1 /*
2 * QEMU Host Memory Backend for hugetlbfs
3 *
4 * Copyright (C) 2013-2014 Red Hat Inc
5 *
6 * Authors:
7 * Paolo Bonzini <pbonzini@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 */
12
13 #include "qemu/osdep.h"
14 #include "qapi/error.h"
15 #include "qemu/error-report.h"
16 #include "qemu/module.h"
17 #include "qemu/madvise.h"
18 #include "sysemu/hostmem.h"
19 #include "qom/object_interfaces.h"
20 #include "qom/object.h"
21 #include "qapi/visitor.h"
22 #include "qapi/qapi-visit-common.h"
23
24 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE)
25
26
27 struct HostMemoryBackendFile {
28 HostMemoryBackend parent_obj;
29
30 char *mem_path;
31 uint64_t align;
32 uint64_t offset;
33 bool discard_data;
34 bool is_pmem;
35 bool readonly;
36 OnOffAuto rom;
37 };
38
39 static bool
file_backend_memory_alloc(HostMemoryBackend * backend,Error ** errp)40 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
41 {
42 #ifndef CONFIG_POSIX
43 error_setg(errp, "backend '%s' not supported on this host",
44 object_get_typename(OBJECT(backend)));
45 return false;
46 #else
47 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
48 g_autofree gchar *name = NULL;
49 uint32_t ram_flags;
50
51 if (!backend->size) {
52 error_setg(errp, "can't create backend with size 0");
53 return false;
54 }
55 if (!fb->mem_path) {
56 error_setg(errp, "mem-path property not set");
57 return false;
58 }
59
60 switch (fb->rom) {
61 case ON_OFF_AUTO_AUTO:
62 /* Traditionally, opening the file readonly always resulted in ROM. */
63 fb->rom = fb->readonly ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
64 break;
65 case ON_OFF_AUTO_ON:
66 if (!fb->readonly) {
67 error_setg(errp, "property 'rom' = 'on' is not supported with"
68 " 'readonly' = 'off'");
69 return false;
70 }
71 break;
72 case ON_OFF_AUTO_OFF:
73 if (fb->readonly && backend->share) {
74 error_setg(errp, "property 'rom' = 'off' is incompatible with"
75 " 'readonly' = 'on' and 'share' = 'on'");
76 return false;
77 }
78 break;
79 default:
80 g_assert_not_reached();
81 }
82
83 backend->aligned = true;
84 name = host_memory_backend_get_name(backend);
85 ram_flags = backend->share ? RAM_SHARED : 0;
86 ram_flags |= fb->readonly ? RAM_READONLY_FD : 0;
87 ram_flags |= fb->rom == ON_OFF_AUTO_ON ? RAM_READONLY : 0;
88 ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
89 ram_flags |= backend->guest_memfd ? RAM_GUEST_MEMFD : 0;
90 ram_flags |= fb->is_pmem ? RAM_PMEM : 0;
91 ram_flags |= RAM_NAMED_FILE;
92 return memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
93 backend->size, fb->align, ram_flags,
94 fb->mem_path, fb->offset, errp);
95 #endif
96 }
97
get_mem_path(Object * o,Error ** errp)98 static char *get_mem_path(Object *o, Error **errp)
99 {
100 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
101
102 return g_strdup(fb->mem_path);
103 }
104
set_mem_path(Object * o,const char * str,Error ** errp)105 static void set_mem_path(Object *o, const char *str, Error **errp)
106 {
107 HostMemoryBackend *backend = MEMORY_BACKEND(o);
108 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
109
110 if (host_memory_backend_mr_inited(backend)) {
111 error_setg(errp, "cannot change property 'mem-path' of %s",
112 object_get_typename(o));
113 return;
114 }
115 g_free(fb->mem_path);
116 fb->mem_path = g_strdup(str);
117 }
118
file_memory_backend_get_discard_data(Object * o,Error ** errp)119 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
120 {
121 return MEMORY_BACKEND_FILE(o)->discard_data;
122 }
123
file_memory_backend_set_discard_data(Object * o,bool value,Error ** errp)124 static void file_memory_backend_set_discard_data(Object *o, bool value,
125 Error **errp)
126 {
127 MEMORY_BACKEND_FILE(o)->discard_data = value;
128 }
129
file_memory_backend_get_align(Object * o,Visitor * v,const char * name,void * opaque,Error ** errp)130 static void file_memory_backend_get_align(Object *o, Visitor *v,
131 const char *name, void *opaque,
132 Error **errp)
133 {
134 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
135 uint64_t val = fb->align;
136
137 visit_type_size(v, name, &val, errp);
138 }
139
file_memory_backend_set_align(Object * o,Visitor * v,const char * name,void * opaque,Error ** errp)140 static void file_memory_backend_set_align(Object *o, Visitor *v,
141 const char *name, void *opaque,
142 Error **errp)
143 {
144 HostMemoryBackend *backend = MEMORY_BACKEND(o);
145 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
146 uint64_t val;
147
148 if (host_memory_backend_mr_inited(backend)) {
149 error_setg(errp, "cannot change property '%s' of %s", name,
150 object_get_typename(o));
151 return;
152 }
153
154 if (!visit_type_size(v, name, &val, errp)) {
155 return;
156 }
157 fb->align = val;
158 }
159
file_memory_backend_get_offset(Object * o,Visitor * v,const char * name,void * opaque,Error ** errp)160 static void file_memory_backend_get_offset(Object *o, Visitor *v,
161 const char *name, void *opaque,
162 Error **errp)
163 {
164 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
165 uint64_t val = fb->offset;
166
167 visit_type_size(v, name, &val, errp);
168 }
169
file_memory_backend_set_offset(Object * o,Visitor * v,const char * name,void * opaque,Error ** errp)170 static void file_memory_backend_set_offset(Object *o, Visitor *v,
171 const char *name, void *opaque,
172 Error **errp)
173 {
174 HostMemoryBackend *backend = MEMORY_BACKEND(o);
175 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
176 uint64_t val;
177
178 if (host_memory_backend_mr_inited(backend)) {
179 error_setg(errp, "cannot change property '%s' of %s", name,
180 object_get_typename(o));
181 return;
182 }
183
184 if (!visit_type_size(v, name, &val, errp)) {
185 return;
186 }
187 fb->offset = val;
188 }
189
190 #ifdef CONFIG_LIBPMEM
file_memory_backend_get_pmem(Object * o,Error ** errp)191 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
192 {
193 return MEMORY_BACKEND_FILE(o)->is_pmem;
194 }
195
file_memory_backend_set_pmem(Object * o,bool value,Error ** errp)196 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
197 {
198 HostMemoryBackend *backend = MEMORY_BACKEND(o);
199 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
200
201 if (host_memory_backend_mr_inited(backend)) {
202 error_setg(errp, "cannot change property 'pmem' of %s.",
203 object_get_typename(o));
204 return;
205 }
206
207 fb->is_pmem = value;
208 }
209 #endif /* CONFIG_LIBPMEM */
210
file_memory_backend_get_readonly(Object * obj,Error ** errp)211 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
212 {
213 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
214
215 return fb->readonly;
216 }
217
file_memory_backend_set_readonly(Object * obj,bool value,Error ** errp)218 static void file_memory_backend_set_readonly(Object *obj, bool value,
219 Error **errp)
220 {
221 HostMemoryBackend *backend = MEMORY_BACKEND(obj);
222 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
223
224 if (host_memory_backend_mr_inited(backend)) {
225 error_setg(errp, "cannot change property 'readonly' of %s.",
226 object_get_typename(obj));
227 return;
228 }
229
230 fb->readonly = value;
231 }
232
file_memory_backend_get_rom(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)233 static void file_memory_backend_get_rom(Object *obj, Visitor *v,
234 const char *name, void *opaque,
235 Error **errp)
236 {
237 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
238 OnOffAuto rom = fb->rom;
239
240 visit_type_OnOffAuto(v, name, &rom, errp);
241 }
242
file_memory_backend_set_rom(Object * obj,Visitor * v,const char * name,void * opaque,Error ** errp)243 static void file_memory_backend_set_rom(Object *obj, Visitor *v,
244 const char *name, void *opaque,
245 Error **errp)
246 {
247 HostMemoryBackend *backend = MEMORY_BACKEND(obj);
248 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
249
250 if (host_memory_backend_mr_inited(backend)) {
251 error_setg(errp, "cannot change property '%s' of %s.", name,
252 object_get_typename(obj));
253 return;
254 }
255
256 visit_type_OnOffAuto(v, name, &fb->rom, errp);
257 }
258
file_backend_unparent(Object * obj)259 static void file_backend_unparent(Object *obj)
260 {
261 HostMemoryBackend *backend = MEMORY_BACKEND(obj);
262 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
263
264 if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
265 void *ptr = memory_region_get_ram_ptr(&backend->mr);
266 uint64_t sz = memory_region_size(&backend->mr);
267
268 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
269 }
270 }
271
272 static void
file_backend_class_init(ObjectClass * oc,void * data)273 file_backend_class_init(ObjectClass *oc, void *data)
274 {
275 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
276
277 bc->alloc = file_backend_memory_alloc;
278 oc->unparent = file_backend_unparent;
279
280 object_class_property_add_bool(oc, "discard-data",
281 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
282 object_class_property_add_str(oc, "mem-path",
283 get_mem_path, set_mem_path);
284 object_class_property_add(oc, "align", "int",
285 file_memory_backend_get_align,
286 file_memory_backend_set_align,
287 NULL, NULL);
288 object_class_property_add(oc, "offset", "int",
289 file_memory_backend_get_offset,
290 file_memory_backend_set_offset,
291 NULL, NULL);
292 object_class_property_set_description(oc, "offset",
293 "Offset into the target file (ex: 1G)");
294 #ifdef CONFIG_LIBPMEM
295 object_class_property_add_bool(oc, "pmem",
296 file_memory_backend_get_pmem, file_memory_backend_set_pmem);
297 #endif
298 object_class_property_add_bool(oc, "readonly",
299 file_memory_backend_get_readonly,
300 file_memory_backend_set_readonly);
301 object_class_property_add(oc, "rom", "OnOffAuto",
302 file_memory_backend_get_rom, file_memory_backend_set_rom, NULL, NULL);
303 object_class_property_set_description(oc, "rom",
304 "Whether to create Read Only Memory (ROM)");
305 }
306
file_backend_instance_finalize(Object * o)307 static void file_backend_instance_finalize(Object *o)
308 {
309 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
310
311 g_free(fb->mem_path);
312 }
313
314 static const TypeInfo file_backend_info = {
315 .name = TYPE_MEMORY_BACKEND_FILE,
316 .parent = TYPE_MEMORY_BACKEND,
317 .class_init = file_backend_class_init,
318 .instance_finalize = file_backend_instance_finalize,
319 .instance_size = sizeof(HostMemoryBackendFile),
320 };
321
register_types(void)322 static void register_types(void)
323 {
324 type_register_static(&file_backend_info);
325 }
326
327 type_init(register_types);
328