1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/errno.h>
3 #include <linux/gfp.h>
4 #include <linux/kernel.h>
5 #include <linux/mm.h>
6 #include <linux/memremap.h>
7 #include <linux/slab.h>
8
9 #include <asm/page.h>
10
11 #include <xen/page.h>
12 #include <xen/xen.h>
13
14 static DEFINE_MUTEX(list_lock);
15 static struct page *page_list;
16 static unsigned int list_count;
17
fill_list(unsigned int nr_pages)18 static int fill_list(unsigned int nr_pages)
19 {
20 struct dev_pagemap *pgmap;
21 struct resource *res;
22 void *vaddr;
23 unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION);
24 int ret = -ENOMEM;
25
26 res = kzalloc(sizeof(*res), GFP_KERNEL);
27 if (!res)
28 return -ENOMEM;
29
30 res->name = "Xen scratch";
31 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
32
33 ret = allocate_resource(&iomem_resource, res,
34 alloc_pages * PAGE_SIZE, 0, -1,
35 PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
36 if (ret < 0) {
37 pr_err("Cannot allocate new IOMEM resource\n");
38 goto err_resource;
39 }
40
41 pgmap = kzalloc(sizeof(*pgmap), GFP_KERNEL);
42 if (!pgmap) {
43 ret = -ENOMEM;
44 goto err_pgmap;
45 }
46
47 pgmap->type = MEMORY_DEVICE_GENERIC;
48 pgmap->range = (struct range) {
49 .start = res->start,
50 .end = res->end,
51 };
52 pgmap->nr_range = 1;
53 pgmap->owner = res;
54
55 #ifdef CONFIG_XEN_HAVE_PVMMU
56 /*
57 * memremap will build page tables for the new memory so
58 * the p2m must contain invalid entries so the correct
59 * non-present PTEs will be written.
60 *
61 * If a failure occurs, the original (identity) p2m entries
62 * are not restored since this region is now known not to
63 * conflict with any devices.
64 */
65 if (!xen_feature(XENFEAT_auto_translated_physmap)) {
66 xen_pfn_t pfn = PFN_DOWN(res->start);
67
68 for (i = 0; i < alloc_pages; i++) {
69 if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
70 pr_warn("set_phys_to_machine() failed, no memory added\n");
71 ret = -ENOMEM;
72 goto err_memremap;
73 }
74 }
75 }
76 #endif
77
78 vaddr = memremap_pages(pgmap, NUMA_NO_NODE);
79 if (IS_ERR(vaddr)) {
80 pr_err("Cannot remap memory range\n");
81 ret = PTR_ERR(vaddr);
82 goto err_memremap;
83 }
84
85 for (i = 0; i < alloc_pages; i++) {
86 struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);
87
88 BUG_ON(!virt_addr_valid(vaddr + PAGE_SIZE * i));
89 pg->zone_device_data = page_list;
90 page_list = pg;
91 list_count++;
92 }
93
94 return 0;
95
96 err_memremap:
97 kfree(pgmap);
98 err_pgmap:
99 release_resource(res);
100 err_resource:
101 kfree(res);
102 return ret;
103 }
104
105 /**
106 * xen_alloc_unpopulated_pages - alloc unpopulated pages
107 * @nr_pages: Number of pages
108 * @pages: pages returned
109 * @return 0 on success, error otherwise
110 */
xen_alloc_unpopulated_pages(unsigned int nr_pages,struct page ** pages)111 int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
112 {
113 unsigned int i;
114 int ret = 0;
115
116 mutex_lock(&list_lock);
117 if (list_count < nr_pages) {
118 ret = fill_list(nr_pages - list_count);
119 if (ret)
120 goto out;
121 }
122
123 for (i = 0; i < nr_pages; i++) {
124 struct page *pg = page_list;
125
126 BUG_ON(!pg);
127 page_list = pg->zone_device_data;
128 list_count--;
129 pages[i] = pg;
130
131 #ifdef CONFIG_XEN_HAVE_PVMMU
132 if (!xen_feature(XENFEAT_auto_translated_physmap)) {
133 ret = xen_alloc_p2m_entry(page_to_pfn(pg));
134 if (ret < 0) {
135 unsigned int j;
136
137 for (j = 0; j <= i; j++) {
138 pages[j]->zone_device_data = page_list;
139 page_list = pages[j];
140 list_count++;
141 }
142 goto out;
143 }
144 }
145 #endif
146 }
147
148 out:
149 mutex_unlock(&list_lock);
150 return ret;
151 }
152 EXPORT_SYMBOL(xen_alloc_unpopulated_pages);
153
154 /**
155 * xen_free_unpopulated_pages - return unpopulated pages
156 * @nr_pages: Number of pages
157 * @pages: pages to return
158 */
xen_free_unpopulated_pages(unsigned int nr_pages,struct page ** pages)159 void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)
160 {
161 unsigned int i;
162
163 mutex_lock(&list_lock);
164 for (i = 0; i < nr_pages; i++) {
165 pages[i]->zone_device_data = page_list;
166 page_list = pages[i];
167 list_count++;
168 }
169 mutex_unlock(&list_lock);
170 }
171 EXPORT_SYMBOL(xen_free_unpopulated_pages);
172
173 #ifdef CONFIG_XEN_PV
init(void)174 static int __init init(void)
175 {
176 unsigned int i;
177
178 if (!xen_domain())
179 return -ENODEV;
180
181 if (!xen_pv_domain())
182 return 0;
183
184 /*
185 * Initialize with pages from the extra memory regions (see
186 * arch/x86/xen/setup.c).
187 */
188 for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
189 unsigned int j;
190
191 for (j = 0; j < xen_extra_mem[i].n_pfns; j++) {
192 struct page *pg =
193 pfn_to_page(xen_extra_mem[i].start_pfn + j);
194
195 pg->zone_device_data = page_list;
196 page_list = pg;
197 list_count++;
198 }
199 }
200
201 return 0;
202 }
203 subsys_initcall(init);
204 #endif
205
