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 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         u32     recv_gpadl;
  62         char    recv_name[32];  /* "recv_4294967295" */
  63
  64         void    *send_buf;
  65         u32     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  */
 108 static void hv_uio_rescind(struct vmbus_channel *channel)
 109 {
 110         struct hv_device *hv_dev = channel->primary_channel->device_obj;
 111         struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
 112
 113         /*
 114          * Turn off the interrupt file handle
 115          * Next read for event will return -EIO
 116          */
 117         pdata->info.irq = 0;
 118
 119         /* Wake up reader */
 120         uio_event_notify(&pdata->info);
 121 }
 122
 123 /* Sysfs API to allow mmap of the ring buffers
 124  * The ring buffer is allocated as contiguous memory by vmbus_open
 125  */
 126 static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
 127                             struct bin_attribute *attr,
 128                             struct vm_area_struct *vma)
 129 {
 130         struct vmbus_channel *channel
 131                 = container_of(kobj, struct vmbus_channel, kobj);
 132         void *ring_buffer = page_address(channel->ringbuffer_page);
 133
 134         if (channel->state != CHANNEL_OPENED_STATE)
 135                 return -ENODEV;
 136
 137         return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
 138                                channel->ringbuffer_pagecount << PAGE_SHIFT);
 139 }
 140
 141 static const struct bin_attribute ring_buffer_bin_attr = {
 142         .attr = {
 143                 .name = "ring",
 144                 .mode = 0600,
 145         },
 146         .size = 2 * HV_RING_SIZE * PAGE_SIZE,
 147         .mmap = hv_uio_ring_mmap,
 148 };
 149
 150 /* Callback from VMBUS subsystem when new channel created. */
 151 static void
 152 hv_uio_new_channel(struct vmbus_channel *new_sc)
 153 {
 154         struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
 155         struct device *device = &hv_dev->device;
 156         const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
 157         int ret;
 158
 159         /* Create host communication ring */
 160         ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
 161                          hv_uio_channel_cb, new_sc);
 162         if (ret) {
 163                 dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
 164                 return;
 165         }
 166
 167         /* Disable interrupts on sub channel */
 168         new_sc->inbound.ring_buffer->interrupt_mask = 1;
 169         set_channel_read_mode(new_sc, HV_CALL_ISR);
 170
 171         ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
 172         if (ret) {
 173                 dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
 174                 vmbus_close(new_sc);
 175         }
 176 }
 177
 178 /* free the reserved buffers for send and receive */
 179 static void
 180 hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
 181 {
 182         if (pdata->send_gpadl) {
 183                 vmbus_teardown_gpadl(dev->channel, pdata->send_gpadl);
 184                 pdata->send_gpadl = 0;
 185                 vfree(pdata->send_buf);
 186         }
 187
 188         if (pdata->recv_gpadl) {
 189                 vmbus_teardown_gpadl(dev->channel, pdata->recv_gpadl);
 190                 pdata->recv_gpadl = 0;
 191                 vfree(pdata->recv_buf);
 192         }
 193 }
 194
 195 /* VMBus primary channel is opened on first use */
 196 static int
 197 hv_uio_open(struct uio_info *info, struct inode *inode)
 198 {
 199         struct hv_uio_private_data *pdata
 200                 = container_of(info, struct hv_uio_private_data, info);
 201         struct hv_device *dev = pdata->device;
 202         int ret;
 203
 204         if (atomic_inc_return(&pdata->refcnt) != 1)
 205                 return 0;
 206
 207         ret = vmbus_connect_ring(dev->channel,
 208                                  hv_uio_channel_cb, dev->channel);
 209
 210         if (ret == 0)
 211                 dev->channel->inbound.ring_buffer->interrupt_mask = 1;
 212         else
 213                 atomic_dec(&pdata->refcnt);
 214
 215         return ret;
 216 }
 217
 218 /* VMBus primary channel is closed on last close */
 219 static int
 220 hv_uio_release(struct uio_info *info, struct inode *inode)
 221 {
 222         struct hv_uio_private_data *pdata
 223                 = container_of(info, struct hv_uio_private_data, info);
 224         struct hv_device *dev = pdata->device;
 225         int ret = 0;
 226
 227         if (atomic_dec_and_test(&pdata->refcnt))
 228                 ret = vmbus_disconnect_ring(dev->channel);
 229
 230         return ret;
 231 }
 232
 233 static int
 234 hv_uio_probe(struct hv_device *dev,
 235              const struct hv_vmbus_device_id *dev_id)
 236 {
 237         struct vmbus_channel *channel = dev->channel;
 238         struct hv_uio_private_data *pdata;
 239         void *ring_buffer;
 240         int ret;
 241
 242         /* Communicating with host has to be via shared memory not hypercall */
 243         if (!channel->offermsg.monitor_allocated) {
 244                 dev_err(&dev->device, "vmbus channel requires hypercall\n");
 245                 return -ENOTSUPP;
 246         }
 247
 248         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 249         if (!pdata)
 250                 return -ENOMEM;
 251
 252         ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE,
 253                                HV_RING_SIZE * PAGE_SIZE);
 254         if (ret)
 255                 goto fail;
 256
 257         set_channel_read_mode(channel, HV_CALL_ISR);
 258
 259         /* Fill general uio info */
 260         pdata->info.name = "uio_hv_generic";
 261         pdata->info.version = DRIVER_VERSION;
 262         pdata->info.irqcontrol = hv_uio_irqcontrol;
 263         pdata->info.open = hv_uio_open;
 264         pdata->info.release = hv_uio_release;
 265         pdata->info.irq = UIO_IRQ_CUSTOM;
 266         atomic_set(&pdata->refcnt, 0);
 267
 268         /* mem resources */
 269         pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
 270         ring_buffer = page_address(channel->ringbuffer_page);
 271         pdata->info.mem[TXRX_RING_MAP].addr
 272                 = (uintptr_t)virt_to_phys(ring_buffer);
 273         pdata->info.mem[TXRX_RING_MAP].size
 274                 = channel->ringbuffer_pagecount << PAGE_SHIFT;
 275         pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
 276
 277         pdata->info.mem[INT_PAGE_MAP].name = "int_page";
 278         pdata->info.mem[INT_PAGE_MAP].addr
 279                 = (uintptr_t)vmbus_connection.int_page;
 280         pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
 281         pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 282
 283         pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
 284         pdata->info.mem[MON_PAGE_MAP].addr
 285                 = (uintptr_t)vmbus_connection.monitor_pages[1];
 286         pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
 287         pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 288
 289         pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
 290         if (pdata->recv_buf == NULL) {
 291                 ret = -ENOMEM;
 292                 goto fail_close;
 293         }
 294
 295         ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
 296                                     RECV_BUFFER_SIZE, &pdata->recv_gpadl);
 297         if (ret)
 298                 goto fail_close;
 299
 300         /* put Global Physical Address Label in name */
 301         snprintf(pdata->recv_name, sizeof(pdata->recv_name),
 302                  "recv:%u", pdata->recv_gpadl);
 303         pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
 304         pdata->info.mem[RECV_BUF_MAP].addr
 305                 = (uintptr_t)pdata->recv_buf;
 306         pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
 307         pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 308
 309         pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
 310         if (pdata->send_buf == NULL) {
 311                 ret = -ENOMEM;
 312                 goto fail_close;
 313         }
 314
 315         ret = vmbus_establish_gpadl(channel, pdata->send_buf,
 316                                     SEND_BUFFER_SIZE, &pdata->send_gpadl);
 317         if (ret)
 318                 goto fail_close;
 319
 320         snprintf(pdata->send_name, sizeof(pdata->send_name),
 321                  "send:%u", pdata->send_gpadl);
 322         pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
 323         pdata->info.mem[SEND_BUF_MAP].addr
 324                 = (uintptr_t)pdata->send_buf;
 325         pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
 326         pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 327
 328         pdata->info.priv = pdata;
 329         pdata->device = dev;
 330
 331         ret = uio_register_device(&dev->device, &pdata->info);
 332         if (ret) {
 333                 dev_err(&dev->device, "hv_uio register failed\n");
 334                 goto fail_close;
 335         }
 336
 337         vmbus_set_chn_rescind_callback(channel, hv_uio_rescind);
 338         vmbus_set_sc_create_callback(channel, hv_uio_new_channel);
 339
 340         ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
 341         if (ret)
 342                 dev_notice(&dev->device,
 343                            "sysfs create ring bin file failed; %d\n", ret);
 344
 345         hv_set_drvdata(dev, pdata);
 346
 347         return 0;
 348
 349 fail_close:
 350         hv_uio_cleanup(dev, pdata);
 351 fail:
 352         kfree(pdata);
 353
 354         return ret;
 355 }
 356
 357 static int
 358 hv_uio_remove(struct hv_device *dev)
 359 {
 360         struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
 361
 362         if (!pdata)
 363                 return 0;
 364
 365         uio_unregister_device(&pdata->info);
 366         hv_uio_cleanup(dev, pdata);
 367         hv_set_drvdata(dev, NULL);
 368
 369         vmbus_free_ring(dev->channel);
 370         kfree(pdata);
 371         return 0;
 372 }
 373
 374 static struct hv_driver hv_uio_drv = {
 375         .name = "uio_hv_generic",
 376         .id_table = NULL, /* only dynamic id's */
 377         .probe = hv_uio_probe,
 378         .remove = hv_uio_remove,
 379 };
 380
 381 static int __init
 382 hyperv_module_init(void)
 383 {
 384         return vmbus_driver_register(&hv_uio_drv);
 385 }
 386
 387 static void __exit
 388 hyperv_module_exit(void)
 389 {
 390         vmbus_driver_unregister(&hv_uio_drv);
 391 }
 392
 393 module_init(hyperv_module_init);
 394 module_exit(hyperv_module_exit);
 395
 396 MODULE_VERSION(DRIVER_VERSION);
 397 MODULE_LICENSE("GPL v2");
 398 MODULE_AUTHOR(DRIVER_AUTHOR);
 399 MODULE_DESCRIPTION(DRIVER_DESC);