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/balloon.h> |
12 | #include <xen/page.h> |
13 | #include <xen/xen.h> |
14 | |
15 | static DEFINE_MUTEX(list_lock); |
16 | static struct page *page_list; |
17 | static unsigned int list_count; |
18 | |
19 | static struct resource *target_resource; |
20 | |
21 | /* |
22 | * If arch is not happy with system "iomem_resource" being used for |
23 | * the region allocation it can provide it's own view by creating specific |
24 | * Xen resource with unused regions of guest physical address space provided |
25 | * by the hypervisor. |
26 | */ |
27 | int __weak __init arch_xen_unpopulated_init(struct resource **res) |
28 | { |
29 | *res = &iomem_resource; |
30 | |
31 | return 0; |
32 | } |
33 | |
34 | static int fill_list(unsigned int nr_pages) |
35 | { |
36 | struct dev_pagemap *pgmap; |
37 | struct resource *res, *tmp_res = NULL; |
38 | void *vaddr; |
39 | unsigned int i, alloc_pages = round_up(nr_pages, PAGES_PER_SECTION); |
40 | struct range mhp_range; |
41 | int ret; |
42 | |
43 | res = kzalloc(size: sizeof(*res), GFP_KERNEL); |
44 | if (!res) |
45 | return -ENOMEM; |
46 | |
47 | res->name = "Xen scratch" ; |
48 | res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; |
49 | |
50 | mhp_range = mhp_get_pluggable_range(need_mapping: true); |
51 | |
52 | ret = allocate_resource(root: target_resource, new: res, |
53 | size: alloc_pages * PAGE_SIZE, min: mhp_range.start, max: mhp_range.end, |
54 | PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); |
55 | if (ret < 0) { |
56 | pr_err("Cannot allocate new IOMEM resource\n" ); |
57 | goto err_resource; |
58 | } |
59 | |
60 | /* |
61 | * Reserve the region previously allocated from Xen resource to avoid |
62 | * re-using it by someone else. |
63 | */ |
64 | if (target_resource != &iomem_resource) { |
65 | tmp_res = kzalloc(size: sizeof(*tmp_res), GFP_KERNEL); |
66 | if (!tmp_res) { |
67 | ret = -ENOMEM; |
68 | goto err_insert; |
69 | } |
70 | |
71 | tmp_res->name = res->name; |
72 | tmp_res->start = res->start; |
73 | tmp_res->end = res->end; |
74 | tmp_res->flags = res->flags; |
75 | |
76 | ret = request_resource(root: &iomem_resource, new: tmp_res); |
77 | if (ret < 0) { |
78 | pr_err("Cannot request resource %pR (%d)\n" , tmp_res, ret); |
79 | kfree(objp: tmp_res); |
80 | goto err_insert; |
81 | } |
82 | } |
83 | |
84 | pgmap = kzalloc(size: sizeof(*pgmap), GFP_KERNEL); |
85 | if (!pgmap) { |
86 | ret = -ENOMEM; |
87 | goto err_pgmap; |
88 | } |
89 | |
90 | pgmap->type = MEMORY_DEVICE_GENERIC; |
91 | pgmap->range = (struct range) { |
92 | .start = res->start, |
93 | .end = res->end, |
94 | }; |
95 | pgmap->nr_range = 1; |
96 | pgmap->owner = res; |
97 | |
98 | #ifdef CONFIG_XEN_HAVE_PVMMU |
99 | /* |
100 | * memremap will build page tables for the new memory so |
101 | * the p2m must contain invalid entries so the correct |
102 | * non-present PTEs will be written. |
103 | * |
104 | * If a failure occurs, the original (identity) p2m entries |
105 | * are not restored since this region is now known not to |
106 | * conflict with any devices. |
107 | */ |
108 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
109 | xen_pfn_t pfn = PFN_DOWN(res->start); |
110 | |
111 | for (i = 0; i < alloc_pages; i++) { |
112 | if (!set_phys_to_machine(pfn: pfn + i, INVALID_P2M_ENTRY)) { |
113 | pr_warn("set_phys_to_machine() failed, no memory added\n" ); |
114 | ret = -ENOMEM; |
115 | goto err_memremap; |
116 | } |
117 | } |
118 | } |
119 | #endif |
120 | |
121 | vaddr = memremap_pages(pgmap, NUMA_NO_NODE); |
122 | if (IS_ERR(ptr: vaddr)) { |
123 | pr_err("Cannot remap memory range\n" ); |
124 | ret = PTR_ERR(ptr: vaddr); |
125 | goto err_memremap; |
126 | } |
127 | |
128 | for (i = 0; i < alloc_pages; i++) { |
129 | struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i); |
130 | |
131 | pg->zone_device_data = page_list; |
132 | page_list = pg; |
133 | list_count++; |
134 | } |
135 | |
136 | return 0; |
137 | |
138 | err_memremap: |
139 | kfree(objp: pgmap); |
140 | err_pgmap: |
141 | if (tmp_res) { |
142 | release_resource(new: tmp_res); |
143 | kfree(objp: tmp_res); |
144 | } |
145 | err_insert: |
146 | release_resource(new: res); |
147 | err_resource: |
148 | kfree(objp: res); |
149 | return ret; |
150 | } |
151 | |
152 | /** |
153 | * xen_alloc_unpopulated_pages - alloc unpopulated pages |
154 | * @nr_pages: Number of pages |
155 | * @pages: pages returned |
156 | * @return 0 on success, error otherwise |
157 | */ |
158 | int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) |
159 | { |
160 | unsigned int i; |
161 | int ret = 0; |
162 | |
163 | /* |
164 | * Fallback to default behavior if we do not have any suitable resource |
165 | * to allocate required region from and as the result we won't be able to |
166 | * construct pages. |
167 | */ |
168 | if (!target_resource) |
169 | return xen_alloc_ballooned_pages(nr_pages, pages); |
170 | |
171 | mutex_lock(&list_lock); |
172 | if (list_count < nr_pages) { |
173 | ret = fill_list(nr_pages: nr_pages - list_count); |
174 | if (ret) |
175 | goto out; |
176 | } |
177 | |
178 | for (i = 0; i < nr_pages; i++) { |
179 | struct page *pg = page_list; |
180 | |
181 | BUG_ON(!pg); |
182 | page_list = pg->zone_device_data; |
183 | list_count--; |
184 | pages[i] = pg; |
185 | |
186 | #ifdef CONFIG_XEN_HAVE_PVMMU |
187 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
188 | ret = xen_alloc_p2m_entry(page_to_pfn(pg)); |
189 | if (ret < 0) { |
190 | unsigned int j; |
191 | |
192 | for (j = 0; j <= i; j++) { |
193 | pages[j]->zone_device_data = page_list; |
194 | page_list = pages[j]; |
195 | list_count++; |
196 | } |
197 | goto out; |
198 | } |
199 | } |
200 | #endif |
201 | } |
202 | |
203 | out: |
204 | mutex_unlock(lock: &list_lock); |
205 | return ret; |
206 | } |
207 | EXPORT_SYMBOL(xen_alloc_unpopulated_pages); |
208 | |
209 | /** |
210 | * xen_free_unpopulated_pages - return unpopulated pages |
211 | * @nr_pages: Number of pages |
212 | * @pages: pages to return |
213 | */ |
214 | void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) |
215 | { |
216 | unsigned int i; |
217 | |
218 | if (!target_resource) { |
219 | xen_free_ballooned_pages(nr_pages, pages); |
220 | return; |
221 | } |
222 | |
223 | mutex_lock(&list_lock); |
224 | for (i = 0; i < nr_pages; i++) { |
225 | pages[i]->zone_device_data = page_list; |
226 | page_list = pages[i]; |
227 | list_count++; |
228 | } |
229 | mutex_unlock(lock: &list_lock); |
230 | } |
231 | EXPORT_SYMBOL(xen_free_unpopulated_pages); |
232 | |
233 | static int __init unpopulated_init(void) |
234 | { |
235 | int ret; |
236 | |
237 | if (!xen_domain()) |
238 | return -ENODEV; |
239 | |
240 | ret = arch_xen_unpopulated_init(res: &target_resource); |
241 | if (ret) { |
242 | pr_err("xen:unpopulated: Cannot initialize target resource\n" ); |
243 | target_resource = NULL; |
244 | } |
245 | |
246 | return ret; |
247 | } |
248 | early_initcall(unpopulated_init); |
249 | |