Bugfix: Handle error if VM Generation ID device not present
[qemu.git] / hw / acpi / vmgenid.c
1 /*
2 * Virtual Machine Generation ID Device
3 *
4 * Copyright (C) 2017 Skyport Systems.
5 *
6 * Author: Ben Warren <ben@skyportsystems.com>
7 *
8 * This work is licensed under the terms of the GNU GPL, version 2 or later.
9 * See the COPYING file in the top-level directory.
10 *
11 */
12
13 #include "qemu/osdep.h"
14 #include "qmp-commands.h"
15 #include "hw/acpi/acpi.h"
16 #include "hw/acpi/aml-build.h"
17 #include "hw/acpi/vmgenid.h"
18 #include "hw/nvram/fw_cfg.h"
19 #include "sysemu/sysemu.h"
20
21 void vmgenid_build_acpi(VmGenIdState *vms, GArray *table_data, GArray *guid,
22 BIOSLinker *linker)
23 {
24 Aml *ssdt, *dev, *scope, *method, *addr, *if_ctx;
25 uint32_t vgia_offset;
26 QemuUUID guid_le;
27
28 /* Fill in the GUID values. These need to be converted to little-endian
29 * first, since that's what the guest expects
30 */
31 g_array_set_size(guid, VMGENID_FW_CFG_SIZE - ARRAY_SIZE(guid_le.data));
32 guid_le = vms->guid;
33 qemu_uuid_bswap(&guid_le);
34 /* The GUID is written at a fixed offset into the fw_cfg file
35 * in order to implement the "OVMF SDT Header probe suppressor"
36 * see docs/specs/vmgenid.txt for more details
37 */
38 g_array_insert_vals(guid, VMGENID_GUID_OFFSET, guid_le.data,
39 ARRAY_SIZE(guid_le.data));
40
41 /* Put this in a separate SSDT table */
42 ssdt = init_aml_allocator();
43
44 /* Reserve space for header */
45 acpi_data_push(ssdt->buf, sizeof(AcpiTableHeader));
46
47 /* Storage for the GUID address */
48 vgia_offset = table_data->len +
49 build_append_named_dword(ssdt->buf, "VGIA");
50 scope = aml_scope("\\_SB");
51 dev = aml_device("VGEN");
52 aml_append(dev, aml_name_decl("_HID", aml_string("QEMUVGID")));
53 aml_append(dev, aml_name_decl("_CID", aml_string("VM_Gen_Counter")));
54 aml_append(dev, aml_name_decl("_DDN", aml_string("VM_Gen_Counter")));
55
56 /* Simple status method to check that address is linked and non-zero */
57 method = aml_method("_STA", 0, AML_NOTSERIALIZED);
58 addr = aml_local(0);
59 aml_append(method, aml_store(aml_int(0xf), addr));
60 if_ctx = aml_if(aml_equal(aml_name("VGIA"), aml_int(0)));
61 aml_append(if_ctx, aml_store(aml_int(0), addr));
62 aml_append(method, if_ctx);
63 aml_append(method, aml_return(addr));
64 aml_append(dev, method);
65
66 /* the ADDR method returns two 32-bit words representing the lower and
67 * upper halves * of the physical address of the fw_cfg blob
68 * (holding the GUID)
69 */
70 method = aml_method("ADDR", 0, AML_NOTSERIALIZED);
71
72 addr = aml_local(0);
73 aml_append(method, aml_store(aml_package(2), addr));
74
75 aml_append(method, aml_store(aml_add(aml_name("VGIA"),
76 aml_int(VMGENID_GUID_OFFSET), NULL),
77 aml_index(addr, aml_int(0))));
78 aml_append(method, aml_store(aml_int(0), aml_index(addr, aml_int(1))));
79 aml_append(method, aml_return(addr));
80
81 aml_append(dev, method);
82 aml_append(scope, dev);
83 aml_append(ssdt, scope);
84
85 /* attach an ACPI notify */
86 method = aml_method("\\_GPE._E05", 0, AML_NOTSERIALIZED);
87 aml_append(method, aml_notify(aml_name("\\_SB.VGEN"), aml_int(0x80)));
88 aml_append(ssdt, method);
89
90 g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
91
92 /* Allocate guest memory for the Data fw_cfg blob */
93 bios_linker_loader_alloc(linker, VMGENID_GUID_FW_CFG_FILE, guid, 4096,
94 false /* page boundary, high memory */);
95
96 /* Patch address of GUID fw_cfg blob into the ADDR fw_cfg blob
97 * so QEMU can write the GUID there. The address is expected to be
98 * < 4GB, but write 64 bits anyway.
99 * The address that is patched in is offset in order to implement
100 * the "OVMF SDT Header probe suppressor"
101 * see docs/specs/vmgenid.txt for more details.
102 */
103 bios_linker_loader_write_pointer(linker,
104 VMGENID_ADDR_FW_CFG_FILE, 0, sizeof(uint64_t),
105 VMGENID_GUID_FW_CFG_FILE, VMGENID_GUID_OFFSET);
106
107 /* Patch address of GUID fw_cfg blob into the AML so OSPM can retrieve
108 * and read it. Note that while we provide storage for 64 bits, only
109 * the least-signficant 32 get patched into AML.
110 */
111 bios_linker_loader_add_pointer(linker,
112 ACPI_BUILD_TABLE_FILE, vgia_offset, sizeof(uint32_t),
113 VMGENID_GUID_FW_CFG_FILE, 0);
114
115 build_header(linker, table_data,
116 (void *)(table_data->data + table_data->len - ssdt->buf->len),
117 "SSDT", ssdt->buf->len, 1, NULL, "VMGENID");
118 free_aml_allocator();
119 }
120
121 void vmgenid_add_fw_cfg(VmGenIdState *vms, FWCfgState *s, GArray *guid)
122 {
123 /* Create a read-only fw_cfg file for GUID */
124 fw_cfg_add_file(s, VMGENID_GUID_FW_CFG_FILE, guid->data,
125 VMGENID_FW_CFG_SIZE);
126 /* Create a read-write fw_cfg file for Address */
127 fw_cfg_add_file_callback(s, VMGENID_ADDR_FW_CFG_FILE, NULL, NULL,
128 vms->vmgenid_addr_le,
129 ARRAY_SIZE(vms->vmgenid_addr_le), false);
130 }
131
132 static void vmgenid_update_guest(VmGenIdState *vms)
133 {
134 Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
135 uint32_t vmgenid_addr;
136 QemuUUID guid_le;
137
138 if (obj) {
139 /* Write the GUID to guest memory */
140 memcpy(&vmgenid_addr, vms->vmgenid_addr_le, sizeof(vmgenid_addr));
141 vmgenid_addr = le32_to_cpu(vmgenid_addr);
142 /* A zero value in vmgenid_addr means that BIOS has not yet written
143 * the address
144 */
145 if (vmgenid_addr) {
146 /* QemuUUID has the first three words as big-endian, and expect
147 * that any GUIDs passed in will always be BE. The guest,
148 * however, will expect the fields to be little-endian.
149 * Perform a byte swap immediately before writing.
150 */
151 guid_le = vms->guid;
152 qemu_uuid_bswap(&guid_le);
153 /* The GUID is written at a fixed offset into the fw_cfg file
154 * in order to implement the "OVMF SDT Header probe suppressor"
155 * see docs/specs/vmgenid.txt for more details.
156 */
157 cpu_physical_memory_write(vmgenid_addr, guid_le.data,
158 sizeof(guid_le.data));
159 /* Send _GPE.E05 event */
160 acpi_send_event(DEVICE(obj), ACPI_VMGENID_CHANGE_STATUS);
161 }
162 }
163 }
164
165 static void vmgenid_set_guid(Object *obj, const char *value, Error **errp)
166 {
167 VmGenIdState *vms = VMGENID(obj);
168
169 if (!strcmp(value, "auto")) {
170 qemu_uuid_generate(&vms->guid);
171 } else if (qemu_uuid_parse(value, &vms->guid) < 0) {
172 error_setg(errp, "'%s. %s': Failed to parse GUID string: %s",
173 object_get_typename(OBJECT(vms)), VMGENID_GUID, value);
174 return;
175 }
176
177 vmgenid_update_guest(vms);
178 }
179
180 /* After restoring an image, we need to update the guest memory and notify
181 * it of a potential change to VM Generation ID
182 */
183 static int vmgenid_post_load(void *opaque, int version_id)
184 {
185 VmGenIdState *vms = opaque;
186 vmgenid_update_guest(vms);
187 return 0;
188 }
189
190 static const VMStateDescription vmstate_vmgenid = {
191 .name = "vmgenid",
192 .version_id = 1,
193 .minimum_version_id = 1,
194 .post_load = vmgenid_post_load,
195 .fields = (VMStateField[]) {
196 VMSTATE_UINT8_ARRAY(vmgenid_addr_le, VmGenIdState, sizeof(uint64_t)),
197 VMSTATE_END_OF_LIST()
198 },
199 };
200
201 static void vmgenid_handle_reset(void *opaque)
202 {
203 VmGenIdState *vms = VMGENID(opaque);
204 /* Clear the guest-allocated GUID address when the VM resets */
205 memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le));
206 }
207
208 static void vmgenid_realize(DeviceState *dev, Error **errp)
209 {
210 VmGenIdState *vms = VMGENID(dev);
211 qemu_register_reset(vmgenid_handle_reset, vms);
212 }
213
214 static void vmgenid_device_class_init(ObjectClass *klass, void *data)
215 {
216 DeviceClass *dc = DEVICE_CLASS(klass);
217
218 dc->vmsd = &vmstate_vmgenid;
219 dc->realize = vmgenid_realize;
220 dc->hotpluggable = false;
221
222 object_class_property_add_str(klass, VMGENID_GUID, NULL,
223 vmgenid_set_guid, NULL);
224 object_class_property_set_description(klass, VMGENID_GUID,
225 "Set Global Unique Identifier "
226 "(big-endian) or auto for random value",
227 NULL);
228 }
229
230 static const TypeInfo vmgenid_device_info = {
231 .name = VMGENID_DEVICE,
232 .parent = TYPE_DEVICE,
233 .instance_size = sizeof(VmGenIdState),
234 .class_init = vmgenid_device_class_init,
235 };
236
237 static void vmgenid_register_types(void)
238 {
239 type_register_static(&vmgenid_device_info);
240 }
241
242 type_init(vmgenid_register_types)
243
244 GuidInfo *qmp_query_vm_generation_id(Error **errp)
245 {
246 GuidInfo *info;
247 VmGenIdState *vms;
248 Object *obj = find_vmgenid_dev();
249
250 if (!obj) {
251 error_setg(errp, "VM Generation ID device not found");
252 return NULL;
253 }
254 vms = VMGENID(obj);
255
256 info = g_malloc0(sizeof(*info));
257 info->guid = qemu_uuid_unparse_strdup(&vms->guid);
258 return info;
259 }