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