xref: /openbmc/qemu/backends/hostmem.c (revision 520e210c) 
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         return;
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     visit_type_uint16List(v, name, &host_nodes, errp);
110 }
111 
112 static void
113 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
114                                    void *opaque, Error **errp)
115 {
116 #ifdef CONFIG_NUMA
117     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
118     uint16List *l, *host_nodes = NULL;
119 
120     visit_type_uint16List(v, name, &host_nodes, errp);
121 
122     for (l = host_nodes; l; l = l->next) {
123         if (l->value >= MAX_NODES) {
124             error_setg(errp, "Invalid host-nodes value: %d", l->value);
125             goto out;
126         }
127     }
128 
129     for (l = host_nodes; l; l = l->next) {
130         bitmap_set(backend->host_nodes, l->value, 1);
131     }
132 
133 out:
134     qapi_free_uint16List(host_nodes);
135 #else
136     error_setg(errp, "NUMA node binding are not supported by this QEMU");
137 #endif
138 }
139 
140 static int
141 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
142 {
143     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
144     return backend->policy;
145 }
146 
147 static void
148 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
149 {
150     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
151     backend->policy = policy;
152 
153 #ifndef CONFIG_NUMA
154     if (policy != HOST_MEM_POLICY_DEFAULT) {
155         error_setg(errp, "NUMA policies are not supported by this QEMU");
156     }
157 #endif
158 }
159 
160 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
161 {
162     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
163 
164     return backend->merge;
165 }
166 
167 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
168 {
169     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
170 
171     if (!host_memory_backend_mr_inited(backend)) {
172         backend->merge = value;
173         return;
174     }
175 
176     if (value != backend->merge) {
177         void *ptr = memory_region_get_ram_ptr(&backend->mr);
178         uint64_t sz = memory_region_size(&backend->mr);
179 
180         qemu_madvise(ptr, sz,
181                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
182         backend->merge = value;
183     }
184 }
185 
186 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
187 {
188     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
189 
190     return backend->dump;
191 }
192 
193 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
194 {
195     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
196 
197     if (!host_memory_backend_mr_inited(backend)) {
198         backend->dump = value;
199         return;
200     }
201 
202     if (value != backend->dump) {
203         void *ptr = memory_region_get_ram_ptr(&backend->mr);
204         uint64_t sz = memory_region_size(&backend->mr);
205 
206         qemu_madvise(ptr, sz,
207                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
208         backend->dump = value;
209     }
210 }
211 
212 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
213 {
214     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
215 
216     return backend->prealloc || backend->force_prealloc;
217 }
218 
219 static void host_memory_backend_set_prealloc(Object *obj, bool value,
220                                              Error **errp)
221 {
222     Error *local_err = NULL;
223     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
224 
225     if (backend->force_prealloc) {
226         if (value) {
227             error_setg(errp,
228                        "remove -mem-prealloc to use the prealloc property");
229             return;
230         }
231     }
232 
233     if (!host_memory_backend_mr_inited(backend)) {
234         backend->prealloc = value;
235         return;
236     }
237 
238     if (value && !backend->prealloc) {
239         int fd = memory_region_get_fd(&backend->mr);
240         void *ptr = memory_region_get_ram_ptr(&backend->mr);
241         uint64_t sz = memory_region_size(&backend->mr);
242 
243         os_mem_prealloc(fd, ptr, sz, smp_cpus, &local_err);
244         if (local_err) {
245             error_propagate(errp, local_err);
246             return;
247         }
248         backend->prealloc = true;
249     }
250 }
251 
252 static void host_memory_backend_init(Object *obj)
253 {
254     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
255     MachineState *machine = MACHINE(qdev_get_machine());
256 
257     backend->merge = machine_mem_merge(machine);
258     backend->dump = machine_dump_guest_core(machine);
259     backend->prealloc = mem_prealloc;
260 }
261 
262 static void host_memory_backend_post_init(Object *obj)
263 {
264     object_apply_compat_props(obj);
265 }
266 
267 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
268 {
269     /*
270      * NOTE: We forbid zero-length memory backend, so here zero means
271      * "we haven't inited the backend memory region yet".
272      */
273     return memory_region_size(&backend->mr) != 0;
274 }
275 
276 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
277 {
278     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
279 }
280 
281 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
282 {
283     backend->is_mapped = mapped;
284 }
285 
286 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
287 {
288     return backend->is_mapped;
289 }
290 
291 #ifdef __linux__
292 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
293 {
294     Object *obj = OBJECT(memdev);
295     char *path = object_property_get_str(obj, "mem-path", NULL);
296     size_t pagesize = qemu_mempath_getpagesize(path);
297 
298     g_free(path);
299     return pagesize;
300 }
301 #else
302 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
303 {
304     return getpagesize();
305 }
306 #endif
307 
308 static void
309 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
310 {
311     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
312     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
313     Error *local_err = NULL;
314     void *ptr;
315     uint64_t sz;
316 
317     if (bc->alloc) {
318         bc->alloc(backend, &local_err);
319         if (local_err) {
320             goto out;
321         }
322 
323         ptr = memory_region_get_ram_ptr(&backend->mr);
324         sz = memory_region_size(&backend->mr);
325 
326         if (backend->merge) {
327             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
328         }
329         if (!backend->dump) {
330             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
331         }
332 #ifdef CONFIG_NUMA
333         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
334         /* lastbit == MAX_NODES means maxnode = 0 */
335         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
336         /* ensure policy won't be ignored in case memory is preallocated
337          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
338          * this doesn't catch hugepage case. */
339         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
340 
341         /* check for invalid host-nodes and policies and give more verbose
342          * error messages than mbind(). */
343         if (maxnode && backend->policy == MPOL_DEFAULT) {
344             error_setg(errp, "host-nodes must be empty for policy default,"
345                        " or you should explicitly specify a policy other"
346                        " than default");
347             return;
348         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
349             error_setg(errp, "host-nodes must be set for policy %s",
350                        HostMemPolicy_str(backend->policy));
351             return;
352         }
353 
354         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
355          * as argument to mbind() due to an old Linux bug (feature?) which
356          * cuts off the last specified node. This means backend->host_nodes
357          * must have MAX_NODES+1 bits available.
358          */
359         assert(sizeof(backend->host_nodes) >=
360                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
361         assert(maxnode <= MAX_NODES);
362         if (mbind(ptr, sz, backend->policy,
363                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
364             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
365                 error_setg_errno(errp, errno,
366                                  "cannot bind memory to host NUMA nodes");
367                 return;
368             }
369         }
370 #endif
371         /* Preallocate memory after the NUMA policy has been instantiated.
372          * This is necessary to guarantee memory is allocated with
373          * specified NUMA policy in place.
374          */
375         if (backend->prealloc) {
376             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
377                             smp_cpus, &local_err);
378             if (local_err) {
379                 goto out;
380             }
381         }
382     }
383 out:
384     error_propagate(errp, local_err);
385 }
386 
387 static bool
388 host_memory_backend_can_be_deleted(UserCreatable *uc)
389 {
390     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
391         return false;
392     } else {
393         return true;
394     }
395 }
396 
397 static bool host_memory_backend_get_share(Object *o, Error **errp)
398 {
399     HostMemoryBackend *backend = MEMORY_BACKEND(o);
400 
401     return backend->share;
402 }
403 
404 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
405 {
406     HostMemoryBackend *backend = MEMORY_BACKEND(o);
407 
408     if (host_memory_backend_mr_inited(backend)) {
409         error_setg(errp, "cannot change property value");
410         return;
411     }
412     backend->share = value;
413 }
414 
415 static bool
416 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
417 {
418     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
419 
420     return backend->use_canonical_path;
421 }
422 
423 static void
424 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
425                                            Error **errp)
426 {
427     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
428 
429     backend->use_canonical_path = value;
430 }
431 
432 static void
433 host_memory_backend_class_init(ObjectClass *oc, void *data)
434 {
435     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
436 
437     ucc->complete = host_memory_backend_memory_complete;
438     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
439 
440     object_class_property_add_bool(oc, "merge",
441         host_memory_backend_get_merge,
442         host_memory_backend_set_merge, &error_abort);
443     object_class_property_set_description(oc, "merge",
444         "Mark memory as mergeable", &error_abort);
445     object_class_property_add_bool(oc, "dump",
446         host_memory_backend_get_dump,
447         host_memory_backend_set_dump, &error_abort);
448     object_class_property_set_description(oc, "dump",
449         "Set to 'off' to exclude from core dump", &error_abort);
450     object_class_property_add_bool(oc, "prealloc",
451         host_memory_backend_get_prealloc,
452         host_memory_backend_set_prealloc, &error_abort);
453     object_class_property_set_description(oc, "prealloc",
454         "Preallocate memory", &error_abort);
455     object_class_property_add(oc, "size", "int",
456         host_memory_backend_get_size,
457         host_memory_backend_set_size,
458         NULL, NULL, &error_abort);
459     object_class_property_set_description(oc, "size",
460         "Size of the memory region (ex: 500M)", &error_abort);
461     object_class_property_add(oc, "host-nodes", "int",
462         host_memory_backend_get_host_nodes,
463         host_memory_backend_set_host_nodes,
464         NULL, NULL, &error_abort);
465     object_class_property_set_description(oc, "host-nodes",
466         "Binds memory to the list of NUMA host nodes", &error_abort);
467     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
468         &HostMemPolicy_lookup,
469         host_memory_backend_get_policy,
470         host_memory_backend_set_policy, &error_abort);
471     object_class_property_set_description(oc, "policy",
472         "Set the NUMA policy", &error_abort);
473     object_class_property_add_bool(oc, "share",
474         host_memory_backend_get_share, host_memory_backend_set_share,
475         &error_abort);
476     object_class_property_set_description(oc, "share",
477         "Mark the memory as private to QEMU or shared", &error_abort);
478     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
479         host_memory_backend_get_use_canonical_path,
480         host_memory_backend_set_use_canonical_path, &error_abort);
481 }
482 
483 static const TypeInfo host_memory_backend_info = {
484     .name = TYPE_MEMORY_BACKEND,
485     .parent = TYPE_OBJECT,
486     .abstract = true,
487     .class_size = sizeof(HostMemoryBackendClass),
488     .class_init = host_memory_backend_class_init,
489     .instance_size = sizeof(HostMemoryBackend),
490     .instance_init = host_memory_backend_init,
491     .instance_post_init = host_memory_backend_post_init,
492     .interfaces = (InterfaceInfo[]) {
493         { TYPE_USER_CREATABLE },
494         { }
495     }
496 };
497 
498 static void register_types(void)
499 {
500     type_register_static(&host_memory_backend_info);
501 }
502 
503 type_init(register_types);
504