xref: /qemu/backends/hostmem.c (revision 19e8ff48) 
1 /*
2  * QEMU Host Memory Backend
3  *
4  * Copyright (C) 2013-2014 Red Hat Inc
5  *
6  * Authors:
7  *   Igor Mammedov <imammedo@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 "sysemu/hostmem.h"
15 #include "hw/boards.h"
16 #include "qapi/error.h"
17 #include "qapi/qapi-builtin-visit.h"
18 #include "qapi/visitor.h"
19 #include "qemu/config-file.h"
20 #include "qom/object_interfaces.h"
21 #include "qemu/mmap-alloc.h"
22 
23 #ifdef CONFIG_NUMA
24 #include <numaif.h>
25 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
26 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
27 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
28 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
29 #endif
30 
31 char *
32 host_memory_backend_get_name(HostMemoryBackend *backend)
33 {
34     if (!backend->use_canonical_path) {
35         return object_get_canonical_path_component(OBJECT(backend));
36     }
37 
38     return object_get_canonical_path(OBJECT(backend));
39 }
40 
41 static void
42 host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
43                              void *opaque, Error **errp)
44 {
45     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
46     uint64_t value = backend->size;
47 
48     visit_type_size(v, name, &value, errp);
49 }
50 
51 static void
52 host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
53                              void *opaque, Error **errp)
54 {
55     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
56     Error *local_err = NULL;
57     uint64_t value;
58 
59     if (host_memory_backend_mr_inited(backend)) {
60         error_setg(&local_err, "cannot change property %s of %s ",
61                    name, object_get_typename(obj));
62         goto out;
63     }
64 
65     visit_type_size(v, name, &value, &local_err);
66     if (local_err) {
67         goto out;
68     }
69     if (!value) {
70         error_setg(&local_err,
71                    "property '%s' of %s doesn't take value '%" PRIu64 "'",
72                    name, object_get_typename(obj), value);
73         goto out;
74     }
75     backend->size = value;
76 out:
77     error_propagate(errp, local_err);
78 }
79 
80 static void
81 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
82                                    void *opaque, Error **errp)
83 {
84     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
85     uint16List *host_nodes = NULL;
86     uint16List **node = &host_nodes;
87     unsigned long value;
88 
89     value = find_first_bit(backend->host_nodes, MAX_NODES);
90     if (value == MAX_NODES) {
91         goto ret;
92     }
93 
94     *node = g_malloc0(sizeof(**node));
95     (*node)->value = value;
96     node = &(*node)->next;
97 
98     do {
99         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
100         if (value == MAX_NODES) {
101             break;
102         }
103 
104         *node = g_malloc0(sizeof(**node));
105         (*node)->value = value;
106         node = &(*node)->next;
107     } while (true);
108 
109 ret:
110     visit_type_uint16List(v, name, &host_nodes, errp);
111 }
112 
113 static void
114 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
115                                    void *opaque, Error **errp)
116 {
117 #ifdef CONFIG_NUMA
118     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
119     uint16List *l, *host_nodes = NULL;
120 
121     visit_type_uint16List(v, name, &host_nodes, errp);
122 
123     for (l = host_nodes; l; l = l->next) {
124         if (l->value >= MAX_NODES) {
125             error_setg(errp, "Invalid host-nodes value: %d", l->value);
126             goto out;
127         }
128     }
129 
130     for (l = host_nodes; l; l = l->next) {
131         bitmap_set(backend->host_nodes, l->value, 1);
132     }
133 
134 out:
135     qapi_free_uint16List(host_nodes);
136 #else
137     error_setg(errp, "NUMA node binding are not supported by this QEMU");
138 #endif
139 }
140 
141 static int
142 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
143 {
144     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
145     return backend->policy;
146 }
147 
148 static void
149 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
150 {
151     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
152     backend->policy = policy;
153 
154 #ifndef CONFIG_NUMA
155     if (policy != HOST_MEM_POLICY_DEFAULT) {
156         error_setg(errp, "NUMA policies are not supported by this QEMU");
157     }
158 #endif
159 }
160 
161 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
162 {
163     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
164 
165     return backend->merge;
166 }
167 
168 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
169 {
170     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
171 
172     if (!host_memory_backend_mr_inited(backend)) {
173         backend->merge = value;
174         return;
175     }
176 
177     if (value != backend->merge) {
178         void *ptr = memory_region_get_ram_ptr(&backend->mr);
179         uint64_t sz = memory_region_size(&backend->mr);
180 
181         qemu_madvise(ptr, sz,
182                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
183         backend->merge = value;
184     }
185 }
186 
187 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
188 {
189     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
190 
191     return backend->dump;
192 }
193 
194 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
195 {
196     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
197 
198     if (!host_memory_backend_mr_inited(backend)) {
199         backend->dump = value;
200         return;
201     }
202 
203     if (value != backend->dump) {
204         void *ptr = memory_region_get_ram_ptr(&backend->mr);
205         uint64_t sz = memory_region_size(&backend->mr);
206 
207         qemu_madvise(ptr, sz,
208                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
209         backend->dump = value;
210     }
211 }
212 
213 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
214 {
215     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
216 
217     return backend->prealloc || backend->force_prealloc;
218 }
219 
220 static void host_memory_backend_set_prealloc(Object *obj, bool value,
221                                              Error **errp)
222 {
223     Error *local_err = NULL;
224     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
225 
226     if (backend->force_prealloc) {
227         if (value) {
228             error_setg(errp,
229                        "remove -mem-prealloc to use the prealloc property");
230             return;
231         }
232     }
233 
234     if (!host_memory_backend_mr_inited(backend)) {
235         backend->prealloc = value;
236         return;
237     }
238 
239     if (value && !backend->prealloc) {
240         int fd = memory_region_get_fd(&backend->mr);
241         void *ptr = memory_region_get_ram_ptr(&backend->mr);
242         uint64_t sz = memory_region_size(&backend->mr);
243 
244         os_mem_prealloc(fd, ptr, sz, smp_cpus, &local_err);
245         if (local_err) {
246             error_propagate(errp, local_err);
247             return;
248         }
249         backend->prealloc = true;
250     }
251 }
252 
253 static void host_memory_backend_init(Object *obj)
254 {
255     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
256     MachineState *machine = MACHINE(qdev_get_machine());
257 
258     backend->merge = machine_mem_merge(machine);
259     backend->dump = machine_dump_guest_core(machine);
260     backend->prealloc = mem_prealloc;
261 }
262 
263 static void host_memory_backend_post_init(Object *obj)
264 {
265     object_apply_compat_props(obj);
266 }
267 
268 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
269 {
270     /*
271      * NOTE: We forbid zero-length memory backend, so here zero means
272      * "we haven't inited the backend memory region yet".
273      */
274     return memory_region_size(&backend->mr) != 0;
275 }
276 
277 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
278 {
279     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
280 }
281 
282 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
283 {
284     backend->is_mapped = mapped;
285 }
286 
287 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
288 {
289     return backend->is_mapped;
290 }
291 
292 #ifdef __linux__
293 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
294 {
295     Object *obj = OBJECT(memdev);
296     char *path = object_property_get_str(obj, "mem-path", NULL);
297     size_t pagesize = qemu_mempath_getpagesize(path);
298 
299     g_free(path);
300     return pagesize;
301 }
302 #else
303 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
304 {
305     return getpagesize();
306 }
307 #endif
308 
309 static void
310 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
311 {
312     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
313     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
314     Error *local_err = NULL;
315     void *ptr;
316     uint64_t sz;
317 
318     if (bc->alloc) {
319         bc->alloc(backend, &local_err);
320         if (local_err) {
321             goto out;
322         }
323 
324         ptr = memory_region_get_ram_ptr(&backend->mr);
325         sz = memory_region_size(&backend->mr);
326 
327         if (backend->merge) {
328             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
329         }
330         if (!backend->dump) {
331             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
332         }
333 #ifdef CONFIG_NUMA
334         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
335         /* lastbit == MAX_NODES means maxnode = 0 */
336         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
337         /* ensure policy won't be ignored in case memory is preallocated
338          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
339          * this doesn't catch hugepage case. */
340         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
341 
342         /* check for invalid host-nodes and policies and give more verbose
343          * error messages than mbind(). */
344         if (maxnode && backend->policy == MPOL_DEFAULT) {
345             error_setg(errp, "host-nodes must be empty for policy default,"
346                        " or you should explicitly specify a policy other"
347                        " than default");
348             return;
349         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
350             error_setg(errp, "host-nodes must be set for policy %s",
351                        HostMemPolicy_str(backend->policy));
352             return;
353         }
354 
355         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
356          * as argument to mbind() due to an old Linux bug (feature?) which
357          * cuts off the last specified node. This means backend->host_nodes
358          * must have MAX_NODES+1 bits available.
359          */
360         assert(sizeof(backend->host_nodes) >=
361                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
362         assert(maxnode <= MAX_NODES);
363         if (mbind(ptr, sz, backend->policy,
364                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
365             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
366                 error_setg_errno(errp, errno,
367                                  "cannot bind memory to host NUMA nodes");
368                 return;
369             }
370         }
371 #endif
372         /* Preallocate memory after the NUMA policy has been instantiated.
373          * This is necessary to guarantee memory is allocated with
374          * specified NUMA policy in place.
375          */
376         if (backend->prealloc) {
377             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
378                             smp_cpus, &local_err);
379             if (local_err) {
380                 goto out;
381             }
382         }
383     }
384 out:
385     error_propagate(errp, local_err);
386 }
387 
388 static bool
389 host_memory_backend_can_be_deleted(UserCreatable *uc)
390 {
391     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
392         return false;
393     } else {
394         return true;
395     }
396 }
397 
398 static bool host_memory_backend_get_share(Object *o, Error **errp)
399 {
400     HostMemoryBackend *backend = MEMORY_BACKEND(o);
401 
402     return backend->share;
403 }
404 
405 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
406 {
407     HostMemoryBackend *backend = MEMORY_BACKEND(o);
408 
409     if (host_memory_backend_mr_inited(backend)) {
410         error_setg(errp, "cannot change property value");
411         return;
412     }
413     backend->share = value;
414 }
415 
416 static bool
417 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
418 {
419     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
420 
421     return backend->use_canonical_path;
422 }
423 
424 static void
425 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
426                                            Error **errp)
427 {
428     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
429 
430     backend->use_canonical_path = value;
431 }
432 
433 static void
434 host_memory_backend_class_init(ObjectClass *oc, void *data)
435 {
436     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
437 
438     ucc->complete = host_memory_backend_memory_complete;
439     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
440 
441     object_class_property_add_bool(oc, "merge",
442         host_memory_backend_get_merge,
443         host_memory_backend_set_merge, &error_abort);
444     object_class_property_set_description(oc, "merge",
445         "Mark memory as mergeable", &error_abort);
446     object_class_property_add_bool(oc, "dump",
447         host_memory_backend_get_dump,
448         host_memory_backend_set_dump, &error_abort);
449     object_class_property_set_description(oc, "dump",
450         "Set to 'off' to exclude from core dump", &error_abort);
451     object_class_property_add_bool(oc, "prealloc",
452         host_memory_backend_get_prealloc,
453         host_memory_backend_set_prealloc, &error_abort);
454     object_class_property_set_description(oc, "prealloc",
455         "Preallocate memory", &error_abort);
456     object_class_property_add(oc, "size", "int",
457         host_memory_backend_get_size,
458         host_memory_backend_set_size,
459         NULL, NULL, &error_abort);
460     object_class_property_set_description(oc, "size",
461         "Size of the memory region (ex: 500M)", &error_abort);
462     object_class_property_add(oc, "host-nodes", "int",
463         host_memory_backend_get_host_nodes,
464         host_memory_backend_set_host_nodes,
465         NULL, NULL, &error_abort);
466     object_class_property_set_description(oc, "host-nodes",
467         "Binds memory to the list of NUMA host nodes", &error_abort);
468     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
469         &HostMemPolicy_lookup,
470         host_memory_backend_get_policy,
471         host_memory_backend_set_policy, &error_abort);
472     object_class_property_set_description(oc, "policy",
473         "Set the NUMA policy", &error_abort);
474     object_class_property_add_bool(oc, "share",
475         host_memory_backend_get_share, host_memory_backend_set_share,
476         &error_abort);
477     object_class_property_set_description(oc, "share",
478         "Mark the memory as private to QEMU or shared", &error_abort);
479     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
480         host_memory_backend_get_use_canonical_path,
481         host_memory_backend_set_use_canonical_path, &error_abort);
482 }
483 
484 static const TypeInfo host_memory_backend_info = {
485     .name = TYPE_MEMORY_BACKEND,
486     .parent = TYPE_OBJECT,
487     .abstract = true,
488     .class_size = sizeof(HostMemoryBackendClass),
489     .class_init = host_memory_backend_class_init,
490     .instance_size = sizeof(HostMemoryBackend),
491     .instance_init = host_memory_backend_init,
492     .instance_post_init = host_memory_backend_post_init,
493     .interfaces = (InterfaceInfo[]) {
494         { TYPE_USER_CREATABLE },
495         { }
496     }
497 };
498 
499 static void register_types(void)
500 {
501     type_register_static(&host_memory_backend_info);
502 }
503 
504 type_init(register_types);
505