xref: /openbmc/qemu/backends/hostmem.c (revision 65a117da) 
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;
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 
227     if (!host_memory_backend_mr_inited(backend)) {
228         backend->prealloc = value;
229         return;
230     }
231 
232     if (value && !backend->prealloc) {
233         int fd = memory_region_get_fd(&backend->mr);
234         void *ptr = memory_region_get_ram_ptr(&backend->mr);
235         uint64_t sz = memory_region_size(&backend->mr);
236 
237         os_mem_prealloc(fd, ptr, sz, backend->prealloc_threads, &local_err);
238         if (local_err) {
239             error_propagate(errp, local_err);
240             return;
241         }
242         backend->prealloc = true;
243     }
244 }
245 
246 static void host_memory_backend_get_prealloc_threads(Object *obj, Visitor *v,
247     const char *name, void *opaque, Error **errp)
248 {
249     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
250     visit_type_uint32(v, name, &backend->prealloc_threads, errp);
251 }
252 
253 static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
254     const char *name, void *opaque, Error **errp)
255 {
256     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
257     Error *local_err = NULL;
258     uint32_t value;
259 
260     visit_type_uint32(v, name, &value, &local_err);
261     if (local_err) {
262         goto out;
263     }
264     if (value <= 0) {
265         error_setg(&local_err,
266                    "property '%s' of %s doesn't take value '%d'",
267                    name, object_get_typename(obj), value);
268         goto out;
269     }
270     backend->prealloc_threads = value;
271 out:
272     error_propagate(errp, local_err);
273 }
274 
275 static void host_memory_backend_init(Object *obj)
276 {
277     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
278     MachineState *machine = MACHINE(qdev_get_machine());
279 
280     /* TODO: convert access to globals to compat properties */
281     backend->merge = machine_mem_merge(machine);
282     backend->dump = machine_dump_guest_core(machine);
283     backend->prealloc_threads = 1;
284 }
285 
286 static void host_memory_backend_post_init(Object *obj)
287 {
288     object_apply_compat_props(obj);
289 }
290 
291 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
292 {
293     /*
294      * NOTE: We forbid zero-length memory backend, so here zero means
295      * "we haven't inited the backend memory region yet".
296      */
297     return memory_region_size(&backend->mr) != 0;
298 }
299 
300 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
301 {
302     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
303 }
304 
305 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
306 {
307     backend->is_mapped = mapped;
308 }
309 
310 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
311 {
312     return backend->is_mapped;
313 }
314 
315 #ifdef __linux__
316 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
317 {
318     Object *obj = OBJECT(memdev);
319     char *path = object_property_get_str(obj, "mem-path", NULL);
320     size_t pagesize = qemu_mempath_getpagesize(path);
321 
322     g_free(path);
323     return pagesize;
324 }
325 #else
326 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
327 {
328     return qemu_real_host_page_size;
329 }
330 #endif
331 
332 static void
333 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
334 {
335     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
336     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
337     Error *local_err = NULL;
338     void *ptr;
339     uint64_t sz;
340 
341     if (bc->alloc) {
342         bc->alloc(backend, &local_err);
343         if (local_err) {
344             goto out;
345         }
346 
347         ptr = memory_region_get_ram_ptr(&backend->mr);
348         sz = memory_region_size(&backend->mr);
349 
350         if (backend->merge) {
351             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
352         }
353         if (!backend->dump) {
354             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
355         }
356 #ifdef CONFIG_NUMA
357         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
358         /* lastbit == MAX_NODES means maxnode = 0 */
359         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
360         /* ensure policy won't be ignored in case memory is preallocated
361          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
362          * this doesn't catch hugepage case. */
363         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
364 
365         /* check for invalid host-nodes and policies and give more verbose
366          * error messages than mbind(). */
367         if (maxnode && backend->policy == MPOL_DEFAULT) {
368             error_setg(errp, "host-nodes must be empty for policy default,"
369                        " or you should explicitly specify a policy other"
370                        " than default");
371             return;
372         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
373             error_setg(errp, "host-nodes must be set for policy %s",
374                        HostMemPolicy_str(backend->policy));
375             return;
376         }
377 
378         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
379          * as argument to mbind() due to an old Linux bug (feature?) which
380          * cuts off the last specified node. This means backend->host_nodes
381          * must have MAX_NODES+1 bits available.
382          */
383         assert(sizeof(backend->host_nodes) >=
384                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
385         assert(maxnode <= MAX_NODES);
386 
387         if (maxnode &&
388             mbind(ptr, sz, backend->policy, backend->host_nodes, maxnode + 1,
389                   flags)) {
390             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
391                 error_setg_errno(errp, errno,
392                                  "cannot bind memory to host NUMA nodes");
393                 return;
394             }
395         }
396 #endif
397         /* Preallocate memory after the NUMA policy has been instantiated.
398          * This is necessary to guarantee memory is allocated with
399          * specified NUMA policy in place.
400          */
401         if (backend->prealloc) {
402             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
403                             backend->prealloc_threads, &local_err);
404             if (local_err) {
405                 goto out;
406             }
407         }
408     }
409 out:
410     error_propagate(errp, local_err);
411 }
412 
413 static bool
414 host_memory_backend_can_be_deleted(UserCreatable *uc)
415 {
416     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
417         return false;
418     } else {
419         return true;
420     }
421 }
422 
423 static bool host_memory_backend_get_share(Object *o, Error **errp)
424 {
425     HostMemoryBackend *backend = MEMORY_BACKEND(o);
426 
427     return backend->share;
428 }
429 
430 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
431 {
432     HostMemoryBackend *backend = MEMORY_BACKEND(o);
433 
434     if (host_memory_backend_mr_inited(backend)) {
435         error_setg(errp, "cannot change property value");
436         return;
437     }
438     backend->share = value;
439 }
440 
441 static bool
442 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
443 {
444     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
445 
446     return backend->use_canonical_path;
447 }
448 
449 static void
450 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
451                                            Error **errp)
452 {
453     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
454 
455     backend->use_canonical_path = value;
456 }
457 
458 static void
459 host_memory_backend_class_init(ObjectClass *oc, void *data)
460 {
461     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
462 
463     ucc->complete = host_memory_backend_memory_complete;
464     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
465 
466     object_class_property_add_bool(oc, "merge",
467         host_memory_backend_get_merge,
468         host_memory_backend_set_merge);
469     object_class_property_set_description(oc, "merge",
470         "Mark memory as mergeable");
471     object_class_property_add_bool(oc, "dump",
472         host_memory_backend_get_dump,
473         host_memory_backend_set_dump);
474     object_class_property_set_description(oc, "dump",
475         "Set to 'off' to exclude from core dump");
476     object_class_property_add_bool(oc, "prealloc",
477         host_memory_backend_get_prealloc,
478         host_memory_backend_set_prealloc);
479     object_class_property_set_description(oc, "prealloc",
480         "Preallocate memory");
481     object_class_property_add(oc, "prealloc-threads", "int",
482         host_memory_backend_get_prealloc_threads,
483         host_memory_backend_set_prealloc_threads,
484         NULL, NULL);
485     object_class_property_set_description(oc, "prealloc-threads",
486         "Number of CPU threads to use for prealloc");
487     object_class_property_add(oc, "size", "int",
488         host_memory_backend_get_size,
489         host_memory_backend_set_size,
490         NULL, NULL);
491     object_class_property_set_description(oc, "size",
492         "Size of the memory region (ex: 500M)");
493     object_class_property_add(oc, "host-nodes", "int",
494         host_memory_backend_get_host_nodes,
495         host_memory_backend_set_host_nodes,
496         NULL, NULL);
497     object_class_property_set_description(oc, "host-nodes",
498         "Binds memory to the list of NUMA host nodes");
499     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
500         &HostMemPolicy_lookup,
501         host_memory_backend_get_policy,
502         host_memory_backend_set_policy);
503     object_class_property_set_description(oc, "policy",
504         "Set the NUMA policy");
505     object_class_property_add_bool(oc, "share",
506         host_memory_backend_get_share, host_memory_backend_set_share);
507     object_class_property_set_description(oc, "share",
508         "Mark the memory as private to QEMU or shared");
509     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
510         host_memory_backend_get_use_canonical_path,
511         host_memory_backend_set_use_canonical_path);
512 }
513 
514 static const TypeInfo host_memory_backend_info = {
515     .name = TYPE_MEMORY_BACKEND,
516     .parent = TYPE_OBJECT,
517     .abstract = true,
518     .class_size = sizeof(HostMemoryBackendClass),
519     .class_init = host_memory_backend_class_init,
520     .instance_size = sizeof(HostMemoryBackend),
521     .instance_init = host_memory_backend_init,
522     .instance_post_init = host_memory_backend_post_init,
523     .interfaces = (InterfaceInfo[]) {
524         { TYPE_USER_CREATABLE },
525         { }
526     }
527 };
528 
529 static void register_types(void)
530 {
531     type_register_static(&host_memory_backend_info);
532 }
533 
534 type_init(register_types);
535