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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 int ret;
39
40 BUG_ON(!page);
41
42 /*
43 * We don't support PV MMU when Linux and Xen is using
44 * different page granularity.
45 */
46 BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
47
48 set_phys_to_machine(pfn, frames[i]);
49
50 ret = HYPERVISOR_update_va_mapping(
51 (unsigned long)__va(pfn << PAGE_SHIFT),
52 mfn_pte(frames[i], PAGE_KERNEL), 0);
53 BUG_ON(ret);
54 }
55}
56EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_update);
57
58void __xenmem_reservation_va_mapping_reset(unsigned long count,
59 struct page **pages)
60{
61 int i;
62
63 for (i = 0; i < count; i++) {
64 struct page *page = pages[i];
65 unsigned long pfn = page_to_pfn(page);
66 int ret;
67
68 /*
69 * We don't support PV MMU when Linux and Xen are using
70 * different page granularity.
71 */
72 BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
73
74 ret = HYPERVISOR_update_va_mapping(
75 (unsigned long)__va(pfn << PAGE_SHIFT),
76 __pte_ma(0), 0);
77 BUG_ON(ret);
78
79 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
80 }
81}
82EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_reset);
83#endif /* CONFIG_XEN_HAVE_PVMMU */
84
85/* @frames is an array of PFNs */
86int xenmem_reservation_increase(int count, xen_pfn_t *frames)
87{
88 struct xen_memory_reservation reservation = {
89 .address_bits = 0,
90 .extent_order = EXTENT_ORDER,
91 .domid = DOMID_SELF
92 };
93
94 /* XENMEM_populate_physmap requires a PFN based on Xen granularity. */
95 set_xen_guest_handle(reservation.extent_start, frames);
96 reservation.nr_extents = count;
97 return HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
98}
99EXPORT_SYMBOL_GPL(xenmem_reservation_increase);
100
101/* @frames is an array of GFNs */
102int xenmem_reservation_decrease(int count, xen_pfn_t *frames)
103{
104 struct xen_memory_reservation reservation = {
105 .address_bits = 0,
106 .extent_order = EXTENT_ORDER,
107 .domid = DOMID_SELF
108 };
109
110 /* XENMEM_decrease_reservation requires a GFN */
111 set_xen_guest_handle(reservation.extent_start, frames);
112 reservation.nr_extents = count;
113 return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
114}
115EXPORT_SYMBOL_GPL(xenmem_reservation_decrease);