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