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 DEBUG 1
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/device.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/uio_driver.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/if_ether.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/hyperv.h>
  31 #include <linux/vmalloc.h>
  32 #include <linux/slab.h>
  33
  34 #include "../hv/hyperv_vmbus.h"
  35
  36 #define DRIVER_VERSION  "0.02.0"
  37 #define DRIVER_AUTHOR   "Stephen Hemminger <sthemmin at microsoft.com>"
  38 #define DRIVER_DESC     "Generic UIO driver for VMBus devices"
  39
  40 #define HV_RING_SIZE     512    /* pages */
  41 #define SEND_BUFFER_SIZE (15 * 1024 * 1024)
  42 #define RECV_BUFFER_SIZE (15 * 1024 * 1024)
  43
  44 /*
  45  * List of resources to be mapped to user space
  46  * can be extended up to MAX_UIO_MAPS(5) items
  47  */
  48 enum hv_uio_map {
  49         TXRX_RING_MAP = 0,
  50         INT_PAGE_MAP,
  51         MON_PAGE_MAP,
  52         RECV_BUF_MAP,
  53         SEND_BUF_MAP
  54 };
  55
  56 struct hv_uio_private_data {
  57         struct uio_info info;
  58         struct hv_device *device;
  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         struct hv_device *dev = channel->primary_channel->device_obj;
 133         u16 q_idx = channel->offermsg.offer.sub_channel_index;
 134         void *ring_buffer = page_address(channel->ringbuffer_page);
 135
 136         dev_dbg(&dev->device, "mmap channel %u pages %#lx at %#lx\n",
 137                 q_idx, vma_pages(vma), vma->vm_pgoff);
 138
 139         return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
 140                                channel->ringbuffer_pagecount << PAGE_SHIFT);
 141 }
 142
 143 static const struct bin_attribute ring_buffer_bin_attr = {
 144         .attr = {
 145                 .name = "ring",
 146                 .mode = 0600,
 147         },
 148         .size = 2 * HV_RING_SIZE * PAGE_SIZE,
 149         .mmap = hv_uio_ring_mmap,
 150 };
 151
 152 /* Callback from VMBUS subsystem when new channel created. */
 153 static void
 154 hv_uio_new_channel(struct vmbus_channel *new_sc)
 155 {
 156         struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
 157         struct device *device = &hv_dev->device;
 158         const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
 159         int ret;
 160
 161         /* Create host communication ring */
 162         ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
 163                          hv_uio_channel_cb, new_sc);
 164         if (ret) {
 165                 dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
 166                 return;
 167         }
 168
 169         /* Disable interrupts on sub channel */
 170         new_sc->inbound.ring_buffer->interrupt_mask = 1;
 171         set_channel_read_mode(new_sc, HV_CALL_ISR);
 172
 173         ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
 174         if (ret) {
 175                 dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
 176                 vmbus_close(new_sc);
 177         }
 178 }
 179
 180 static void
 181 hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
 182 {
 183         if (pdata->send_gpadl)
 184                 vmbus_teardown_gpadl(dev->channel, pdata->send_gpadl);
 185         vfree(pdata->send_buf);
 186
 187         if (pdata->recv_gpadl)
 188                 vmbus_teardown_gpadl(dev->channel, pdata->recv_gpadl);
 189         vfree(pdata->recv_buf);
 190 }
 191
 192 static int
 193 hv_uio_probe(struct hv_device *dev,
 194              const struct hv_vmbus_device_id *dev_id)
 195 {
 196         struct hv_uio_private_data *pdata;
 197         int ret;
 198
 199         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 200         if (!pdata)
 201                 return -ENOMEM;
 202
 203         ret = vmbus_open(dev->channel, HV_RING_SIZE * PAGE_SIZE,
 204                          HV_RING_SIZE * PAGE_SIZE, NULL, 0,
 205                          hv_uio_channel_cb, dev->channel);
 206         if (ret)
 207                 goto fail;
 208
 209         /* Communicating with host has to be via shared memory not hypercall */
 210         if (!dev->channel->offermsg.monitor_allocated) {
 211                 dev_err(&dev->device, "vmbus channel requires hypercall\n");
 212                 ret = -ENOTSUPP;
 213                 goto fail_close;
 214         }
 215
 216         dev->channel->inbound.ring_buffer->interrupt_mask = 1;
 217         set_channel_read_mode(dev->channel, HV_CALL_ISR);
 218
 219         /* Fill general uio info */
 220         pdata->info.name = "uio_hv_generic";
 221         pdata->info.version = DRIVER_VERSION;
 222         pdata->info.irqcontrol = hv_uio_irqcontrol;
 223         pdata->info.irq = UIO_IRQ_CUSTOM;
 224
 225         /* mem resources */
 226         pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
 227         pdata->info.mem[TXRX_RING_MAP].addr
 228                 = (uintptr_t)page_address(dev->channel->ringbuffer_page);
 229         pdata->info.mem[TXRX_RING_MAP].size
 230                 = dev->channel->ringbuffer_pagecount << PAGE_SHIFT;
 231         pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_LOGICAL;
 232
 233         pdata->info.mem[INT_PAGE_MAP].name = "int_page";
 234         pdata->info.mem[INT_PAGE_MAP].addr
 235                 = (uintptr_t)vmbus_connection.int_page;
 236         pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
 237         pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 238
 239         pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
 240         pdata->info.mem[MON_PAGE_MAP].addr
 241                 = (uintptr_t)vmbus_connection.monitor_pages[1];
 242         pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
 243         pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 244
 245         pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
 246         if (pdata->recv_buf == NULL) {
 247                 ret = -ENOMEM;
 248                 goto fail_close;
 249         }
 250
 251         ret = vmbus_establish_gpadl(dev->channel, pdata->recv_buf,
 252                                     RECV_BUFFER_SIZE, &pdata->recv_gpadl);
 253         if (ret)
 254                 goto fail_close;
 255
 256         /* put Global Physical Address Label in name */
 257         snprintf(pdata->recv_name, sizeof(pdata->recv_name),
 258                  "recv:%u", pdata->recv_gpadl);
 259         pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
 260         pdata->info.mem[RECV_BUF_MAP].addr
 261                 = (uintptr_t)pdata->recv_buf;
 262         pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
 263         pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 264
 265
 266         pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
 267         if (pdata->send_buf == NULL) {
 268                 ret = -ENOMEM;
 269                 goto fail_close;
 270         }
 271
 272         ret = vmbus_establish_gpadl(dev->channel, pdata->send_buf,
 273                                     SEND_BUFFER_SIZE, &pdata->send_gpadl);
 274         if (ret)
 275                 goto fail_close;
 276
 277         snprintf(pdata->send_name, sizeof(pdata->send_name),
 278                  "send:%u", pdata->send_gpadl);
 279         pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
 280         pdata->info.mem[SEND_BUF_MAP].addr
 281                 = (uintptr_t)pdata->send_buf;
 282         pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
 283         pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 284
 285         pdata->info.priv = pdata;
 286         pdata->device = dev;
 287
 288         ret = uio_register_device(&dev->device, &pdata->info);
 289         if (ret) {
 290                 dev_err(&dev->device, "hv_uio register failed\n");
 291                 goto fail_close;
 292         }
 293
 294         vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
 295         vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
 296
 297         ret = sysfs_create_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
 298         if (ret)
 299                 dev_notice(&dev->device,
 300                            "sysfs create ring bin file failed; %d\n", ret);
 301
 302         hv_set_drvdata(dev, pdata);
 303
 304         return 0;
 305
 306 fail_close:
 307         hv_uio_cleanup(dev, pdata);
 308         vmbus_close(dev->channel);
 309 fail:
 310         kfree(pdata);
 311
 312         return ret;
 313 }
 314
 315 static int
 316 hv_uio_remove(struct hv_device *dev)
 317 {
 318         struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
 319
 320         if (!pdata)
 321                 return 0;
 322
 323         uio_unregister_device(&pdata->info);
 324         hv_uio_cleanup(dev, pdata);
 325         hv_set_drvdata(dev, NULL);
 326         vmbus_close(dev->channel);
 327         kfree(pdata);
 328         return 0;
 329 }
 330
 331 static struct hv_driver hv_uio_drv = {
 332         .name = "uio_hv_generic",
 333         .id_table = NULL, /* only dynamic id's */
 334         .probe = hv_uio_probe,
 335         .remove = hv_uio_remove,
 336 };
 337
 338 static int __init
 339 hyperv_module_init(void)
 340 {
 341         return vmbus_driver_register(&hv_uio_drv);
 342 }
 343
 344 static void __exit
 345 hyperv_module_exit(void)
 346 {
 347         vmbus_driver_unregister(&hv_uio_drv);
 348 }
 349
 350 module_init(hyperv_module_init);
 351 module_exit(hyperv_module_exit);
 352
 353 MODULE_VERSION(DRIVER_VERSION);
 354 MODULE_LICENSE("GPL v2");
 355 MODULE_AUTHOR(DRIVER_AUTHOR);
 356 MODULE_DESCRIPTION(DRIVER_DESC);