1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * uio_hv_generic - generic UIO driver for VMBus 4 * 5 * Copyright (c) 2013-2016 Brocade Communications Systems, Inc. 6 * Copyright (c) 2016, Microsoft Corporation. 7 * 8 * Since the driver does not declare any device ids, you must allocate 9 * id and bind the device to the driver yourself. For example: 10 * 11 * Associate Network GUID with UIO device 12 * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \ 13 * > /sys/bus/vmbus/drivers/uio_hv_generic/new_id 14 * Then rebind 15 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \ 16 * > /sys/bus/vmbus/drivers/hv_netvsc/unbind 17 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \ 18 * > /sys/bus/vmbus/drivers/uio_hv_generic/bind 19 */ 20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 21 22 #include <linux/device.h> 23 #include <linux/kernel.h> 24 #include <linux/module.h> 25 #include <linux/uio_driver.h> 26 #include <linux/netdevice.h> 27 #include <linux/if_ether.h> 28 #include <linux/skbuff.h> 29 #include <linux/hyperv.h> 30 #include <linux/vmalloc.h> 31 #include <linux/slab.h> 32 33 #include "../hv/hyperv_vmbus.h" 34 35 #define DRIVER_VERSION "0.02.1" 36 #define DRIVER_AUTHOR "Stephen Hemminger <sthemmin at microsoft.com>" 37 #define DRIVER_DESC "Generic UIO driver for VMBus devices" 38 39 #define SEND_BUFFER_SIZE (16 * 1024 * 1024) 40 #define RECV_BUFFER_SIZE (31 * 1024 * 1024) 41 42 /* 43 * List of resources to be mapped to user space 44 * can be extended up to MAX_UIO_MAPS(5) items 45 */ 46 enum hv_uio_map { 47 TXRX_RING_MAP = 0, 48 INT_PAGE_MAP, 49 MON_PAGE_MAP, 50 RECV_BUF_MAP, 51 SEND_BUF_MAP 52 }; 53 54 struct hv_uio_private_data { 55 struct uio_info info; 56 struct hv_device *device; 57 atomic_t refcnt; 58 59 void *recv_buf; 60 struct vmbus_gpadl recv_gpadl; 61 char recv_name[32]; /* "recv_4294967295" */ 62 63 void *send_buf; 64 struct vmbus_gpadl send_gpadl; 65 char send_name[32]; 66 }; 67 68 static void set_event(struct vmbus_channel *channel, s32 irq_state) 69 { 70 channel->inbound.ring_buffer->interrupt_mask = !irq_state; 71 if (!channel->offermsg.monitor_allocated && irq_state) { 72 /* MB is needed for host to see the interrupt mask first */ 73 virt_mb(); 74 vmbus_set_event(channel); 75 } 76 } 77 78 /* 79 * This is the irqcontrol callback to be registered to uio_info. 80 * It can be used to disable/enable interrupt from user space processes. 81 * 82 * @param info 83 * pointer to uio_info. 84 * @param irq_state 85 * state value. 1 to enable interrupt, 0 to disable interrupt. 86 */ 87 static int 88 hv_uio_irqcontrol(struct uio_info *info, s32 irq_state) 89 { 90 struct hv_uio_private_data *pdata = info->priv; 91 struct hv_device *dev = pdata->device; 92 struct vmbus_channel *primary, *sc; 93 94 primary = dev->channel; 95 set_event(primary, irq_state); 96 97 mutex_lock(&vmbus_connection.channel_mutex); 98 list_for_each_entry(sc, &primary->sc_list, sc_list) 99 set_event(sc, irq_state); 100 mutex_unlock(&vmbus_connection.channel_mutex); 101 102 return 0; 103 } 104 105 /* 106 * Callback from vmbus_event when something is in inbound ring. 107 */ 108 static void hv_uio_channel_cb(void *context) 109 { 110 struct vmbus_channel *chan = context; 111 struct hv_device *hv_dev; 112 struct hv_uio_private_data *pdata; 113 114 chan->inbound.ring_buffer->interrupt_mask = 1; 115 virt_mb(); 116 117 /* 118 * The callback may come from a subchannel, in which case look 119 * for the hv device in the primary channel 120 */ 121 hv_dev = chan->primary_channel ? 122 chan->primary_channel->device_obj : chan->device_obj; 123 pdata = hv_get_drvdata(hv_dev); 124 uio_event_notify(&pdata->info); 125 } 126 127 /* 128 * Callback from vmbus_event when channel is rescinded. 129 * It is meant for rescind of primary channels only. 130 */ 131 static void hv_uio_rescind(struct vmbus_channel *channel) 132 { 133 struct hv_device *hv_dev = channel->device_obj; 134 struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); 135 136 /* 137 * Turn off the interrupt file handle 138 * Next read for event will return -EIO 139 */ 140 pdata->info.irq = 0; 141 142 /* Wake up reader */ 143 uio_event_notify(&pdata->info); 144 145 /* 146 * With rescind callback registered, rescind path will not unregister the device 147 * from vmbus when the primary channel is rescinded. 148 * Without it, rescind handling is incomplete and next onoffer msg does not come. 149 * Unregister the device from vmbus here. 150 */ 151 vmbus_device_unregister(channel->device_obj); 152 } 153 154 /* Function used for mmap of ring buffer sysfs interface. 155 * The ring buffer is allocated as contiguous memory by vmbus_open 156 */ 157 static int 158 hv_uio_ring_mmap(struct vmbus_channel *channel, struct vm_area_struct *vma) 159 { 160 void *ring_buffer = page_address(channel->ringbuffer_page); 161 162 if (channel->state != CHANNEL_OPENED_STATE) 163 return -ENODEV; 164 165 return vm_iomap_memory(vma, virt_to_phys(ring_buffer), 166 channel->ringbuffer_pagecount << PAGE_SHIFT); 167 } 168 169 /* Callback from VMBUS subsystem when new channel created. */ 170 static void 171 hv_uio_new_channel(struct vmbus_channel *new_sc) 172 { 173 struct hv_device *hv_dev = new_sc->primary_channel->device_obj; 174 struct device *device = &hv_dev->device; 175 const size_t ring_bytes = SZ_2M; 176 int ret; 177 178 /* Create host communication ring */ 179 ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0, 180 hv_uio_channel_cb, new_sc); 181 if (ret) { 182 dev_err(device, "vmbus_open subchannel failed: %d\n", ret); 183 return; 184 } 185 186 /* Disable interrupts on sub channel */ 187 new_sc->inbound.ring_buffer->interrupt_mask = 1; 188 set_channel_read_mode(new_sc, HV_CALL_ISR); 189 ret = hv_create_ring_sysfs(new_sc, hv_uio_ring_mmap); 190 if (ret) { 191 dev_err(device, "sysfs create ring bin file failed; %d\n", ret); 192 vmbus_close(new_sc); 193 } 194 } 195 196 /* free the reserved buffers for send and receive */ 197 static void 198 hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata) 199 { 200 if (pdata->send_gpadl.gpadl_handle) { 201 vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl); 202 if (!pdata->send_gpadl.decrypted) 203 vfree(pdata->send_buf); 204 } 205 206 if (pdata->recv_gpadl.gpadl_handle) { 207 vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl); 208 if (!pdata->recv_gpadl.decrypted) 209 vfree(pdata->recv_buf); 210 } 211 } 212 213 /* VMBus primary channel is opened on first use */ 214 static int 215 hv_uio_open(struct uio_info *info, struct inode *inode) 216 { 217 struct hv_uio_private_data *pdata 218 = container_of(info, struct hv_uio_private_data, info); 219 struct hv_device *dev = pdata->device; 220 int ret; 221 222 if (atomic_inc_return(&pdata->refcnt) != 1) 223 return 0; 224 225 vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind); 226 vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel); 227 228 ret = vmbus_connect_ring(dev->channel, 229 hv_uio_channel_cb, dev->channel); 230 if (ret == 0) 231 dev->channel->inbound.ring_buffer->interrupt_mask = 1; 232 else 233 atomic_dec(&pdata->refcnt); 234 235 return ret; 236 } 237 238 /* VMBus primary channel is closed on last close */ 239 static int 240 hv_uio_release(struct uio_info *info, struct inode *inode) 241 { 242 struct hv_uio_private_data *pdata 243 = container_of(info, struct hv_uio_private_data, info); 244 struct hv_device *dev = pdata->device; 245 int ret = 0; 246 247 if (atomic_dec_and_test(&pdata->refcnt)) 248 ret = vmbus_disconnect_ring(dev->channel); 249 250 return ret; 251 } 252 253 static int 254 hv_uio_probe(struct hv_device *dev, 255 const struct hv_vmbus_device_id *dev_id) 256 { 257 struct vmbus_channel *channel = dev->channel; 258 struct hv_uio_private_data *pdata; 259 void *ring_buffer; 260 int ret; 261 size_t ring_size = hv_dev_ring_size(channel); 262 263 if (!ring_size) 264 ring_size = SZ_2M; 265 266 pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL); 267 if (!pdata) 268 return -ENOMEM; 269 270 ret = vmbus_alloc_ring(channel, ring_size, ring_size); 271 if (ret) 272 return ret; 273 274 set_channel_read_mode(channel, HV_CALL_ISR); 275 276 /* Fill general uio info */ 277 pdata->info.name = "uio_hv_generic"; 278 pdata->info.version = DRIVER_VERSION; 279 pdata->info.irqcontrol = hv_uio_irqcontrol; 280 pdata->info.open = hv_uio_open; 281 pdata->info.release = hv_uio_release; 282 pdata->info.irq = UIO_IRQ_CUSTOM; 283 atomic_set(&pdata->refcnt, 0); 284 285 /* mem resources */ 286 pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings"; 287 ring_buffer = page_address(channel->ringbuffer_page); 288 pdata->info.mem[TXRX_RING_MAP].addr 289 = (uintptr_t)virt_to_phys(ring_buffer); 290 pdata->info.mem[TXRX_RING_MAP].size 291 = channel->ringbuffer_pagecount << PAGE_SHIFT; 292 pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA; 293 294 pdata->info.mem[INT_PAGE_MAP].name = "int_page"; 295 pdata->info.mem[INT_PAGE_MAP].addr 296 = (uintptr_t)vmbus_connection.int_page; 297 pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE; 298 pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL; 299 300 pdata->info.mem[MON_PAGE_MAP].name = "monitor_page"; 301 pdata->info.mem[MON_PAGE_MAP].addr 302 = (uintptr_t)vmbus_connection.monitor_pages[1]; 303 pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE; 304 pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL; 305 306 if (channel->device_id == HV_NIC) { 307 pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE); 308 if (!pdata->recv_buf) { 309 ret = -ENOMEM; 310 goto fail_free_ring; 311 } 312 313 ret = vmbus_establish_gpadl(channel, pdata->recv_buf, 314 RECV_BUFFER_SIZE, &pdata->recv_gpadl); 315 if (ret) { 316 if (!pdata->recv_gpadl.decrypted) 317 vfree(pdata->recv_buf); 318 goto fail_close; 319 } 320 321 /* put Global Physical Address Label in name */ 322 snprintf(pdata->recv_name, sizeof(pdata->recv_name), 323 "recv:%u", pdata->recv_gpadl.gpadl_handle); 324 pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name; 325 pdata->info.mem[RECV_BUF_MAP].addr = (uintptr_t)pdata->recv_buf; 326 pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE; 327 pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL; 328 329 pdata->send_buf = vzalloc(SEND_BUFFER_SIZE); 330 if (!pdata->send_buf) { 331 ret = -ENOMEM; 332 goto fail_close; 333 } 334 335 ret = vmbus_establish_gpadl(channel, pdata->send_buf, 336 SEND_BUFFER_SIZE, &pdata->send_gpadl); 337 if (ret) { 338 if (!pdata->send_gpadl.decrypted) 339 vfree(pdata->send_buf); 340 goto fail_close; 341 } 342 343 snprintf(pdata->send_name, sizeof(pdata->send_name), 344 "send:%u", pdata->send_gpadl.gpadl_handle); 345 pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name; 346 pdata->info.mem[SEND_BUF_MAP].addr = (uintptr_t)pdata->send_buf; 347 pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE; 348 pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL; 349 } 350 351 pdata->info.priv = pdata; 352 pdata->device = dev; 353 354 ret = uio_register_device(&dev->device, &pdata->info); 355 if (ret) { 356 dev_err(&dev->device, "hv_uio register failed\n"); 357 goto fail_close; 358 } 359 360 /* 361 * This internally calls sysfs_update_group, which returns a non-zero value if it executes 362 * before sysfs_create_group. This is expected as the 'ring' will be created later in 363 * vmbus_device_register() -> vmbus_add_channel_kobj(). Thus, no need to check the return 364 * value and print warning. 365 * 366 * Creating/exposing sysfs in driver probe is not encouraged as it can lead to race 367 * conditions with userspace. For backward compatibility, "ring" sysfs could not be removed 368 * or decoupled from uio_hv_generic probe. Userspace programs can make use of inotify 369 * APIs to make sure that ring is created. 370 */ 371 hv_create_ring_sysfs(channel, hv_uio_ring_mmap); 372 373 hv_set_drvdata(dev, pdata); 374 375 return 0; 376 377 fail_close: 378 hv_uio_cleanup(dev, pdata); 379 fail_free_ring: 380 vmbus_free_ring(dev->channel); 381 382 return ret; 383 } 384 385 static void 386 hv_uio_remove(struct hv_device *dev) 387 { 388 struct hv_uio_private_data *pdata = hv_get_drvdata(dev); 389 390 if (!pdata) 391 return; 392 393 hv_remove_ring_sysfs(dev->channel); 394 uio_unregister_device(&pdata->info); 395 hv_uio_cleanup(dev, pdata); 396 397 vmbus_free_ring(dev->channel); 398 } 399 400 static struct hv_driver hv_uio_drv = { 401 .name = "uio_hv_generic", 402 .id_table = NULL, /* only dynamic id's */ 403 .probe = hv_uio_probe, 404 .remove = hv_uio_remove, 405 }; 406 407 static int __init 408 hyperv_module_init(void) 409 { 410 return vmbus_driver_register(&hv_uio_drv); 411 } 412 413 static void __exit 414 hyperv_module_exit(void) 415 { 416 vmbus_driver_unregister(&hv_uio_drv); 417 } 418 419 module_init(hyperv_module_init); 420 module_exit(hyperv_module_exit); 421 422 MODULE_VERSION(DRIVER_VERSION); 423 MODULE_LICENSE("GPL v2"); 424 MODULE_AUTHOR(DRIVER_AUTHOR); 425 MODULE_DESCRIPTION(DRIVER_DESC); 426