xref: /qemu/backends/hostmem.c (revision a81df1b6) 
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 "sysemu/sysemu.h"
16 #include "hw/boards.h"
17 #include "qapi/error.h"
18 #include "qapi/qapi-builtin-visit.h"
19 #include "qapi/visitor.h"
20 #include "qemu/config-file.h"
21 #include "qom/object_interfaces.h"
22 #include "qemu/mmap-alloc.h"
23 
24 #ifdef CONFIG_NUMA
25 #include <numaif.h>
26 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
27 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
28 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
29 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
30 #endif
31 
32 char *
33 host_memory_backend_get_name(HostMemoryBackend *backend)
34 {
35     if (!backend->use_canonical_path) {
36         return g_strdup(object_get_canonical_path_component(OBJECT(backend)));
37     }
38 
39     return object_get_canonical_path(OBJECT(backend));
40 }
41 
42 static void
43 host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
44                              void *opaque, Error **errp)
45 {
46     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
47     uint64_t value = backend->size;
48 
49     visit_type_size(v, name, &value, errp);
50 }
51 
52 static void
53 host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
54                              void *opaque, Error **errp)
55 {
56     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
57     uint64_t value;
58 
59     if (host_memory_backend_mr_inited(backend)) {
60         error_setg(errp, "cannot change property %s of %s ", name,
61                    object_get_typename(obj));
62         return;
63     }
64 
65     if (!visit_type_size(v, name, &value, errp)) {
66         return;
67     }
68     if (!value) {
69         error_setg(errp,
70                    "property '%s' of %s doesn't take value '%" PRIu64 "'",
71                    name, object_get_typename(obj), value);
72         return;
73     }
74     backend->size = value;
75 }
76 
77 static void
78 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
79                                    void *opaque, Error **errp)
80 {
81     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
82     uint16List *host_nodes = NULL;
83     uint16List **node = &host_nodes;
84     unsigned long value;
85 
86     value = find_first_bit(backend->host_nodes, MAX_NODES);
87     if (value == MAX_NODES) {
88         goto ret;
89     }
90 
91     *node = g_malloc0(sizeof(**node));
92     (*node)->value = value;
93     node = &(*node)->next;
94 
95     do {
96         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
97         if (value == MAX_NODES) {
98             break;
99         }
100 
101         *node = g_malloc0(sizeof(**node));
102         (*node)->value = value;
103         node = &(*node)->next;
104     } while (true);
105 
106 ret:
107     visit_type_uint16List(v, name, &host_nodes, errp);
108 }
109 
110 static void
111 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
112                                    void *opaque, Error **errp)
113 {
114 #ifdef CONFIG_NUMA
115     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
116     uint16List *l, *host_nodes = NULL;
117 
118     visit_type_uint16List(v, name, &host_nodes, errp);
119 
120     for (l = host_nodes; l; l = l->next) {
121         if (l->value >= MAX_NODES) {
122             error_setg(errp, "Invalid host-nodes value: %d", l->value);
123             goto out;
124         }
125     }
126 
127     for (l = host_nodes; l; l = l->next) {
128         bitmap_set(backend->host_nodes, l->value, 1);
129     }
130 
131 out:
132     qapi_free_uint16List(host_nodes);
133 #else
134     error_setg(errp, "NUMA node binding are not supported by this QEMU");
135 #endif
136 }
137 
138 static int
139 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
140 {
141     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
142     return backend->policy;
143 }
144 
145 static void
146 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
147 {
148     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
149     backend->policy = policy;
150 
151 #ifndef CONFIG_NUMA
152     if (policy != HOST_MEM_POLICY_DEFAULT) {
153         error_setg(errp, "NUMA policies are not supported by this QEMU");
154     }
155 #endif
156 }
157 
158 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
159 {
160     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
161 
162     return backend->merge;
163 }
164 
165 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
166 {
167     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
168 
169     if (!host_memory_backend_mr_inited(backend)) {
170         backend->merge = value;
171         return;
172     }
173 
174     if (value != backend->merge) {
175         void *ptr = memory_region_get_ram_ptr(&backend->mr);
176         uint64_t sz = memory_region_size(&backend->mr);
177 
178         qemu_madvise(ptr, sz,
179                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
180         backend->merge = value;
181     }
182 }
183 
184 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
185 {
186     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
187 
188     return backend->dump;
189 }
190 
191 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
192 {
193     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
194 
195     if (!host_memory_backend_mr_inited(backend)) {
196         backend->dump = value;
197         return;
198     }
199 
200     if (value != backend->dump) {
201         void *ptr = memory_region_get_ram_ptr(&backend->mr);
202         uint64_t sz = memory_region_size(&backend->mr);
203 
204         qemu_madvise(ptr, sz,
205                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
206         backend->dump = value;
207     }
208 }
209 
210 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
211 {
212     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
213 
214     return backend->prealloc;
215 }
216 
217 static void host_memory_backend_set_prealloc(Object *obj, bool value,
218                                              Error **errp)
219 {
220     Error *local_err = NULL;
221     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
222 
223     if (!host_memory_backend_mr_inited(backend)) {
224         backend->prealloc = value;
225         return;
226     }
227 
228     if (value && !backend->prealloc) {
229         int fd = memory_region_get_fd(&backend->mr);
230         void *ptr = memory_region_get_ram_ptr(&backend->mr);
231         uint64_t sz = memory_region_size(&backend->mr);
232 
233         os_mem_prealloc(fd, ptr, sz, backend->prealloc_threads, &local_err);
234         if (local_err) {
235             error_propagate(errp, local_err);
236             return;
237         }
238         backend->prealloc = true;
239     }
240 }
241 
242 static void host_memory_backend_get_prealloc_threads(Object *obj, Visitor *v,
243     const char *name, void *opaque, Error **errp)
244 {
245     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
246     visit_type_uint32(v, name, &backend->prealloc_threads, errp);
247 }
248 
249 static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
250     const char *name, void *opaque, Error **errp)
251 {
252     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
253     uint32_t value;
254 
255     if (!visit_type_uint32(v, name, &value, errp)) {
256         return;
257     }
258     if (value <= 0) {
259         error_setg(errp, "property '%s' of %s doesn't take value '%d'", name,
260                    object_get_typename(obj), value);
261         return;
262     }
263     backend->prealloc_threads = value;
264 }
265 
266 static void host_memory_backend_init(Object *obj)
267 {
268     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
269     MachineState *machine = MACHINE(qdev_get_machine());
270 
271     /* TODO: convert access to globals to compat properties */
272     backend->merge = machine_mem_merge(machine);
273     backend->dump = machine_dump_guest_core(machine);
274     backend->prealloc_threads = 1;
275 }
276 
277 static void host_memory_backend_post_init(Object *obj)
278 {
279     object_apply_compat_props(obj);
280 }
281 
282 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
283 {
284     /*
285      * NOTE: We forbid zero-length memory backend, so here zero means
286      * "we haven't inited the backend memory region yet".
287      */
288     return memory_region_size(&backend->mr) != 0;
289 }
290 
291 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
292 {
293     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
294 }
295 
296 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
297 {
298     backend->is_mapped = mapped;
299 }
300 
301 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
302 {
303     return backend->is_mapped;
304 }
305 
306 #ifdef __linux__
307 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
308 {
309     Object *obj = OBJECT(memdev);
310     char *path = object_property_get_str(obj, "mem-path", NULL);
311     size_t pagesize = qemu_mempath_getpagesize(path);
312 
313     g_free(path);
314     return pagesize;
315 }
316 #else
317 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
318 {
319     return qemu_real_host_page_size;
320 }
321 #endif
322 
323 static void
324 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
325 {
326     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
327     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
328     Error *local_err = NULL;
329     void *ptr;
330     uint64_t sz;
331 
332     if (bc->alloc) {
333         bc->alloc(backend, &local_err);
334         if (local_err) {
335             goto out;
336         }
337 
338         ptr = memory_region_get_ram_ptr(&backend->mr);
339         sz = memory_region_size(&backend->mr);
340 
341         if (backend->merge) {
342             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
343         }
344         if (!backend->dump) {
345             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
346         }
347 #ifdef CONFIG_NUMA
348         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
349         /* lastbit == MAX_NODES means maxnode = 0 */
350         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
351         /* ensure policy won't be ignored in case memory is preallocated
352          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
353          * this doesn't catch hugepage case. */
354         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
355 
356         /* check for invalid host-nodes and policies and give more verbose
357          * error messages than mbind(). */
358         if (maxnode && backend->policy == MPOL_DEFAULT) {
359             error_setg(errp, "host-nodes must be empty for policy default,"
360                        " or you should explicitly specify a policy other"
361                        " than default");
362             return;
363         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
364             error_setg(errp, "host-nodes must be set for policy %s",
365                        HostMemPolicy_str(backend->policy));
366             return;
367         }
368 
369         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
370          * as argument to mbind() due to an old Linux bug (feature?) which
371          * cuts off the last specified node. This means backend->host_nodes
372          * must have MAX_NODES+1 bits available.
373          */
374         assert(sizeof(backend->host_nodes) >=
375                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
376         assert(maxnode <= MAX_NODES);
377 
378         if (maxnode &&
379             mbind(ptr, sz, backend->policy, backend->host_nodes, maxnode + 1,
380                   flags)) {
381             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
382                 error_setg_errno(errp, errno,
383                                  "cannot bind memory to host NUMA nodes");
384                 return;
385             }
386         }
387 #endif
388         /* Preallocate memory after the NUMA policy has been instantiated.
389          * This is necessary to guarantee memory is allocated with
390          * specified NUMA policy in place.
391          */
392         if (backend->prealloc) {
393             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
394                             backend->prealloc_threads, &local_err);
395             if (local_err) {
396                 goto out;
397             }
398         }
399     }
400 out:
401     error_propagate(errp, local_err);
402 }
403 
404 static bool
405 host_memory_backend_can_be_deleted(UserCreatable *uc)
406 {
407     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
408         return false;
409     } else {
410         return true;
411     }
412 }
413 
414 static bool host_memory_backend_get_share(Object *o, Error **errp)
415 {
416     HostMemoryBackend *backend = MEMORY_BACKEND(o);
417 
418     return backend->share;
419 }
420 
421 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
422 {
423     HostMemoryBackend *backend = MEMORY_BACKEND(o);
424 
425     if (host_memory_backend_mr_inited(backend)) {
426         error_setg(errp, "cannot change property value");
427         return;
428     }
429     backend->share = value;
430 }
431 
432 static bool
433 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
434 {
435     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
436 
437     return backend->use_canonical_path;
438 }
439 
440 static void
441 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
442                                            Error **errp)
443 {
444     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
445 
446     backend->use_canonical_path = value;
447 }
448 
449 static void
450 host_memory_backend_class_init(ObjectClass *oc, void *data)
451 {
452     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
453 
454     ucc->complete = host_memory_backend_memory_complete;
455     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
456 
457     object_class_property_add_bool(oc, "merge",
458         host_memory_backend_get_merge,
459         host_memory_backend_set_merge);
460     object_class_property_set_description(oc, "merge",
461         "Mark memory as mergeable");
462     object_class_property_add_bool(oc, "dump",
463         host_memory_backend_get_dump,
464         host_memory_backend_set_dump);
465     object_class_property_set_description(oc, "dump",
466         "Set to 'off' to exclude from core dump");
467     object_class_property_add_bool(oc, "prealloc",
468         host_memory_backend_get_prealloc,
469         host_memory_backend_set_prealloc);
470     object_class_property_set_description(oc, "prealloc",
471         "Preallocate memory");
472     object_class_property_add(oc, "prealloc-threads", "int",
473         host_memory_backend_get_prealloc_threads,
474         host_memory_backend_set_prealloc_threads,
475         NULL, NULL);
476     object_class_property_set_description(oc, "prealloc-threads",
477         "Number of CPU threads to use for prealloc");
478     object_class_property_add(oc, "size", "int",
479         host_memory_backend_get_size,
480         host_memory_backend_set_size,
481         NULL, NULL);
482     object_class_property_set_description(oc, "size",
483         "Size of the memory region (ex: 500M)");
484     object_class_property_add(oc, "host-nodes", "int",
485         host_memory_backend_get_host_nodes,
486         host_memory_backend_set_host_nodes,
487         NULL, NULL);
488     object_class_property_set_description(oc, "host-nodes",
489         "Binds memory to the list of NUMA host nodes");
490     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
491         &HostMemPolicy_lookup,
492         host_memory_backend_get_policy,
493         host_memory_backend_set_policy);
494     object_class_property_set_description(oc, "policy",
495         "Set the NUMA policy");
496     object_class_property_add_bool(oc, "share",
497         host_memory_backend_get_share, host_memory_backend_set_share);
498     object_class_property_set_description(oc, "share",
499         "Mark the memory as private to QEMU or shared");
500     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
501         host_memory_backend_get_use_canonical_path,
502         host_memory_backend_set_use_canonical_path);
503 }
504 
505 static const TypeInfo host_memory_backend_info = {
506     .name = TYPE_MEMORY_BACKEND,
507     .parent = TYPE_OBJECT,
508     .abstract = true,
509     .class_size = sizeof(HostMemoryBackendClass),
510     .class_init = host_memory_backend_class_init,
511     .instance_size = sizeof(HostMemoryBackend),
512     .instance_init = host_memory_backend_init,
513     .instance_post_init = host_memory_backend_post_init,
514     .interfaces = (InterfaceInfo[]) {
515         { TYPE_USER_CREATABLE },
516         { }
517     }
518 };
519 
520 static void register_types(void)
521 {
522     type_register_static(&host_memory_backend_info);
523 }
524 
525 type_init(register_types);
526