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 "sysemu/hostmem.h" 16 #include "sysemu/sysemu.h" 17 #include "qom/object_interfaces.h" 18 19 /* hostmem-file.c */ 20 /** 21 * @TYPE_MEMORY_BACKEND_FILE: 22 * name of backend that uses mmap on a file descriptor 23 */ 24 #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" 25 26 #define MEMORY_BACKEND_FILE(obj) \ 27 OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE) 28 29 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 30 31 struct HostMemoryBackendFile { 32 HostMemoryBackend parent_obj; 33 34 bool share; 35 char *mem_path; 36 }; 37 38 static void 39 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 40 { 41 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 42 43 if (!backend->size) { 44 error_setg(errp, "can't create backend with size 0"); 45 return; 46 } 47 if (!fb->mem_path) { 48 error_setg(errp, "mem-path property not set"); 49 return; 50 } 51 #ifndef CONFIG_LINUX 52 error_setg(errp, "-mem-path not supported on this host"); 53 #else 54 if (!memory_region_size(&backend->mr)) { 55 gchar *path; 56 backend->force_prealloc = mem_prealloc; 57 path = object_get_canonical_path(OBJECT(backend)); 58 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 59 path, 60 backend->size, fb->share, 61 fb->mem_path, errp); 62 g_free(path); 63 } 64 #endif 65 } 66 67 static void 68 file_backend_class_init(ObjectClass *oc, void *data) 69 { 70 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 71 72 bc->alloc = file_backend_memory_alloc; 73 } 74 75 static char *get_mem_path(Object *o, Error **errp) 76 { 77 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 78 79 return g_strdup(fb->mem_path); 80 } 81 82 static void set_mem_path(Object *o, const char *str, Error **errp) 83 { 84 HostMemoryBackend *backend = MEMORY_BACKEND(o); 85 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 86 87 if (memory_region_size(&backend->mr)) { 88 error_setg(errp, "cannot change property value"); 89 return; 90 } 91 g_free(fb->mem_path); 92 fb->mem_path = g_strdup(str); 93 } 94 95 static bool file_memory_backend_get_share(Object *o, Error **errp) 96 { 97 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 98 99 return fb->share; 100 } 101 102 static void file_memory_backend_set_share(Object *o, bool value, Error **errp) 103 { 104 HostMemoryBackend *backend = MEMORY_BACKEND(o); 105 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 106 107 if (memory_region_size(&backend->mr)) { 108 error_setg(errp, "cannot change property value"); 109 return; 110 } 111 fb->share = value; 112 } 113 114 static void 115 file_backend_instance_init(Object *o) 116 { 117 object_property_add_bool(o, "share", 118 file_memory_backend_get_share, 119 file_memory_backend_set_share, NULL); 120 object_property_add_str(o, "mem-path", get_mem_path, 121 set_mem_path, NULL); 122 } 123 124 static void file_backend_instance_finalize(Object *o) 125 { 126 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 127 128 g_free(fb->mem_path); 129 } 130 131 static const TypeInfo file_backend_info = { 132 .name = TYPE_MEMORY_BACKEND_FILE, 133 .parent = TYPE_MEMORY_BACKEND, 134 .class_init = file_backend_class_init, 135 .instance_init = file_backend_instance_init, 136 .instance_finalize = file_backend_instance_finalize, 137 .instance_size = sizeof(HostMemoryBackendFile), 138 }; 139 140 static void register_types(void) 141 { 142 type_register_static(&file_backend_info); 143 } 144 145 type_init(register_types); 146