1// SPDX-License-Identifier: GPL-2.0
2
3/******************************************************************************
4 * Xen memory reservation utilities.
5 *
6 * Copyright (c) 2003, B Dragovic
7 * Copyright (c) 2003-2004, M Williamson, K Fraser
8 * Copyright (c) 2005 Dan M. Smith, IBM Corporation
9 * Copyright (c) 2010 Daniel Kiper
10 * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
11 */
12
13#include <asm/xen/hypercall.h>
14
15#include <xen/interface/memory.h>
16#include <xen/mem-reservation.h>
17#include <linux/moduleparam.h>
18
19bool __read_mostly xen_scrub_pages = IS_ENABLED(CONFIG_XEN_SCRUB_PAGES_DEFAULT);
20core_param(xen_scrub_pages, xen_scrub_pages, bool, 0);
21
22/*
23 * Use one extent per PAGE_SIZE to avoid to break down the page into
24 * multiple frame.
25 */
26#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)
27
28#ifdef CONFIG_XEN_HAVE_PVMMU
29void __xenmem_reservation_va_mapping_update(unsigned long count,
30 struct page **pages,
31 xen_pfn_t *frames)
32{
33 int i;
34
35 for (i = 0; i < count; i++) {
36 struct page *page = pages[i];
37 unsigned long pfn = page_to_pfn(page);
38
39 BUG_ON(!page);
40
41 /*
42 * We don't support PV MMU when Linux and Xen is using
43 * different page granularity.
44 */
45 BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
46
47 set_phys_to_machine(pfn, frames[i]);
48
49 /* Link back into the page tables if not highmem. */
50 if (!PageHighMem(page)) {
51 int ret;
52
53 ret = HYPERVISOR_update_va_mapping(
54 (unsigned long)__va(pfn << PAGE_SHIFT),
55 mfn_pte(frames[i], PAGE_KERNEL),
56 0);
57 BUG_ON(ret);
58 }
59 }
60}
61EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_update);
62
63void __xenmem_reservation_va_mapping_reset(unsigned long count,
64 struct page **pages)
65{
66 int i;
67
68 for (i = 0; i < count; i++) {
69 struct page *page = pages[i];
70 unsigned long pfn = page_to_pfn(page);
71
72 /*
73 * We don't support PV MMU when Linux and Xen are using
74 * different page granularity.
75 */
76 BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
77
78 if (!PageHighMem(page)) {
79 int ret;
80
81 ret = HYPERVISOR_update_va_mapping(
82 (unsigned long)__va(pfn << PAGE_SHIFT),
83 __pte_ma(0), 0);
84 BUG_ON(ret);
85 }
86 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
87 }
88}
89EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_reset);
90#endif /* CONFIG_XEN_HAVE_PVMMU */
91
92/* @frames is an array of PFNs */
93int xenmem_reservation_increase(int count, xen_pfn_t *frames)
94{
95 struct xen_memory_reservation reservation = {
96 .address_bits = 0,
97 .extent_order = EXTENT_ORDER,
98 .domid = DOMID_SELF
99 };
100
101 /* XENMEM_populate_physmap requires a PFN based on Xen granularity. */
102 set_xen_guest_handle(reservation.extent_start, frames);
103 reservation.nr_extents = count;
104 return HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
105}
106EXPORT_SYMBOL_GPL(xenmem_reservation_increase);
107
108/* @frames is an array of GFNs */
109int xenmem_reservation_decrease(int count, xen_pfn_t *frames)
110{
111 struct xen_memory_reservation reservation = {
112 .address_bits = 0,
113 .extent_order = EXTENT_ORDER,
114 .domid = DOMID_SELF
115 };
116
117 /* XENMEM_decrease_reservation requires a GFN */
118 set_xen_guest_handle(reservation.extent_start, frames);
119 reservation.nr_extents = count;
120 return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
121}
122EXPORT_SYMBOL_GPL(xenmem_reservation_decrease);
123