drivers/uio/uio_hv_generic.c

   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 /*
  69  * This is the irqcontrol callback to be registered to uio_info.
  70  * It can be used to disable/enable interrupt from user space processes.
  71  *
  72  * @param info
  73  *  pointer to uio_info.
  74  * @param irq_state
  75  *  state value. 1 to enable interrupt, 0 to disable interrupt.
  76  */
  77 static int
  78 hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
  79 {
  80         struct hv_uio_private_data *pdata = info->priv;
  81         struct hv_device *dev = pdata->device;
  82
  83         dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
  84         virt_mb();
  85
  86         if (!dev->channel->offermsg.monitor_allocated && irq_state)
  87                 vmbus_setevent(dev->channel);
  88
  89         return 0;
  90 }
  91
  92 /*
  93  * Callback from vmbus_event when something is in inbound ring.
  94  */
  95 static void hv_uio_channel_cb(void *context)
  96 {
  97         struct vmbus_channel *chan = context;
  98         struct hv_device *hv_dev = chan->device_obj;
  99         struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
 100
 101         chan->inbound.ring_buffer->interrupt_mask = 1;
 102         virt_mb();
 103
 104         uio_event_notify(&pdata->info);
 105 }
 106
 107 /*
 108  * Callback from vmbus_event when channel is rescinded.
 109  * It is meant for rescind of primary channels only.
 110  */
 111 static void hv_uio_rescind(struct vmbus_channel *channel)
 112 {
 113         struct hv_device *hv_dev = channel->device_obj;
 114         struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
 115
 116         /*
 117          * Turn off the interrupt file handle
 118          * Next read for event will return -EIO
 119          */
 120         pdata->info.irq = 0;
 121
 122         /* Wake up reader */
 123         uio_event_notify(&pdata->info);
 124
 125         /*
 126          * With rescind callback registered, rescind path will not unregister the device
 127          * from vmbus when the primary channel is rescinded.
 128          * Without it, rescind handling is incomplete and next onoffer msg does not come.
 129          * Unregister the device from vmbus here.
 130          */
 131         vmbus_device_unregister(channel->device_obj);
 132 }
 133
 134 /* Sysfs API to allow mmap of the ring buffers
 135  * The ring buffer is allocated as contiguous memory by vmbus_open
 136  */
 137 static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
 138                             const struct bin_attribute *attr,
 139                             struct vm_area_struct *vma)
 140 {
 141         struct vmbus_channel *channel
 142                 = container_of(kobj, struct vmbus_channel, kobj);
 143         void *ring_buffer = page_address(channel->ringbuffer_page);
 144
 145         if (channel->state != CHANNEL_OPENED_STATE)
 146                 return -ENODEV;
 147
 148         return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
 149                                channel->ringbuffer_pagecount << PAGE_SHIFT);
 150 }
 151
 152 static const struct bin_attribute ring_buffer_bin_attr = {
 153         .attr = {
 154                 .name = "ring",
 155                 .mode = 0600,
 156         },
 157         .size = 2 * SZ_2M,
 158         .mmap = hv_uio_ring_mmap,
 159 };
 160
 161 /* Callback from VMBUS subsystem when new channel created. */
 162 static void
 163 hv_uio_new_channel(struct vmbus_channel *new_sc)
 164 {
 165         struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
 166         struct device *device = &hv_dev->device;
 167         const size_t ring_bytes = SZ_2M;
 168         int ret;
 169
 170         /* Create host communication ring */
 171         ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
 172                          hv_uio_channel_cb, new_sc);
 173         if (ret) {
 174                 dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
 175                 return;
 176         }
 177
 178         /* Disable interrupts on sub channel */
 179         new_sc->inbound.ring_buffer->interrupt_mask = 1;
 180         set_channel_read_mode(new_sc, HV_CALL_ISR);
 181
 182         ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
 183         if (ret) {
 184                 dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
 185                 vmbus_close(new_sc);
 186         }
 187 }
 188
 189 /* free the reserved buffers for send and receive */
 190 static void
 191 hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
 192 {
 193         if (pdata->send_gpadl.gpadl_handle) {
 194                 vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl);
 195                 if (!pdata->send_gpadl.decrypted)
 196                         vfree(pdata->send_buf);
 197         }
 198
 199         if (pdata->recv_gpadl.gpadl_handle) {
 200                 vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl);
 201                 if (!pdata->recv_gpadl.decrypted)
 202                         vfree(pdata->recv_buf);
 203         }
 204 }
 205
 206 /* VMBus primary channel is opened on first use */
 207 static int
 208 hv_uio_open(struct uio_info *info, struct inode *inode)
 209 {
 210         struct hv_uio_private_data *pdata
 211                 = container_of(info, struct hv_uio_private_data, info);
 212         struct hv_device *dev = pdata->device;
 213         int ret;
 214
 215         if (atomic_inc_return(&pdata->refcnt) != 1)
 216                 return 0;
 217
 218         vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
 219         vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
 220
 221         ret = vmbus_connect_ring(dev->channel,
 222                                  hv_uio_channel_cb, dev->channel);
 223         if (ret == 0)
 224                 dev->channel->inbound.ring_buffer->interrupt_mask = 1;
 225         else
 226                 atomic_dec(&pdata->refcnt);
 227
 228         return ret;
 229 }
 230
 231 /* VMBus primary channel is closed on last close */
 232 static int
 233 hv_uio_release(struct uio_info *info, struct inode *inode)
 234 {
 235         struct hv_uio_private_data *pdata
 236                 = container_of(info, struct hv_uio_private_data, info);
 237         struct hv_device *dev = pdata->device;
 238         int ret = 0;
 239
 240         if (atomic_dec_and_test(&pdata->refcnt))
 241                 ret = vmbus_disconnect_ring(dev->channel);
 242
 243         return ret;
 244 }
 245
 246 static int
 247 hv_uio_probe(struct hv_device *dev,
 248              const struct hv_vmbus_device_id *dev_id)
 249 {
 250         struct vmbus_channel *channel = dev->channel;
 251         struct hv_uio_private_data *pdata;
 252         void *ring_buffer;
 253         int ret;
 254         size_t ring_size = hv_dev_ring_size(channel);
 255
 256         if (!ring_size)
 257                 ring_size = SZ_2M;
 258
 259         pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
 260         if (!pdata)
 261                 return -ENOMEM;
 262
 263         ret = vmbus_alloc_ring(channel, ring_size, ring_size);
 264         if (ret)
 265                 return ret;
 266
 267         set_channel_read_mode(channel, HV_CALL_ISR);
 268
 269         /* Fill general uio info */
 270         pdata->info.name = "uio_hv_generic";
 271         pdata->info.version = DRIVER_VERSION;
 272         pdata->info.irqcontrol = hv_uio_irqcontrol;
 273         pdata->info.open = hv_uio_open;
 274         pdata->info.release = hv_uio_release;
 275         pdata->info.irq = UIO_IRQ_CUSTOM;
 276         atomic_set(&pdata->refcnt, 0);
 277
 278         /* mem resources */
 279         pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
 280         ring_buffer = page_address(channel->ringbuffer_page);
 281         pdata->info.mem[TXRX_RING_MAP].addr
 282                 = (uintptr_t)virt_to_phys(ring_buffer);
 283         pdata->info.mem[TXRX_RING_MAP].size
 284                 = channel->ringbuffer_pagecount << PAGE_SHIFT;
 285         pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
 286
 287         pdata->info.mem[INT_PAGE_MAP].name = "int_page";
 288         pdata->info.mem[INT_PAGE_MAP].addr
 289                 = (uintptr_t)vmbus_connection.int_page;
 290         pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
 291         pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 292
 293         pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
 294         pdata->info.mem[MON_PAGE_MAP].addr
 295                 = (uintptr_t)vmbus_connection.monitor_pages[1];
 296         pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
 297         pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 298
 299         pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
 300         if (pdata->recv_buf == NULL) {
 301                 ret = -ENOMEM;
 302                 goto fail_free_ring;
 303         }
 304
 305         ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
 306                                     RECV_BUFFER_SIZE, &pdata->recv_gpadl);
 307         if (ret) {
 308                 if (!pdata->recv_gpadl.decrypted)
 309                         vfree(pdata->recv_buf);
 310                 goto fail_close;
 311         }
 312
 313         /* put Global Physical Address Label in name */
 314         snprintf(pdata->recv_name, sizeof(pdata->recv_name),
 315                  "recv:%u", pdata->recv_gpadl.gpadl_handle);
 316         pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
 317         pdata->info.mem[RECV_BUF_MAP].addr
 318                 = (uintptr_t)pdata->recv_buf;
 319         pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
 320         pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 321
 322         pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
 323         if (pdata->send_buf == NULL) {
 324                 ret = -ENOMEM;
 325                 goto fail_close;
 326         }
 327
 328         ret = vmbus_establish_gpadl(channel, pdata->send_buf,
 329                                     SEND_BUFFER_SIZE, &pdata->send_gpadl);
 330         if (ret) {
 331                 if (!pdata->send_gpadl.decrypted)
 332                         vfree(pdata->send_buf);
 333                 goto fail_close;
 334         }
 335
 336         snprintf(pdata->send_name, sizeof(pdata->send_name),
 337                  "send:%u", pdata->send_gpadl.gpadl_handle);
 338         pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
 339         pdata->info.mem[SEND_BUF_MAP].addr
 340                 = (uintptr_t)pdata->send_buf;
 341         pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
 342         pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 343
 344         pdata->info.priv = pdata;
 345         pdata->device = dev;
 346
 347         ret = uio_register_device(&dev->device, &pdata->info);
 348         if (ret) {
 349                 dev_err(&dev->device, "hv_uio register failed\n");
 350                 goto fail_close;
 351         }
 352
 353         ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
 354         if (ret)
 355                 dev_notice(&dev->device,
 356                            "sysfs create ring bin file failed; %d\n", ret);
 357
 358         hv_set_drvdata(dev, pdata);
 359
 360         return 0;
 361
 362 fail_close:
 363         hv_uio_cleanup(dev, pdata);
 364 fail_free_ring:
 365         vmbus_free_ring(dev->channel);
 366
 367         return ret;
 368 }
 369
 370 static void
 371 hv_uio_remove(struct hv_device *dev)
 372 {
 373         struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
 374
 375         if (!pdata)
 376                 return;
 377
 378         sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
 379         uio_unregister_device(&pdata->info);
 380         hv_uio_cleanup(dev, pdata);
 381
 382         vmbus_free_ring(dev->channel);
 383 }
 384
 385 static struct hv_driver hv_uio_drv = {
 386         .name = "uio_hv_generic",
 387         .id_table = NULL, /* only dynamic id's */
 388         .probe = hv_uio_probe,
 389         .remove = hv_uio_remove,
 390 };
 391
 392 static int __init
 393 hyperv_module_init(void)
 394 {
 395         return vmbus_driver_register(&hv_uio_drv);
 396 }
 397
 398 static void __exit
 399 hyperv_module_exit(void)
 400 {
 401         vmbus_driver_unregister(&hv_uio_drv);
 402 }
 403
 404 module_init(hyperv_module_init);
 405 module_exit(hyperv_module_exit);
 406
 407 MODULE_VERSION(DRIVER_VERSION);
 408 MODULE_LICENSE("GPL v2");
 409 MODULE_AUTHOR(DRIVER_AUTHOR);
 410 MODULE_DESCRIPTION(DRIVER_DESC);