xen/balloon: Share common memory reservation routines

Memory {increase|decrease}_reservation and VA mappings update/reset
code used in balloon driver can be made common, so other drivers can
also re-use the same functionality without open-coding.
Create a dedicated file for the shared code and export corresponding
symbols for other kernel modules.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/include/xen/mem-reservation.h b/include/xen/mem-reservation.h
new file mode 100644
index 000000000000..80b52b4945e9
--- /dev/null
+++ b/include/xen/mem-reservation.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * 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.
+ */
+
+#ifndef _XENMEM_RESERVATION_H
+#define _XENMEM_RESERVATION_H
+
+#include <linux/highmem.h>
+
+#include <xen/page.h>
+
+static inline void xenmem_reservation_scrub_page(struct page *page)
+{
+#ifdef CONFIG_XEN_SCRUB_PAGES
+        clear_highpage(page);
+#endif
+}
+
+#ifdef CONFIG_XEN_HAVE_PVMMU
+void __xenmem_reservation_va_mapping_update(unsigned long count,
+                                            struct page **pages,
+                                            xen_pfn_t *frames);
+
+void __xenmem_reservation_va_mapping_reset(unsigned long count,
+                                           struct page **pages);
+#endif
+
+static inline void xenmem_reservation_va_mapping_update(unsigned long count,
+                                                        struct page **pages,
+                                                        xen_pfn_t *frames)
+{
+#ifdef CONFIG_XEN_HAVE_PVMMU
+        if (!xen_feature(XENFEAT_auto_translated_physmap))
+                __xenmem_reservation_va_mapping_update(count, pages, frames);
+#endif
+}
+
+static inline void xenmem_reservation_va_mapping_reset(unsigned long count,
+                                                       struct page **pages)
+{
+#ifdef CONFIG_XEN_HAVE_PVMMU
+        if (!xen_feature(XENFEAT_auto_translated_physmap))
+                __xenmem_reservation_va_mapping_reset(count, pages);
+#endif
+}
+
+int xenmem_reservation_increase(int count, xen_pfn_t *frames);
+
+int xenmem_reservation_decrease(int count, xen_pfn_t *frames);
+
+#endif