(reservation.extent_start, frame_list);
- reservation.nr_extents = nr_pages;
- ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
+ ret = xenmem_reservation_decrease(nr_pages, frame_list);
BUG_ON(ret != nr_pages);
balloon_stats.current_pages -= nr_pages;
diff --git a/drivers/xen/mem-reservation.c b/drivers/xen/mem-reservation.c
new file mode 100644
index 000000000000..29882e4324f5
--- /dev/null
+++ b/drivers/xen/mem-reservation.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+/******************************************************************************
+ * Xen memory reservation utilities.
+ *
+ * Copyright (c) 2003, B Dragovic
+ * Copyright (c) 2003-2004, M Williamson, K Fraser
+ * Copyright (c) 2005 Dan M. Smith, IBM Corporation
+ * Copyright (c) 2010 Daniel Kiper
+ * Copyright (c) 2018, Oleksandr Andrushchenko, EPAM Systems Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#include <asm/tlb.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/interface/memory.h>
+#include <xen/page.h>
+
+/*
+ * Use one extent per PAGE_SIZE to avoid to break down the page into
+ * multiple frame.
+ */
+#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)
+
+void xenmem_reservation_scrub_page(struct page *page)
+{
+#ifdef CONFIG_XEN_SCRUB_PAGES
+ clear_highpage(page);
+#endif
+}
+EXPORT_SYMBOL(xenmem_reservation_scrub_page);
