xref: /openbmc/qemu/backends/hostmem.c (revision 2a886794) 
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 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     Error *local_err = NULL;
58     uint64_t value;
59 
60     if (host_memory_backend_mr_inited(backend)) {
61         error_setg(&local_err, "cannot change property %s of %s ",
62                    name, object_get_typename(obj));
63         goto out;
64     }
65 
66     visit_type_size(v, name, &value, &local_err);
67     if (local_err) {
68         goto out;
69     }
70     if (!value) {
71         error_setg(&local_err,
72                    "property '%s' of %s doesn't take value '%" PRIu64 "'",
73                    name, object_get_typename(obj), value);
74         goto out;
75     }
76     backend->size = value;
77 out:
78     error_propagate(errp, local_err);
79 }
80 
81 static void
82 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
83                                    void *opaque, Error **errp)
84 {
85     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
86     uint16List *host_nodes = NULL;
87     uint16List **node = &host_nodes;
88     unsigned long value;
89 
90     value = find_first_bit(backend->host_nodes, MAX_NODES);
91     if (value == MAX_NODES) {
92         goto ret;
93     }
94 
95     *node = g_malloc0(sizeof(**node));
96     (*node)->value = value;
97     node = &(*node)->next;
98 
99     do {
100         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
101         if (value == MAX_NODES) {
102             break;
103         }
104 
105         *node = g_malloc0(sizeof(**node));
106         (*node)->value = value;
107         node = &(*node)->next;
108     } while (true);
109 
110 ret:
111     visit_type_uint16List(v, name, &host_nodes, errp);
112 }
113 
114 static void
115 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
116                                    void *opaque, Error **errp)
117 {
118 #ifdef CONFIG_NUMA
119     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
120     uint16List *l, *host_nodes = NULL;
121 
122     visit_type_uint16List(v, name, &host_nodes, errp);
123 
124     for (l = host_nodes; l; l = l->next) {
125         if (l->value >= MAX_NODES) {
126             error_setg(errp, "Invalid host-nodes value: %d", l->value);
127             goto out;
128         }
129     }
130 
131     for (l = host_nodes; l; l = l->next) {
132         bitmap_set(backend->host_nodes, l->value, 1);
133     }
134 
135 out:
136     qapi_free_uint16List(host_nodes);
137 #else
138     error_setg(errp, "NUMA node binding are not supported by this QEMU");
139 #endif
140 }
141 
142 static int
143 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
144 {
145     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
146     return backend->policy;
147 }
148 
149 static void
150 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
151 {
152     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
153     backend->policy = policy;
154 
155 #ifndef CONFIG_NUMA
156     if (policy != HOST_MEM_POLICY_DEFAULT) {
157         error_setg(errp, "NUMA policies are not supported by this QEMU");
158     }
159 #endif
160 }
161 
162 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
163 {
164     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
165 
166     return backend->merge;
167 }
168 
169 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
170 {
171     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
172 
173     if (!host_memory_backend_mr_inited(backend)) {
174         backend->merge = value;
175         return;
176     }
177 
178     if (value != backend->merge) {
179         void *ptr = memory_region_get_ram_ptr(&backend->mr);
180         uint64_t sz = memory_region_size(&backend->mr);
181 
182         qemu_madvise(ptr, sz,
183                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
184         backend->merge = value;
185     }
186 }
187 
188 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
189 {
190     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
191 
192     return backend->dump;
193 }
194 
195 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
196 {
197     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
198 
199     if (!host_memory_backend_mr_inited(backend)) {
200         backend->dump = value;
201         return;
202     }
203 
204     if (value != backend->dump) {
205         void *ptr = memory_region_get_ram_ptr(&backend->mr);
206         uint64_t sz = memory_region_size(&backend->mr);
207 
208         qemu_madvise(ptr, sz,
209                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
210         backend->dump = value;
211     }
212 }
213 
214 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
215 {
216     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
217 
218     return backend->prealloc || backend->force_prealloc;
219 }
220 
221 static void host_memory_backend_set_prealloc(Object *obj, bool value,
222                                              Error **errp)
223 {
224     Error *local_err = NULL;
225     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
226     MachineState *ms = MACHINE(qdev_get_machine());
227 
228     if (backend->force_prealloc) {
229         if (value) {
230             error_setg(errp,
231                        "remove -mem-prealloc to use the prealloc property");
232             return;
233         }
234     }
235 
236     if (!host_memory_backend_mr_inited(backend)) {
237         backend->prealloc = value;
238         return;
239     }
240 
241     if (value && !backend->prealloc) {
242         int fd = memory_region_get_fd(&backend->mr);
243         void *ptr = memory_region_get_ram_ptr(&backend->mr);
244         uint64_t sz = memory_region_size(&backend->mr);
245 
246         os_mem_prealloc(fd, ptr, sz, ms->smp.cpus, &local_err);
247         if (local_err) {
248             error_propagate(errp, local_err);
249             return;
250         }
251         backend->prealloc = true;
252     }
253 }
254 
255 static void host_memory_backend_init(Object *obj)
256 {
257     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
258     MachineState *machine = MACHINE(qdev_get_machine());
259 
260     backend->merge = machine_mem_merge(machine);
261     backend->dump = machine_dump_guest_core(machine);
262     backend->prealloc = mem_prealloc;
263 }
264 
265 static void host_memory_backend_post_init(Object *obj)
266 {
267     object_apply_compat_props(obj);
268 }
269 
270 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
271 {
272     /*
273      * NOTE: We forbid zero-length memory backend, so here zero means
274      * "we haven't inited the backend memory region yet".
275      */
276     return memory_region_size(&backend->mr) != 0;
277 }
278 
279 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
280 {
281     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
282 }
283 
284 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
285 {
286     backend->is_mapped = mapped;
287 }
288 
289 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
290 {
291     return backend->is_mapped;
292 }
293 
294 #ifdef __linux__
295 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
296 {
297     Object *obj = OBJECT(memdev);
298     char *path = object_property_get_str(obj, "mem-path", NULL);
299     size_t pagesize = qemu_mempath_getpagesize(path);
300 
301     g_free(path);
302     return pagesize;
303 }
304 #else
305 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
306 {
307     return qemu_real_host_page_size;
308 }
309 #endif
310 
311 static void
312 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
313 {
314     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
315     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
316     MachineState *ms = MACHINE(qdev_get_machine());
317     Error *local_err = NULL;
318     void *ptr;
319     uint64_t sz;
320 
321     if (bc->alloc) {
322         bc->alloc(backend, &local_err);
323         if (local_err) {
324             goto out;
325         }
326 
327         ptr = memory_region_get_ram_ptr(&backend->mr);
328         sz = memory_region_size(&backend->mr);
329 
330         if (backend->merge) {
331             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
332         }
333         if (!backend->dump) {
334             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
335         }
336 #ifdef CONFIG_NUMA
337         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
338         /* lastbit == MAX_NODES means maxnode = 0 */
339         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
340         /* ensure policy won't be ignored in case memory is preallocated
341          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
342          * this doesn't catch hugepage case. */
343         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
344 
345         /* check for invalid host-nodes and policies and give more verbose
346          * error messages than mbind(). */
347         if (maxnode && backend->policy == MPOL_DEFAULT) {
348             error_setg(errp, "host-nodes must be empty for policy default,"
349                        " or you should explicitly specify a policy other"
350                        " than default");
351             return;
352         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
353             error_setg(errp, "host-nodes must be set for policy %s",
354                        HostMemPolicy_str(backend->policy));
355             return;
356         }
357 
358         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
359          * as argument to mbind() due to an old Linux bug (feature?) which
360          * cuts off the last specified node. This means backend->host_nodes
361          * must have MAX_NODES+1 bits available.
362          */
363         assert(sizeof(backend->host_nodes) >=
364                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
365         assert(maxnode <= MAX_NODES);
366         if (mbind(ptr, sz, backend->policy,
367                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
368             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
369                 error_setg_errno(errp, errno,
370                                  "cannot bind memory to host NUMA nodes");
371                 return;
372             }
373         }
374 #endif
375         /* Preallocate memory after the NUMA policy has been instantiated.
376          * This is necessary to guarantee memory is allocated with
377          * specified NUMA policy in place.
378          */
379         if (backend->prealloc) {
380             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
381                             ms->smp.cpus, &local_err);
382             if (local_err) {
383                 goto out;
384             }
385         }
386     }
387 out:
388     error_propagate(errp, local_err);
389 }
390 
391 static bool
392 host_memory_backend_can_be_deleted(UserCreatable *uc)
393 {
394     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
395         return false;
396     } else {
397         return true;
398     }
399 }
400 
401 static bool host_memory_backend_get_share(Object *o, Error **errp)
402 {
403     HostMemoryBackend *backend = MEMORY_BACKEND(o);
404 
405     return backend->share;
406 }
407 
408 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
409 {
410     HostMemoryBackend *backend = MEMORY_BACKEND(o);
411 
412     if (host_memory_backend_mr_inited(backend)) {
413         error_setg(errp, "cannot change property value");
414         return;
415     }
416     backend->share = value;
417 }
418 
419 static bool
420 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
421 {
422     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
423 
424     return backend->use_canonical_path;
425 }
426 
427 static void
428 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
429                                            Error **errp)
430 {
431     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
432 
433     backend->use_canonical_path = value;
434 }
435 
436 static void
437 host_memory_backend_class_init(ObjectClass *oc, void *data)
438 {
439     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
440 
441     ucc->complete = host_memory_backend_memory_complete;
442     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
443 
444     object_class_property_add_bool(oc, "merge",
445         host_memory_backend_get_merge,
446         host_memory_backend_set_merge, &error_abort);
447     object_class_property_set_description(oc, "merge",
448         "Mark memory as mergeable", &error_abort);
449     object_class_property_add_bool(oc, "dump",
450         host_memory_backend_get_dump,
451         host_memory_backend_set_dump, &error_abort);
452     object_class_property_set_description(oc, "dump",
453         "Set to 'off' to exclude from core dump", &error_abort);
454     object_class_property_add_bool(oc, "prealloc",
455         host_memory_backend_get_prealloc,
456         host_memory_backend_set_prealloc, &error_abort);
457     object_class_property_set_description(oc, "prealloc",
458         "Preallocate memory", &error_abort);
459     object_class_property_add(oc, "size", "int",
460         host_memory_backend_get_size,
461         host_memory_backend_set_size,
462         NULL, NULL, &error_abort);
463     object_class_property_set_description(oc, "size",
464         "Size of the memory region (ex: 500M)", &error_abort);
465     object_class_property_add(oc, "host-nodes", "int",
466         host_memory_backend_get_host_nodes,
467         host_memory_backend_set_host_nodes,
468         NULL, NULL, &error_abort);
469     object_class_property_set_description(oc, "host-nodes",
470         "Binds memory to the list of NUMA host nodes", &error_abort);
471     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
472         &HostMemPolicy_lookup,
473         host_memory_backend_get_policy,
474         host_memory_backend_set_policy, &error_abort);
475     object_class_property_set_description(oc, "policy",
476         "Set the NUMA policy", &error_abort);
477     object_class_property_add_bool(oc, "share",
478         host_memory_backend_get_share, host_memory_backend_set_share,
479         &error_abort);
480     object_class_property_set_description(oc, "share",
481         "Mark the memory as private to QEMU or shared", &error_abort);
482     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
483         host_memory_backend_get_use_canonical_path,
484         host_memory_backend_set_use_canonical_path, &error_abort);
485 }
486 
487 static const TypeInfo host_memory_backend_info = {
488     .name = TYPE_MEMORY_BACKEND,
489     .parent = TYPE_OBJECT,
490     .abstract = true,
491     .class_size = sizeof(HostMemoryBackendClass),
492     .class_init = host_memory_backend_class_init,
493     .instance_size = sizeof(HostMemoryBackend),
494     .instance_init = host_memory_backend_init,
495     .instance_post_init = host_memory_backend_post_init,
496     .interfaces = (InterfaceInfo[]) {
497         { TYPE_USER_CREATABLE },
498         { }
499     }
500 };
501 
502 static void register_types(void)
503 {
504     type_register_static(&host_memory_backend_info);
505 }
506 
507 type_init(register_types);
508