drivers/xen/xen-acpi-memhotplug.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2012 Intel Corporation
   4  *    Author: Liu Jinsong <jinsong.liu@intel.com>
   5  *    Author: Jiang Yunhong <yunhong.jiang@intel.com>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/types.h>
  14 #include <linux/acpi.h>
  15 #include <xen/acpi.h>
  16 #include <xen/interface/platform.h>
  17 #include <asm/xen/hypercall.h>
  18
  19 #define PREFIX "ACPI:xen_memory_hotplug:"
  20
  21 struct acpi_memory_info {
  22         struct list_head list;
  23         u64 start_addr;         /* Memory Range start physical addr */
  24         u64 length;             /* Memory Range length */
  25         unsigned short caching; /* memory cache attribute */
  26         unsigned short write_protect;   /* memory read/write attribute */
  27                                 /* copied from buffer getting from _CRS */
  28         unsigned int enabled:1;
  29 };
  30
  31 struct acpi_memory_device {
  32         struct acpi_device *device;
  33         struct list_head res_list;
  34 };
  35
  36 static bool acpi_hotmem_initialized __read_mostly;
  37
  38 static int xen_hotadd_memory(int pxm, struct acpi_memory_info *info)
  39 {
  40         int rc;
  41         struct xen_platform_op op;
  42
  43         op.cmd = XENPF_mem_hotadd;
  44         op.u.mem_add.spfn = info->start_addr >> PAGE_SHIFT;
  45         op.u.mem_add.epfn = (info->start_addr + info->length) >> PAGE_SHIFT;
  46         op.u.mem_add.pxm = pxm;
  47
  48         rc = HYPERVISOR_dom0_op(&op);
  49         if (rc)
  50                 pr_err(PREFIX "Xen Hotplug Memory Add failed on "
  51                         "0x%lx -> 0x%lx, _PXM: %d, error: %d\n",
  52                         (unsigned long)info->start_addr,
  53                         (unsigned long)(info->start_addr + info->length),
  54                         pxm, rc);
  55
  56         return rc;
  57 }
  58
  59 static int xen_acpi_memory_enable_device(struct acpi_memory_device *mem_device)
  60 {
  61         int pxm, result;
  62         int num_enabled = 0;
  63         struct acpi_memory_info *info;
  64
  65         if (!mem_device)
  66                 return -EINVAL;
  67
  68         pxm = xen_acpi_get_pxm(mem_device->device->handle);
  69         if (pxm < 0)
  70                 return pxm;
  71
  72         list_for_each_entry(info, &mem_device->res_list, list) {
  73                 if (info->enabled) { /* just sanity check...*/
  74                         num_enabled++;
  75                         continue;
  76                 }
  77
  78                 if (!info->length)
  79                         continue;
  80
  81                 result = xen_hotadd_memory(pxm, info);
  82                 if (result)
  83                         continue;
  84                 info->enabled = 1;
  85                 num_enabled++;
  86         }
  87
  88         if (!num_enabled)
  89                 return -ENODEV;
  90
  91         return 0;
  92 }
  93
  94 static acpi_status
  95 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
  96 {
  97         struct acpi_memory_device *mem_device = context;
  98         struct acpi_resource_address64 address64;
  99         struct acpi_memory_info *info, *new;
 100         acpi_status status;
 101
 102         status = acpi_resource_to_address64(resource, &address64);
 103         if (ACPI_FAILURE(status) ||
 104             (address64.resource_type != ACPI_MEMORY_RANGE))
 105                 return AE_OK;
 106
 107         list_for_each_entry(info, &mem_device->res_list, list) {
 108                 if ((info->caching == address64.info.mem.caching) &&
 109                     (info->write_protect == address64.info.mem.write_protect) &&
 110                     (info->start_addr + info->length == address64.address.minimum)) {
 111                         info->length += address64.address.address_length;
 112                         return AE_OK;
 113                 }
 114         }
 115
 116         new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
 117         if (!new)
 118                 return AE_ERROR;
 119
 120         INIT_LIST_HEAD(&new->list);
 121         new->caching = address64.info.mem.caching;
 122         new->write_protect = address64.info.mem.write_protect;
 123         new->start_addr = address64.address.minimum;
 124         new->length = address64.address.address_length;
 125         list_add_tail(&new->list, &mem_device->res_list);
 126
 127         return AE_OK;
 128 }
 129
 130 static int
 131 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 132 {
 133         acpi_status status;
 134         struct acpi_memory_info *info, *n;
 135
 136         if (!list_empty(&mem_device->res_list))
 137                 return 0;
 138
 139         status = acpi_walk_resources(mem_device->device->handle,
 140                 METHOD_NAME__CRS, acpi_memory_get_resource, mem_device);
 141
 142         if (ACPI_FAILURE(status)) {
 143                 list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 144                         kfree(info);
 145                 INIT_LIST_HEAD(&mem_device->res_list);
 146                 return -EINVAL;
 147         }
 148
 149         return 0;
 150 }
 151
 152 static int acpi_memory_get_device(acpi_handle handle,
 153                                   struct acpi_memory_device **mem_device)
 154 {
 155         struct acpi_device *device = NULL;
 156         int result = 0;
 157
 158         acpi_scan_lock_acquire();
 159
 160         acpi_bus_get_device(handle, &device);
 161         if (acpi_device_enumerated(device))
 162                 goto end;
 163
 164         /*
 165          * Now add the notified device.  This creates the acpi_device
 166          * and invokes .add function
 167          */
 168         result = acpi_bus_scan(handle);
 169         if (result) {
 170                 pr_warn(PREFIX "ACPI namespace scan failed\n");
 171                 result = -EINVAL;
 172                 goto out;
 173         }
 174         device = NULL;
 175         acpi_bus_get_device(handle, &device);
 176         if (!acpi_device_enumerated(device)) {
 177                 pr_warn(PREFIX "Missing device object\n");
 178                 result = -EINVAL;
 179                 goto out;
 180         }
 181
 182 end:
 183         *mem_device = acpi_driver_data(device);
 184         if (!(*mem_device)) {
 185                 pr_err(PREFIX "driver data not found\n");
 186                 result = -ENODEV;
 187                 goto out;
 188         }
 189
 190 out:
 191         acpi_scan_lock_release();
 192         return result;
 193 }
 194
 195 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 196 {
 197         unsigned long long current_status;
 198
 199         /* Get device present/absent information from the _STA */
 200         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
 201                                 "_STA", NULL, &current_status)))
 202                 return -ENODEV;
 203         /*
 204          * Check for device status. Device should be
 205          * present/enabled/functioning.
 206          */
 207         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 208               && (current_status & ACPI_STA_DEVICE_ENABLED)
 209               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 210                 return -ENODEV;
 211
 212         return 0;
 213 }
 214
 215 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 216 {
 217         pr_debug(PREFIX "Xen does not support memory hotremove\n");
 218
 219         return -ENOSYS;
 220 }
 221
 222 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 223 {
 224         struct acpi_memory_device *mem_device;
 225         struct acpi_device *device;
 226         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 227
 228         switch (event) {
 229         case ACPI_NOTIFY_BUS_CHECK:
 230                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 231                         "\nReceived BUS CHECK notification for device\n"));
 232                 fallthrough;
 233         case ACPI_NOTIFY_DEVICE_CHECK:
 234                 if (event == ACPI_NOTIFY_DEVICE_CHECK)
 235                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 236                         "\nReceived DEVICE CHECK notification for device\n"));
 237
 238                 if (acpi_memory_get_device(handle, &mem_device)) {
 239                         pr_err(PREFIX "Cannot find driver data\n");
 240                         break;
 241                 }
 242
 243                 ost_code = ACPI_OST_SC_SUCCESS;
 244                 break;
 245
 246         case ACPI_NOTIFY_EJECT_REQUEST:
 247                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 248                         "\nReceived EJECT REQUEST notification for device\n"));
 249
 250                 acpi_scan_lock_acquire();
 251                 if (acpi_bus_get_device(handle, &device)) {
 252                         acpi_scan_lock_release();
 253                         pr_err(PREFIX "Device doesn't exist\n");
 254                         break;
 255                 }
 256                 mem_device = acpi_driver_data(device);
 257                 if (!mem_device) {
 258                         acpi_scan_lock_release();
 259                         pr_err(PREFIX "Driver Data is NULL\n");
 260                         break;
 261                 }
 262
 263                 /*
 264                  * TBD: implement acpi_memory_disable_device and invoke
 265                  * acpi_bus_remove if Xen support hotremove in the future
 266                  */
 267                 acpi_memory_disable_device(mem_device);
 268                 acpi_scan_lock_release();
 269                 break;
 270
 271         default:
 272                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 273                                   "Unsupported event [0x%x]\n", event));
 274                 /* non-hotplug event; possibly handled by other handler */
 275                 return;
 276         }
 277
 278         (void) acpi_evaluate_ost(handle, event, ost_code, NULL);
 279         return;
 280 }
 281
 282 static int xen_acpi_memory_device_add(struct acpi_device *device)
 283 {
 284         int result;
 285         struct acpi_memory_device *mem_device = NULL;
 286
 287
 288         if (!device)
 289                 return -EINVAL;
 290
 291         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 292         if (!mem_device)
 293                 return -ENOMEM;
 294
 295         INIT_LIST_HEAD(&mem_device->res_list);
 296         mem_device->device = device;
 297         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 298         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 299         device->driver_data = mem_device;
 300
 301         /* Get the range from the _CRS */
 302         result = acpi_memory_get_device_resources(mem_device);
 303         if (result) {
 304                 kfree(mem_device);
 305                 return result;
 306         }
 307
 308         /*
 309          * For booting existed memory devices, early boot code has recognized
 310          * memory area by EFI/E820. If DSDT shows these memory devices on boot,
 311          * hotplug is not necessary for them.
 312          * For hot-added memory devices during runtime, it need hypercall to
 313          * Xen hypervisor to add memory.
 314          */
 315         if (!acpi_hotmem_initialized)
 316                 return 0;
 317
 318         if (!acpi_memory_check_device(mem_device))
 319                 result = xen_acpi_memory_enable_device(mem_device);
 320
 321         return result;
 322 }
 323
 324 static int xen_acpi_memory_device_remove(struct acpi_device *device)
 325 {
 326         struct acpi_memory_device *mem_device = NULL;
 327
 328         if (!device || !acpi_driver_data(device))
 329                 return -EINVAL;
 330
 331         mem_device = acpi_driver_data(device);
 332         kfree(mem_device);
 333
 334         return 0;
 335 }
 336
 337 /*
 338  * Helper function to check for memory device
 339  */
 340 static acpi_status is_memory_device(acpi_handle handle)
 341 {
 342         char *hardware_id;
 343         acpi_status status;
 344         struct acpi_device_info *info;
 345
 346         status = acpi_get_object_info(handle, &info);
 347         if (ACPI_FAILURE(status))
 348                 return status;
 349
 350         if (!(info->valid & ACPI_VALID_HID)) {
 351                 kfree(info);
 352                 return AE_ERROR;
 353         }
 354
 355         hardware_id = info->hardware_id.string;
 356         if ((hardware_id == NULL) ||
 357             (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 358                 status = AE_ERROR;
 359
 360         kfree(info);
 361         return status;
 362 }
 363
 364 static acpi_status
 365 acpi_memory_register_notify_handler(acpi_handle handle,
 366                                     u32 level, void *ctxt, void **retv)
 367 {
 368         acpi_status status;
 369
 370         status = is_memory_device(handle);
 371         if (ACPI_FAILURE(status))
 372                 return AE_OK;   /* continue */
 373
 374         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 375                                              acpi_memory_device_notify, NULL);
 376         /* continue */
 377         return AE_OK;
 378 }
 379
 380 static acpi_status
 381 acpi_memory_deregister_notify_handler(acpi_handle handle,
 382                                       u32 level, void *ctxt, void **retv)
 383 {
 384         acpi_status status;
 385
 386         status = is_memory_device(handle);
 387         if (ACPI_FAILURE(status))
 388                 return AE_OK;   /* continue */
 389
 390         status = acpi_remove_notify_handler(handle,
 391                                             ACPI_SYSTEM_NOTIFY,
 392                                             acpi_memory_device_notify);
 393
 394         return AE_OK;   /* continue */
 395 }
 396
 397 static const struct acpi_device_id memory_device_ids[] = {
 398         {ACPI_MEMORY_DEVICE_HID, 0},
 399         {"", 0},
 400 };
 401 MODULE_DEVICE_TABLE(acpi, memory_device_ids);
 402
 403 static struct acpi_driver xen_acpi_memory_device_driver = {
 404         .name = "acpi_memhotplug",
 405         .class = ACPI_MEMORY_DEVICE_CLASS,
 406         .ids = memory_device_ids,
 407         .ops = {
 408                 .add = xen_acpi_memory_device_add,
 409                 .remove = xen_acpi_memory_device_remove,
 410                 },
 411 };
 412
 413 static int __init xen_acpi_memory_device_init(void)
 414 {
 415         int result;
 416         acpi_status status;
 417
 418         if (!xen_initial_domain())
 419                 return -ENODEV;
 420
 421         /* unregister the stub which only used to reserve driver space */
 422         xen_stub_memory_device_exit();
 423
 424         result = acpi_bus_register_driver(&xen_acpi_memory_device_driver);
 425         if (result < 0) {
 426                 xen_stub_memory_device_init();
 427                 return -ENODEV;
 428         }
 429
 430         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 431                                      ACPI_UINT32_MAX,
 432                                      acpi_memory_register_notify_handler,
 433                                      NULL, NULL, NULL);
 434
 435         if (ACPI_FAILURE(status)) {
 436                 pr_warn(PREFIX "walk_namespace failed\n");
 437                 acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
 438                 xen_stub_memory_device_init();
 439                 return -ENODEV;
 440         }
 441
 442         acpi_hotmem_initialized = true;
 443         return 0;
 444 }
 445
 446 static void __exit xen_acpi_memory_device_exit(void)
 447 {
 448         acpi_status status;
 449
 450         if (!xen_initial_domain())
 451                 return;
 452
 453         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 454                                      ACPI_UINT32_MAX,
 455                                      acpi_memory_deregister_notify_handler,
 456                                      NULL, NULL, NULL);
 457         if (ACPI_FAILURE(status))
 458                 pr_warn(PREFIX "walk_namespace failed\n");
 459
 460         acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
 461
 462         /*
 463          * stub reserve space again to prevent any chance of native
 464          * driver loading.
 465          */
 466         xen_stub_memory_device_init();
 467         return;
 468 }
 469
 470 module_init(xen_acpi_memory_device_init);
 471 module_exit(xen_acpi_memory_device_exit);
 472 ACPI_MODULE_NAME("xen-acpi-memhotplug");
 473 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
 474 MODULE_DESCRIPTION("Xen Hotplug Mem Driver");
 475 MODULE_LICENSE("GPL");