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 backend->force_prealloc = mem_prealloc; 56 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 57 object_get_canonical_path(OBJECT(backend)), 58 backend->size, fb->share, 59 fb->mem_path, errp); 60 } 61 #endif 62 } 63 64 static void 65 file_backend_class_init(ObjectClass *oc, void *data) 66 { 67 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 68 69 bc->alloc = file_backend_memory_alloc; 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 (memory_region_size(&backend->mr)) { 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_share(Object *o, Error **errp) 93 { 94 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 95 96 return fb->share; 97 } 98 99 static void file_memory_backend_set_share(Object *o, bool value, Error **errp) 100 { 101 HostMemoryBackend *backend = MEMORY_BACKEND(o); 102 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 103 104 if (memory_region_size(&backend->mr)) { 105 error_setg(errp, "cannot change property value"); 106 return; 107 } 108 fb->share = value; 109 } 110 111 static void 112 file_backend_instance_init(Object *o) 113 { 114 object_property_add_bool(o, "share", 115 file_memory_backend_get_share, 116 file_memory_backend_set_share, NULL); 117 object_property_add_str(o, "mem-path", get_mem_path, 118 set_mem_path, NULL); 119 } 120 121 static const TypeInfo file_backend_info = { 122 .name = TYPE_MEMORY_BACKEND_FILE, 123 .parent = TYPE_MEMORY_BACKEND, 124 .class_init = file_backend_class_init, 125 .instance_init = file_backend_instance_init, 126 .instance_size = sizeof(HostMemoryBackendFile), 127 }; 128 129 static void register_types(void) 130 { 131 type_register_static(&file_backend_info); 132 } 133 134 type_init(register_types); 135