1 /* 2 * QEMU Host Memory Backend for hugetlbfs 3 * 4 * Copyright (C) 2013-2014 Red Hat Inc 5 * 6 * Authors: 7 * Paolo Bonzini <pbonzini@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 #include "qemu/osdep.h" 13 #include "qapi/error.h" 14 #include "qemu-common.h" 15 #include "qemu/error-report.h" 16 #include "sysemu/hostmem.h" 17 #include "sysemu/sysemu.h" 18 #include "qom/object_interfaces.h" 19 20 /* hostmem-file.c */ 21 /** 22 * @TYPE_MEMORY_BACKEND_FILE: 23 * name of backend that uses mmap on a file descriptor 24 */ 25 #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" 26 27 #define MEMORY_BACKEND_FILE(obj) \ 28 OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE) 29 30 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 31 32 struct HostMemoryBackendFile { 33 HostMemoryBackend parent_obj; 34 35 char *mem_path; 36 uint64_t align; 37 bool discard_data; 38 bool is_pmem; 39 }; 40 41 static void 42 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 43 { 44 #ifndef CONFIG_POSIX 45 error_setg(errp, "backend '%s' not supported on this host", 46 object_get_typename(OBJECT(backend))); 47 #else 48 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 49 gchar *name; 50 51 if (!backend->size) { 52 error_setg(errp, "can't create backend with size 0"); 53 return; 54 } 55 if (!fb->mem_path) { 56 error_setg(errp, "mem-path property not set"); 57 return; 58 } 59 60 /* 61 * Verify pmem file size since starting a guest with an incorrect size 62 * leads to confusing failures inside the guest. 63 */ 64 if (fb->is_pmem) { 65 Error *local_err = NULL; 66 uint64_t size; 67 68 size = qemu_get_pmem_size(fb->mem_path, &local_err); 69 if (!size) { 70 error_propagate(errp, local_err); 71 return; 72 } 73 74 if (backend->size > size) { 75 error_setg(errp, "size property %" PRIu64 " is larger than " 76 "pmem file \"%s\" size %" PRIu64, backend->size, 77 fb->mem_path, size); 78 return; 79 } 80 } 81 82 backend->force_prealloc = mem_prealloc; 83 name = host_memory_backend_get_name(backend); 84 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 85 name, 86 backend->size, fb->align, 87 (backend->share ? RAM_SHARED : 0) | 88 (fb->is_pmem ? RAM_PMEM : 0), 89 fb->mem_path, errp); 90 g_free(name); 91 #endif 92 } 93 94 static char *get_mem_path(Object *o, Error **errp) 95 { 96 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 97 98 return g_strdup(fb->mem_path); 99 } 100 101 static void set_mem_path(Object *o, const char *str, Error **errp) 102 { 103 HostMemoryBackend *backend = MEMORY_BACKEND(o); 104 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 105 106 if (host_memory_backend_mr_inited(backend)) { 107 error_setg(errp, "cannot change property 'mem-path' of %s", 108 object_get_typename(o)); 109 return; 110 } 111 g_free(fb->mem_path); 112 fb->mem_path = g_strdup(str); 113 } 114 115 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 116 { 117 return MEMORY_BACKEND_FILE(o)->discard_data; 118 } 119 120 static void file_memory_backend_set_discard_data(Object *o, bool value, 121 Error **errp) 122 { 123 MEMORY_BACKEND_FILE(o)->discard_data = value; 124 } 125 126 static void file_memory_backend_get_align(Object *o, Visitor *v, 127 const char *name, void *opaque, 128 Error **errp) 129 { 130 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 131 uint64_t val = fb->align; 132 133 visit_type_size(v, name, &val, errp); 134 } 135 136 static void file_memory_backend_set_align(Object *o, Visitor *v, 137 const char *name, void *opaque, 138 Error **errp) 139 { 140 HostMemoryBackend *backend = MEMORY_BACKEND(o); 141 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 142 Error *local_err = NULL; 143 uint64_t val; 144 145 if (host_memory_backend_mr_inited(backend)) { 146 error_setg(&local_err, "cannot change property '%s' of %s", 147 name, object_get_typename(o)); 148 goto out; 149 } 150 151 visit_type_size(v, name, &val, &local_err); 152 if (local_err) { 153 goto out; 154 } 155 fb->align = val; 156 157 out: 158 error_propagate(errp, local_err); 159 } 160 161 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 162 { 163 return MEMORY_BACKEND_FILE(o)->is_pmem; 164 } 165 166 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 167 { 168 HostMemoryBackend *backend = MEMORY_BACKEND(o); 169 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 170 171 if (host_memory_backend_mr_inited(backend)) { 172 173 error_setg(errp, "cannot change property 'pmem' of %s.", 174 object_get_typename(o)); 175 return; 176 } 177 178 #ifndef CONFIG_LIBPMEM 179 if (value) { 180 Error *local_err = NULL; 181 182 error_setg(&local_err, 183 "Lack of libpmem support while setting the 'pmem=on'" 184 " of %s. We can't ensure data persistence.", 185 object_get_typename(o)); 186 error_propagate(errp, local_err); 187 return; 188 } 189 #endif 190 191 fb->is_pmem = value; 192 } 193 194 static void file_backend_unparent(Object *obj) 195 { 196 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 197 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 198 199 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 200 void *ptr = memory_region_get_ram_ptr(&backend->mr); 201 uint64_t sz = memory_region_size(&backend->mr); 202 203 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 204 } 205 } 206 207 static void 208 file_backend_class_init(ObjectClass *oc, void *data) 209 { 210 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 211 212 bc->alloc = file_backend_memory_alloc; 213 oc->unparent = file_backend_unparent; 214 215 object_class_property_add_bool(oc, "discard-data", 216 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data, 217 &error_abort); 218 object_class_property_add_str(oc, "mem-path", 219 get_mem_path, set_mem_path, 220 &error_abort); 221 object_class_property_add(oc, "align", "int", 222 file_memory_backend_get_align, 223 file_memory_backend_set_align, 224 NULL, NULL, &error_abort); 225 object_class_property_add_bool(oc, "pmem", 226 file_memory_backend_get_pmem, file_memory_backend_set_pmem, 227 &error_abort); 228 } 229 230 static void file_backend_instance_finalize(Object *o) 231 { 232 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 233 234 g_free(fb->mem_path); 235 } 236 237 static const TypeInfo file_backend_info = { 238 .name = TYPE_MEMORY_BACKEND_FILE, 239 .parent = TYPE_MEMORY_BACKEND, 240 .class_init = file_backend_class_init, 241 .instance_finalize = file_backend_instance_finalize, 242 .instance_size = sizeof(HostMemoryBackendFile), 243 }; 244 245 static void register_types(void) 246 { 247 type_register_static(&file_backend_info); 248 } 249 250 type_init(register_types); 251