xref: /openbmc/qemu/backends/hostmem.c (revision 64c9a921) 
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 **tail = &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     QAPI_LIST_APPEND(tail, value);
92 
93     do {
94         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
95         if (value == MAX_NODES) {
96             break;
97         }
98 
99         QAPI_LIST_APPEND(tail, value);
100     } while (true);
101 
102 ret:
103     visit_type_uint16List(v, name, &host_nodes, errp);
104     qapi_free_uint16List(host_nodes);
105 }
106 
107 static void
108 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
109                                    void *opaque, Error **errp)
110 {
111 #ifdef CONFIG_NUMA
112     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
113     uint16List *l, *host_nodes = NULL;
114 
115     visit_type_uint16List(v, name, &host_nodes, errp);
116 
117     for (l = host_nodes; l; l = l->next) {
118         if (l->value >= MAX_NODES) {
119             error_setg(errp, "Invalid host-nodes value: %d", l->value);
120             goto out;
121         }
122     }
123 
124     for (l = host_nodes; l; l = l->next) {
125         bitmap_set(backend->host_nodes, l->value, 1);
126     }
127 
128 out:
129     qapi_free_uint16List(host_nodes);
130 #else
131     error_setg(errp, "NUMA node binding are not supported by this QEMU");
132 #endif
133 }
134 
135 static int
136 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
137 {
138     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
139     return backend->policy;
140 }
141 
142 static void
143 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
144 {
145     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
146     backend->policy = policy;
147 
148 #ifndef CONFIG_NUMA
149     if (policy != HOST_MEM_POLICY_DEFAULT) {
150         error_setg(errp, "NUMA policies are not supported by this QEMU");
151     }
152 #endif
153 }
154 
155 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
156 {
157     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
158 
159     return backend->merge;
160 }
161 
162 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
163 {
164     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
165 
166     if (!host_memory_backend_mr_inited(backend)) {
167         backend->merge = value;
168         return;
169     }
170 
171     if (value != backend->merge) {
172         void *ptr = memory_region_get_ram_ptr(&backend->mr);
173         uint64_t sz = memory_region_size(&backend->mr);
174 
175         qemu_madvise(ptr, sz,
176                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
177         backend->merge = value;
178     }
179 }
180 
181 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
182 {
183     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
184 
185     return backend->dump;
186 }
187 
188 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
189 {
190     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
191 
192     if (!host_memory_backend_mr_inited(backend)) {
193         backend->dump = value;
194         return;
195     }
196 
197     if (value != backend->dump) {
198         void *ptr = memory_region_get_ram_ptr(&backend->mr);
199         uint64_t sz = memory_region_size(&backend->mr);
200 
201         qemu_madvise(ptr, sz,
202                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
203         backend->dump = value;
204     }
205 }
206 
207 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
208 {
209     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
210 
211     return backend->prealloc;
212 }
213 
214 static void host_memory_backend_set_prealloc(Object *obj, bool value,
215                                              Error **errp)
216 {
217     Error *local_err = NULL;
218     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
219 
220     if (!host_memory_backend_mr_inited(backend)) {
221         backend->prealloc = value;
222         return;
223     }
224 
225     if (value && !backend->prealloc) {
226         int fd = memory_region_get_fd(&backend->mr);
227         void *ptr = memory_region_get_ram_ptr(&backend->mr);
228         uint64_t sz = memory_region_size(&backend->mr);
229 
230         os_mem_prealloc(fd, ptr, sz, backend->prealloc_threads, &local_err);
231         if (local_err) {
232             error_propagate(errp, local_err);
233             return;
234         }
235         backend->prealloc = true;
236     }
237 }
238 
239 static void host_memory_backend_get_prealloc_threads(Object *obj, Visitor *v,
240     const char *name, void *opaque, Error **errp)
241 {
242     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
243     visit_type_uint32(v, name, &backend->prealloc_threads, errp);
244 }
245 
246 static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
247     const char *name, void *opaque, Error **errp)
248 {
249     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
250     uint32_t value;
251 
252     if (!visit_type_uint32(v, name, &value, errp)) {
253         return;
254     }
255     if (value <= 0) {
256         error_setg(errp, "property '%s' of %s doesn't take value '%d'", name,
257                    object_get_typename(obj), value);
258         return;
259     }
260     backend->prealloc_threads = value;
261 }
262 
263 static void host_memory_backend_init(Object *obj)
264 {
265     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
266     MachineState *machine = MACHINE(qdev_get_machine());
267 
268     /* TODO: convert access to globals to compat properties */
269     backend->merge = machine_mem_merge(machine);
270     backend->dump = machine_dump_guest_core(machine);
271     backend->prealloc_threads = 1;
272 }
273 
274 static void host_memory_backend_post_init(Object *obj)
275 {
276     object_apply_compat_props(obj);
277 }
278 
279 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
280 {
281     /*
282      * NOTE: We forbid zero-length memory backend, so here zero means
283      * "we haven't inited the backend memory region yet".
284      */
285     return memory_region_size(&backend->mr) != 0;
286 }
287 
288 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
289 {
290     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
291 }
292 
293 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
294 {
295     backend->is_mapped = mapped;
296 }
297 
298 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
299 {
300     return backend->is_mapped;
301 }
302 
303 #ifdef __linux__
304 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
305 {
306     Object *obj = OBJECT(memdev);
307     char *path = object_property_get_str(obj, "mem-path", NULL);
308     size_t pagesize = qemu_mempath_getpagesize(path);
309 
310     g_free(path);
311     return pagesize;
312 }
313 #else
314 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
315 {
316     return qemu_real_host_page_size;
317 }
318 #endif
319 
320 static void
321 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
322 {
323     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
324     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
325     Error *local_err = NULL;
326     void *ptr;
327     uint64_t sz;
328 
329     if (bc->alloc) {
330         bc->alloc(backend, &local_err);
331         if (local_err) {
332             goto out;
333         }
334 
335         ptr = memory_region_get_ram_ptr(&backend->mr);
336         sz = memory_region_size(&backend->mr);
337 
338         if (backend->merge) {
339             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
340         }
341         if (!backend->dump) {
342             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
343         }
344 #ifdef CONFIG_NUMA
345         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
346         /* lastbit == MAX_NODES means maxnode = 0 */
347         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
348         /* ensure policy won't be ignored in case memory is preallocated
349          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
350          * this doesn't catch hugepage case. */
351         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
352 
353         /* check for invalid host-nodes and policies and give more verbose
354          * error messages than mbind(). */
355         if (maxnode && backend->policy == MPOL_DEFAULT) {
356             error_setg(errp, "host-nodes must be empty for policy default,"
357                        " or you should explicitly specify a policy other"
358                        " than default");
359             return;
360         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
361             error_setg(errp, "host-nodes must be set for policy %s",
362                        HostMemPolicy_str(backend->policy));
363             return;
364         }
365 
366         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
367          * as argument to mbind() due to an old Linux bug (feature?) which
368          * cuts off the last specified node. This means backend->host_nodes
369          * must have MAX_NODES+1 bits available.
370          */
371         assert(sizeof(backend->host_nodes) >=
372                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
373         assert(maxnode <= MAX_NODES);
374 
375         if (maxnode &&
376             mbind(ptr, sz, backend->policy, backend->host_nodes, maxnode + 1,
377                   flags)) {
378             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
379                 error_setg_errno(errp, errno,
380                                  "cannot bind memory to host NUMA nodes");
381                 return;
382             }
383         }
384 #endif
385         /* Preallocate memory after the NUMA policy has been instantiated.
386          * This is necessary to guarantee memory is allocated with
387          * specified NUMA policy in place.
388          */
389         if (backend->prealloc) {
390             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
391                             backend->prealloc_threads, &local_err);
392             if (local_err) {
393                 goto out;
394             }
395         }
396     }
397 out:
398     error_propagate(errp, local_err);
399 }
400 
401 static bool
402 host_memory_backend_can_be_deleted(UserCreatable *uc)
403 {
404     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
405         return false;
406     } else {
407         return true;
408     }
409 }
410 
411 static bool host_memory_backend_get_share(Object *o, Error **errp)
412 {
413     HostMemoryBackend *backend = MEMORY_BACKEND(o);
414 
415     return backend->share;
416 }
417 
418 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
419 {
420     HostMemoryBackend *backend = MEMORY_BACKEND(o);
421 
422     if (host_memory_backend_mr_inited(backend)) {
423         error_setg(errp, "cannot change property value");
424         return;
425     }
426     backend->share = value;
427 }
428 
429 static bool
430 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
431 {
432     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
433 
434     return backend->use_canonical_path;
435 }
436 
437 static void
438 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
439                                            Error **errp)
440 {
441     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
442 
443     backend->use_canonical_path = value;
444 }
445 
446 static void
447 host_memory_backend_class_init(ObjectClass *oc, void *data)
448 {
449     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
450 
451     ucc->complete = host_memory_backend_memory_complete;
452     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
453 
454     object_class_property_add_bool(oc, "merge",
455         host_memory_backend_get_merge,
456         host_memory_backend_set_merge);
457     object_class_property_set_description(oc, "merge",
458         "Mark memory as mergeable");
459     object_class_property_add_bool(oc, "dump",
460         host_memory_backend_get_dump,
461         host_memory_backend_set_dump);
462     object_class_property_set_description(oc, "dump",
463         "Set to 'off' to exclude from core dump");
464     object_class_property_add_bool(oc, "prealloc",
465         host_memory_backend_get_prealloc,
466         host_memory_backend_set_prealloc);
467     object_class_property_set_description(oc, "prealloc",
468         "Preallocate memory");
469     object_class_property_add(oc, "prealloc-threads", "int",
470         host_memory_backend_get_prealloc_threads,
471         host_memory_backend_set_prealloc_threads,
472         NULL, NULL);
473     object_class_property_set_description(oc, "prealloc-threads",
474         "Number of CPU threads to use for prealloc");
475     object_class_property_add(oc, "size", "int",
476         host_memory_backend_get_size,
477         host_memory_backend_set_size,
478         NULL, NULL);
479     object_class_property_set_description(oc, "size",
480         "Size of the memory region (ex: 500M)");
481     object_class_property_add(oc, "host-nodes", "int",
482         host_memory_backend_get_host_nodes,
483         host_memory_backend_set_host_nodes,
484         NULL, NULL);
485     object_class_property_set_description(oc, "host-nodes",
486         "Binds memory to the list of NUMA host nodes");
487     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
488         &HostMemPolicy_lookup,
489         host_memory_backend_get_policy,
490         host_memory_backend_set_policy);
491     object_class_property_set_description(oc, "policy",
492         "Set the NUMA policy");
493     object_class_property_add_bool(oc, "share",
494         host_memory_backend_get_share, host_memory_backend_set_share);
495     object_class_property_set_description(oc, "share",
496         "Mark the memory as private to QEMU or shared");
497     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
498         host_memory_backend_get_use_canonical_path,
499         host_memory_backend_set_use_canonical_path);
500 }
501 
502 static const TypeInfo host_memory_backend_info = {
503     .name = TYPE_MEMORY_BACKEND,
504     .parent = TYPE_OBJECT,
505     .abstract = true,
506     .class_size = sizeof(HostMemoryBackendClass),
507     .class_init = host_memory_backend_class_init,
508     .instance_size = sizeof(HostMemoryBackend),
509     .instance_init = host_memory_backend_init,
510     .instance_post_init = host_memory_backend_post_init,
511     .interfaces = (InterfaceInfo[]) {
512         { TYPE_USER_CREATABLE },
513         { }
514     }
515 };
516 
517 static void register_types(void)
518 {
519     type_register_static(&host_memory_backend_info);
520 }
521 
522 type_init(register_types);
523