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 HV_RING_SIZE 512 /* pages */ 40 #define SEND_BUFFER_SIZE (16 * 1024 * 1024) 41 #define RECV_BUFFER_SIZE (31 * 1024 * 1024) 42 43 /* 44 * List of resources to be mapped to user space 45 * can be extended up to MAX_UIO_MAPS(5) items 46 */ 47 enum hv_uio_map { 48 TXRX_RING_MAP = 0, 49 INT_PAGE_MAP, 50 MON_PAGE_MAP, 51 RECV_BUF_MAP, 52 SEND_BUF_MAP 53 }; 54 55 struct hv_uio_private_data { 56 struct uio_info info; 57 struct hv_device *device; 58 atomic_t refcnt; 59 60 void *recv_buf; 61 struct vmbus_gpadl recv_gpadl; 62 char recv_name[32]; /* "recv_4294967295" */ 63 64 void *send_buf; 65 struct vmbus_gpadl send_gpadl; 66 char send_name[32]; 67 }; 68 69 /* 70 * This is the irqcontrol callback to be registered to uio_info. 71 * It can be used to disable/enable interrupt from user space processes. 72 * 73 * @param info 74 * pointer to uio_info. 75 * @param irq_state 76 * state value. 1 to enable interrupt, 0 to disable interrupt. 77 */ 78 static int 79 hv_uio_irqcontrol(struct uio_info *info, s32 irq_state) 80 { 81 struct hv_uio_private_data *pdata = info->priv; 82 struct hv_device *dev = pdata->device; 83 84 dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state; 85 virt_mb(); 86 87 return 0; 88 } 89 90 /* 91 * Callback from vmbus_event when something is in inbound ring. 92 */ 93 static void hv_uio_channel_cb(void *context) 94 { 95 struct vmbus_channel *chan = context; 96 struct hv_device *hv_dev = chan->device_obj; 97 struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); 98 99 chan->inbound.ring_buffer->interrupt_mask = 1; 100 virt_mb(); 101 102 uio_event_notify(&pdata->info); 103 } 104 105 /* 106 * Callback from vmbus_event when channel is rescinded. 107 * It is meant for rescind of primary channels only. 108 */ 109 static void hv_uio_rescind(struct vmbus_channel *channel) 110 { 111 struct hv_device *hv_dev = channel->device_obj; 112 struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); 113 114 /* 115 * Turn off the interrupt file handle 116 * Next read for event will return -EIO 117 */ 118 pdata->info.irq = 0; 119 120 /* Wake up reader */ 121 uio_event_notify(&pdata->info); 122 123 /* 124 * With rescind callback registered, rescind path will not unregister the device 125 * from vmbus when the primary channel is rescinded. 126 * Without it, rescind handling is incomplete and next onoffer msg does not come. 127 * Unregister the device from vmbus here. 128 */ 129 vmbus_device_unregister(channel->device_obj); 130 } 131 132 /* Sysfs API to allow mmap of the ring buffers 133 * The ring buffer is allocated as contiguous memory by vmbus_open 134 */ 135 static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj, 136 struct bin_attribute *attr, 137 struct vm_area_struct *vma) 138 { 139 struct vmbus_channel *channel 140 = container_of(kobj, struct vmbus_channel, kobj); 141 void *ring_buffer = page_address(channel->ringbuffer_page); 142 143 if (channel->state != CHANNEL_OPENED_STATE) 144 return -ENODEV; 145 146 return vm_iomap_memory(vma, virt_to_phys(ring_buffer), 147 channel->ringbuffer_pagecount << PAGE_SHIFT); 148 } 149 150 static const struct bin_attribute ring_buffer_bin_attr = { 151 .attr = { 152 .name = "ring", 153 .mode = 0600, 154 }, 155 .size = 2 * HV_RING_SIZE * PAGE_SIZE, 156 .mmap = hv_uio_ring_mmap, 157 }; 158 159 /* Callback from VMBUS subsystem when new channel created. */ 160 static void 161 hv_uio_new_channel(struct vmbus_channel *new_sc) 162 { 163 struct hv_device *hv_dev = new_sc->primary_channel->device_obj; 164 struct device *device = &hv_dev->device; 165 const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE; 166 int ret; 167 168 /* Create host communication ring */ 169 ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0, 170 hv_uio_channel_cb, new_sc); 171 if (ret) { 172 dev_err(device, "vmbus_open subchannel failed: %d\n", ret); 173 return; 174 } 175 176 /* Disable interrupts on sub channel */ 177 new_sc->inbound.ring_buffer->interrupt_mask = 1; 178 set_channel_read_mode(new_sc, HV_CALL_ISR); 179 180 ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr); 181 if (ret) { 182 dev_err(device, "sysfs create ring bin file failed; %d\n", ret); 183 vmbus_close(new_sc); 184 } 185 } 186 187 /* free the reserved buffers for send and receive */ 188 static void 189 hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata) 190 { 191 if (pdata->send_gpadl.gpadl_handle) { 192 vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl); 193 if (!pdata->send_gpadl.decrypted) 194 vfree(pdata->send_buf); 195 } 196 197 if (pdata->recv_gpadl.gpadl_handle) { 198 vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl); 199 if (!pdata->recv_gpadl.decrypted) 200 vfree(pdata->recv_buf); 201 } 202 } 203 204 /* VMBus primary channel is opened on first use */ 205 static int 206 hv_uio_open(struct uio_info *info, struct inode *inode) 207 { 208 struct hv_uio_private_data *pdata 209 = container_of(info, struct hv_uio_private_data, info); 210 struct hv_device *dev = pdata->device; 211 int ret; 212 213 if (atomic_inc_return(&pdata->refcnt) != 1) 214 return 0; 215 216 vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind); 217 vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel); 218 219 ret = vmbus_connect_ring(dev->channel, 220 hv_uio_channel_cb, dev->channel); 221 if (ret == 0) 222 dev->channel->inbound.ring_buffer->interrupt_mask = 1; 223 else 224 atomic_dec(&pdata->refcnt); 225 226 return ret; 227 } 228 229 /* VMBus primary channel is closed on last close */ 230 static int 231 hv_uio_release(struct uio_info *info, struct inode *inode) 232 { 233 struct hv_uio_private_data *pdata 234 = container_of(info, struct hv_uio_private_data, info); 235 struct hv_device *dev = pdata->device; 236 int ret = 0; 237 238 if (atomic_dec_and_test(&pdata->refcnt)) 239 ret = vmbus_disconnect_ring(dev->channel); 240 241 return ret; 242 } 243 244 static int 245 hv_uio_probe(struct hv_device *dev, 246 const struct hv_vmbus_device_id *dev_id) 247 { 248 struct vmbus_channel *channel = dev->channel; 249 struct hv_uio_private_data *pdata; 250 void *ring_buffer; 251 int ret; 252 253 /* Communicating with host has to be via shared memory not hypercall */ 254 if (!channel->offermsg.monitor_allocated) { 255 dev_err(&dev->device, "vmbus channel requires hypercall\n"); 256 return -ENOTSUPP; 257 } 258 259 pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL); 260 if (!pdata) 261 return -ENOMEM; 262 263 ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE, 264 HV_RING_SIZE * PAGE_SIZE); 265 if (ret) 266 return ret; 267 268 set_channel_read_mode(channel, HV_CALL_ISR); 269 270 /* Fill general uio info */ 271 pdata->info.name = "uio_hv_generic"; 272 pdata->info.version = DRIVER_VERSION; 273 pdata->info.irqcontrol = hv_uio_irqcontrol; 274 pdata->info.open = hv_uio_open; 275 pdata->info.release = hv_uio_release; 276 pdata->info.irq = UIO_IRQ_CUSTOM; 277 atomic_set(&pdata->refcnt, 0); 278 279 /* mem resources */ 280 pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings"; 281 ring_buffer = page_address(channel->ringbuffer_page); 282 pdata->info.mem[TXRX_RING_MAP].addr 283 = (uintptr_t)virt_to_phys(ring_buffer); 284 pdata->info.mem[TXRX_RING_MAP].size 285 = channel->ringbuffer_pagecount << PAGE_SHIFT; 286 pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA; 287 288 pdata->info.mem[INT_PAGE_MAP].name = "int_page"; 289 pdata->info.mem[INT_PAGE_MAP].addr 290 = (uintptr_t)vmbus_connection.int_page; 291 pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE; 292 pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL; 293 294 pdata->info.mem[MON_PAGE_MAP].name = "monitor_page"; 295 pdata->info.mem[MON_PAGE_MAP].addr 296 = (uintptr_t)vmbus_connection.monitor_pages[1]; 297 pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE; 298 pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL; 299 300 pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE); 301 if (pdata->recv_buf == NULL) { 302 ret = -ENOMEM; 303 goto fail_free_ring; 304 } 305 306 ret = vmbus_establish_gpadl(channel, pdata->recv_buf, 307 RECV_BUFFER_SIZE, &pdata->recv_gpadl); 308 if (ret) { 309 if (!pdata->recv_gpadl.decrypted) 310 vfree(pdata->recv_buf); 311 goto fail_close; 312 } 313 314 /* put Global Physical Address Label in name */ 315 snprintf(pdata->recv_name, sizeof(pdata->recv_name), 316 "recv:%u", pdata->recv_gpadl.gpadl_handle); 317 pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name; 318 pdata->info.mem[RECV_BUF_MAP].addr 319 = (uintptr_t)pdata->recv_buf; 320 pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE; 321 pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL; 322 323 pdata->send_buf = vzalloc(SEND_BUFFER_SIZE); 324 if (pdata->send_buf == NULL) { 325 ret = -ENOMEM; 326 goto fail_close; 327 } 328 329 ret = vmbus_establish_gpadl(channel, pdata->send_buf, 330 SEND_BUFFER_SIZE, &pdata->send_gpadl); 331 if (ret) { 332 if (!pdata->send_gpadl.decrypted) 333 vfree(pdata->send_buf); 334 goto fail_close; 335 } 336 337 snprintf(pdata->send_name, sizeof(pdata->send_name), 338 "send:%u", pdata->send_gpadl.gpadl_handle); 339 pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name; 340 pdata->info.mem[SEND_BUF_MAP].addr 341 = (uintptr_t)pdata->send_buf; 342 pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE; 343 pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL; 344 345 pdata->info.priv = pdata; 346 pdata->device = dev; 347 348 ret = uio_register_device(&dev->device, &pdata->info); 349 if (ret) { 350 dev_err(&dev->device, "hv_uio register failed\n"); 351 goto fail_close; 352 } 353 354 ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr); 355 if (ret) 356 dev_notice(&dev->device, 357 "sysfs create ring bin file failed; %d\n", ret); 358 359 hv_set_drvdata(dev, pdata); 360 361 return 0; 362 363 fail_close: 364 hv_uio_cleanup(dev, pdata); 365 fail_free_ring: 366 vmbus_free_ring(dev->channel); 367 368 return ret; 369 } 370 371 static void 372 hv_uio_remove(struct hv_device *dev) 373 { 374 struct hv_uio_private_data *pdata = hv_get_drvdata(dev); 375 376 if (!pdata) 377 return; 378 379 sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr); 380 uio_unregister_device(&pdata->info); 381 hv_uio_cleanup(dev, pdata); 382 383 vmbus_free_ring(dev->channel); 384 } 385 386 static struct hv_driver hv_uio_drv = { 387 .name = "uio_hv_generic", 388 .id_table = NULL, /* only dynamic id's */ 389 .probe = hv_uio_probe, 390 .remove = hv_uio_remove, 391 }; 392 393 static int __init 394 hyperv_module_init(void) 395 { 396 return vmbus_driver_register(&hv_uio_drv); 397 } 398 399 static void __exit 400 hyperv_module_exit(void) 401 { 402 vmbus_driver_unregister(&hv_uio_drv); 403 } 404 405 module_init(hyperv_module_init); 406 module_exit(hyperv_module_exit); 407 408 MODULE_VERSION(DRIVER_VERSION); 409 MODULE_LICENSE("GPL v2"); 410 MODULE_AUTHOR(DRIVER_AUTHOR); 411 MODULE_DESCRIPTION(DRIVER_DESC); 412